Bonding aluminum to plywood

[HarmsWay]

I think this has been discussed here but not exactly in the same application as I'm planning. I'm making a smoker for a friend and it will be made of plywood and construction lumber and lined with 16 gauge aluminum sheeting to make it easier to clean. Stainless steel was too expensive. Originally I was planning to bond the aluminum and plywood using red RTV. I figured if it could keep the tiles mostly attached to the space shuttle it should be good enough for this. The internal temperature of the smoker will be under 200 F. A collegue said RTV would outgas too much. So then it was screws, but for some reason 3/8" truss head screws seem to be difficult to find - not to mention it would be a lot of work to screw all the sheets on and it would no longer be easy to clean and the aluminum would easily deform when screwed.

Any suggestions? Is this doomed to fail?

Thanks.

[Tom Slick]

scuff the aluminum really well and use epoxy on it. use a long setting epoxy, not the 5 min stuff.

[Jeffrey Schronce]

scuff the aluminum really well and use epoxy on it. use a long setting epoxy, not the 5 min stuff.

I have used aluminum and epoxied it to white oak to form recessed pulls. They have functioned perfectly. Check the heat issue with epoxy, but I think 200 degrees would be no problem.

[HarmsWay]

Thanks guys!

Bob

[jwaterdawg]

http://www.thistothat.com/

[gary]

Best stuff going!

[mpc]

Another good epoxy is T-88 from SystemThree. It's rated for lots of nasty petroleum chemicals, cures even in cold weather, and survives high temps. It'll even bond to "damp wood" according to SystemThree as long as you "work it well into the surface." I've used it on parts under the hood of a turbocharged engine and it's held for over a year now - that's a pretty hot environment.

It's available at Rockler too if you need it right now.

mpc

[HarmsWay]

Looks like temperature will be a problem. Typically rated for 60-70 C maximum. Oh well, back to screws. Thanks anyway.

[Cheeky]

may want to consider using "green" plywood, without formaldehyde and other toxins.

there is sealants for bbq's and fireplaces, but how about thinset/mortar?

[LCHIEN]

Have you considered aluminum pop rivets?

[maxparot]

First I need to ask the size this smoker is going to be? My father and I made a smoker a number of years ago out of an old refrigerator. The type you'd need is an antique w/ an all metal enameled interior and the small freezer in the top. This type had all metal racks which work well to space out stuff for smoking. To convert it to a smoker simply strip out the freezer and motor, use a hole saw to cut a hole for a 2-3" smokestack in the top use PVC to create the smokestack and use a electric hotplate on the bottom with a steel pan for your wood chips. The gasket on the door should be in good shape to help keep the smoke inside. Oh and 1 very important thing about a smokerbox.....NEVER CLEAN THE INSIDE OF THE BOX clean the racks only as needed. The smoker gets better with use due to the buildup of resins on the interior.

[HarmsWay]

Pete, I never really considered toxins from the plywood, but as the interior will be lined with aluminum it should be an issue. I hope. The toxins in the smoke will probably be a much bigger issue!

Loring, I hadn't thought of pop rivets until a few days ago. The biggest problem there is that I think they would deform the aluminum sheets too much. Plus I'm trying to make it as clean as possible and using rivets would leave a fastener end on both sides.

Max, I looked for some high temperature sealant at the Borg last night and couldn't find any. I gave up easily though. I don't know that I'll find anything suitable for bonding the sheet aluminum to the plywood but I may use something like that to seal the corners. Never considered a fridge. Good idea. My buddy's smoker is mostly built so I'm committed. It's 5' tall x 2' wide x 18" deep with four adjustable metal racks. The top can be removed to load hanging sausages. I don't know much about the smoker part so I'm following his wish list in terms of features. No cleaning eh?

Bob

[HarmsWay]

Another good epoxy is T-88 from SystemThree. It's rated for lots of nasty petroleum chemicals, cures even in cold weather, and survives high temps. It'll even bond to "damp wood" according to SystemThree as long as you "work it well into the surface." I've used it on parts under the hood of a turbocharged engine and it's held for over a year now - that's a pretty hot environment.

It's available at Rockler too if you need it right now.

Hey, I missed this post last night. T-88 would probably do the job although they rate the maximum service temperature at 160 F. The biggest down side would be the cost though, which would be around $250 for the volume I need.

Bob

[greencat]

I use to work for an epoxy mfg. None of it was rated for food contact. Something in the catalyst was considered a carcinogenic. You can ask the mfg for a MSD.

I would use Maxport's suggestion and never plan on cleaning the walls. How about carbon steel or ceramic tiles? The mass would help hold the heat.

[mashtun]

Bonding aluminum to plywood

I have done a lot of thinking about this issue this summer, and I would suggest a different material.

My choice would be Cement board. Will not catch fire, can be screwed on without messing it, then just seal it with Silicone caulk. Most silicone caulk is food grade and some are good for up to 500 degrees.

John