Epoxy Help

[Pbmaster11]

I'm new to the epoxy scene and would like some advice.

Why use it?

What to buy? Ive been seeing alot of West Systems. Two parts to the equation? Please explain?

How to apply?

Advantages? Disadvantages?

[iSawitFirst]

Because of its cost, I try to use it only for gluing things that PVA glue won't work on and for filling gaps. You can buy it with different cure times but I most often use 5 minute.

I've used it for filling knots, gluing lead to wood and when my zero clearance plate became not-so zero clearance, I filled it with epoxy and re-cut it. Some use it when a wood joint will undergo a lot of stress, but since a PVA glue joint is stronger than the wood, it seems to be an over-kill. I believe Mark used it to glue an end grain-to-end grain joint with loose tenons. Probably a good idea.

[PaulMarcel]

I'm new to the epoxy scene and would like some advice.

Why use it?

Great rigid strength; can bond to more materials than PVA. The rigidity is also a weakness: if your design relies on some give, it won't.

What to buy? Ive been seeing alot of West Systems. Two parts to the equation? Please explain?

I like the West System stuff. Got turned on to it my Marc a couple years ago. Reason? I like that you buy one resin then alter the epoxy by choosing from different hardeners. I buy the resin by the quart. I just recently bought my second quart and my first is still going strong. It keeps indefinitely as long as you keep the two parts separated

Two parts: it cures chemically, not through evaporation. The exact makeup of the epoxy is, from what I understand, a closely guarded secret. Hardeners from one brand may or may not harden the resins of another (and if they do, it may not be a good cure). Stick to one vendor.

If you are at all familiar with Bondo (body filler), you mix the hardener into the paste, after you mix, it cures to a rock. Epoxy is the same thing (literally); bondo is epoxy with, hmm, blanking... nylon I believe.

How to apply?

Mix EXACTLY as specified by the maker. If you remember chemistry, the forumla only works if all the parts are there. Usually vendors will state that too much hardener will make a brittle result, too little a matrix of hardened epoxy with goo. Get it close and you're okay, but the point is "winging it" fails.

I usually use a silicone pallet stick because epoxy doesn't stick to high-energy plastics like silicone (or most CD cake-box containers; mixing bowl!). If you need to brush it, use an acid brush you plan on throwing away when done.

I usually paint some onto a scrap and set it aside after gluing up the main project. Once the thin coat on that offcut is hard, I'll give the project another 30 minutes in clamps. before considering it ready to go. You don't want to go by any left-over epoxy in the mixing bowl as a thicker mass of epoxy cures faster than a thin swipe.

Advantages? Disadvantages?

I like that I can use West System's slower hardeners like 206 and 207; I live in Arizona and ambient temperature exponentially affects the speed of epoxy curing (hence why a blob hardens before a thin swipe; the cure is exothermic). Having a hardener designed to give me 40 minutes of open time is amazing out here. As a rule, out here, any glue that states an open time of X to Y minutes will actually have an open time of X/2 in Arizona; stuff seizes immediately.

Disadvantage: if you are gluing up open-pored wood, squeeze-out will setting in the pores. Ply pushed into a dado may wick epoxy between the plys and this may be visible depending on your finish (any oil-based finish will hide this).

It's a great glue, though

[Pbmaster11]

Thank you both for the replies.

So my next question, what do I need to buy to get started? Obviously a resin and a hardner? Which ones?

I live in North Dakota and my small shop is in a small two stall garage.

[Vic]

Exactly what Paul said. He's a wealth of knowledge! Also, during the curing process it gets HOT...very, very HOT. Be careful where you sit it down. I mix in little dixie cups, which I keep a very close eye on. I think they could spontaneously combust. THAT would not be good.

[iSawitFirst]

Since I use such small amounts infrequently I buy "5 Minute Epoxy" made by ITW Performance Polymers. It comes in a double barrel syringe looking applicator, one for the resin, one for the catalyst. I just squeeze out what I need and mix (quickly).

[PaulMarcel]

Thank you both for the replies.

So my next question, what do I need to buy to get started? Obviously a resin and a hardner? Which ones?

I live in North Dakota and my small shop is in a small two stall garage.

Sorry I intended to put that in the posting.

There is actually another thread on West System epoxy where I likely typed too much. But here's a shopping list from my favorite purveyor:

- 105 resin

- 205 hardener ("fast" hardener will likely work well for you except maybe in summer when you actually will have to move fast... slower than PVA still)

- Measuring pumps; may sound like a convenience, and they are, but do you plan on weighing the stuff? I graduated the pumps further to get half units as that is typically exactly what I need; a full pump is too much.

- You might find a need for the extra-clear hardener; epoxies cure to a light yellow. I don't remember the hardener number (208?)

- 404 filler; if you need to fill any void, this stuff is structural. Many other fillers they sell are designed as filletting fillers.

Okay, the purveyor is JamestownDistributors.com. I normally like to put hyperlinks in the posting, but just realized I have to leave for an appointment!

[Robert T.]

How do you color or dye the epoxy to match. Say you were filling a knot hole or crack.

[PaulMarcel]

Transtint dye can be used to color the epoxy. Adding sawdust to it will work, too, like any glue. If you are mixing in color or sawdust, mix it in the resin _before_ adding the hardener. There's no clock until the hardener is in it.

For a deep crack, I've poured it on and pushed it in with the silicone stick (any popsicle stick wil do). Then wipe it off the surface hard enough so there isn't epoxy to the topmost edge. Let it cure then follow up by beading hide glue into the crack, let it set a bit, then sand across the crack. I like that method better since the hide glue finishes well, could be easily removed if you don't like how it came out, etc, but you still get the crack stabilization.

As a rule, stain and dye won't adhere to epoxy; I'm guessing you could shellac the epoxy patch first then stain or glaze over it, but I haven't tried that. For a knot, black additive works the best. If you use a black dye, it's like black semi-transparent glass filling the knot. If you use black additive (carbon powder), it is absolutely pitch black and opaque, like the chunk of missing knot.

[ztifpatrick]

I'm new to the epoxy scene and would like some advice.

Why use it?

What to buy? Ive been seeing alot of West Systems. Two parts to the equation? Please explain?

How to apply?

Advantages? Disadvantages?

You should look at System three T-88 epoxy too, it has a long open time for furniture and is stronger than 5 minute. Another thing I like about it is it's mixed in a 1:1 ratio as opposed to the West I had which was 5:1. IMHO its harder to mess up a 1:1 ratio. Clean up is with white vinegar. One last point about epoxy, you have to be careful to wear gloves, don't get it on your skin. You can work with it for years with out a reaction, but if you have too much skin contact you risk dermatitis, once that happens you can't go near it without breaking out.

[jbratton]

I'm new to the epoxy scene and would like some advice.

Why use it?

What to buy? Ive been seeing alot of West Systems. Two parts to the equation? Please explain?

How to apply?

Advantages? Disadvantages?

I use the West Systems epoxy when I build my kayaks with the fiberglass part of the job. Just some 5 minute epoxy for general woodworking should be enough for the average woodworker who is not doing any glassing.

Also store it in the refrigerator for a nice long shelf life....be sure it is warm before you use it otherwise it is slow to cure. BE SURE TO MIX COMPLETELY! stir stir and stir some more!