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Degassing Jar for Epoxy Adhesive

02/17/2009 3:00 AM

I'm going to be using Epoxy Adhesive on my next bow (Asiatic Composite with modern materials) I'm thinking of using a peristaltic pump hooked upto a glass pickle jar or somesuch to make a little 'soft vacuum' chamber to put my paper up of ahesive in to degas.it.
Will a glass jar be strong enough?
What do you guys think?

Del

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#1

Re: Degassing jar for epoxy adhesive

02/17/2009 7:55 AM

How about one of the old glass water bottles from the coolers? Plastic might even work if your not looking for a huuuuuuuuuuge vacuum. Might be a little hard crawling inside though. Besides, the pickles come with a vacuum anyway for sealing. Shouldn't be a problem.

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#2

Re: Degassing jar for epoxy adhesive

02/17/2009 8:09 AM

Glass scares me, unless you get a real vacuum bell jar. I'd go with a piece of molded plastic labware. It'll be easier to clean those nasty spills, too. You don't need to see inside, you can figure out how long to de-gas by experiment.

And if the adhesive container runs over, you'll know soon enough.

A little heat added will lower the viscosity of the adhesive and allow it to de-gas more quickly. Not too much, or your epoxy will set up before you can use it.

Good luck!

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#3
In reply to #2

Re: Degassing jar for epoxy adhesive

02/17/2009 8:19 AM

I'll have a look in some of the catalogues, see what I can find.

Del
(I wonder if they supplier labware with free pickles inside)

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#4

Re: Degassing Jar for Epoxy Adhesive

02/17/2009 7:48 PM

Del, why use epoxy as a composite bonding resin ?

It is brittle at relatively low pressure bending levels, even when used with fiber.

http://materials.globalspec.com/Industrial-Directory/composite_resin

http://www.netcomposites.com/education.asp?sequence=8

http://myais.fsktm.um.edu.my/2166/

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#13
In reply to #4

Re: Degassing Jar for Epoxy Adhesive

02/18/2009 2:50 AM

Normal gassfibre resins are too brittle, most epoxies are fine, I've used 'em before, and comercial laminated bows use epoxies.
Of course the ultimate aim is to build a bow from entirely traditional materials (horn, sinew, fish/hide glue) this is just a bow for learning the geometry.
Del

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#5

Re: Degassing Jar for Epoxy Adhesive

02/17/2009 11:38 PM

Del, Some Epoxies will foam when placed, in bulk, under a vacuum. I have used a plastic bucket placed inside of a converted paint pressure pot for the vacuum chamber. The epoxy foamed over into the pot and kicked off. It was a mess.

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#7
In reply to #5

Re: Degassing Jar for Epoxy Adhesive

02/18/2009 12:45 AM

The foaming of the epoxy was probably due to exotherming, not vacuum. Any large mass of epoxy will exotherm (in which the heat of reaction increases the reaction speed, which increases the heat, etc.). Over the years I've left epoxy mixes in the cup and have ended up with interesting looking "sculptures". In at least one, the plastic cup partially melted.

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#6

Re: Degassing Jar for Epoxy Adhesive

02/18/2009 12:43 AM

I have used glass jars as vacuum chambers in the past with no problems- small projects, like drying out a watch that had been submerged accidentally (it worked fine afterwards...)

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#8

Re: Degassing Jar for Epoxy Adhesive

02/18/2009 12:45 AM

Del,

I think a glass jar, fish bowl, water tumbler or pint beer glass would probably withstand enough vacuum to do the job. The more rotund the shape the better. You could probably test your vessel by putting it underwater and applying a harder vacuum than you need for degassing. Even if you couldn't test to destruction, it would give you some confidence in it's limits.

Remember the old electronic vacuum tubes (valves)? The glass envelope was quite thin and had a pretty hard vacuum inside.

Good luck

Dave

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#12
In reply to #8

Re: Degassing Jar for Epoxy Adhesive

02/18/2009 2:48 AM

Ah vacuum tubes...good point!
Ta!

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#9

Re: Degassing Jar for Epoxy Adhesive

02/18/2009 1:34 AM

I don't recall ever seeing a pickle jar implode. Even the big ones. But a bell jar would be elegant.

If you use a jar, wrap it in clear reinforced tape for safety.

How about a stainless mixing bowl. Once you have your time figured out, you won't need to observe it.

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#10

Re: Degassing Jar for Epoxy Adhesive

02/18/2009 2:01 AM

? Why degas an epoxy adhesive - for potting maybe for glueing ??

A peristaltic pump will not pull a very high vacuum it is not positive displacement. Certainly no more than a pickle jar which has been heated to jam temperatures sealed and then cooled - that is what it is made for!

Any way they are cheap enough - try it with one and if it implodes (cover it with a sheet) it is not going to be too big a hassle. Exploding would be another story.

