Gluing brass

That's beautiful, Michael.

Since the thin brass doesn't appear to overhang anything, the peel issue shouldn't be too bad.

We used the stuff in spray guns, I still remember not being able to remember.

Sand the brass. I'll bet this is shim stock? They coat it with some kind of plastic stuff to prevent it from tarnishing. I photoetch shim stock and couldn't get the resist to stick or the etchant to etch the stuff until I sanded it first.

Jon

Thank you.

The reason I am going through the trial again is that during one of those processes the whole brass face just popped off. Today I am sad to report another failed trial using the scratch-in technique. There was not even a pretense of adhesion. I am running a few more test pieces with different scrap brass and two different epoxies. I am also running steel-to-steel parallel trial as a control.

After that it is the turn of the solder paste...

That is what I meant by "abrade". Press-n-Peel sticks to mine OK.

Jeez. You're snake-bitten on this job. Something is funny here, because, even with vulnerability to peel, no adhesive appropriate for metal should just "pop off," especially after you've given the work some tooth. You may not be getting much chemical adhesion but just the mechanical adhesion, alone, should prevent that from happening.

Now it sounds like an adhesive problem. What adhesive are you using?

Excellent. Tests are good.

Ok, but after looking at the photos, I'm wondering why you're using such thin brass stock. It looks like you're doing it the hard way, but maybe there's something that isn't apparent from the photos.

What about contact cement? Either Pliobond or Weldwood. (It might take it a while to dry properly given the metal film which the vapors have to go out through.

Good Luck, DoN.

That is what I meant by "abrade". Press-n-Peel sticks to mine OK.

Thank you.

The reason I am going through the trial again is that during one of those processes the whole brass face just popped off. Today I am sad to report another failed trial using the scratch-in technique. There was not even a pretense of adhesion. I am running a few more test pieces with different scrap brass and two different epoxies. I am also running steel-to-steel parallel trial as a control.

After that it is the turn of the solder paste...

I wonder if you'd have better luck if you brush-plated the brass with nickel or tin.

Looks like this may have to be explored. BTW my reply to your PM was bounced. Your points were noted, thanks.

OK, is that a heat application?

No.

I continue to scratch my head over this one. Is the popping-off happening when you subject the assembly to a significant change in temperature? The thermal coefficient for brass is around 40% greater than that for steel. Although a 0.006"-thick sheet of brass isn't going to develop a lot of shear force, it could be enough, if heat is an issue.

Otherwise, I suspect your epoxy. I assume you're not using one of the quick-cure types, "5-minute" or "10-minute" stuff, because that's all but useless for making a permanent bond to metal.

A normal amine-cure, hardware-story epoxy adhesive, like Elmer's, ought to do the job. But, again, I think you'd be better off with a laminating adhesive than with epoxy.

maybe it's time for 1700s technology - have you tried soft solder? Tin the brass sheet and solder in an oven - it's not hard to get to 640 deg - a sheet of stainless on top and a clamp will make sure it's flat, proper surface preparation and tinning will ensure a complete bond

--Happened by TAP Plastics yesterday and they sell 2-sided sticky tape, industrial grade, in 2 different thicknesses. Maybe one of them would be worth a try?

Pop off? My suspicion is that the pieces are not clean enough. It can be surprisingly hard to get *all* the grease et al off of things.

Joe Gwinn

You me and all!

This is getting curiouser and curiouser. Yesterday I thought I would try gluing different brass to the same steel just to see what happens. I found two scraps - one from a candle stick from a garage sale and one from a unidentified plate I had for years. I did two set ups with steel-to-steel controls, one with JB Weld and one with Devcon 2-ton epoxy (I wish this one worked - it is clear and relatively low viscosity, therefore easy to spread over large areas). Today, after 24 hours of curing, I could not separate either of the JB Weld joints by hand. The Devcon joints could both be separated with moderate degree of force. Thus it is not the brass per se but *this* particular brass. It's not like the glue sticks to it in patches, it seems to positively repel any sort of glue.

I thought that if there was some weird coating on it it should show by the way it takes solder. I took a piece and cleaned half of it with 120 grit and left the other half intact. I coated both halves with flux and put a small pallion of solder on each half. Both pallions melted and flowed easily coating the foil flawlessly.

In the end the answer may be simply to use different brass. All things considered I would rather avoid using heat in this particular application and 0.006" foil is a pain to work with anyway. By now however, I am obsessed with finding an answer to this irritating problem.

You've really got me on this one, Michael. I can't imagine what's going on, unless there is some kind of coating (possibly a protective coating applied at the mill) that's just not coming off with normal cleaning and abrasion.

FWIW, regular JB Weld is only 30% - 40% epoxy. The rest is filler -- calcium carbonate, a little iron, and some polymer or other. If that's working better for you than the Devcon, then something is doubly strange.

I'm glad to hear you're obsessed about it, however. That means we'll probably learn more from your efforts. d8-)

Good luck. There has to be something unsuspected going on. Brass isn't that hard to glue, once you've gotten under the transparent layer of oxide.