This one is good for a laugh.
https://www.youtube.com/watch?v=VjwtB-Sc3Og
Enjoy.

Literally!

$hit!!!!

.
Oddly enough, that's pretty much how they come off. Sliver solder requires a LOT of heat. I would probably prefer a cherry blossom head and a more carborizing flame. Cutting heads are pretty intense and localized heat. I would also prefer to run argon through the barrel or drive piece of hardwood into the barrel to displace oxygen and prevent scaling.

I've taken silver soldered rearsights off British rifles...so the "bed" length is the same...but never had to get them that (red) hot.

How hot you have to get it generally depends on what it was put on with. Brownells Force 44 which is a low temp silver, melts at about 475F and wicks at about 500F. It's a bit better than soft solder but it is in no way as strong as hard silver solder. Brownells Silvaloy 355 is a good example of the hard silver solders which are often used on gun sights. It melts at around 1100F and flows and wicks at about 1200F. Steel starts to turn red at about 1000F and at 1200F it is decidedly red even to a layman. So if you want to put something on, or take something off and it involves high temp silver, it's gonna get red hot. No ifs, ands, buts or maybes.

If it didn't get red hot, then it wasn't high temp hard silver solder and yabbuts live in the bush !

Any time I'm using silver braze, solder is the low temp stuff, I coat the bore I'm going to heat with black flux to prevent scaling. Too easy to ruin a bore with heat scaling.

i was screaming STOP way before "you might see smoke at 4:14" .. and this gumsmit doesn't seem to know about GRAVITY .. turn it upside down, they fall of

If the sight is not going to be reused, (most will not) I clamp a vise grip to the heavy part by the blade and twist them as I heat them. Hard silver solder loses structural integrity at about 800F and careful twisting will break it off long before the barrel gets red. If you are really sneaky and careful you can use a medium welding tip or TIG and super heat the sight only, starting at the blade area and break it off progressively from front to back, heating as you go, without even bringing the barrel past a light straw color. It does take a bit of practice but it can be done though. A TIG works best for this but gas can be used too.

What is black flux.

The problem is that the temperature required to melt silver braze will destroy the temper of the barrel unless you are really careful.
You would like to think the factories would install them under carefully controlled conditions.
I wouldn't risk it, best to just mill or grind it off.

Black Flux

It's great for brazing on Remington 700 bolt handles. Coat inside and out and when your done there's no discoloration of the bolt. Dave Kiff told me about it years ago and I've used it ever since.

Looking at the attached video link it gets a little scary at one point. I have a sight to remove and fear of damaging the barrel.

Do you guys think that too much heat was used or at the wrong location or the wrong flame ?


Is high temperature silver solder required for these barrel attachments?
Thanks
BB

quote:

Originally posted by Toomany Tools:
Any time I'm using silver braze, solder is the low temp stuff, I coat the bore I'm going to heat with black flux to prevent scaling. Too easy to ruin a bore with heat scaling.

I don't know that I would put it on the inside of the bore to prevent scaling. Most fluxes have a heavy etching action to clean the metal and give roughened footprint for the solder to bite on too. I would polish a piece of steel to a mirror finish, apply a good coating of the flux and then heat it up to 1100F and then inspect it after to see if it has etched the surface. It's a very novel idea that I have never pondered. But you might be creating a big copper magnet if it etches the surface. It does bear a bit of experimentation though. I'd be interested in seeing the results.

Hard to beat an Argon purge. May be a bit expensive to set up. Having silver brazed quite a bit, I would have been testing the bond as temperature rose, not deciding how hot it needs to be. I like the gravity idea. The last time I dealt with this was on an older Sako. Someone had removed the ramp and left brazing materials on the barrel. I warmed it with a torch and wiped it off with an old leather glove. The barrel then took bluing. One can see the difference in bluing quality, not as glaringly obvious as the solder left behind.

I use a product called Lucas Milhaupt Handy Flux so I used it to try my own experiment. I polished a piece of a material as far as I had ambition and heated it with flux just to the point where .005 inch silver leaf hard solder wicked and did before and after photos. The flux did indeed leave a heavy etch behind it that can be felt quite easily with your fingernail. So I won't be putting that inside a barrel. Although it may be a handy method of removing carbonation from the inside a barrel AFTER you have scaled it by accident. Depending on which of the two evils I feel are worse at the time of disaster.

flux by Rod Henrickson, on Flickr

JUST AS A MATTER OF NOTE:
The etching completely ate away most of the polishing marks that I had left in the material. I'm not sure how that helps me at this point, but I'm sure it must be important ! LOL

I guaran-God-damn-tee you any "etch" caused by black flux is minuscule compared to heat scaling. Do what you want.

I silver solder stainless steel to copper for high vacuum applications at work. If you have access to argon it is much cleaner than flux for anti scaling.

John,

It's as easy as putting your TIG torch up the the chamber and pulsing for flow. My Lincoln has a 30 second post "purge" so every 30 second you have to tap the pedal.

With Brownells hi force solder I have never bothered. When "permanently" attaching something to meet BATFE requirements with hi temp solder, I do.

quote:

Originally posted by jeffeosso:
i was screaming STOP way before "you might see smoke at 4:14" .. and this gumsmit doesn't seem to know about GRAVITY .. turn it upside down, they fall of

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