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#14
In reply to #10

Re: Degassing Jar for Epoxy Adhesive

02/18/2009 2:56 AM

I don't want bubbles in the glue line, and thorough mixing of the epoxy can introduce a fair bit of air.

It's for laminating a bow, a buble in the glue line could cause catastrophic failure...which is unpleasant if you are holding the bow at full draw when it goes bang.
A peristaltic should be able to pull enough vacuum to help outgassing (I work for a pump/control system manufacturer, so am very familiar with them)
Del

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#16
In reply to #14

Re: Degassing Jar for Epoxy Adhesive

02/18/2009 3:41 AM

Agree that epoxy is the way to go and degassing is belt and braces but there must be as many epoxy adhesives as there are possibilities for supper. Choose carefully - avoid quick-sets. A polyamide cured material which should not embrittle & would be my choice. Do some dummy runs putting the test pieces in a warm oven for a while and seeing if the flexibility stays.

You should use you vac system by putting the laid up component in a plastic bag and so do a pressure moulding which will also de-areate the joints as well as the glue. Vac bag moulding is very effective.

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#11

Re: Degassing Jar for Epoxy Adhesive

02/18/2009 2:25 AM

Hi Del,

best is polycarbonate as this is very tough and you will not be able to crack this material with blows of a hammer - but may be not vailable.

So any glass bottle will do the job, we used 1 liter and 0,5 liter cucumber or marmalade glasses - protection with wrapped nets is a necessity. Commercial protection is using wire mesh (1mm wires woven with 5 to 8 mm holes, also used for microwaves to be confined to the interior.)

Last one I built separated the epoxy container from the Plexiglas (PMMA) vacuum container, so we could take a tube and 2 plates and 2 O-ring seals and screws outside the tubes to clamp.

It would be wise to mix the epoxy very carefully not to introduce much air.

We used to fill the epoxy container to 10 to 20% of maximum capacity, some severe bubbling may produce a lot of cleaning necessities.

Look at the specs of the epoxy to which pressure you are allowed to evacuate, there may be early evaporation of one component.

Have success

RHABE

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#15

Re: Degassing Jar for Epoxy Adhesive

02/18/2009 2:58 AM

Thanks for all the replies guys...
It looks like it's worth a go, but a bit of tape around it is prob' a good idea, if only as a security blanket.

I'll report back when I get to that stage in the bow making...
Del

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#28
In reply to #15

Re: Degassing Jar for Epoxy Adhesive

02/18/2009 10:19 AM

I wouldn't worry about degassing the epoxy , but instead worry about vacuum bagging the lamination, which will adequately degass the structure. About the only reason to degass epoxy before its use is for cosmetics, (such as in a clear coat) but even then, you will end up with bubbles on the surface that come about from applying the epoxy to the surface (assuming it is not simply poured on). Those surface bubbles are best broken with a foam paintbrush, or a dry paintbrush by "tipping" as you would for a glossy varnished surface.

Even in laying up experimental aircraft pieces, the epoxy is not typically degassed before use, but is squeegeed and vacuum bagged before the cure has progressed far.

The best time to apply epoxy is immediately after mixing it (although "mixing" it may be a two step process with some epoxies, in which you thoroughly mix, and then let it sit, and then mix again.) Otherwise it is likely to exotherm in the cup, leaving you with a hot bunch of foam.

BTW, avoid sanding anything that epoxy should stick to with sanding discs (or hand paper) that are stearate treated (which helps keep the the sandpaper from clogging, but which "greases" the laminate, interfering with bond integrity).

If this bow is to be stiff and light, there is a significant advantage to using unidirectional glass or carbon fiber. In woven materials, the fiber strength and stiffness do not come into play until the fibers are pulled straight, so initially you are relying on the adhesive for stiffness, because the fibers weave back and forth in the cloth. (The adhesive holds them in that position, and deflects as they straighten.) "Bidirectional" fabrics, in which one unidirectional layer is stitched onto another, avoid this issue.

Another BTW: I have seen many many dollars of carbon fiber essentially wasted by applying if to one side of a beam rather than both*. The "plank" on a land yacht or ice yacht works as a leaf spring, and I saw one iceboat in which one side of the plank had been laminated with carbon fiber, but the other side was not. This has very little effect on the beam stiffness until the carbon is so thick that it is effectively the whole beam, and the wood is along for the ride.

Elongation in carbon fiber is only 1.3% or so, (depending on modulus) so it is worth checking to see how far the surface is stretch under the planned amount of bending. Obviously, if the the bow material is thick, you may find that the surface stretches more than the carbon allows for the intended loaded curve. If so, the solution is just to bake the bow thinner.

