Aluminum Oxide vs "Paper" for Sharpening

Thank you.

The netting is a twine. It is Dyneema. Its soft enough to cut through but very hard as far as being able to cut cleanly. I have hot knife and it does work, it is just very slow going.

I was looking for a faster method like I am used to with standard twines and nettings.

However, i do not want to burn or ruin my cutlery tools. They are all high dollar steel and work fine on the other materials I use.

Thnak you again.

I use diamond hones to sharpen with. They seem to do a faster job. Also you may want to try a set of pruning shears that they use in florist shops. They seem to do well in tough materials and hold a pretty good edge.

Not sure what type of hot knife you use but should cut it pretty easy. The material is spun UHMW. If you have the type you have to hold a button to let it heat up they can be slow. I suggest you look at the small butane solder irons that have several attachments one is a knife. They stay hot and the heat level can be adjusted.

In doing automotive trimming, sharp scissors are a must. I use Fiskars and hone them with a diamond sharpening stone made for the fisherman. I picked it up at Harbor Freight for a song. A little sewing machine oil for lube and it is as sharp as new.

I have used Fiskars for almost 25 years. They work fine on everything else.....but this material has a residual hardness and stringy-ness in the fibers.....the Fiskars have to be sharpened repeatedly.

Those smooth blades slide the netting before they grab and cut. I sliced a trough through my hand a month ago when the Fiskars 'slid' along the netting and caught my left hand. They work excellent on rougher netting like nylon and polyester.

Diamond tools, properly chosen for grit size, are the fast way to sharpen anything. GA

I have a diamond sharpener. It works fine. I think it eats too much of the blade though. I am getting convinced that standard hard carbon steel is not the right tool for this material.

thank you.

The diamond hones come in several grit sizes the 900 is pretty fine. I don't see it taking that much off. DMT makes four grit sizes an 180, 300, 600, and a 900. I have one of each use them depending how much work need to be done to the blade. Smith makes a 400 and a 720.

I use a propane tip on really heavy sizes like 4-6mm thick x 250mm to 600mm mesh size. It does work. This netting, however, is more like .75 and 1.00mm dia. and 38-50mm in mesh size.

Thank you.

On some hot knives the heat conducts from the electrical element to a blade at the end. I think these tend to be slow. There is another type in which the blade itself is the element, with a low transformer voltage applied at either end. In my crab-fishing days, this type would cut like butter through 5/8" polypropylene pot lines, but probably not as fast in your material, nor nylon.

I have tried several hot knives. They cut through but they soon heat up to a point that i fear the wire will melt.

I am cutting approximately 400 meshes with each mesh have two - 1.00 mm strands. The Dyneema just burns slowly away. The cuts are long and time consuming with any of hot knives. The model I have is very good with HDPE, PP, PA and Polyester.

This Dyneema is a tough netting to work with but it allows me to do so much more with net geometry ( design ) than any of the standard nettings.

I really need to cut with a knife or scissors. I just need a surgical sharp blade and a way to re-hone it qucikly.....if there is no sure way to hone it quickly, i will just go back to my Arkansas whetstone and ceramic finisher.

Thank you all.

The kind we used to use for crab pot lines was the second one in this link:

https://www.wirecare.com/land_hotknife.asp

It reaches 600°C. The melting point of Dyneema is about 150°C, polypropylene 160°C, and nylon (6/6) 256°C. Some Weller soldering guns have a hot knife attachment that reaches 600°C also, and might be handier for netting. I am puzzled that this wouldn't work, plus seal the ends against fraying. (Or is it monofilament?)

....the hot knife works fine....its just too slow and the smell kills me. Plus it was exagerating my already swollen carpal tunnel by having to manuever the blades in and out of the smaller mesh. That thing weighs about 2 lbs. and is clumsy.....or maybe I am the clumsy one.

Have you tried rotary shears?

Apparently, they are used in the textile and carpet industry.

Here is a link to one brand:

http://jacobowitzinc.com/rotary_shear_cutters.htm

Just a suggestion.

Thank you.

I will usually work with a section of material that is 25-30' deep x 120'-150' long.

I hang one corner on a hook and start cutting angles into the dimaond shaped meshes.

i do use Rotary shears on the 3,4,5 and 6mm mesh we build nets for the capture of the Young of the Year (YOY) fishes. It is a raschel textile and usually 120" wide by 60 yards long.....rolled up as we go along cutting.

