Bonding Wood to Aluminum

[majohnson]

I working on a sign and it requires bonding an aluminum overlay on a pine background. The owners like the Beetle Kill Pine for a rustic look. Signs totaling 4, are both indoors and outdoors.

[donek]

I working on a sign and it requires bonding an aluminum overlay on a pine background. The owners like the Beetle Kill Pine for a rustic look. Signs totaling 4, are both indoors and outdoors.

Aluminum is very difficult to bond as it generates an oxide layer almost as soon as it is exposed to air. We work with a material treated for bonding in our snowboard production. Minimums are extensive and lead time from the manufacturer in Austria is 4 months.

When laminating most aluminums it is necessary to perform an acid etch shortly before laminating with epoxy if the material has not been treated. Our bonds are structural in nature, so must be extremely strong. You may find another solution, but I would not expect the bond to be very long lived.

[gc3]

http://www.woodweb.com/cgi-bin/forums/cabinetmaking.pl?read=759363

[Xray]

I have had good luck bonding thin aluminum to mdf with 3M spray adhesive. You need to soak both pieces pretty good, wait a few minutes for it to get tacky, then join them.
After an hour or so I couldn't pry it off it I wanted to.

[joe]

Now that's a tough one to pull off.

It can be done but not easy. Here are some of the considerations. For outdoors there will be a difference in expansion rates from wood and Aluminum. Through bolts can be used as long as there are allowances in hole diameters.

Without knowing more about the project, sized, thicknesses, materials to be used any advice is would be sketchy.

A mature sign artist will try to advise the customer against calling out for potential disasters. It's seldom when a customer knows the proper materials for lamination. For that reason I almost NEVER let a client work me into a corner like this.

www.normansignco.com (http://www.normansignco.com)

[brian]

I've got another question.
Would powder coated aluminum letters bonded with marine adhesive to a sealed wood have the same problems?

Brian

[donek]

I've got another question.
Would powder coated aluminum letters bonded with marine adhesive to a sealed wood have the same problems?

Brian

I would check with the powder coater. You may get the epoxy to stick to it, but how well does the powder coating stick to the aluminum. If you cut the aluminum after it's powder coated, you may have peeling issues. You still have that expansion issue. You need a rubbery buffer zone between the two materials.

[brian]

So a high grade silicon would work.
The aluminum is used for traffic signs and the edges would be painted.

Brian