*Another thing that bugs me is the use of carbon fiber for decoration, as in Porsche interiors. All these dodads and widgets in the interior covered with non functional carbon fiber, typically adding rather than removing weight. Demand is already too high, meaning that it costs more for people who actually want to use it as a structural material... and Porsche (and many others) are throwing the stuff away. Give me a 356, with plenty of the interior surfaces painted!

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#30
In reply to #28

Re: Degassing Jar for Epoxy Adhesive

02/18/2009 10:28 AM

Cheers Ken, ta for the advice, sounds like I'll give the degassing a miss..I have enough to be getting on with.
I normally apply pressure with the good 'ol rubber straps cut from inner tube, it's been pretty effective in the past.
Rest assured, the glass is unidirectional and will be on both back and belly of the bow.

I though I might add some little inlays of carbon cloth just for show....
I'm kidding I'm kidding...Ken...Ken.
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(sorry about the insanity...couldn't resist it)

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#17

Re: Degassing Jar for Epoxy Adhesive

02/18/2009 3:54 AM

is this going to be a tiny test bow, because I cannot for the life of me imagine a a pickle jar big enough otherwise!!

If you want to degas a longer bow, may I suggest heavy duty plastic sewer piping. Maybe two lengths of two different diameters, one inside the other, long spacers between them and the rest filled with maybe builders foam? it would not take a complete vacuum, but should be enough to do what you want......

Have you ever tried carbon fibers on the side of the bow farthest away from you (front or back?) on the tension side?

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#20
In reply to #17

Re: Degassing Jar for Epoxy Adhesive

02/18/2009 4:31 AM

I'm aiming to degas the adhesive before applying it...not the whole bow!

My Chinese Repeating Crossbow is laminated with glassfibre/Maple, carbon fibre is better but not vastly, and is V expensive.
Del

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#18

Re: Degassing Jar for Epoxy Adhesive

02/18/2009 4:22 AM

Glass has good compressive strength but, due to it's sensitivity to notches and defects, poor and unreliable tensile strength.

For a cylinder, the stress = P x D/2 x T

P =pressure

D = diameter

T = wall thickness.

You can do some checks if you are worried, but it is unlikely that a glass vacuum vessel will fail.

The suggestion of PVC drain pipe is a good one. This way you could lay up thew entire bow (if a longbow) and Degas the finished assembly.

A recurved bow would probably need an impractical diameter pipe.

Of course, if all you want to do is Degas the mixture before laying up, then an ordinary glass jar will do the job.

Be interesting if you post a picture of the finished article, just to satisfy peoples curiosity.

Best wishes

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#19

Re: Degassing Jar for Epoxy Adhesive

02/18/2009 4:23 AM

Del, did you see Richard Hammond's 'Engineering Connections' Programme where he looked at the Airbus A380? As part of his rather tenuous explanation of laminates he briefly looked at the bow construction used by Attila's army which used horn & sinew to reinforce the structure. The episode is still available on the BBC iPlayer.

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#21
In reply to #19

Re: Degassing Jar for Epoxy Adhesive

02/18/2009 4:35 AM

Yup, saw it, nice to see some 'popular science'.
Nice demo of smashing a short self wood bow...
That's the sort of bow I'll be making...except a tad more punch than the one he was shooting. (I eventually want to make the proper horn/sinew version).
Del
P.S. I do wish they wouldn't say 'fire' a bow...you 'shoot' a bow...as no fire is involved, you 'fire' firearms. (Sorry just being a sad old pedant now)

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#22

Re: Degassing Jar for Epoxy Adhesive

02/18/2009 6:13 AM

I have a vacum system with two bells I will sell you

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#23

Re: Degassing Jar for Epoxy Adhesive

02/18/2009 7:03 AM

Del,

What I've done in the past to dry out hygroscopic printed circuit boards and VPI them is a section of steel pipe (150 to 200mm) with a cap on one end and a flange on the other end. The flanged end is capped off with a gasket and blank flange and 1/4 SAE flare male fitting silver soldered into the blank to allow the connection of a refrigeration vacuum pump. To monitor the vaccum I just used my refrigeration manifold, same same when applying mild pressure. I used the system to salvage a telemetry system that would not work in the tropical maritime environment. It worked well and delayed the replacement of the system until reliable off the shelf systems were available at least 8 years later.

The encapsulant was 3M 444 re-enterable compound. I had no real problems with foaming and with the use of Vacuum Pressure Impregnation by this method I was able to remove voids from around the electronic components. The surface of some modules displayed a few burst bubble remains but the encapsulant integrity was spot on. The modules were mounted in 13R relay cases from which I removed the tops with a soldering iron. After degassing the chamber is pressurised to about 5 psi and the product allowed to set.

Yes the device will require quality welding.

You will be able to remove all traces of moisture from your substrates before glueing by evacuating the pot for around 24hrs.

