Adhesive for metal

Robin Croskery Howard <robin.croskery<-at->gmail<.>com> writes

>I am searching for the appropriate adhesive for metal.  I am
>currently working to re-adhere a trigger guard on a late
>eighteenth/early nineteenth century pepperbox pistol.  ...
>...
>I have done some research on B-48N and Butvar B-76, but not come up
>with anything conclusive.  Does anyone have any suggestions for the
>best metal to metal adhesive?

First, where is the trigger guard broken?  Is the old repair stable?
If so, you should probably leave it alone.  Use a UV light (short /
long wave) and see if the old adhesive fluoresces.  The color under
UV light can be a fairly good indicator of what the old adhesive is.
You'll also have to solvent test it for solubility.

For most situations with metals the methacrylates such as B-72 and
B-48 are poor structural adhesives.  Usually the best approach is,
after cleaning, to apply a dilute 10-15% coating of B-72 to each
end.  Then you can use an epoxy to mend the break.  Then do any
filling and inpainting as needed.  This will allow you or someone in
the future to reverse the mend if needed.

For broken metal that is structural, that has to support weight,
like a chandelier arm, you have to consider doing a solder repair
using a low-temperature solder, if possible, depending on how strong
the mend has to be and if any historic solder joins are near it.
Iron, steel, and cast-iron structural repairs may require
welding--that is best left to a professional after a thorough
discussion with a conservator.

I am teaching a new online course on the "Care and Conservation of
Historic Firearms" again next week starting on Jan 26, 2015.  If you
are interested see

    <URL:http://firearmscareclass3.eventbrite.com>

David Harvey
Senior Conservator and Museum Consultant
Los Angeles CA


                                  ***
                  Conservation DistList Instance 28:33
                 Distributed: Friday, January 30, 2015
                       Message Id: cdl-28-33-001
                                  ***