Using Cable Gland for 10mm Cu Pipe?

Are these KrisDel^TM glands or something a bit more up-market?

These are our special 'Look what I've found in stores' range.
We use 'em at work by the thousand, and I'm allowed to have a couple no prob. The proper brass fitting would be about £8 each and would be more hastle too.
My only real concern would be the ageing of the Nylon?
Del

Is the heat transfer fluid just water or has it something in it like antifreeze or corrosion inhibitors?

The water in the cylinder (which will be in contact with the gland) will be potable. The water in the coiled pipe will have antifreeze, but the pipe itself goes right through the glands with no break, (that's the attraction).
Some of the brass fittings I've found have a compression fitting either side of the bulkhead, which would give 4 joints to get the coil through the plate, whereas the gland solution has zero pipe joins!...
4/0 that's an infinite improvement ratio
Del

Qn the brass bulkhead fitting use a reamer to open the brass so the tubing goes through. This should still leave enough of a taper for the ferule to seal. The brass ferules i believe would give you an better seal. Use just one of the ferules. On which ever side ease of assembly works better for you.

Yup, that was my plan B, but I'm a cheapskate.
It's pretty easy to drain the tank and do a try out, if I have probs I can go the brass fittings. Or maybe I'll order 'em anyway while I'm making the coil gotta check p&p and vat on that sort of thing else you suddenly find the price has doubled.

It pretty much looks like I'm going ahead with the DIY 10mm coil now, as I bought 10metres of the stuff at lunchtime.... mmmm shiny copper coil
Del

Issue I see with your plan A is the dissimilar materials of those types of fittings. The expansion and contraction will be continuously working the nylon seal. You will be tightening it up continuously until you can't tighten no more.

This would be a good choice, but be sure the grommet (as well as the Nylon 6) can withstand the water temperature.

I think 10mm tube can be bent to a small enough o.d. to fit several layers of "trombone coil" through the inspection hole; the 15mm option mentioned in the original thread might be hard to fit.

Good luck with this upgrade.

Ask your self what the tradeoff is between paying for a fitting specifically designed for the service you have in mind and the cost/effort/time down that will be required when the plastic fitting fails. Oh, and where will all the water go?

So your assertion is that it will fail?
I take your point, but what failure mode are you suggesting?
The pressure rating looks ok, the material looks ok.
I could buy a plastic 'Speedfit' tank connector but they are made of plastic too. Although to be fair the back nut is more substantial, but they only sell the damn things in packs of 10 for about £16... or maybe I could sell you 8? (I'd let you have 'em for £15.99)

Now look you've got me arguing with myself..
No he hasn't... yes he has.
Del
_{(BTW. The water will run down into the kitchen and Mrs Cat will give me hell)}

Let's talk about knit lines in round plastic parts for a moment. The knit line is the area where the molten plastic joins after flowing around the core(thingy that makes the hole in the part). It will be directly opposite the gate (little hole where the molten plastic is injected into the mold). If there are two gates, you will have two knit lines, etc. etc. If it fails, the knit line will probably be what separates.

Constant exposure to water is not good for plastics, nylon included. Thermal cycling is also a potential contributor to failure of the part.

For this reason, I'd go with a metal seal.

But, hey, it's not my wife who will be standing there, arms crossed, giving you the scowl of death.

It will probably fail. The mains pressure (as you call it there) will leak through as your coolant moves through a temp cycle. Also, as you consume potable, the tank is resupplied with ambient temp water,even if you took on 2 gallons of the top at 90 C., which is even more thermal shock. It usually is close to the heat x coil, if your potable supply is at the bottom of your tank. As someone who groans when something leaks, because this is not usually the customers fault, I go fix it, for free.

Sweat a fitting to your coil. Insert collared fitting into plate. use a thread (BSP) in your world) to sweat fitting with a collar on the sweat side. Brass is good. Drill two holes, insert fittings (that are already sweated to heat x coil) with thin teflon washers at collar on one side, though plate, with nut and teflon washer on the outside. Tighten. Tighten Again. Install plate (with attached heat x coil into tank) Attach your supply and return to the threaded portions.