For a real simple alternative use a cryovac bag and cryovac machine eg., Sunbeam. This way will allow the use of vacuum clamping. You will not get the dehydrating vacuum as above, but it would be so easy.

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#24

Re: Degassing Jar for Epoxy Adhesive

02/18/2009 9:08 AM

Del, the issue with foaming is a valid one. I would suggest you SLOWLY reduce the pressure. But to do that you will need an epoxy with a very long pot life. An epoxy with a low viscosity will also help to allow gasses to diffuse out of the mix. In a former life we attempted to do this for potting PCB's that were then installed in a vacuum chamber. But the potting compound we wanted to use which was filled with thermally conductive powder had a short pot life and was very thick and viscous. It did not work out well. We ended up filling the chamber with dry nitrogen instead of drawing a vacuum and dispensing with the degas step.

Something you might consider is that many industrial epoxies can be purchased in a two part syringe type dispenser with a mixing tube on the end. These do not tend to entrain air into the mix.

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#25
In reply to #24

Re: Degassing Jar for Epoxy Adhesive

02/18/2009 9:28 AM

Cheers.
The whole 'which epoxy' issue is another kettle of tuna.

I have 5 of those 'double syringe' packs of 5min epoxy (I was miss sold 'em as being good for glueing sinew ..., but they were dirt cheap) which I'd quite like to use up...but I don't want to risk ruining expensive laminations/wasting time through being a cheapskate...
Of course the 5minute stuff wouldn't give time to mess about de-gassing.

Decisions decisions... the slower setting stuff only seems to be available in silly small packs.
I can get a nice 200ml of Devcon 2ton epoxy which sounds quite good with the mixing nozzle, but they say the nozzle cant be reused, which means, I'd have to lay it all up in on hit, which isn't how I'm planning to do it.
Still it's all a good coffee time exercise at the mo'.
Del
(I have made a former to lay it up onto).

Maybe the whole de-gassing is a red herring and not worth the effort?

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#26
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Re: Degassing Jar for Epoxy Adhesive

02/18/2009 9:52 AM

What about a regular mason jar. They withstand heat and are small enough to easily draw a vac on. They have better seals and you can solder the connector right to the lid. Then place the jar in a good solid plastic container with the lid on in case of implosion. You'd still be able to see through both!

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#27
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Re: Degassing Jar for Epoxy Adhesive

02/18/2009 10:02 AM

Mason jar? Is that the US equivalent of a 'Kilner' jar...like wot you do your pickled onions, chutney or jam in?
Del

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#29
In reply to #27

Re: Degassing Jar for Epoxy Adhesive

02/18/2009 10:23 AM

Exactly Del and the mason jar is fantastic for degassing - I've used them for small projects before - like you mentioned earlier, a good wrapping with tape for a little extra cushion is a good idea - clear tape if possible. Also, some epoxies will boil at room temp under vacuum, so be prepared for a mess.

As far as the Devcon 5min epoxy, the stuff is fantastic - I've used it in a variety of weird situations where a normal epoxy wasn't practical, but I wouldn't recommend it for laminating a bow - probably would be a bit too brittle.

Good Luck

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#31
In reply to #27

Re: Degassing Jar for Epoxy Adhesive

02/18/2009 10:38 AM

I'm not familiar with a kilner jar. Is this what you mean?

Here are some pictures that might help.

here are the lids.

Note the lids are two pieces: a threaded ring and a domed flat lid that has a bead of unvulcanized gum rubber around the edge. when canning, the lid is put on loosely(fingertip tight) and the whole thing is put in a pressure cooker and boiled. then the pressure is released, and as the jar and it's contents cools it creates a partial vacuum that sucks the lid down tight and melts the gum rubber seal around the top of the jar. then the ring is tightened to hold the lid in place.

and the jars with lids on.

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#32
In reply to #31

Re: Degassing Jar for Epoxy Adhesive

02/18/2009 10:48 AM

Yup, that thar's what we call a Kilner jar.
Del

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#37
In reply to #25

Re: Degassing Jar for Epoxy Adhesive

02/18/2009 3:23 PM

I've got it!

Take that old centrifuge you have sitting in the corner and centrifuge the stuff.

No muss and it won't boil over.

Seriously, I've done this with high viscosity resins.

LL

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#33

Re: Degassing Jar for Epoxy Adhesive

02/18/2009 11:29 AM

Del, my experience is that one gets very little, if any, air release and bubble breaking, especially in viscous materials, until the vacuum reaches 25 to 27 inches of vacuum. Tricks I have used to "fool Mother Nature" is to (a) add a small amount of a volatile solvent, such as acetone, THF, etc; or (b) to add an air release agent such as Byk 051. Both methods reduce the amount of vacuum required for degassing. Also, suggest that you coat the glass pickle jar with either a PU or acrylic etc just in case the glass jar implodes. It would be nice to restrain the glass fragments!

