Need a slow(er)-cure epoxy

[WolfeMacleod]

Ok, we're working on some prototype stuff here that needs to be epoxied. For the first few protos, I used some junk that I picked up at HomeDespot. - comes in a twin-tube, squeeze it out, mix it quickly. Clearish. Didn't pour---had to scoop it in, more or less.
It was a little too thick and gummy to work easily with, and started setting up in less than 5 mins after starting the mixing.

So, I'm loking for an epoxy that's a little thinner and could be poured into the cavity, and won't start setting up right away... Maybe 1/2 hour to full set? Black in color would be awesome.

Any epoxies like this?

It should also be inexpensive...

[slodave]

Yes. You can dye it as well.

Kwik Bond Epoxy - 30 Minute 9 Oz

Look up transtint. You should be able to use that.
http://www.homesteadfinishingproducts.com/htdocs/TransTint.htm

P.S. You should be able to find the epoxy at your local hobby store.

[sc_rufctr]

A better/cheaper option is to buy standard epoxy resin and hardener.
The same stuff used for fiberglass... Not polyester resin.

I bought some from the local boat dealership. I was making something that had to hold up under higher temperatures
and was advised that epoxy resin was the way to go over polyester resin.

It's crystal clear and pours easily. About the same viscosity as olive oil.

[WolfeMacleod]

Thanks, Dave

This is for the hum-cancelling P-90 design that'll be epoxied into the no-holes cover. Since I don't know how many will wind up being made, I'm keeping my eye out for something like half-gallon containers... small batches of epoxy could add up fa$t.

Might be looking for something along the lines of a softer epoxy, too, something that's not so rock-freaking-hard, so it'll dampen/absorb the some amount of vibration, which should help reduce feedback issues.
I'm almost wondering if a hard Silicone might be suitable, too...

[slodave]

Then what Peter said. I've used both for my R/C glider. You should still be able to use the transtint with the standard stuff. Since you are near the water, should be easy for you to find as well.

If you don't want it to be as hard, you have to adjust the mixture. Really can't tell you which way to go, but I have screwed up batches before and ended up with a rubbery epoxy. Instead of 50/50, go 60(resin)/40(hardener) or less. Should make it more pliable.

[WolfeMacleod]

Originally Posted by slodave

Then what Peter said. I've used both for my R/C glider. You should still be able to use the transtint with the standard stuff. Since you are near the water, should be easy for you to find as well.

If you don't want it to be as hard, you have to adjust the mixture. Really can't tell you which way to go, but I have screwed up batches before and ended up with a rubbery epoxy. Instead of 50/50, go 60(resin)/40(hardener) or less. Should make it more pliable.

Ahha, I didn't even see that reply when I saw yours.
"Rubbery" eh? Now that may work, if I can adjust the mix and get different hardnesses.

Thanks, Peter!

[Grog]

Try a marine adhesive, comes in a caulking type tube.

[Tim Hancock]

I use West System epoxy. You can order it from Aircraft Spruce & Specialty on-line or buy it from a local marine dealership. Get the slow hardener for more working time. One can add toner cartridge powder from an old printer to dye it black. West Systems Epoxy from Aircraft Spruce

The thing you have to realize is that epoxy once mixed generates heat and if left too long in a mixing cup it will exotherm and cure faster than normal. When trying to pour it into a mold, one must do it in several small batches or you risk generating too much heat which can cause bubbling from too sudden of a cure.

You could also use industrial two part urethanes or silicons.... We mold parts at work with the stuff sometimes and it can be ordered in various durometers. We buy ours locally from a custom mold shop. Might be able to search on-line for these kinds of products.

Another option would be the product used to glue in modern car windshields... It comes in caulk gun type tubes and is black. The only problem is that once it is opened, it tends to cure in the nozzle. If you are careful, you might be able to plug the end and re-use it again for a while. It drys harder than silicon, but softer than epoxy.
Advance Auto Parts: Window-Weld™ Super Fast Urethane - Black (10.5 fl. oz.) by 3M - Part 08609

[john walker's workshop]

sikaflex 292. white or black. rubbery and tough as nails. fisheries supply has it, among others.

[turbo6bar]

If you're looking for cost effective, buy epoxy from stone/granite tool companies.

braxton-bragg.com, granquartz.com

You can use polyester or epoxy, I suppose. I have no idea if either will provide damping. Two types: flowing and knife grade. Flowing is just like it sounds. Knife grade is more viscous.

A premium brand is Akemi (German) which offers a variety of epoxies. I've used the house brands and never had a problem with fixing granite.

Tim's urethane suggestion sounds good.

[gtc]

There are a huge number of electronics potting materials out there that should work for your application. I would probably use a large syringe to dispense it, rather than just trying to pour it.

The ones I've used are urethane based and seem like they'd work for you. I can't remember the name of the product we used, though.

[VincentVega]

I've used lots of Raka epoxy on my boats, Raka, Inc. 772-489-4070 . Great results and much cheaper than some of the bigger names.

However, sikaflex 292 or something similar might be a better fit your application.

[cashflyer]

For potting and bonding, I use a few Loctite (Henkel) products sold under the Hysol brand.

Hysol formulas are available in a variety of viscosities, cure times and hardnesses.


How about this one [LINK]
Loctite® E-60NC™ Hysol® Epoxy Adhesive is a general purpose, electrically non-corrosive potting compound and multi-surface structural adhesive with a 60-minute working life. Black, opaque, low viscosity.

The ad copy says "low viscosity" but it is about 8,000 cP ... probably about like pouring syrup.


Here is the whole catalog: [LINK]

[cashflyer]

Originally Posted by Tim Hancock

I use West System epoxy. You can order it from Aircraft Spruce & Specialty

Tim... have you used their Poly Epoxy?
If so, how does it compare to the West System?

I use Poly Epoxy for repairs to fairings. I like it, but it doesn't have much of a shelf life.

[MysticLlama]

Maybe swing by TAP Plastics and ask them, they have all sorts of stuff and you could custom mix something until you're happy with it. They can also tell you what it will/won't bond to, curing times, etc.

[look 171]

West Marine have stuff like that for boats.

[1990C4S]

System West. And they have good telephone tech support. Just call them.

[Tim Hancock]

Originally Posted by cashflyer

Tim... have you used their Poly Epoxy?
If so, how does it compare to the West System?

I use Poly Epoxy for repairs to fairings. I like it, but it doesn't have much of a shelf life.

No I have not used that, but I have used "Pro-Set" (made by the the same guys as West System... Gougeon Brothers) for doing large layups. A friend of mine, Greg Panzl, who builds Staudacher aerobatic plane clones (Panzl S-330's) turned me on to it for glassing the skins of my One Design wings. AFAIK, he still uses the ProSet for vacuum bagged carbon fiber parts. He still however uses the regular West System for bonding his wood wings.

I have also used T-88 for some stuff, but I have the most experience with West System and used it exclusively to build my all wood MiniMax. There are probably hundreds of brands of good epoxies on the market today across many different industries. I like still use West System simply because I am familiar with their additives and recommended bonding techniques.

I have some old gallon cans of both ProSet and West system stored in my relatively climate controlled hangar and other than darkening hardener, the stuff is still usable.