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wierdscience
02-26-2008, 08:47 AM
I need some epoxy to laminate some wood together,there will be over 100 laminations in this job so a long working time is in order.

The parts are small and I am planning on using a hydraulic press for pressure and doing the job in a vaccum jar so there are no voids in the finished lamination.

The only other requirement is that it be clear,any ideas?

mike petree
02-26-2008, 09:35 AM
You may want to take a look at West Systems epoxy. Slow setting, clear and quite strong. It's popular for marine applications but very useful in many situations.

Mike

Pete H
02-26-2008, 10:22 AM
I second Mike's recommendation - West System. You can get three different "levels" of hardener - for cool, normal, or hot environments (i.e., fast, normal, or slow-acting). The people who make the stuff - Gougeon Brothers - are really good about support, and if you call them, will (or used to) send you a free pamphlet that pretty much tells you everything you need to know about epoxy. They also sell books and booklets with MORE info.

If you call or e-mail them, they'll offer you information and advice specific to your task, usually within 24 hours. Free.

There are a couple of things to consider with epoxy. First, it usually doesn't contain a UV absorber, so it eventally will yellow in sunlight. You can get UV absorbent additives. Second, it's a bit tricky to work with. The curing reaction is exothermic, so if you mix, say a pint (which is a LOT for one batch) in a container, it may very well "cook itself off" and start to smoke before you use it. The best ways I've found to prevent this are to (A) not mix up too much at a time, and (B) keep a pan of ice-water handy to stand the container in. Once you get the stuff spread out on the workpiece, there's enough surface area to keep it cool.

Cleanup - White vinegar will kill the hardener (an amine) and will start to dissolve the epoxy. I keep a little bucket of it handy when I'm working with epoxy. Just dump the tools (spreaders, rollers, etc.) right in when I'm done with them, and then come back in a while to wire-brush them down. It even works on skin (although rubber gloves are best). Go-Jo or equivalent for the final cleanup, tools as well as skin.

One final (and repeated) safety note - some people get sensitized to epoxies after working with them for a while, so rubber gloves are pretty much necessary. And remember to pee before you start the job, because once your gloves are all gooped up with resin, and the resin is warming rapidly in the mixing container, you ain't gonna want to call a potty-break.

Pete in NJ

ptjw7uk
02-26-2008, 01:23 PM
Does it have to be epoxy.
I have used Cascamite which is a one part waterproof which dries clear similar to the glue they used in the last war for aeroplanes but that was a 2 part mix very messy and stains as one part is an acid.
It also has a fairly long open time not sure on epoxy open times.
Peter

thistle
02-26-2008, 04:04 PM
west system is the most expensive-


I have used raka epoxy for a couple of boats

www.raka.com

works out cheaper, and i actually liked it better than west.

do you really need to use epoxy?
glues such as resorcinol are better
for laminating wood (isnt that what ply is stuck together with?)

pcarpenter
02-26-2008, 04:34 PM
Are you talking about 100 layers in this item or 100 pieces made up of some smaller number of laminations? In any case, I would work hard not to try to do it all at once. Once Epoxy starts to thicken, it doesn't penetrate as well.

Others with more experience can perhaps tell you I am crazy, but I tend to wonder if the hydraulic press will end up being a glue remover? I know for lots of things, firm, even pressure, but not enough to make diamonds is what you are after:D

Paul

Seastar
02-26-2008, 04:49 PM
How about making a sleve of nylon or some other insulator and pressing in the brass part with an interference fit after soldering?
Bill

pcarpenter
02-26-2008, 04:54 PM
Deleted to remove stupidity. I think Seastar posted the answer to a question from a different thread here...and then I responded to it as though it belonged here:-)

Paul

wierdscience
02-26-2008, 09:47 PM
It's one lay up with 100 laminations.No curves or anything fancy,just glue and press.I may have to do four stacks of 25 and then laminate the four stacks into a soild.

Epoxy is my first choice for durability/clarity.I am open to something better so far as it is-
#1 water proof
#2 slow drying
#3 clear

Low visc and UV resistant would be a plus,but not required.

darryl
02-26-2008, 11:05 PM
I haven't tried the West System products-

What I found useful is two types of coffee table resin- one is called Envirotex, and the other is Nu-Lustre 55. Both are two-part, both are strong and a bit flexible. I think for wood this is a bonus. I've used Cold Cure epoxy, and while good it's a bit too inflexible for my taste. It is apparently made for wood laminating, etc.

My friend has the envirotex, and it seems a bit clearer, though the 'manual' that comes with the Nu-Lustre states that it is clear high gloss.

There are differences in how the various epoxies cure up. Working time is about 20 minutes for Nu-Lustre, and it should be applied within that time, but I find that it can be worked for more than an hour after it's mixed. That might be a bonus for laminating, since you can 'paint' it onto the pieces so it gets time to 'bite', then you have considerable time to fiddle with positioning of the pieces, etc. I've found that it will still 'flow out' after 45 minutes (temperature dependent of course), so I'd have to say it's quite forgiving. It has become my epoxy of choice where I need the slower setting, toughness, and I don't mind the longer full curing time, which might be a couple days depending on temperature. I find the epoxies that cure tack-free within a few to several hours are more brittle and chip more easily.

Whatever you use, it might be wise to consider 'post treatment'- that might mean how well does it sand after the cure, can it be re-coated without problem, will it take some other final finish ok, can it be left as a final finish as is, will it run or will it stay put on a vertical surface-

dan s
02-27-2008, 01:37 AM
weired,

how big are the laminates (length x width)?

For wood i can personally recommend west systems or system 3.

this is one of my projects finished with system 3. balsa planked model yacht covered in light fiberglass.

http://img407.imageshack.us/img407/3884/img02907wkwo4.th.jpg (http://img407.imageshack.us/my.php?image=img02907wkwo4.jpg)

ckelloug
02-27-2008, 02:55 PM
Hi all,

I'm the head lunatic from the epoxy granite thread on cnczone. Some of the folks that do composites for a living over there suggested uscomposites as a cheap and ready source of various epoxy. They have cheap low viscosity resin. I have investigated and their low viscosity epoxy with slow hardener is reichhold 37-127 resin with reichhold 37-606 hardener. We've kinda standardized on this one in our discussion on E/G because it's cheap and available. YMMV.

http://www.uscomposites.com/

The market is filled with epoxies but most of the stuff available to us is in tiny expensive tubes while the good stuff like araldite is often available only in barrels or truckloads. From what folks have told me over on cnczone, west is one of the most expensive epoxies.

Regards all,

Cameron

wierdscience
02-27-2008, 08:25 PM
The size is small like on the order of 3x6" and at 100 plys adds up to 3" high until it compresses down to about 2-5/8".