How does silver soldering mount bases affect the temper of rifle receivers?

I am mulling over a new rifle design that would be made from thick cylindrical stock but might be improved with more metal in the form of a Sako-type dovetail screwed and soldered on.

The steel would be the best tough modern type available, perhaps hardened at the lug engagement before or after the dovetail is installed, as makes most sense.

Thanks for any ideas.

If you are starting a scratch built receiver, mill the bases integral to it like all of the other guys do. If for some reason you just HAD TO braze them on, do it like Remington does when they make their bolts and fuse the parts during heat treatment.

If you are really going to silver solder onto a rifle receiver which has been heat treated, which I do not recommend, you will destroy all heat treatment it had. Silver soldering, is a very high temperature process; silver melts at 1700 degrees, and it actually brazing.
What I suspect you want to do is to Solder the bases on using something with at most, a few percent of silver in it, with the bulk off the alloy being tin. Which melts at 450 degrees and will not hurt your receiver.
Do not silver, or brass, braze anything on to your receiver. 96% tin and 4% solder is fine. Terminology is not precise here and a lot of people call soft low temp soldering, "Silver Soldering", which is isn't.
Now, if you are building receivers from scratch, them why not mill the bases integral with them. Or, as Speer said, then you can braze them on.

Thanks Rod and dpcd,
sorry it has taken so long to reply; I've been a bit preoccupied the past few days and tended to just look at the top of forum-content pages.

I have been doubtful in the past about makers who apparently welded on recoil lugs, so would be a bit reluctant to braze. If the cost were not prohibitive, I guess it could be a possibility, though.

If real silver soldering destroys previous heat treatment, can it be restored without wrecking the solder?

Is it possible screws and simple soldering could add any useful stiffness or strength?

Thanks again for your advice.

quote:

Originally posted by sambarman338:
Thanks Rod and dpcd,
sorry it has taken so long to reply; I've been a bit preoccupied the past few days and tended to just look at the top of forum-content pages.

I have been doubtful in the past about makers who apparently welded on recoil lugs, so would be a bit reluctant to braze. If the cost were not prohibitive, I guess it could be a possibility, though.

If real silver soldering destroys previous heat treatment, can it be restored without wrecking the solder?

Is it possible screws and simple soldering could add any useful stiffness or strength?

Thanks again for your advice.

Well, re-heat treating goes above solder temperature so your parts would all delaminate. Screwing and soldering would add a certain measure of rigidity but if you are making an action from scratch you are far better off to simply machine the base into the receiver. It would be a lot less pissing around. Also, if you ever did want to solder or braze a one piece base on it, the best method to do it would be while heat treating to avoid different stretch and shrink rates of differing sized parts. Spot heating to sweat on a one piece base invariably leaves the action and or the base twisted up a bit after they are cooled. In the kiln the parts cool very slowly and differing sized and shaped parts cool at exactly the same rate so you don't have the distortion cause by one part cooling faster and shrinking against the slower cooling heavy parts.

Most of the processes of using heat to "fuse" mounts, after the fact, like welding or high heat soldering, i.e. "silver solder", involve mucking up the heat treatment and require re-heat treating period...no question about it.

You can plasma weld the part in place, which I would do IF I could find someone with knowledge and expertise AND can, correctly, re-heat treat afterwards.

But baring Rod's way, making the receiver from scratch, I would just screw the mount on. Most single piece mounts add extra stiffness to receivers. Stay away from mauser style receivers as they have way too much metal removed for obvious reasons. Remington's are the stiffest of the factory offerings...argumentatively...or similar clones, and single shots stiffen even more, add sleeving helps even more.

Single shot, integral mount, thick walled benchrest style with the smallest ejection port would be your best bet to look at for ideas. Check out 50 cal Armalite single shot actions and make something similar...and BIGGER AROUND if you want more strength.

There are MANY ways to add a modicum of strength through the use of "stiffening bars", i.e. full length, wider, different metallurgy in the mount material, more and larger screws, higher tensile strength screws torqued down to a higher number, larger diameter receiver, again, made of higher strength material, but all that has been done already by someone, somewhere.

If you use steel you add weight and if aluminum you need to make it 3 times larger just to equal steels strength...more or less.

What do you want to make that needs higher tensile/yield numbers? Rhetorical question, no answer required.

Luck

To summarize, do not rely on a scope mount to stiffen a receiver which you are making from scratch. Make the receiver a solid top one; look at the Remington 788, and others, with a solid top and small ejection port. Mill the scope bases integral with that top (or not) and you will have what you want without any brazing or welding or heat treatment drams.

Thanks again Guys,
I'll read over all the posts a time or two and work something out. The design ideas are mine but I am not the one one who will do the work, if it happens. I would use stock of rectangular section but my fitter/turner mate would prefer round bar, hence my questions. Since it may result in a patent, I'd better not give away too much at this stage.

Your help much appreciated.
Cheers

Id use 440 from Brownells, it melts at about 400 best I recall..Havn't done that in a long time, I use use 8/40s and lock tite on fitted bases..I may want to sell the gun or change mounts..If really concerned I will glass the 8/40s in..That will hold until hell freezes over..and you can take them out with a soldering iron, or I use a little pistol looking butane torch,( available at cooking stores,) that has a pinpoint flame that will go direct on the screw and not hurt the surrounding blue..The glassed screws come right out.