On 12/14/2010 3:57 PM, wrote:
On Tue, 14 Dec 2010 15:23:41 -0600, The Daring Dufas
wrote:

On 12/14/2010 12:06 AM, Willie The Wimp wrote:
On Tue, 14 Dec 2010 12:55:17 -0500, wrote:

You should be able to do it with soft solder and a propane torch if you
use "Tinners Fluid" (acid soldering flux, available at many hardware
stores.) to get the solder to wet the steel u-bolts.

Jeff
But you need the steel CLEAN. NO ZINC.
Solder can be used on steel, copper, brass and several other metals
(including Aluminum, but soldering that stuff is no fun) - and can
solder virtually any two solderable materials to each other.

Many thanks to numerous respondents.

I'm starting to get an idea of the details ...

Wire wheel on bench grinder is likely to suffice to remove zinc, etc?

I *think* I've got a little bit of silver solder left from
AC work. Any good for copper/u-bolts??

Thx,
Willie

Your best bet is to get the brazing rods coated with a special flux.
I mentioned in another post that I use it for joining steel service
valves to copper pipe. The regular 15% silver solder would not work.
Been there done that, already ruined some material. Remember:
"Experience is a fools best teacher." Ralph Waldo Emerson :-)

TDD
silphos, I believe the stuff is called.Silicon/phosphor bronze. Used
extensively in refrigeration.
SNAG is also becomming pretty common.

It's Sil-Fos 15. It doesn't work for that, I tried it for installing the
steel fittings to copper pipe. The brazing rods I used had a blue flux
coating and I would have to call my buddy at the supply house to find
out the name of the darn things. I do a lot of silver solder and brazing
for refrigeration and HVAC.

http://www.silfos.com/index.html

TDD