The fittings can be made from a short threaded nipple(pipe). You would need to create a collar with a nut assembly on the inside, and sweat an adaptor to your heat x. Obviously, the order of assembly is important, as you should not sweat close to a threaded assembly, ie sweat the adaptor to the heat ex first, screw the nipple into the adaptor, build the inner nut collar, insert the fitting through the plate, then proceed as previous. That's how we do it, when we don't buy the unit.

Nylon 6 swells pretty badly in contact with water, particularly with hot water. it also will "cold flow" and eventually no longer seal without tightening again. the brass bits would certainly be better, but the cable gland would certainly work for a while, perhaps even a long while.

Woo hoo, looks like I've just blagged a couple of freebie bulkhead fittings from one of our suppliers. Mind they are Speedfit plastic ones, but designed for the job (scowl of death... tee hee)
better get on with some work now.
Del
_{(I have been working on checking software all day, honest)}

Yes! Nylon cold flows, hence it does not take kindly to temperature cycling. It will lose pressure seal. Neoprene and silicon rubber are expected to bounce back in temperature cycles.

Metal to metal works, as long as corrosion concerns are taken into account.

Ha, but see #19 which sets out the current state of play.
I'm going to use a thick rubber washer under the latest candidate.
C'mon, you've got to keep up...
when in trouble, when in doubt, run in circles, scream and shout.
Quick quick Dels off on one, he's changing his mind faster than a politician talking to the public
If you're confused, how do you think I feel?
Del

Sealing between the pipe and the gland is the easy part. Sealing between the gland and the tank is where you are most likely to get a leak. (bigger diameter, curved tank surface, inconsistent thickness of internal/external tank anti-corrosion coating or internal tank corrosion)

Go for a £1.20 electrical 20mm brass TRS compression gland with a standard neoprene rubber seal to insert the pipe. (plenty of room to insert a pre-coiled pipe)

Use a brass back nut £0.40. Make sure that you clean off all the external varnish layer around the gland hole, then flux-solder the tank/gland joint after it is screwed tight.

The neoprene will deteriorate with water and heat. Recommended maintenance schedule: Replace the rubber seal every twenty years.

I remember this discussion...go copper. You don't use cable glands as tubing connectors, period; since there is no adequate seal (ferrule/ olive) against the tube.

Waterproof to 5bar means protection of ingress of water to the cable conductors, is all.

Two 'samples' arrived this morning from one of our suppliers. 'Speedfit' bulkhead connectors. They are a pushfit fitting from each side.
Del

I hope you guys can keep up with me, there are some replies which are just soooo yesterday.
But seriously, thanks for all the great posts, it's your input which is driving me inexorably towards a good solution.

It turns out the fittings I have are really air/pneumatic fittings, but are rated as ok for water or non agressive chemicals, and upto 65C.
Hmmm now that's a bit marginal as the hot water from the panels can get above that, but the surrounding water in the cylinder is likely to be less (especially as it's near the bottom of the tank).
I've contacted the manufacturer, obviously they won't endorse their use for what I'm doing, but I've asked if they can tell me if they are deffinitely no good.
Hmmm It looks like I may end up going for brass in the end, or am I being a wuss?
Del
(PS I had root canal treatment this morning... that's a real treat)

let me tell you a story about two companies called Celanese and Shell...Back in the late 70's through the mid 90's they came up with a tube system and push fittings using polybutylene tubing and fittings for use in home plumbing systems. The idea was to make it simple to plumb a house quickly and cheaply. And it worked! at least for a while, the cost of plumbing a house with the stuff was about half or less of doing it using PVC or Copper or Galvanized pipe and the time was cut in half or more as well. Thousands of homes were plumbed this way. And things worked fine for sometimes as long as 5 or 6 years but then the leaks began.... usually on the hot water side. they were slow leaks at first, slow enough that they leaked for quite some time growing black aspergillis mold in the attics and wall cavities for in some cases years before the leaks were big enough to be readily detectible. The class action lawsuit was absolutely monumental in size and it spun off into other class action lawsuits against the insurance companies, and then the builders, and the plumbing subcontractors. The problem was cold flow and swelling from water absorption causing the sealing mechanisms to eventually fail.

