On Wed, 01 Jun 2011 22:18:20 -0400, "Steve W."
wrote:

john B. wrote:
On Wed, 1 Jun 2011 12:28:26 -0500, "David Courtney"
wrote:

"john B." wrote in message
...
On Wed, 1 Jun 2011 11:05:43 +0000 (UTC), xpzzzz wrote:

On Wed, 01 Jun 2011 16:33:43 +0700, john B. wrote:

I'm in the process of rebuilding a bicycle frame and am left with some
minor dings and scratches which I want to fill and fair. The tubes are
rather remarkably thin and I really do not want to use a file to clean
them up. My idea is to use lead solder as a filler and my problem is
that I have no idea what to use for flux.

The reason for using a metal filler is that the frame will eventually be
powder coated and the preparation used here is a good glass bead
blasting and I don't think that conventional painting fillers would
stand that, or the high temperature baking.
Use LabMetal: http://www.alvinproducts.com/Products/Products.asp?ID=1


My powder coating guys tell me that they cure at around 200 degrees(C)
minimum.


As someone who did a LOT of powder coating (12+ years) I can tell you
soft lead solder will not handle the heat of the powder cure.

Ah Ha! Now that is something I didn't know. Thank you.

However all is not lost. Silver solder or brazing will handle the heat.
OR there are special high temp fillers that most powder coaters can get
that will work.

I can use a fairly low temp. silver braze that I know will be safe for
powder coating. The reason I had for using the lead was that it is
much softer then the steel and so easier to file down flush without
taking too much off the tube.

I guess it would have turned into doing it the easy way only to
discover that the easy way got considerably more complex and costly by
the time you got it finished.

Also make SURE that ALL threaded holes, bearing surfaces, anything you
don't want powder on/in is masked very well. Powder does NOT come off
easy. Get it in threads and you will have a ton of fun trying to get it out.

Yes, the powder coating guys briefed me on that.

Since I've got you (so to speak :-) I had given some thought to trying
to do a two color powder coating - spray the frame and bake one color.
Then mask off the portions that are to be the initial color and spray
a second color and bake again. The second coat would be darker then
the first coat, if that matters, and I also believe that the thickness
of the second coat would show. I also understand that the masking
tape(?) is fairly stiff so the masked edges would be pretty much
straight lines but I can live with that.

Any words of wisdom here?