I want to soft solder a sight base onto a stainless steel barrel. Are there any particular tricks or fluxing agents I have to use?

I've already tried silver solder but the barrel is seriously distorted by the heat and when restraightened the solder joint breaks.

Andrew---

Your barrel was distorted after 1150 degrees?? And you straightened it?

It seems to me you have a VERY serious problem that may not be curable without another barrel.

Silver solder has been used for 50 years for sight bases without a problem on stainless and CM steels. I suspect a problem with application.

Any 440 deg. NON-lead solder works well. I use Stay Bright which is common in welding shops and jewelry supply stores. Force 44 from Brownell's is good also, but most any of them will work.

Sadly, if your barrel has warped and then been straightened it's likely to be good for nothing but a stake for your tomatoes.

Use only the best for tomatoes. I guess Belk is a gardener too. To clarify things -- silver SOLDER ( Tin with small amounts of silver ) melts at about 400F --- silver BRAZE melts at 1100-1300F. Many are confused by the two. To braze a barrel without distortion would take either a furnace or great skill.

andrew375... you must be carefull "soft" or "easy" silver solders are not the same in all trades... most soft silver solders for electronics work and modeling are 96 tin 4% silver... these flow around 430' F. However "soft" or easy solders for jewlery are oftan between 56% and 65% silver with the balance copper, these flow around 1100-1240' F. They work on an entirely different principals.
Perhaps you bought the wrong one? The 96/4 should have just about turned into toast at 1100'F

"Silver Solder" in about as confusing as the difference between "Flammable" and "Inflammable".

The mistake ya'll are making is speaking another "language" when defining solders. All the gunsmithing books, classes and instructors use "silver solder" and "silver braze" interchangably. It melts at about 1100 F and flows about 50 degrees higher. It's been used since WW-II to hold on sights, bolt heads, bolt handles and to assemble small parts and housings.

The Rockmount Gemini G that I use has a tensile strength of 88,000 psi and flows at 1090F.

"Low temp" or "soft solder" is usually tin bearing and flows at less than 450F. It's used for most quarter ribs, sights, and some funiture. The tensile strength is about 16,000 psi. That's plenty for most gun applications.

Jewelers, electronics guys, and tinsmiths have a totally different language that's handy to know if you buy from their supply houses, otherwise you can ignore them. What they're doing doesn't equate to what a gunsmith does even though the techniques and solders are almost identical.

I would say the most casual use between the two vernaculars is made by jewlers, they for the most part, stick to "silver solders"(silver brazes) but if you speak with them or are in the trade they will oftan define "soft solders" as what is known as easy flowing silver brazes. This discrepancy I believe came from suppliers in the jewlery industry trying to convey that their silver brazes have a low(er) flow temp. I do see and hear this oftan and like Jack said... unless you deal with these people (jewlers) ignor them.

Those crazzy jewlers huh

[ 02-12-2003, 10:00: Message edited by: smallfry ]

The silver solder I am using is the stuff used for general engineering work, not jewelery, where brazing (with brass "spelter") would be too hot. The grade of solder, and more importantly the flux, are intended for stainless.

As far as the barrel is concerned a new one is not, in my opinion, required. It is only on a revolver and will only be used for short range. You can imagine though how my heart sank as I watched that barrel curve up like a banana as it heated. I straightened it out with proper barrel blocks and the bore is now straight and round. But it just shows what stresses were in the barrel during manufacture.

I do realize that the optimum situation is not to have to straighten a barrel, but is there any need to consign them to scrap? If this was the case why do the top makers of sporting rifles, like Hollands, Purdy, Westerly Richards, Ferlach, etc, all employ barrel straightening machines and skilled barrel straighteners?

The silver solder I am using is the stuff used for general engineering work, not jewelery, where brazing (with brass "spelter") would be too hot. The grade of solder, and more importantly the flux, were intended for stainless.