The UHDPE is larger mesh and really tough..........

Scissors and small, hard steel knives have worked for 3 decades. My old fingers are just used to that . * Old Dog Rule* Ha! Ha!

netmaker,

As dvmdsc in post 1 mentioned, a whet wheel (the larger diameter the better) might give you control of the surface speed to get an edge quickly without overheating the edge. A magnified view of the edge will show microscopic serrations which may be what you need to cut this material.

Maybe you could borrow an old foot-powered one and try it.

I used to use air powered diagonal cutters (dykes). They reduced the finger force to a light touch....jaws closed, open,move and so on.

Cutting with scissors is painful as the dyneema is made tough for it's job and your fingers wear out.

They can be purchased in AC powered form as well as air powered, and the jaws swap out so you can sharpen 10 pair and use them over time and then sharpen 10 pair.

Another method is the hot wire with a trigger. You use a high melting alloy and pull the trigger to cut and the wire gets hot fast...cut... then release...next

From places that provide tools and materials for the construction of home built or experimental (anythings), you can get shears that are made to last when cutting carbon fiber fabric. Carbon fiber is much more difficult to cut than PE. They may be made of materials with a ceramic cutting edge. And you can find shears at industrial tools and material suppliers. I have even seen them in local hardware stores.

TooMuchFun

I am going to look "outside-the - box" for something .

Thank you.

If you are willing to look outside the box, I suggest you consider using a laser to cut the dyneema. Many companies will do test cuts on a sample basis. IMHO a Q-switched laser will do the best job.

netmaker, welderman has a point, Gerber makes big CNC laser cutters for use making things like sails and patterns for clothes. such a setup would probably be expensive as hell, but it might be just the tool for the job. Most steel suppliers have CNC laser cutters as do many sheet metal fab shops. but they tend to be no more than 10 or 12 feet on a side.

I could not even begin to pay off something like that. These little hand cutters will work fine. Thank you for the thought though.

* I'd shoot myself or the dog with the dang thingt............*

Yeah, I figured that, but it was worth mentioning even so.

No such luck around here with that kind of industry.

Any ideas on where they might sell something extra-tough with this coating already on the blades? I am not in touch with any company like this and the guys who use this stuff already use it mostly for baseball backstops.....long straight cuts where you can gather up 2-3 feet of netting and slice it with a hot knife. My work is on trawls and seines where we cut angles and tapers.

I am going to contact these guys with the ceramic blades. I hope they make a more contoured grip as i can cut for 2-3 hours at a time and carpal tunnel tears me up already. 2-1/2" blades are ok.....its just those little "eye" hole handles.

Getting old .....getting old.........

Thank you again.

Fiskars makes some that are Titanium Nitride coated. TiN is gold colored. if you want help finding someone that can coat the blades look for companies that grind threading tool inserts for oilfield premium threads, they'll have the equipment you need. LA is chock full of oilfield machine shops and they'll know who to refer you to. you'd be surprised how much of that kind of industry is all around you and you just don't notice it. Since nobody in LA is working in the oil patch these days, they'll be hungry for the work probably. If you had the blades made from titanium (6Al4V) and sent them to a heat treater to have them nitrided you won't have to sputter them. Maybe that is an idea for when the carpal tunnel gets too bad for you to work making nets, you can go into the high tech scissor biz.... =b

Talk to the Dyneema people, I'd bet they have some ideas on this too.

....thanks for the info. I know a shop that does stuff with threading all the time. They are not that far away.

I have a feeling that we will be getting some business for some extra heavy gears when those scientists start looking into those deep areas in the G.O.M. for marine critters. I'll need a small bladed cutter that can get inside the smaller mesh. I did not know fiskars made such a tough tool. Thanks again.

Hi netmaker,

I don't have an answer for your sharpening question, but another suggestion for cutting the material. I use a Metabo brand grinder with a 1/8" thick by 5" diameter cutting disk to cut everthing from PVC pipe, to carbon steel pipe (which it was designed for) to masonry backing board for tile. I know it would make quick work of the net, but for precision I don't know.

Sounds like you need something 'single shot' for precision and durable.

A bit like contract pruning?

Used a set already, the netting slips inbetween the blades. This netting is only 1mm or less in dia..