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#34

Re: Degassing Jar for Epoxy Adhesive

02/18/2009 12:03 PM

Glass is dangerous. No doubt you'll be watching the degassing in order to bleed vacuum and avoid container overflow, as well as to judge completion, thus preserving pot life. Larger bell jars are equipped with metal mesh shields to avoid injury. The overall force on the jar will be over 14 pounds per square inch of glass surface at sea level, regardless of a soft or hard vacuum. The smaller the jar, the less overall pressure will be applied. And small jars are much stonger than larger ones. Steve

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#35

Re: Degassing Jar for Epoxy Adhesive

02/18/2009 2:42 PM

A good way to degrease anything before glueing is to wipe down with methylated spirits and not touch the surface again with your fingers. Use a lot and give it time to evaporate on things that absorb fluids.....

Even things that are intrinsically "greasy" can be glued to using this method. So this may well open up to bow making, woods that you might otherwise reject....

Meths is also good for cleaning anything that should not get epoxy on it, fingers for example. But it only works up to the point just before the epoxy hardens....!! Make sure you have a big bottle handy at all times, so you don't have to search after a spill!!!

The carbon fiber/or fiber glass ribbon needs to be applied on the tension side after being tensioned itself to almost its top limit. The bow needs to be somehow held flat and straight while glueing, so that it cannot return to its true shape.....till the epoxy has set. Something like blocks glued on the compression side, that you can use screws on and after glueing, can be cut or sanded off.....

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#36
In reply to #35

Re: Degassing Jar for Epoxy Adhesive

02/18/2009 3:10 PM

when you say Methylated Spirits do you mean Methyl Ethyl Ketone (MEK) or do you mean Mineral Spirits, or perhaps denatured wood alcohol (Methanol)? I'm not familiar with anything sold here in the states under that name.

Be careful with MEK. If you find crystals forming around the mouth of the can DO NOT TOUCH it. That is MEKP and it is very shock sensitive (it blows up). MEK can oxidize and change to MEKP.

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#40
In reply to #36

Re: Degassing Jar for Epoxy Adhesive

02/18/2009 4:57 PM

Methyl Alcohol.

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#41
In reply to #40

Re: Degassing Jar for Epoxy Adhesive

02/18/2009 5:36 PM

Ah ok, that is sold as methanol or wood alcohol here in the states. Isopropyl alcohol 90% should work too.

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#42
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Re: Degassing Jar for Epoxy Adhesive

02/18/2009 10:44 PM

In Australia, methylated spirits is 90% ethanol, about 9% methanol and about 1% of something to give a nasty taste.

The methanol and other stuff is simply to make the meths undrinkable. A dedicated alcoholic will still drink, often with fatal results.

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#43
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Re: Degassing Jar for Epoxy Adhesive

02/18/2009 10:52 PM

Is that also referred to as denatured alcohol?

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#44
In reply to #43

Re: Degassing Jar for Epoxy Adhesive

02/18/2009 11:36 PM

Yep. That is exactly what it is. They often also add something that makes it smell really unpleasant too (burns the eyes and makes you nauseated if you breathe it very long.) to prevent people from huffing it.

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#45
In reply to #44

Re: Degassing Jar for Epoxy Adhesive

02/19/2009 2:56 AM

Yeah, it's coloured purple over here, and I don't wan't the colour to stain my bow...it's a swine to get off my nice white fur too

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#47
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Re: Degassing Jar for Epoxy Adhesive

02/19/2009 3:05 AM
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#51
In reply to #43

Re: Degassing Jar for Epoxy Adhesive

02/19/2009 6:19 AM

Hi Jaguar:

Yes. Denatured alcohol is the correct description.

Everyone usually refers to it as methylated spirits.

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#46
In reply to #41

Re: Degassing Jar for Epoxy Adhesive

02/19/2009 3:03 AM

Methyl- is cheaper (at least here in Europe) and is available in hardware stores and many super markets. Isopropyl- is far more expensive, not anywhere as easy to find (ordering at a chemist here in Germany) and around 8 x the price.....

Also, having used Meth- many times for just this purpose, I know it works, I have never used Iso- for this, it might or might not, but why use something that (at least here) is so much more expensive?

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#48
In reply to #46

Re: Degassing Jar for Epoxy Adhesive

02/19/2009 5:20 AM

This is getting dodgy!

First there is difference between methylated spirits, Methyl Alcohol (methanol) and Ethyl Alcohol (Ethanol)l

Methyl Alcohol is highly toxic and so was banned for use in methylated spirits in most countries. It was used as a denaturant - now it has been replaced with all sorts of other nasty tasting solvents - including petrol (gasoline) so the alcoholics won't make themselves blind or hasten their end if they do drink it. The blue colour is only for distinguishing. Denatured Alcohol is the best definition.