As far as the barrel is concerned a new one is not, in my opinion, required. It is only on a revolver and will only be used for short range. You can imagine though how my heart sank as I watched that barrel curve up like a banana as it heated. I straightened it out with proper barrel blocks and the bore is now straight and round. But it just shows what stresses were in the barrel during manufacture.

I do realize that the optimum situation is not to have to straighten a barrel, but is there any need to consign them to scrap? If this was the case why do the top makers of sporting rifles, like Hollands, Purdy, Westerly Richards, Ferlach, etc, all employ barrel straightening machines and skilled barrel straighteners? I read an article just a year ago that showed a barrel straightener in action at Anschutz!

Also I used to work at a factory where they made big (76 m.m. to 205 m.m.) guns and these barrel were deliberatly bent to counter the effect of gravity. That is the barrel was bent to point upwards so that when mounted gravity would pull the muzzle down. These guns were capable of a degree of precision for both first and follow up shots that is mind blowing. Yes, a tank is a large target; but not at ten+ miles!

smallfry---

"Those crazy jewelers......." Well said.

I notice one catalog list EIGHT different temperature ranges for "solders for silver". They do that so complicated pieces can be soldered together in steps using the highest temperature first and gradually stepping down as parts are added.

andrew375--

It would take a book to explain barrel making, straightning, stress relieving and soldering, but I'll try to shorten it.

Barrels are straightened at three stages in European factories-- at the drilled stage, the reamed stage, and the finished stage. (That's why they tend to string their groups)
Premium barrels are usually never straightened after the reaming stage. That's why they win the matches.

In forty years of gunsmithing I've NEVER heard of a barrel so badly made it warped as you describe. It staggers my imagination to think of a short revolver barrel warping enough to see unless it arc welded on one side. Please name the revolver and I'll try to find one to experiment on.

I'm still puzzled about the solder you used. Hi temperature "silver braze" is used on barrels all the time without damage, but it takes carefull technique and even heat. I used it to install a secondary recoil lug just yesterday.

BTW-- It's impossible to bend a round hole and keep it round....it can't be done. Straightened barrels have to be lapped back round.

The barrel is on a .44 Ruger Super RedHawk. When I say I managed to straighten the barrel, I meant that it was as straight and round as I could measure. On the outside surface this was with a DTI calibrated to .001 m.m. (about .0004") and for the bore I made a plug gauge approx. 2 inches long that was a sliding fit in the bore; I could detect no change in resistence to sliding it through. Also I have since put well over a thousand cast bullets down the barrel and there is no sign of any change in fouling after the point where the barrel was bent, which I would expect if the barrel's dimensions had changed.

I would agree that using a straightened barrel for real precision work would be far from ideal, but this is for a revolver I'll be shooting from the end of my arm, using iron sights, at 25 yards. Do you really think I would detect the difference?

At the moment I am using Araldite Rapid to fix the sight base onto the barrel and whilst loads with 250 grain bullets are no problem, a few rounds of the 330 gr. LBT bullet sends the sight block to hit the back wall of the range. I've tried the various Loctite products with the same result. And yes, I am preparing the surfaces properly.

I've found some low temp. (430 f) solder (easy weld) I had hidden away, I'll give that a try.

Andrew375---

I've never heard of "Araldite Rapid" and don't know the physical properties of it. I DO know that if the bore is oval it will pop the sights off even if high temp solder is used....it's common to see Colt revolvers and Remington M-721/722 with missing sights if the barrel is bulged just a little.

The plug gauge was a good idea but doesn't actually show you anything except the smallest portion of the barrel is the same size as the plug. I think you'll have much better luck slugging the bore with a soft lead plug. A variance of .0002 is easy to feel. Most Ruger barrels are "choked" at the barrel thread and that will be the smallest area so it's best to slug from both directions to figure out what you actually have.

Let me know if you don't know the process for slugging bores and I'll write it up.

BTW-- Before they made the Super Redhawk with intergral scope mounts I silver soldered a set of mounts to a SS barrel. As far as I know it's still shooting.