Epoxy is HOT!

[doninvegas]

I have watched Marc’s video about stabilizing knots with epoxy and one by Charles Neil as well. I needed to do this so I went to the box store and get me some 2 part epoxy. I mixed it up per package direction. I poured it into the knot tapped it off and turned it over. I was putting some in the other side when I saw some of the epoxy leaking out through the tape. I flipped it back over and went to wipe the excess off and that’s when I got burned. None of the videos or any blog or forum posts mentioned that this stuff generates a lot of heat. It’s not even mentioned on the package. Just thought you should know if you didn’t already.

[Vic]

Good to know! Thanks, Don. I've got some nice crotch wood to stabilize. I got the West System stuff Marc uses.

[PaulMarcel]

Epoxy curing is exothermic. The West System stuff with 105 hardener will certainly get warm, but I wouldn't think you'd get burned. Did you use something that cures faster than 60 minutes? Faster the cure, more exothermic. Just curious. I haven't gotten any on me (yet!)

As an aside, the warmer the resin and hardener are to start, the faster it will cure. Here in the desert, I keep my resin in the fridge in the summer. Otherwise, it sets way too fast.

[NYHump]

Epoxy curing is exothermic. The West System stuff with 105 hardener will certainly get warm, but I wouldn't think you'd get burned. Did you use something that cures faster than 60 minutes? Faster the cure, more exothermic. Just curious. I haven't gotten any on me (yet!)

As an aside, the warmer the resin and hardener are to start, the faster it will cure. Here in the desert, I keep my resin in the fridge in the summer. Otherwise, it sets way too fast.

Paul,

Can you send me info on this West System stuff. Where I can buy it, is it available at the big box stores?

Thanks

NYHump

[PaulMarcel]

NYH,

It's the epoxy that Marc uses. I've seen it at Woodcraft and Rockler, but never at a big box.

There's a "West System Kit", but that includes more stuff than you'd need (unless you are going to do some fiberglass boat repair on the side )

Here's the parts from Jamestown Distributors:

Cool thing about the West System stuff is that you mix the components to make the epoxy you need for a project. You'll see that more below.

You'll need the 105 Resin. You always need the resin.

You need a hardener. This is the cool part because you can pick the hardener for your application: fast, slow, self-leveling. I use the fast one even though it can be too fast in a really hot garage (I don't woodwork much in summer; too hot anyway). 205 Fast Hardener.

Thing is, the above keep forever. I bough a quart of resin and pint of hardener. Very nice to have always available.

While the above is all you need, to make mixing absolutely trivial, buy the pump dispensers. Worth their weight in gold.

Other optional things to consider for different situations:

403 Filler. There are many different fillers available for different purposes. For woodworking, I found the 403 the best. You hardly use any so that canister will last a lifetime. You mix a bit into your resin before mixing in the hardener and it thickens up the epoxy to make it work well for gap-filling applications.

There are also things like graphite powder for coloring the epoxy jet black; very useful for stabilizing knots.

While it looks expensive at first, it is still much cheaper than those smaller tubes at the big box stores.

[mlehikoinen]

You can also get the West Systems epoxy from Lee Valley outlets if you don't have a Rockler or Woodcraft store near you.

[samhell]

Some of them get hot, some don't. The stuff you use for gluing in plugs for removable fins on a surfboard gets very hot... I usually put a wet rag over it when I use it. The 5 / 30 minute stuff gets slightly warm but I've never experienced any that I would say was "hot".

[doninvegas]

I used the Locktite brand of 60 min. two part. You messure by guessing. The first time the stuff took forever to cure so I figured I didn't use enough hardener. This time I used "a little" more. It really got hot. The west stuff is pricey and I don't think I would use it ehough to justify the cost. So I went cheap. I'v learned a good lesson.

[Vic]

Don, after I'd spent over $60 on the two part tubes from Lowes', I finally broke down and bought the West System stuff. But, I DO have a couple of large crotch boards to stabilize.