Alcohols are good solvents for some things but not for greases & oils. Ketones (eg acetone, MEK & MIBK) are also good solvents but are also good paint removers so be careful. Aliphatic Hydrocarbons eg White or Mineral spirits or turpentine substitute - are excellent for removing grease and do not remove paint easily. Gasoline also belongs here but is very fast evaporating and so tends to spread the grease around rather than remove it. Aromatic Hydrocarbons eg Toluene and Xylene are the next in line but are stronger as solvents for grease but also can attack surface coatings.

Best way is to run tests but a good do-it-yourself degreaser is probably mineral spirits but then a wash with a detergent and water.

Commercial degreasers have the upper hand as they contain a selection of solvents including couplers which allow them to be washed away with water.

If, after degreasing, the surface will wet with water and not break into blobs you are winning.

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#49
In reply to #48

Re: Degassing Jar for Epoxy Adhesive

02/19/2009 5:50 AM

Ah, you reckon white spirit is good for de-greasing, I wondered as it sort of feels almost slightly greasy itself?
Anyhow, I maynot need to degrease as the components have been kept wrapped up.
this is a good thread, wandering slightly, but all very helpful.

I think I have a small tin of Acetone somewhere (if it hasn't all evaporated)...I use it for geting my nail claw varnish off
Del

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#72
In reply to #49

Re: Degassing Jar for Epoxy Adhesive

02/23/2009 4:48 AM

Lets not confuse a good solvent with a good cleaner.

Acetone is an excellent solvent and will dissolve most of the contaminants found on surfaces but it is too quick in evaporating so it has the same problem as dusting - all you do is move the contaminant around and removes that which stays in the cloth.

White spirit does not evaporate so quickly and so allows more to be removed as you can dry the surface with the cloth. There is a half life problem here every time you wife you move some contaminant and leave some behind. White spirit is generally a good enough solvent for day to day contaminants - some strong solvent in the spirit will assist in its solvency powers.

I all depends upon upon how clean you want it. Even solvent dips have been found to be deficient as they gradually build up a a concentration. That is where the Vapour Degreaser is so efficient it uses condensing vapours to dissolve and carry away the contaminants. The muck is retained in the sump. It stops working when the object is the same temperature as the vapour.

To remove grease efficiently from a surface a hard surface cleaner which contains a wetting agent works well it dissolves the grease and then puts into a water soluble state so that it can be rinsed away.

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#50
In reply to #48

Re: Degassing Jar for Epoxy Adhesive

02/19/2009 5:57 AM

Methylated Spirits are not dangerous as long as you do not try and drink it, or use it near any form of flame heating/cooking or naked lights. it can be obtained relatively cheaply over most of Europe. I feel it belongs in almost every household for many different uses.

For example, it is useful as an Antifreeze in car windscreen washer bottles, especially good when combined with a few drops of washing up liquid. In tests in Germany by the "AutoBild" Magazine, this mixture, with water was as good as the best expensive additives available.

It will carry/bind water found in fuel tanks and similar through the engine if for some reason water is in the fuel. In diesel engines, which usually have a water trap in the filter, due to the fact that it does not lubricate as well as Diesel does, its probably best to either not use it at all, or only in small amounts per tankful.....

A good reference for anyone needing one for Methylated Spirits will be found at the following link, which explains the name and the contents rather better than I have seen elsewhere and with less drama!!:-

Methylated Spirits

A short excerpt from this link being here:-

Denatured alcohol

From Wikipedia, the free encyclopedia
Methylated spirit

Denatured alcohol is ethanol which has been rendered toxic or otherwise undrinkable, and in some cases dyed. It is used for purposes such as fuel for spirit burners and camping stoves, and as a solvent. Traditionally, the main additive was 10% methanol, which gave rise to methylated spirit. There are diverse industrial uses for ethanol, and therefore literally hundreds of recipes for denaturing ethanol. Typical additives are methanol, isopropyl alcohol, acetone, methyl ethyl ketone, methyl isobutyl ketone, denatonium,[1] and even (uncommonly) aviation gasoline.

In the phrase denatured alcohol, denatured means "a specific property of ethanol, its usefulness as a beverage, is removed". The ethanol molecule is not denatured in the sense that its chemical structure is altered.

There is no duty on denatured alcohol in most countries, making it considerably cheaper than pure ethanol. Consequently, its composition is tightly defined by government regulations which vary between countries. Different additives are used to make it both unpalatable and poisonous in such a way that is hard to rectify through distillation or other simple processes. Methanol is commonly used for this in part because it has a boiling point close to that of ethanol, and separating it by distillation is difficult, but not impossible as methanol and ethanol form a zeotropic mixture (the opposite of an azeotropic mixture). In many countries, it is also required to be dyed blue or purple with an aniline dye.

