[mgalusha]

Has anyone here ever applied wood veneer over metal? I have an ugly aluminum chassis I was thinking of painting but then I thought of veneering it with a nice mahogany or something.

Thoughts, tips, techniques?

Mike

[lonewolfny42]

Mike...Would you mean something like this...?

[JoshK]

Don't see why it wouldn't work. I'd sand the aluminum first.  But before I'd commit to doing it on the chassis, I'd try it on a small piece first.  I'd think contact cement would stick to aluminum but I've never tried it.

I have a couple molded aluminum hammond boxes that I primed and painted.  I was pretty impressed with the outcome.  I just did many light coats and sanded with steel wool intermittanly.  My goal was just to see if I could get a nice looking box for tube PSU's etc for cheap.  The box was $17 I think and primer and paint were $4-5/ea iirc...but I didn't use up the paint so I have it for future use too. 

[mgalusha]

Chris, something like that but I'm thinkng of covering the whole chassis except for the rear panel.

Josh, oh yea, I'll definately be testing first. The chassis is a Bud box and it's pretty nasty in present form. I'm sure with some filler, sanding and paint I could make it look good but I'm hoping to make it look like a full wood cabinet just to see if I can.

[Christof]

Will the enclosure get warm?  If not I would probably do a small test by applying a light coat of dewaxed shellac to the clean metal first to act as a barrier coat and help the adhesive hold.  Then use contact adhesive with paper backed veneer.....just an idea.

[BradJudy]

Mike, depending on the challenge level you're going for, I've got some figured Makore raw veneer that's been sitting on a shelf for a long time. I also have some heavily figured sapelle, not as much, but more than enough for something like this, also in raw form.   Either is yours if you want it and I could bring it down to the RMAF. 

[mgalusha]

Christof,

In this case the warming would be very minimal as it will be a solid state device. Thanks for the suggestion of using a dewaxed shellac as an undercoat. I was planning on cleaning with denatured alcohol to remove all oils and was wondering what might be a good coating for the contact adhesive.

Brad,

Wow, that's a mighty nice offer, I'd love either one of them. I think I'm going to paint the chassis except for the front panel. I took another look at it last night and it's just not rigid enough and I'm afraid the veneer would pop off when it flexes. The front panel is 1/8" material, so it should be plenty rigid enough to resist flexing. I'd need a piece about 20 x 4 or so. That will allow it to overhang a bit and allow flush trimming.

I think you have my cell number but if not PM me so we can hook up at RMAF. I certainly owe you a beer for that.

Mike

[CButterworth]

Wouldn't gluing a thin sheet of wood to metal be asking for trouble?  Afterall, wood and metal have different expansion co-efficients, likely causing your veneer to split.

What I would do is to do something like on the Usher amp, but make the moutning holes in the metal into very short slots to allow for differential expansion.

Charlie

[Daygloworange]

I would be very concerned, particularly with aluminum, about applying a veneer.

CButterworth is right about the expansion rate of aluminum thing. Aluminum is a terrific conductor of heat and expands quite a bit. Wood is a great insulator, and expands and contracts with humidty as well. Bad, bad mix.

The other thing is that aluminum oxidizes. It does so very, very quickly. Almost immediately after cleaning it (via abrasion, alcohol won't do anything in this regard). This aluminum oxide (which is very hard) doesn't allow for proper bonding to the aluminum surface, even if you have a toothed (sanded) surface.

Aluminum is very hard to paint, let alone glue something to it. There are special epoxies for bonding to aluminum, but these are very high performance epoxies ( ie: very expensive ) used in the aviation, aerospace, and transport industries.

I have a buddy that worked for a bus manufacturer and gave me a few samples of some stuff that they used to bond the aluminum panels to the bus chassis in lieu of rivets. The stuff was amazing. If they mis-aligned the panels, and waited more than 20 minutes, they would have to cut the panels off.

I'm afraid your efforts will not yield good results in the long run. It would really suck if you did all that work, and the veneer was to not take well.

Makore veneer is notorious for cracking and checking anyways. Even when it's paperbacked. 

If the case was steel, or stainless steel, I would be more optimistic.

Sorry Mike,     just don't wanna see you waste your efforts.

Cheers

[CButterworth]

Mike,

I would take a visit to your local wood supplier and choose some 4/4 or 2/4 wood.  Something real nice.  Cut a length for the face plate, and maybe for each side plate and mount them to the aluminum chassis.  If you paint is with a black rustoleum enamel paint first, then metal showing at the corners and edges of the chassis could look really good.

Then align your wood panels, drill though them and the chassis.  Then enlarge the chassis holes a little, or make them into slots. This would allow you to mount the wood to the chassis using really nice bolts and the aluminum could expand without stressing the wood.

A nice wood finish say with Danish Oil and wax would look amazing.

I recently made the Cornet2 (Hagtech) and put it in a Quilted Maple chassis:

http://homepage.mac.com/butterworthfam/AudioDIY

Regards,
Charlie

[some young guy]

are you talking about the transcendence amps? if so, why not make wood face plates? then you don't have to worry about veneers.

[mgalusha]

Thanks for all the input. I did a hard maple faceplate for my last DIY preamp and it came out very well. In this case I've already machined the AL plate for the front and really didn't want to make another from wood. Part of the reason for that is this piece has a digital display and three  small buttons. I have already machined some brass buttons that work very nicely in the AL panel but it wouldn't be a problem to turn up three more long enough to extend through a solid wood panel.

I have decided not to attempt to veneer anything except the front panel and perhaps I will not attempt that either. The piece won't run warm, so there won't be a huge amount of thermal expansion but of course there will be some since AL is so efficient at transmitting heat. I can of course just paint the panel and it would look fine but I like wood. I have some maple, oak and birch on hand but nothing exceptional. Perhaps a visit to a local supplier is in order.

Mike

[some young guy]

So I'm looking at doing this same exact thing now and I'm wondering if you went through with it. If you did, can you give me the run-down on how it went. I would surely appreciate hearing about any pitfalls, advice and outcome.

[nodiak]

You might want to consider making panels by applying the veneer to thin plywood (ex. .25" BB) first. Could attach these panels to the amp with a few lines of thick adhesive, or screw on. Trim panels edges with solid wood (maybe just .25" strips) or make solid corners. Could avoid the metal/veneer issues.
Don 

[JoshK]

Mike if you machines the AL already then you could use that piece as a pattern for cutting the wood with a router using a pattern cutting bit.  Would make it simpler. 

[mgalusha]

Wow, was surprised to see this old thread pop up. I ended up never building the project. It was going to be a preamp with a remote stepped attenuator and when I decided to go with a modified DCX this wasn't needed.

Josh, I had actually machined the panel on the mill and it would be pretty easy to use it as the master to make a pattern from wood but it won't ever happen, at least not in my current setup. Of course that will likely change at some point so never say never.

[TomS]

....so you have your own mill?  Must be nice   

I eyed one of those little Chinese mini mill/drills but even I (the master of rationalizing) couldn't justify that one.  It would be really cool to play with though.  Uh, I better stop thinking about that.

[mgalusha]

Tom, I did purchase one of the Chinese square column mills and a 8 x 14 lathe a few years ago. My wife asked what I was going to make. The only answer I could provide was "whatever I want". Not the last word in quality but so far they have been OK for the kind of things I build. Fortunately I have a good friend who owns a CNC mill and teaches machining at CU Denver, so for those things I just can't make, I call him and grovel.