* Those factory ships you might see at YOUR dockside have this netting on their pelgaic trawls.....but it is 3mm through 6mm dia. and up to 2 meters in mesh size.*

Thank you anyway.

Change the cutting angle so the blades pull together in shear - not push apart.

It's a balance of thickness and material shear angle.

It may be worth trying shears with one fine sharkstooth edge, rather than smooth edge, in stainless or chrome-molybdenum alloy. I have cut thin HD polyethylene, and it is quick and accurate, but the finished edges are not perfectly neat and clean. I have not used them for lengthy runs, so do not know how the edge will be with time. Readily available with plastic handles (which may not be reliable in the long run) at discount stores and haberdashers.

It seems to me that the mesh makers might be able to make some suggestions, after all, they need to cut it and they manufacture it.

Found this online

http://www.needlesports.com/Catalogue/Rock-Climbing-Equipment/Cord-Tape/Cutting-Equipment/Electric-Rope-Cutter-Hot-Knife-HSG-ROPECUT

looks like you pull the trigger. I wonder if they coat it for not sticking etc?

Maybe ask them. a bit costly

Yes, the netting manufacturers all say a variety of things from hot knife to high end scissors and serrated edges. Every shop that uses this netting has their own technique for cutting. The issue is my shop utilizes the smallest of the diameters where most of the big shops in Europe, use much larger diameter which they have to cut through slowly.

My issue is that my hands hurt, carpal tunnel, arthiritus and sometimes , the shakes. I am used to working with small , fine edged knives and scissors. If I could, I'd like to stcik to this type tool. But if I need to adjust......I'll just do that too.

thank you.

You may also like to try http://www.assystbullmer.co.uk/handcutters.shtml

It sounds like an interesting problem ripe for creative solutions. The reason you don't want to use a high speed grinder to sharpen your blades is because the heat developed during sharpening will soften (anneal) the steel. If you can locate scissors made from high speed steel like M2, you will have longer lasting cutting edges that will also survive high speed sharpening without loosing hardness. You might also consider other hard edges, like carbide or ceramic. While these provide long lasting edges, they will be more prone to chipping.

Thank you.

I think i was misguided at the get-go about the grinder wheels.

I am going to start looking for something harder.

I also think I should look for something with a serrated edge as this netting slides when you cut it ....if you do not put a tension on it. Tensioning every mesh in a 400 mesh deep cut is sooooo time consuming.

Thank you.

Have you tried some of thoes Ceramic blade knives.

I have seen them advertised on TV and they claim they will cut about any thing and still stay sharp.

The knives I use are very small. I hold the entire blade in my palm, and use my thumb to push the netting onto the razor sharp blade. Its a scissors-like motion and I can cut through 400 meshes in about 20 minutes.....but not with this UHDPE.

The knives I see advertised are really large in size. My longest blade is maybe 2-1/2" inches max.

Thank you for comment though. I am going to try a ceramic blade or scissors though.

A ceramic blade require some initial pressure, so that when it bites you may not have complete control over where it goes.

http://www.azom.com/details.asp?ArticleID=3310 http://en.wikipedia.org/wiki/Ceramic_knife

Thank you too Guest.

I just had a thought:: I don't fully understand exactly how you are handling the knife,

but caution.... the ceramic blades may be brittle.......... Don't cut your self

If I go more than a month without something requiring antiseptic and a bandage , i consider I am not working much! ha ha !!!

I too was going to suggest a wet stone (slow revs) but I have been beaten to it!
The 3M (Minnesota Mining and Manuf. Co) specialise in grits and papers.

Also, had a slow boat to China myself with "hot wires" and found the best
quickest "knife" to use was a hooked one. The point of the knife curved
around (160 degrees,) and sharpened on the inside, which "scythed" the strands.

I think these are made for s special purpose, carpets or something. (tool merchants)

Hope this helps.

jt.

Excellent! Take the girl out for some boudain and shrimp etufee! she deserves it!

She cooks better boudin and ettouffe then we can find.....she is spolied on Ribeye and cold Coors at the restaurant in Lafayette! ha ha........

Netmaker -- Very interesting topic discussion here; full of good information. I'm not sure I can add anything specific; but I will throw out some comments about sharpening you and others may find useful for some situations.

