Heat Gun for Soldering and a few other questions

[MSzychulda]

I recently ordered a Chambers fowler kit and am assembling my supplies. My last two guns used dovetails, but the lugs and sight on the new gun will be soldered. I will need to get some low temp silver solder, and have both a propane torch and a heat gun (650/1000 degree settings).

I was wondering if anyone has used a heat gun for soldering parts, as it seems to me less likely to damage the barrel and parts and create the oxidation problems an open flame poses. Also had anyone tried plumbers solder?

What fluxes work well with the barrel and lugs/sights? I read that borax makes a good flux but have not tried it before having only used rosin.

I have looked through past postes and found some great tips, but not too much addressing these questions.

Also to locate the front site before soldering, do you simply center it on the barrel or tape in place and shoot the gun to locate its final spot?

Thanks!

 

[Roy]

I really like the soft solder I get from Brownells, I use it with their liquid flux (not cheap, but it works sooooo well). As far as using a heat gun I haven't tried that one, I believe that the solder I use flows around 800 F, so it could possibly work, but I normally just use a torch. The one thing about using the liquid is that you have to heat the piece without letting the flame on the fluxed area or it will scorch. Now for silver solder I once again use Brownells with a paste flux. Direct flame heat it up red and Bobs your uncle. :thumbsup:

 

[Cherokee]

I have never hear dof a heat gun being used to solder with. There might be a reason for that.
Seems there would be plenty of plumbers using them.

 

[MSzychulda]

Actually I know several plumbers who use one. You can buy a reflector adapter with a curved tip to go around copper pipe. It heats the pipe and melts the solder really well. The problem is you need electricity, which is hard to run under some of the houses, so propane torches work well for the hard to reach places.
The barrel is quite a bit heavier than the copper pipe, so I don't know how well it would work.

Here is the owners manual for my heat gun with the soldering info and tips shown on it FYI.

I will check out the supplies on Brownells, thanks. Matt
[url] http://www.milwaukeetool.com/...D86256F410060173F/$file/58-14-2842d8.pdf[/url]

 

Matt, ya might try checking out this place for low temp solders. Link to solder You don't really need silver solder 50/40 will hold if yer prep is good. Bill

 

[Cherokee]

I been learned on it :hatsoff:

 

[MSzychulda]

Thanks, I may try to do it with the 40/60 or 50/50 solders. I thought it had to be done with silver solder, but the more I read the more i realize how much "plumber" solders are used. I checked out brownells, and the other site and the prices are not bad. I do have a jewlers store close by so silver solder is not hard to get; but if the softer solders work well why pay extra?

I may try to do a very slight dovetail for a little added strength, but will decide on that when I get the barrel. I just hate cutting into the barrel metal! My last rifle almost gave me the fits, but did turn out well. The smoothbore barrels are just so much thinner.

I found these instructions on the American Longrifle board under their building instructionals:

If you find it necessary to silver braze the barrel lugs on a fowler first fill the bore with charcoal. File a tiny flat where the lug will go apply a thin coat of borax mixed with %99 alcohol. Place a thin- i.e.. .010 piece of silver solder sheet on the flat. apply an equal amount of borax to the lug. Wire the lug in place with iron tie wire. Paint the surrounding area with anti flux. Heat the whole barrel with a large tip torch or forge. If the tie wire gets red before the barrel you are heating too fast .As soon as you see the solder melt and flow stop and let it cool slowly. The charcoal will prevent excessive oxidization in the bore and save you a lot of work cleaning or having to lap it out. Be sure to heat the barrel equally all the way around the circumference or it will warp to one side. Let it cool slowly until it is well below a red heat.
Cleanup on a wire brush and polish . You are now an expert lug brazer. I Hope.

Packing the bore with charcoal sounds intresting, but with the lower temp solders may not be neccessary.

 

[Zonie]

There are several different types of Silver Solder.
The true Silver solder with a high percentage of silver like a jeweler would use melts at over 1000 degrees F. IMO, this is way beyond anything that is needed for a gun.

There are several different silver solders which contain less than 4 percent silver and melt below 750 degrees F. In fact, there is a "Silver bearing" solder that melts at about 450 degrees F.

All of the solders containing silver are stronger than any of the lead/tin or other high tin solders.
IMO, This becomes important in gun work because the shear strength (force is in line with the surface of the joint) is measured in Pounds per Square Inch. The square inch is the area of the joint, so, if the object is 1/4 inch wide and 3/8 inch long the area is .25 X .375 or .093 square inches.
If the solder has a shear strength of 4000 psi a side load of 4000 X .093 or 375 pounds of impact force will knock it off. If the solder has a shear strength of 6500 psi the impact load would have to be 609 pounds. (Note, I'm guessing at the shear strengths as I don't have any data on these at this time).

As for the flux, for a steel to steel joint those containing Aluminum Chloride, zink chloride or both should work. These fluxes are corrosive so they must be removed after soldering.

 

[MSzychulda]

I was just looking at the silver solder paste on the site Bill recommemnded, and that may be the ticket for this build. It comes premixed with the silver bearing solder and flux, and melts at 450 degrees. I agree the silver solder would be stronger, and maybe a better option.

Would a 1/4 oz tube be enough for 4 lugs and a front site? Seems like it would be.

Great tips guys, thanks!

 

[CoyoteJoe]

You'd be surprised how far 1/4 ounce goes, just a thin coat on one part will give you a good joint. OK maybe not as good as the one I rolled last night--

 

Matt, a couple things to try before you get to the real thing. First, the local Hardware probably has low heat, low silver content solder(saves shipping), secondly very little is needed on your joint(not the one Coyote Joe's talkin about :rotf: ) Get some scrap material and practice with that. I've found that tinning both surfaces work best for me( flux, and tin seperately) then just mate and apply heat til they bond. This guarentees no voids in the joint(no, not Joe's:haha: ) Bill

 

[MSzychulda]

Thanks, yeah I don't think I would try Coyote Joe's joint technique while soldering :shocked2: Burning brain cells and barrels at the same time :grin:
I will definately practice. I plan to go to the local hardware store and get some solder and paste flux. I have some scrap pipe and steel in the garage and will work on it some. I think the tinning and then joining sounds the safest. I will definately give that a try first. Matt

 

[Mr. Chester]

Make sure you CLEAN the surface well where you want the solder, and tin both pieces as others have suggested. Sweat the two together without adding anymore solder. Preheat your barrel in an oven first as the barrel mass with draw away heat from your work area.