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#73
In reply to #50

Re: Degassing Jar for Epoxy Adhesive

02/23/2009 4:57 AM

I repeat.

Because Methyl alcohol is so toxic and it is difficult to stop idiots from drinking "methylated" spirits most governments (Here in South Africa and the UK at least) require "meths" for sale to the general public to be denatured with other substances.

As ethyl alcohol is strictly controlled - high tax revenue - there is pretty good policing. Just compare the price of a bottle of meths with that of Vodka (only 50% alcohol)

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#74
In reply to #73

Re: Degassing Jar for Epoxy Adhesive

02/23/2009 10:20 AM

I would add that all of these substances (ethyl, methyl, and isopropyl alcohol, acetone, and MEK) are readily absorbed through the skin and through the lungs so proper PPE is mandatory for safety.

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#52
In reply to #48

Re: Degassing Jar for Epoxy Adhesive

02/19/2009 7:40 AM

I wonder if water and Tri-sodium Phosphate (TSP) might be a good alternative. It should help clean that white fur too....=D

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#53
In reply to #46

Re: Degassing Jar for Epoxy Adhesive

02/19/2009 7:57 AM

There may be an issue of taxes or regulations over there but here in the states, 90% Isopropyl can be bought off the shelf in small quantities at your local drug store. You can buy it in larger quantities at your local Home Improvement Store. It is not any more expensive than lacquer thinner or acetone.

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#54
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Re: Degassing Jar for Epoxy Adhesive

02/19/2009 8:16 AM

I've written a little jingle for you..

'Cleaning is no trouble at all...
With Iso propyl alcoh-all'
Del

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#55
In reply to #53

Re: Degassing Jar for Epoxy Adhesive

02/19/2009 8:29 AM

I have used Isopropyl many, many times as it was the preferred agent for cleaning both Hard Disk heads and Tape unit heads in the field 30-40 years ago.

I actually find it "too mild" in its cleaning action for most things.....

"Meths" is "active" enough to do a great job in many, many areas.

Isopropyl is more expensive & less easy to source here.....

I have cleaned VHS tape drive heads for years with Isopropyl, but today I just use meths, I have had no problems with any of our 4 units, one is15 years old now!! The youngest is 4 years old....the original heads are all still in use.

Meths is a "tool" that I am happy with, the fumes are light and dissipate themselves upwards, no worries about heavy vapours collecting in low areas.....another plus for me......

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#56
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Re: Degassing Jar for Epoxy Adhesive

02/19/2009 8:53 AM

Back when I worked at a photoplotting office we used acetone to clean the optics of the laser photoplotter. It left no residue whereas alcohol would leave a cloudy film on the optics.

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#57
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Re: Degassing Jar for Epoxy Adhesive

02/19/2009 9:02 AM

In the production of optical & semiconductor surfaces we use Isopropyl for most cleaning operations & acetone where something more aggressive is needed. This is after pre-cleaning in water soluble cleaners & ultrasonic cleaning in demin water.

I think we pay about £5/litre for Isopropyl in the UK.

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#60
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Re: Degassing Jar for Epoxy Adhesive

02/19/2009 9:18 AM

Is that a "quantity" price? Its very cheap in comparison to here, a 1/2 liter costs around €12 in a Chemists and I have to sign the "Poison Book!"

A liter of Meths costs around €2.50 almost anywhere.....I find that expensive as I use a lot each year....several liters.....

But each to his own favourites!

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#62
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Re: Degassing Jar for Epoxy Adhesive

02/19/2009 9:29 AM

"Is that a "quantity" price?"

Yes, we get through crates of the stuff.

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#63
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Re: Degassing Jar for Epoxy Adhesive

02/19/2009 9:33 AM

What does the "man on the street" pay in the UK nowadays?

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#64
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Re: Degassing Jar for Epoxy Adhesive

02/19/2009 9:50 AM
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#65
In reply to #63

Re: Degassing Jar for Epoxy Adhesive

02/19/2009 9:59 AM

Nothing. If he's in the street he's a bum...=D

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#58
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Re: Degassing Jar for Epoxy Adhesive

02/19/2009 9:14 AM

For sensitive optics, I am sure that acetone is best.

I clean my digital cameras though with meths- and see no residue, even with an eyeglass (10x)....that's good enough for me!

I dislike acetone for other reasons, it dissolves many surfaces on contact, a drop on some plastics and you get a mark!!! I use it only when I need its special properties, never on "home" optics....or magnetic heads......

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#70
In reply to #56

Re: Degassing Jar for Epoxy Adhesive

02/23/2009 2:54 AM

Hi,

your suggestion of water plus phosphate is likely the best you can do.