First off, model builders like the folks who mess with small scale train, aircraft and ship models treat #11 Xacto blades as a base standard. Some have observed that the quality of those blades has gone down in recent years. In answer to this they hang on to the 20-30 year old blades and resharpen them. Best way to do that in the model building environment where things need to stay clean and dry seems to be a combination of a flat plate like glass and successive finer grits of abrasive paper down into the 800-1200 range. It does take some technique I'm still trying to master.

Another has to do much with my own mindset. Over the years I've messed with a variety of approaches to sharpening, oil stones, water stones, aluminum oxide slow speed wheels turning in the 1200-1800 rpm range, fine belt sanding followed by a manual fine grit finish step, ceramic rods, etc. My pocket knife and the kitchen knives were always dull because it was too much effort to sharpen them, especially when my brain was in it's usual frazzle from a general lack of bandwidth.

Years ago I bought an old 10 inch wet grinder at a swap meet and set it up with a new motor and belt drive. But lacking a place to put it in my cramped shop it just sat in my storage area. Recently I found a place for it and started using it for the pocket knife as well as a number of other sharpening jobs, especially garden tools and of all things the tips of replaceable utility knife blades. Turns out this method has become very fast and convenient and does a much better job of reforming the edge of a dull blade than I ever was able to do with the other methods. Now my pocket knife stays actually sharp enough for most things and when I resharpen it only takes 2-3 minutes to get the blade to where it can shave the hairs on my left arm. (my personal test criteria). (Took me til Age 71 to discover all this)

Ed Weldon

Thank you for that Ed.

A lot of folks wrote in and mentioned wet stones for knives.

Thank you and enjoy the nice weather in Ca.

"I suspect that it will dull quicker than quality steel"

good find. I had assumed that simple bladed were not up to the task.

To make it last longer you could lubricate it, as facial blaed last longer when lubed.

Pack of 100 replacement blades can be bought for a couple of bucks = all solved, except after a while you will be knee deep in broken off sharp bits. So get a magnet to pile those on until disposed.

wow, I got beat to it! I was going to suggest breakaway wallpaper knives. I go through a dozen blades a week myself!

Good that you found something!

Been out netmaker, went the other way, maybe LA next time, and just saw this. i use those little knifes all the time and OLFA makes the best holders for the pocket. the OLFA blades seem to be sharper but a lot more expensive, holder is too but worth it to me. http://www.amazon.com/Cutter-Graphics-Stainless-Steel-SAC-1/dp/accessories/B000BKA6IA

stay safe netmaker, let us know when you are going to build your "shade tree"

Your problem is not what you are using to sharpen with. The problem is holding an edge. If you are using a very hard steel, sharpen with a diamond sharpener of around 1200 grit, being careful not to change the cutting angle as diamond cuts quickly. A motorized diamond sharpener may be the answer as it will maintain the cutting angle.

All noted. I can see that the further we go into needing extra sharp, we need to look at options in the cutting tools themselves.

Thank you.

Netmaker,

When you are cutting strands, the blades should be like a parrot mouth, but scissorlike.

You can find an example in professional nail trimming cutters for dogs. I have one that still does the work and is 15 years old. I felt very disappointed when the workers here started to cut electrical wire with it. The cut became dull after wiring a 20,000 ft residence. But I fixed it up and it cuts again like new. The angle is somewhat sharper what means it will do the work better. It also has a spring, so that your old hands have some help in the come- back move. BTW, this is a forum of aspirant fossils? The 60 plussers may now raise the hand. So we are the golden boyzz?

Thank you.

When I had to make some 3000 cubic foot fish cages with a 700 denier plus netting (strands the size of 5/16" solid line), I bought a pair of curved pruning scissors. After about 400 lbs. of the 700 pounds of netting was cut, I switched over to a fine propane point.

But I do remember how well they cut until my hands just gave out.

As for old guys ( and gals) I'll still run two 25 year old apprentices out of here by noon.....vertigo, carpal tunnel and all............. ha ha!

I'm not THAT old, I just have some really hard miles along the way.........

Thank you again.

Putting a pneumatic cylinder (www.beswick.com) on those pruning scissors could ease the strain on your arms. Note: Median nerve trouble often comes from the pronator teres muscle in the forearm or another muscle-bone-gristle area just above the elbow. Don't get your wrist cut on only to find that it is your Popeye arms or beat up neck that need attention.