[PaulMarcel]

Don, after I'd spent over $60 on the two part tubes from Lowes', I finally broke down and bought the West System stuff. But, I DO have a couple of large crotch boards to stabilize.

Vic, enough about your large crotch.

Oh, when you first mentioned it was really hot, all I could think of was hardener overdose, but you didn't mention it setting crazy fast either. Guessing sucks for this. Yeah, West System is pricey. Get on JD's email list and you'll find out about sales which often include that Epoxy. Or, that 20% coupon at Rockler (expires tomorrow?) could be used to get whatever is the most expensive of the West System stuff. The measured doses from the pumps makes everything consistent.

I know different epoxies warn that using too much hardener cures it too quickly and loses a lot of strength. Define "a lot", I know.

[Ben H]

True Story:

About 15 years ago when I was a rookie in the car audio biz, I got my hands on fiberglass. I fell in love. Making a MDF frame, stretch the fabric, and make whatever I could think of. Awesome.

Time was always a problem, so we always mixed it "a little hot". Meaning more hardener than what should have been used. Since the whole shop drank soda's like they weren't going to made the next day, we always had a good supply of plastic bottles lying around. Cut the top off and you've got yourself a decent little mixing cup.

Well, anyone who has ever messed with fiberglass knows it gets warm while curing. But, when you mix it hot, it gets.....HOT while curing.

I learned the hard way not to throw away that bottle until it's fully cured. It only took one trash can fire to learn that lesson. Let your resin cure before you trash it, same with epoxy. If you don't, you might get to call your insurance agent.

[NYHump]

NYH,

It's the epoxy that Marc uses. I've seen it at Woodcraft and Rockler, but never at a big box.

There's a "West System Kit", but that includes more stuff than you'd need (unless you are going to do some fiberglass boat repair on the side )

Here's the parts from Jamestown Distributors:

Cool thing about the West System stuff is that you mix the components to make the epoxy you need for a project. You'll see that more below.

You'll need the 105 Resin. You always need the resin.

You need a hardener. This is the cool part because you can pick the hardener for your application: fast, slow, self-leveling. I use the fast one even though it can be too fast in a really hot garage (I don't woodwork much in summer; too hot anyway). 205 Fast Hardener.

Thing is, the above keep forever. I bough a quart of resin and pint of hardener. Very nice to have always available.

While the above is all you need, to make mixing absolutely trivial, buy the pump dispensers. Worth their weight in gold.

Other optional things to consider for different situations:

403 Filler. There are many different fillers available for different purposes. For woodworking, I found the 403 the best. You hardly use any so that canister will last a lifetime. You mix a bit into your resin before mixing in the hardener and it thickens up the epoxy to make it work well for gap-filling applications.

There are also things like graphite powder for coloring the epoxy jet black; very useful for stabilizing knots.

While it looks expensive at first, it is still much cheaper than those smaller tubes at the big box stores.

Paul,

You da man,

Thanks for all the links. Now I have to figure out if buying all this stuff is worth saving a $60 piece of wood;).......

[GNiessen]

The longer you keep a batch of epoxy in your mixing container the faster it will heat up. So mixing only what you need for one section and then pouring it out onto the work surface quickly can extend the working time. And it can get hot enough to melt through a plastic cup.

Epoxy Tip: Using a small postage digital scale is a great way to ensure accurate measurements. Put the mixing cup on the scale empty and zero the scale. Then pour in part A until you have 20 grams (for example). Then zero again. Now you can add 20 grams of part B without having to do higher math.

Most epoxies are equal parts A and B, but some are 2 parts A (Resin) and 1 part B (Hardener). Always check if trying a new brand.

[Dan S]

Most epoxies are equal parts A and B, but some are 2 parts A (Resin) and 1 part B (Hardener). Always check if trying a new brand.

Just adding a little info; make sure you read the directions closely, as the ratio is different for by weight than it is by volume. for example west system is 3 to 1 by volume and 3.5 to 1 by weight.