I mentioned in the previous entry, my intent to use an 1/8” endgrain veneer on the table top. Rather than dive in head first (and break my neck), I thought it might be a god idea to make a small sample to test the viablility of this.
I cut a few pieces of endgrain birch, and glued them up on some scrap Extira. A few days ago, I applied the epoxy, pouring it on, and warming it with a heat gun to thin it, and allow better penetration, as the goal is to have it fully penetrated and bond the veneer to the substrate. After curing for a few days, I mounted the sample on the CNC, and routed about .01” off the top. Got a nice, smooth finish.
What I really needed to see, was if the epoxy went all the way through. So I routed away half of the sample, and left about .01” of the endgrain left on the substrate. Success!. You can see the spots where the CA glue was used to attach the pieces, as it started to tear away. But everywhere else, where the epoxy penetrated, the veneer is still attached.
Just to be sure the epoxy did penetrate into the Extira, I made two more passes of .005”, just slightly into the Extira. You can see the spots where the CA glue was, and you can clearly see the epoxy everywhere else. So I’m confident I can move forward and I’ll have a good solid bond.
Now, here’s the bad part. This is a lot of work. I spent about 4-5 hours, and got about 7” covered. The table is about 60” long. Although the first row took quite a bit longer than the rest. The rest of the rows go fairly fast.
One problem is that because the scrap I’m using is fairly short (~12”), I really couldn’t plane or joint it. The majority of it was exactly 3/4” thick, but a few pieces vary a little. For the width, I cut them on the table saw, using a caliper to try to get the fence set to exactly 1-1/2”. Due to tension in the wood, the width varies a little as well. The end result is a few very small gaps here and there (less than 1/64”) which I may fill with some slivers, or an epoxy sawdust filler. Hopefully I can get the top done in the next two weeks. I need to do the epoxy on a weekend, as I’ll need to keep the garage warm for at least two days for it to cure, so I’d rather be working in the garage while I’m paying to heat it. It’s warm today, but it’ll be back to around 20° by the end of the week.
-- Gerry, http://g-forcecnc.com/jointcam.html