Epoxy Inlays - where did I go terribly wrong?

[eagle55]

A couple of weeks ago I tried a v-carve in Brazilian Teak and wanted to try an epoxy inlay.  Used MAS table top and some liquid dye that I had purchased off ebay a couple years ago.  It turned out ok and smooth like you would expect but with a very dark wood, it was too transparent and didn't show up very well.....  but looked smooth and sanded down and acted as expected... just not the color effect I was looking.  I wanted an opaque color.  Not remembering exactly what I had, I went to the Woodcraft store and talked to an "expert".  He told me he uses Alumilite Clear Slow and always uses mica powder colors and recommended Black Diamond powders.  Glad to follow and expert's advise I bought some and some colors and gave it a try on a test piece that I had done in the same wood.  Everything looked great, epoxy sucked down into the engraving a looked great.  I tried the torch method of bringing out the bubbles but with the 12 minute work time, it didn't seem to do anything like the MAS Table Top epoxy did that I had used before.  It seemed as though it was already setting up but it didn't appear to have any air bubbles trap and the pours were solid and smooth and now to the point of being just tacky.  Went to bed and was looking forward to milling down and seeing what various colors had done in the morning after curing to sand-able point.  In the morning I went to see what it looked like and instead of the glass smooth, slightly overfilled engraving I had left the night before, I saw what I would describe as a festered foam full of air bubbles.  Still hoping it might just be on the surface I milled it down but wasn't very encourage.  Well, after cutting down to wood level it still looked like foamy shit.   At this point, I am at a loss as to what went wrong.  At first I though, well obviously there was a chemical reaction that was going on with the wood.  But I remembered the MAS table top and how well it had done in the same exact wood.  I didn't seal either one of the tests projects and though that might have been it, but since the MAS table top didn't react anything like that, I begun to think it was something else that I am grossly overlooking.  Hoping to find an epoxy inlay fount of knowledge that can get me back on the right road

[loren]

The  bubbles are probably air escaping from the wood grain. When you do a v carve for an inlay, you are basically pouring epoxy into end grain and each of those little pores have air that can bubble up into the epoxy. 

I find that a quick coat of shellac after carving does the trick to seal up those pores and avoid subsequent bubbles after the initial flashing. 

[eagle55]

That was my initial thoughts also but I almost discounted that theory because I had don the exact same carve in the same wood when I used the MAS table top epoxy and didn't have any of that. Now to say this, I may have discovered my problem but it may be a few hours before I know. For many things like my AR8 and my Saw Stop, I am a stickler for following instructions (because of the high cost of mistakes), but I may have rushed into my epoxy extravaganza. I went back through everything to realize that MAS is a 1:1 ratio by VOLUME where Alumilite and maybe most of the others are 1:1 ratio by WEIGHT. I have redone my test piece and this time mixed by weight instead of volume. Have already noticed that I had much more time to torch the air bubbles out and have done it 4 times. Hoping this may be where I went astray.

[eagle55]

After doing the mix by weight instead of by volume in the second test as mentioned above, it provided the same crap results. To determine if I was totally insane, I tried the same test with the MAS Table Top and although I still have some work to do on my graphics and coloring, it did provide decent results, as was indicated the first time I tried it. So I decided to call Alumilite and beg for instructions of where I am so far off track. After describing my results, she instantly knew the problem. Turns out what I had was a clear urethane casting resin, which required a pressure pot or vacuum chamber in order to keep the bubbles from forming or evacuate the bubbles when they form. She explained that it was because of being the "wrong product" for what I was trying to do, which is "epoxy" inlay. I kind of think the guy that was recommending it as the one he "preferred" either misunderstood what I was wanting to do, or possibly even that I didn't clearly state epoxy inlay (but I really think I did) I might use this for something at some point but don't have a pressure pot or a vacuum chamber and really don't want to get into casting if thats what it has to entail. I used casting resin years ago for hobby stuff and never had to have all that. Not sure what kind of resin that was but never did anything but mix, color and pour. Anyway, for now I will go back to the MAS product and work on techniques and coloring.

[raven]

You didn't say that when you purchased the epoxy that it was meant for WOOD. Use an epoxy that is meant solely for WOOD and to remove those air bubbles I use a heat gun set on 600 degrees. I give it a fast pass, until the epoxy turns liquidy (like water) then double check the level. I always over fill so if the wood sucks some in then no problem. After 3-4 days, I go back and level with my CNC or whatever means. Then sand from 120 grit down to 3000 grit, don't skip grits, then with automotive scratch remover I buff until it shines.

[pedro]

1) For opaque colors, I use "Armor Art Opaque Epoxy Pigment" , form Amazon, I used Turquoise, red, white, black...they are EXCELLENT, just a few drops and the epoxy turns opaque with a bright color

2) Bubbles, are not an issue with a heat gun. Torch can be too much for what I do (charcuterie boards), so I stick with the heat gun, about 800F and 10 inches distance...several passes until I don't see the pops happening anymore

3) Something you did not mention...bleeding. I tried it all, and the best solution is to apply a thin skin of epoxy with one use brushes... and then pour the colored epoxy the next day. This has a secondary benefit: it covers the pores so that the wood will not introduce more bubbles when you pour it.