Adhesive for bonding aluminum to cast iron

Bonding aluminum to steel can be tricky due to the difference in coefficients of thermal expansion. As the temperature changes, the bonded pieces will pull against one another if rigidly bonded. The bond will be the loser, and the piece will just pop off one fine day, for no obvious reason.

Solutions? The best solution is mechanical, using screws.

Failing that, use a slightly soft adhesive, one that can flex without breaking. Or, bond a piece of steel to the iron (thus matching coefficients) and run screws into the steel. And make sure that the surfaces to be bonded are roughened and *completely* clean.

Joe Gwinn

Silicone sealant is cheap and easy to find. You would want to use some of the stuff that does not smell of vinegar, I think. Sensor safe sealant from the auto parts place.

PRC two part sealant would work better. Commonly used to seal aircraft structure and fuel tanks. (PRC Desoto, maker, probably want a B-1/2 version, with a half hour set time.)

You may be able to scrounge some from an aircraft mechanic, as it has a shelf life, for certified use. Still quite usefull after it's expiry, just not legal, so it tends to not get thrown away.

Cheers Trevor Jones

Ask for "5200"

Hey Louis,

One of the best "glues" is the stuff that is used to fasten rear-view mirrors to car windshields. You can get both a primer and an accelerator for it, although I don't know why as it "sticks" pretty good and fast.

If thermal expansion co-efficient's are going to be a problem (I doubt it on a Seig), then fastening one end of the scale quite solidly while allowing the other end to be held but allow linear movement should work.

Take care. Good luck.

Brian Lawson, Bothwell, Ontario.

Have you given any thought on how you will get it off when you need to? I have used Liquid Nails in the past with sucess

You might try some VHB tape. Pretty impressive stuff!

"I'm not grown up enough to be so old!"