Silver Solder

Ron B.
F4Fguy

Subject:Silver Solder

Apparently lost in the crash was a thread on"Silver Solder".I'd like to pick it up again,as several important points were left unsaid.

(1)Igor got it right.Everything he said is correct.Not only that,he showed us how a soldered and a brazed horn should look.OH!to be able to bend wire like that!

(2)True silver soldering is a brazing operation since,depending on the "solder" used,required temperatures are 1000 to 1300 deg.F,whichis why a torch is required.Brazing in most cases will develop the full strength of the parent metal.Soldering is only as strong as the solder.

(3)Most "Silver Soldering"alloys are primarily silver with other metals added to improve properties for different applications.

(4)"Staybrite"is NOT the same as silver solder,it is a silver bearing soft solder with only 2.5-5% silver.It melts at ~600 deg.F and has a significant loss of strength long before that.

Hi Ron,
I spoke of brazing using Safty-Silv 56% brazing wire. It's the minimum I would trust to make horns from, but is easy enough to use with a *normal* household torch.
I do use stay brite for tanks and such without problems.
BTW: got some material on the Avenger..... will be a long term project but I plan to use everything I have seen from you and Al. Not too proud to *steal* ideas!
Bill <><

isclaimer: I am neither a NATS Champion, engine reworker, engine producer, column writer, Hobby Shop owner, *rockeet* scientist, nor otherwise. Just an old Advanced flier.

Ron B.
F4Fguy

Bill:
No criticism intended or implied.I was simply speaking to the commonly held belief that "Staybrite" is a silver solder in the true sense of the term.

Hi Ron,
None taken!
I was trying to agree with what you said. Maybe it didn't come out that way. (??) Stay Brite "isn't" the *silver solder* I think of when I am really used to calling real silver solder "brazing wire". What I usually use is the 56% silver. Make sense?
Thanks, Buddy!
Bill <><

Ron,

I intended to bookmark that thread. I have frequently made my own horns but always had someone else braze them for me. My latest (Snaggletooth) home made horns, I sent to Tom Morris for brazing. I have the necessary equipment, in the form of propane torches (if that is enough) but always feared weakening the horn wire. There was some references in that thread to retempering the wire. With this information on retempering, I think I'd try brazing and testing some joints and, perhaps, start brazing my own horns. Will you replace the lost information on horn brazing?

I don't use Sta-Bright for anything. It isn't necessary for tanks and too weak for horns. Regular rosin core solder works fine for tanks. Higher temp solders probably wouldn't work as well. Tanks are best built with solder guns not torches.

LAST EDITED ON Jan-01-04 AT 01:59 AM (CDT)
 
Ron B.
F4Fguy

Al:
Just go to your local welding supply store and ask for silver brazing wire.As Bill says above,Safety-Silv is a good one.While you're there,pick up a can of brazing flux(the small can is a lifetime supply).If there is any doubt ask the counter guy,tell him the materials you're brazing and he can advise.Be sure to tell him you need the lowest temp BRAZING wire.
As to re-heat treating the wire,the simplest solution is to us air hardening drill rod.The brazing temp is high enough to take it past the critical and the air will quench it when you remove the flame.all you need to do at that point is reheat it to 600-700deg F to draw it a little.
Another point;brazing is not a very good gap filler,so good part fit is essential,i.e.no more than .005" nor less than .002".
To make the joint,clean everything thoroughly.Then apply a small amount of flux to both sides of the joint.Make a small ring of brazing wire,and slip it on the wire and against the horn.Adjust the torch to a slightly reducing flame(just on the rich side),and apply heat to the "back" side of the joint.Keep the torch moving to ensure even heating,but always heat the parts,not the brazing wire.Observe the ring of wire closely,at the proper temp,the flux will melt and ,shortly after,the brazing wire will melt.Capillary action will draw the braze material into the joint.As soon as this happens,remove the heat and allow to air cool.As soon as it is cool enough to handle,wire brush the flux residue off and make sure the joint is completely clean.
If you decide to use music wire,heat the entire assembly to a bright red heat and quench in a container of oil.I don't advise water quenching,as it usually is very erratic due to steam generation at the surface of the part,causing uneven hardening and,usually,warping.After hardening the drawing is similar to the drill rod.

Ron,

Will a propane torch work?

LAST EDITED ON Jan-01-04 AT 03:06 PM (CDT)
 
Ron B.
F4Fguy

Like a champ,in fact,the broader the flame ,the better.Flame temp is no problem.While I'm back on the subject,always try to put the most heat into the part with most mass,allowing conduction to heat the smaller, thinner parts.What we're really after here is uniform heating of the entire mass to brazing temp.