Pnuematic cutters would be too clumsy to manuever through the small meshes. If we were doing baseball , golf or soccer nets ....or the bigger commercial type nets, we might be able to use this.

These smaller , custom research nets have meshes that range from 50mm down to 4mm. Its a business that involves very fine and precise cuts and tapers and so far only scissors and small bladed knives work on this.

Thank you for the input.

Here's a wild idea that might work--or totally collapse. Plasma cutters are meant for metal, but maybe they could handle this as well. I'm also wondering if anyone makes a hand-held "laser pencil," say 500 watts (but 5000 bucks).

dremel tool with alum-oxide cutter wheels

.............and this tool comes from where? Thank you.

Isn't this a toe nail cutter for dogs?

Hi Rorschach,

I took a picture of the only toe nail cutter we had here. The history is very simple: before starting to build a very big building here, we secured the property with fence and 5 dogs. Because they were running on soft ground, the nails had to be cut on a regular basis. When the electricity had to be installed the electricians prefered to work with this tool to cut all the wiring, up to #1. It seemed to work a lot faster than cutter-pliers and also didn't compromise the round shape of the wire that much.

Actually for bigger wires there is a similar heavy duty cutter up to 3/0 available.

I must confess that the #1 wires are a bit too heavy for the dog nail cutter, but it works. The shape of the cutter is very interesting, because round wires don't shafe the edge a lot less that a straight one.

Besides that, there is room for sharpening and adjusting the friction or distance between the blades, or for experiments with the right angle.

It has a reasonable gap and has not been resharpened after maybe 3000 copper wire cuts. One extra: you can trim also the nails for dogs AND cats (for Dell)

To have an idea of the size: that cylinder is a cigarette filter. (I should stop smoking)

It's sometimes difficult to predict what cutting material will stand up best in a given situation. I have tasks where dendritic cobalt blades made by David Boye are superior. There are also tasks where custom forged Damascus steel stands up best. If I were in your position, I might consider a real blade comparison test; sort of a blade shoot-out between materials for cutting UHDPE. You might find sponsors for such a test and it would cost nothing.

Welder,

Thank you for the input on this. Right now I am going to be satisfied with the end result of the little break away blades. During the slow season, I might investigate further. However, I will look into your cobalt blades and see if they come with a thin blade like these box cutters have.

The thinnest of the blade as well as the sharpness seems to have an impact on the cutting. My knives are razor sharp but do not cut this smaller Dyneema as well as those thin little blades seem to.

Thank you for contributing.

Got into this one late, but my suggestion is to leave the scissors in the kitchen and buy a good pair of tinsnips.

Modern styles have good steel, good edges and many have one serated surface to assist in gripping. They also have significant mechanical advantage that should assist your hands.

Whenever cutting plastic strap or heavy cord these were my first choice. Might cost a littel more than scissors, but should only cost a few bucks and then no sharpening.

Thank you for the input. The tin snips I used and I had 2 different pair made by Wiss, only cut the larger twines of 2.00mm and larger. They just mashed the smaller twine in the 1.00mm and smaller sizes.

They do cut the big stuff though.

In the sheetmetal shop where I worked, we processed some thin metal (down to 0.1mm thick) and the snips used for that were as good as scissors with paper and plastic sheet.

As you say, in the "off season" you can investigate further.

Thanks for being so good at providing feedback to our input. It is appreciated.

Netmaker,

Thank you for teaching us about netmaking. Thats got to be a "lost art" like ship rigger or sail maker.

Thank you for the thought.

Net design and net making are not rocket science.....but on occasion i can use the brains of some of these CR4 rocket scientists to assist me in keeping our little family business alive. The information I receive here on this site is always appreciated.....always!

industrial diamond coated wet stone and a very light touch

wet silicon carbide use water so you don't ruin the temper of the steel. Keith Moffett metallurgist

On occasion I have to install 1/8" stainless steel cables on structures for hurricane bracing in order to meet the 130 mph wind requirement on coastal structures.

These snips are the only thing I have that will cut the cable.

Not good clines, side cutters, cable cutters, or any other snips will cut the 1/8" ss cable at all.

These cut it like it is string!

http://www.qualitydist.net/irw-207.html

Thank you for the input on this.

I'll check them out also.