This is why I say plastic pressure fittings should never be used for long term use, particularly when the consequences of failure are unacceptable. Sure they're fine for short term non-critical uses, but don't bet the farm on them.

Ok, it's begining to look like I might buy the brass bulkhead fittings. I guess I'd pay £20 to not have a leak.
On the plus side I just tried bending an offcut of 10mm copper, I filled it with block paving sand (which is v fine and kiln dried) and crimped the ends. It bent like a dream .
So what I'm saving on the coil, I can spend on the connectors.
Del

Was just talking to a lady that had one of the early solar water heaters (granted it was here in Houston, just down the road from Hell itself in the summer) andshe was telling me how on really hot days the water got over 170 degrees F and was hot enough to cause her PVC drain piping to melt. You probably need to think about a thermostatic mixing valve to mix cold water with the hot if the temp gets above say 120-140 degrees F, if nothing else to prevent scalding Mrs. Kitty. There's nothing worse than a scalded cat!

C'mon this is the UK I'm talking about, we have to tune in to the weather man to see if it's Summer.
Del

Granted, and that was the reason why I qualified my statement with the fact that it was here in Houston. But if you are a good enough engineer (which I suspect you are.), and you get an especially sunny warm day, you COULD start tickling the upper limit of "safe". You at least should monitor the water temp. on really hot sunny days to see if you are twisting the dragon's tail a bit. Besides, one must assume someone is going to wander by and read this thread years in the future and may not realize that... so it pays to document that thought for the next guy.

Right, are you sitting comfortably?
Current game plan is to maybe use my plastic push fit fittings (see pic a few posts back) but modified by reaming out the stop in the centre.
The pipe can then go right through and thus the antifreeze in the solar panel water won't contact the plastic.
To avioid differential expansion stressing the plastic I shall use a nice big rubber washer on the wet side.
How am I doing now?
Del

_{(Just realized, this project may be cheap for me, but it's costing worldwide industry a fortune in this consultation... but it's all development I tell you)}

I think you are not doing well. Because most of us say don't do it, and you are going to do it. I for one enjoy going against the crowd.

Let her rip! But what's the worst that can happen? The leak will be potable water through the plate. Your solar lineset pressure will be lower than mains, so a leak there raises that pressure, a gauge on the solar lineset will give that away. If you indeed run the tube through, you are not going to leak there. If you run the tube through, you actually have more joints to seal, just a thought, because you are creating a grommet.

BTW, while most of the answers are good solid thoughtful replies, mine come from being exactly, and I mean exactly, where you are right now. You may be able to more accurately construct the materials than me. And don't bump it.

_{Mental picture: Mrs. Cat, standing at kitchen stove, cooking catnip for the hubby. All of a sudden, drip, drip, drip, drip, splash, splash, splash right onto her head, from above.................................................}

Better hide the bows and arrows.... Mrs. Kitty is going to be a might pissed off. Kitties don't LIKE getting their fur wet....

The filling it with sand trick worked a treat.

Del

Del this is a typical join or bulkhead plumbing solution - meaning the pipe can pass through, or not.

Water stuff is usually brass. The nipple (miss termed "body") is tapped, or back nutted, into the bulkhead. Generally using Teflon tape as a thread seal.

The "ferule" in your case would be a 'hot water olive' - generally neoprene these days.

"Cold water" olives are nylon and not recommended for soft drawn copper (aka annealed) as your tube looks to be. They will crush the tube with thermal cycling and both restrict the flow and develop leaks.

Cost wise a link

Cheers, great link at sensible prices, dunno why my endless searching didn't bring 'em up.
I'm sure one of those fittings will do for me. Some of them have a rather small hex area which won't give much seat, but I'me sure it I'm careful not to oversize the hole I'll be ok.
This will prob do me nicely with a back nut, I can stuff the pipe right through and leave a short stub to connect onto.

Only £1.02 ! The bulkhead connector I'd found was over a fiver and ended up being £20 for 2 with postage. Blimey I'll buy a dozen of the cheap ones
Del

Just ordered a couple of the above fittings less than a tenner.
The irony is that the backnuts would cost more than the fittings, but fortunately I have a couple of them from the freebie connectors I got!
Thanks everyone for you help in nudging me to a sensible solution.
I'll post pics when it's done.
Del