Bonding Aluminum to steel??

O

OJ86

Promoted Users
I have a buddy that wants to put some prefabricated vents on his hood. The vents are made of aluminum and the hood is steel. My plan(as if I ever have one) was to cut the holes in the hood, crimp the edges of the hood around the holes creating a recess, prep with a 36 grinder and use glorious amounts of bonding adhesive to create a bond and barrier between the metals. sound good? I just dont want a reaction between the metals over time.

I've included a pic. Yes its a Saturn Sky LOL, but it has a 1000hp LS7 twin turbo setup in it, so the racey vents are OK!
hoodvents.jpeg
 
I have only used adhesive for collision type work. I currently use IES, but several years ago when I still worked at a gm dealership we had a 3m rep come in and he was telling us that the adhesives had microspheres in them to prevent in his words over clamping and allow for joining dissimilar materials. I've always prepped my flanges with 36 grit and applied adhesive straight to bare metal, but in a situation like this I wonder if you could epoxy the flanges, give it 3 or 4 days, then scuff with a red scotch bright and glue together. the epoxy would definitely give a piece of mind for preventing galvanic corrosion. Maybe some else has experience with adhesives on epoxy, curious to hear others thoughts.
 
I've bonded the 2 metals together with 3-m 8115 panel adhesives before with no issues. Make sure each surface gets at least a thin amount spread over every inch of it with a popsicle stick or other spreader & it will be fine. Nothing wrong with coating with spi epoxy first & 2 days drying time, but don't see it needed as the panel adhesive is epoxy also.

Only issue I've seen with panel bonding such a project is you can never expect to hide a flanged seam from shadowing if you ever wanted to do so.

Ps , I've recently used several packs of finishmaster's smart line adhesive , which is about 33 bucks as opposed to forty something for the 3-m. Can't tell a difference.

Always wanted to build an LS powered sky myself.
 
The SMART brand is all I use for bonding adhesives. Infact, I use all of the smart brand products minus the primers and paints. No complaints from me about that line of stuff.
 
I havent seen the pieces yet in person. I'm hoping they are somewhat thicker and I can taper off the edge in an effort to avoid the line from ghosting back.
 
Ya, you are probably right. Maybe Ill insert them and bodywork is to where there is a line already and it just looks like an insert.
 
only good stuff I have used is 3M scotchweld, but it has to be baked.

I would add to the design with rivets and just drill a hole every 2 or 3 inches and pop them in. If you choose this route, just make sure you use rivets with aluminum mandrels so the center that sometimes stays in wont be rusting after the first rain.
 
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