Wood veneer inlay on brass panel - suggestions?

I think you need to stay away from epoxy and use a flexible glue instead. Both the wood and the brass will expand and contract at different rates with changes in temperature (and for the wood) with humidity. This expansion and contraction will cause the veneer to separate from the brass. I would consider using a contact cement - this has a "rubbery" consistency which can accommodate some movement.
The elasticity of epoxy varies. Because System 3 started making epoxy for boat builders, their formulas have some
elasticity since the wood tends to move. Other epoxies don't. I would again suggest calling System 3: you can actually
speak with a human there.
 
I wouldn't worry about expansion/contraction of the veneers given the small sizes your are going to use. When using epoxies don't over compress the joints. It needs some thickness to work well. Vacuum pressing works extremely well as it is totally uniform, even if there are variations in thickness. A shop vac will provide plenty of vacuum, the atmosphere provides the pressure. The suggestion of soaking the veneer in thin epoxy seems like a good way of preventing any brass from getting forced into the pours during later sanding. If you are skilled with a cabinet scraper you don't need to use sanding. Are you going to coat the finished top to prevent the brass from tarnishing?
 
So first attempts came out pretty good.

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Tiles are both 1.5" square. I used DEFT gloss spray lacquer. It seems to want to orange peal on the brass pretty easily, although it's pretty fine. I didn't make any attempt to get high gloss. I'll take a swipe or two on 800 grit and hit it again supper light and see how it goes. I've got a lot of experience with this lacquer on wood and I got to say it love/hate. I really don't want to go for supper-gloss mirror finish on the wood. I want the contrast with the brass. The brass wants to be shiny and needs a coat to keep it from tarnishing. Will see how these two age.

The System 3 clear coat worked just fine. I don't think there is much chance of veneer every popping out. I may try to force temperature and humidity cycles on these test pieces - but not sure how I'd do that. The final work is expected to be something you'd display in a (potentially uncontrolled) internal environment - but could be rain forest or desert anywhere! (I have had to deal with this with my woodworking pieces).

Now for some bigger panels with more interesting patterns.
 
The classic for this type of work is "rubber contact cement". You thinly apply it to the brass, and one side of the veneer. You let each piece dry until it is just past "tacky", usually about 15 minutes. Then you (oh so carefully) place them together with perfect alignment. Once the two surfaces coated with rubber contact cement touch, they are there forever. There are no "do-overs" with contact cement. You can run a roller over it after the two surface are mated to get a very smooth junction.

Other than the two surfaces being clean of any oils, there is no surface prep required on either the brass or the veneer. After they are bonded, and have sat a day... I double dog dare you to try to remove the veneer.. please video tape it if you do, it takes an act of congress.
 
they are there forever
Sort of! Be careful when you apply finish. Lacquer thinner will dissolve most contact cements. A heavy coat of lacquer may cause the corners to lift.
If you screw up when you lay the veneer you can strip it with acetone or lacquer thinner. Probably can't salvage the veneer.
 
That would take a lot of lacquer thinner once cured. Normally I don't mix lacquer with that much thinner.
 
I would try shoe goo possibly thinned with Toluene to make it easier to apply.
Aaron
 
if i were to do this i would use thin super glue and saturate the wood. then when sanded no worries about getting brass imbeded in the wood. if super glue will stick a copper penny to a pane of glass it will surely glue wood to brass.
 
I am not so sure about the super glue for this application, at least not the pure stuff.

Unlike many other glues, super glue (cyanoacrylate) normally works best on two matched surfaces, very smooth surfaces, or surfaces that make intimate contact over large areas It does not work well when there are large gaps to be filled. Does not always work, or work well, on rough surfaces.... Hence, it works on flat glass to flat glass, skin against skin etc. Wood is porous and so normally one wants a glue that will fill the holes and bond via mechanical gripping to the holes. Even things like epoxy does not stick well to very smooth surfaces but at least the material itself it somewhat strong. But works to hole metal to wood if the metal is first made rough. Hence, white glue, yellow glue, etc works well for wood to wood etc.

If you really want to try super glue, I would get one of the gels. These have stuff in them and are not a pure cyanoacrylate (super glue), but more rubbery like an epoxy.

Wood and brass are two very different types of materials and makes the bonding a difficult problem. Keeping the brass out of the wood when polishing is a separate issue, where the wood holes need to be filled with something acceptable, (transparent, hard, etc) prior to the brass getting into them.

@dbb-the-bruce
Your first passes look pretty nice. I suppose if you wanted to really give them your hard environmental test you mentioned, you could temperature cycle them in an oven/freezer. (When I purchased my current house my wife wanted new appliances and so I kept the old oven and installed in in the basement. I some times use it for such experiments.) Temperature cycling would cause the metal to expand contract but once the water is out of the wood head has less effect. However, water is what really makes the wood expand and contract. Keeping the water out is the key. I am not advocating that you do it, but steaming the wood, then drying it would be a harsh test. No mater what you do, these accelerated tests only go so far in predicting the normal cycle behavior. By the way, I am not for sure what your lacquer is made from as there are so many synthetic materials any more, many of which are somewhat soluble in water due to the EPA rules, exspecially paints. Old fashioned stuff was soluble in alcohols, but not water.


By the way, I recently needed a thinner sheet of Aluminum than I had on hand. I only cared about one surface looking nice. It was for a instrument panel and its final thickness needed to sort of match the rest of the panel. So after cutting all of the holes in it that I needed. I milled off about a third of the thickness of the entire sheet of material to get it down to about 0.070. I did this on a backer board with clamping around the edges. However, when I got it out the stresses from the surface cutting were so bad that the sheet was warped like a potato chip. Over a length of about 10inches it was bent about 3 -4 inches. Not to give up, I decided to try to relieve the stress. I clamped the sheet between two sheets of 3/8" steel plate with c-clamps. I then put it into the oven at about as high a temperature that it would go to ~500F and heated it for a couple of hours and then let it cool to where I could handle it. Afterwards it was pretty flat. Flat enough for me to use.

Good luck.

Dave
 
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