Any of these alcohols contains a lot of non-wanted residuals: either nonvolatile film (if in solution) or particulate if ordinary particles from process or bottles or acids or very slowly evaporating liquids.

Acids: very nasty but not in cleaning for epoxi.

If you want "no traces at evaporation" you need minimum spectroscopic grade cleanliness: 100€/l would be the mean price.

Alcohol is not really good in solvent characteristics: traces of grease are sometimes pretty difficult to remove. Acetone is much better.

If nothing works on optical surfaces: try your own saliva, likely to be better than any organic solvent.

RHABE

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#38

Re: Degassing Jar for Epoxy Adhesive

02/18/2009 3:37 PM

Out of interest here's one I did about 20 yrs ago, for a crossbow, with it's wood form. The nails are there to loop the rubber binding back and forth and over the bow.
I bought some very expensive Epoxy from Ceiba Geigy at the time...
The glass is bought already layed up in sheetform.

Del

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#39

Re: Degassing Jar for Epoxy Adhesive

02/18/2009 3:54 PM

Hi Del,

any used tools with epoxi can be cleaned easily by brushing in warm,hot water.

Uncured both parts are soluble.

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#59

Re: Degassing Jar for Epoxy Adhesive

02/19/2009 9:17 AM

I think this thread is going in ever de-greasing circles.

Oh, I've made I larf now.
Del

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#61
In reply to #59

Re: Degassing Jar for Epoxy Adhesive

02/19/2009 9:25 AM

GROAN!=b

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#66

Re: Degassing Jar for Epoxy Adhesive

02/19/2009 3:56 PM

DEL, THIS SHOULD BE A LINK TO A BOOK THAT DESCRIBES A SINEW BACKED BOW MADE BY THE CALIFORNIA INDIANS. THE TITLE IS SURVIVAL SKILLS OF NATIVE CALIFORNIA AUTOR: PAUL DOUGLAS CAMBELL. HOPE THIS HELPS YOUR BOW MAKING. BEST OF LUCK, LES HARVEY http://books.google.com/books?id=qSRLW5ziVFAC&pg=PA255&lpg=PA255&dq=YAHI+BOWS&source=web&ots=Gs3m0gSUmu&sig=7EIlOFZ3tspHNgPHrkcnIzqLKaY&hl=en&ei=i8GdSfqHPJPHtgeo2JneBA&sa=X&oi=book_result&resnum=8&ct=result#PPA258,M1

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#67
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Re: Degassing Jar for Epoxy Adhesive

02/19/2009 4:23 PM

Cheers,
Nice, I've read a fair bit about sinew backing etc, but there's some new stuff there and some great pics.

Del

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#68

Re: Degassing Jar for Epoxy Adhesive

02/22/2009 5:10 PM

We use sealed twin-packs for potting. These are mixed in the bag, so no air is added during mixing.

And for cleaning.

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#69

Re: Degassing Jar for Epoxy Adhesive

02/22/2009 7:50 PM

Del, the thought occurs to me that you could avoid the whole mixing thing by using a single component epoxy that is UV cured. That way you are not entraining any air by mixing it AND you have all the pot life you could ever need.

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#75
In reply to #69

Re: Degassing Jar for Epoxy Adhesive

02/23/2009 2:32 PM

U/v curing means exposing it to sunlight or artificial source. That is a bit difficult if it is between two laminates. There are hundreds of epoxy adhesives - but generally for this job I would not use a quick cure and go for the polyamide one. A good press or a vacuum bag would be a good choice.

A water based degreaser and a good dry - use alcohol -["meths"] as drying agent would probably be what you need. Forget the fancy stuff - there should be no oils or fats if they were not present in the tooling and you keep your hands clean.

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#76
In reply to #75

Re: Degassing Jar for Epoxy Adhesive

02/24/2009 5:35 AM

I agree, that's good advice for anyone......and what I have been doing since I discovered Epoxy at the age of 12 years old....could not live without it and my hobbies...

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#71

Re: Degassing Jar for Epoxy Adhesive

02/23/2009 2:56 AM

Thanks guys....
I've set the whole project on hold by means of a BIG F**k up .

I was laminating two of the wooden cores for one limb (I'm doing it in stages as it's a weird and complicated bow...not a quick 'one lay up' job).
One core is parallel the other tapered.
So I've got everything set out to glue and bind onto the former.
I spread adhesive onto one face of the parallel lamination and lie it on the former.
I pick up the tapered lamination and spread adhesive onto the face, turning it round to enable me to spread it on each end.....
Can you see where I've just screwed up?
The former is curved, and having turned my tapered lam' I've now got the thick end at the tip of the bow limb....

Hey ho...it was all left over material, but of course, I don't have any spare laminations.

Never mind I'll buy a couple more next time I'm near the archery shop, I'll get back to making self wood bows.

Del (You can all stop laughing now)

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