Confused by epoxy

[Victor Robinson]

Specifically, West System.

I'm making a coffee table out of reclaimed wood, and the boss has requested that cracks and gaps and knots in the wood be filled, but since they add character, we're looking to fill with something as clear as possible.

I figured West System epoxy might be a good way to go, but having never worked with the stuff before, I'm a bit confused as to which product(s) would be best for this application. I'm looking at their offerings on the Lee Valley website...any help would be appreciated.

http://www.leevalley.com/US/wood/pag...110,42965&ap=1

[Thomas S Stockton]

go to the west system web page they have a lot more info http://www.westsystem.com/ss/

[Kent A Bathurst]

I think you want the 205 or 206 hardener. How fast do you want to it to kick?

On a related topic - when I use epoxy, I mix it up and spread it out on a plastic picnic dinner plate, then set the plant on top of a pan full of ice. That brings the cure rate to about zero - plenty of time to get it applied, then the temp rises, and off we go........So I wouldn't worry with either hardener system, if you take that route.

Caution: if you use, say, a baking pan from the kitchen, and SWMBO is home, put the pan in a plastic trash bag, then put in the ice, so the pan is protected. If she is not home, you don't need the trash bag, because you won't have all the drama to deal with while you are working it up.

[Mike Ontko]

Kent - it sounds as if there's another story hidden between the lines of your cautionary statement

[John Donhowe]

Ooooooh! I like that ice trick- nothing quite as exciting as racing to get epoxy on your project while it's beginning to harden Any reason that wouldn't work with Bondo, as well?

[Allan Speers]

On a related topic - when I use epoxy, I mix it up and spread it out on a plastic picnic dinner plate, then set the plant on top of a pan full of ice. That brings the cure rate to about zero - plenty of time to get it applied, then the temp rises, and off we go........

Say, that's a great idea, Kent !

[Allan Speers]

Victor,

Using clear epoxy on very small knots & defects works great. However, be careful if you need to fill larger areas & cracks, because most epoxies don't have any give to them, and so the repairs can crack later.

One epoxy product that definitely does flex is "Gluvit." http://www.marinetex.com/gluvit.html

[Victor Robinson]

Alright, fast-cure kit it is! (thanks to Kent's ice trick)

I was probably overthinking this...got confused by all the fillers and additives.

Thanks gang!

[Steve Peterson]

You will probably want to mound up the epoxy and sand it off so it is flat. It will try to self level, so it really only builds up about 1/16" above the surface. It is OK to go back and fill in a few holes where the epoxy kept flowing into the hole. Add a piece of tape to the bottom side if the holes go all the way through. This will avoid you having a coffee table glued to your workbench. Flip it over in an hour to fill in the holes on the bottom.

Epoxy sands fairly easily, but may be harder than the surrounding wood so you will have to be careful to not dish out the wood while sanding. You may want to sand the "overflow" epoxy completely if you are planning to stain. Normal finish doesn't look too bad over epoxy, but stain may react differently to areas where epoxy soaked into the wood if it isn't completely sanded out.

Steve

[Jim Dwight]

I use cheapo 5 minute epoxy from Harbor Freight. It is pretty clear.

[Peter Quinn]

Use the 105 epoxy and the 207 clear hardener for the best knot filling properties. If this is for stain grade projects, the other hardeners produce through their reaction and cure what is called aniline blush. It gives a slightly cloudy appearance to the cured patches, but more importantly it is caused by a water soluble wax that forms as part of the curing of mot epoxies, and that wax will cause problems with clear finishes that go over it. I learned this the hard way. You can remove the surface wax by scrubbing with warm water, if you don't you will get craters and fish eyes where you used the epoxy, best to avoid this. They sell the 207 hardener in some pretty small quantities, so if you plan to do some less visible structural work with epoxy you could certainly use the appropriate speed of hardener for your climate conditions and work process, but for filling and priming the 207 is best.

[Allan Speers]

Epoxy sands fairly easily, but may be harder than the surrounding wood so you will have to be careful to not dish out the wood while sanding.
Steve

Indeed. For this reason I like to use a scraper, or even just scrape with a razor blade.

[Andrew Hughes]

Here's the stuff I use I don't remember how much it cost but I remember it's expensive.The bigger the batch the faster it hardens so Kents ice trick is a good one.

[Kent A Bathurst]

Kent - it sounds as if there's another story hidden between the lines of your cautionary statement

I don't think it was hidden at all, Mike.

I just do what I can to pass on lessons learned to my fellow adventurers...........avoiding the drama is always worth the effort, IMO.

Or, consider buying "your own damn stuff", as it was once suggested to me. Hence my own:
> iron [premelt edging];
> double boiler [heating oil, beeswax, a mason jar with leftover cold coffee, etc.];
> a roll of waxed paper [for obvious reasons].
> second hand yard-sale coffee grinder [shellac flakes];
> and one of those "one time" aluminum cooking pans at the grocery store for the epoxy ice trick.

I still borrow the nutrition digital gram scale for shellac mix.....but I get the evil eye each time she slooooooowly hands it to me......cover it with a big sheet of waxed paper, even though shellac flakes are a solid, and are edible.........

But - all of these items together don't come close to the last plane I bought - LN 4-1/2C, here on the creek. So - what the heck? Keep the peace, no drama.

[Kent A Bathurst]

Here's the stuff I use I don't remember how much it cost but I remember it's expensive.The bigger the batch the faster it hardens so Kents ice trick is a good one.

It is an exothermic cure - gives off heat, which accelerates the cure.

So - one big lump in a mix cup versus spread thin on the plastic plate - that slows it down right there. Then the ice takes care of the rest.