doublegunshop.com - home Forums General Discussion DIY Gunsmithing @ doublegunshop.com Resoldering barrels

I have been given a nice old Scott doublegun that was going to be sent to the authorities for destruction, as the upper rib is almost unsoldered, and no one wanted it.

For me it is a great opportunity to work on it and try to salvage it. Of course I am not going to make soldering work on a perfectly working gun, so as this one is not working, it is a great candidate to punt my hands on jajaja


I have seen several videos in barrel re-soldering, but would like to know if any one has a good recommendation if a book/video/blog, where I can get as much technical information about flux used, solder, process, etc....

Also the stock is horrible, with several coats of lacquer, and almost all the checkering gone, so it would be a great project of restoration and see what level I can achieve as a DIY "gunsmith"

pacomb,
This work is beyond my abilities, but I am given to understand the best way to do it is with an oven, especially made for the purpose. The joints must be cleaned, flux and solder applied, then the ribs have to be wired and held to the barrels with soft iron wire, blocks/wedges and then heated to the flow point of the solder in the oven. The main part of the ribs are traditionally soft soldered on. There is usually a section over the lugs and chamber area that is silver soldered. The soft solder is usually 50/50 Tin/Lead, or some may have used 60/40. Rosin flux was traditionally used to avoid corrosion caused by being unable to clean acid flux from between the barrels and ribs. Soft Iron wire is used as "tie wire" for reinforcing rods in concrete construction and is available at building supply stores. My limited experience is only with very short sections of loose rib, but it enough to indicate that it would be difficult to get enough heat, evenly, on full length ribs with a handheld torch. If it is not necessary to resolder the entire length of rib, you should wire and block the whole thing to prevent other sections from coming loose. I hope this helps.

Thanks for your advice Der Ami

As far as I understand, the most important thing is tinning the barrels and ribs separately, using a strong flux, and then clean VERY well the flux rest so there is no corrosion in the future. Once all places together with the wire, apply the rosin flux, and parts should solder nicely as they have been previously tinned.

I am concerned with the "rosin flux", as I am not sure about what the correct translation into Spanish and I don't know if I will be able to find it locally.

I share interesting videos I have found on the subject:

https://www.youtube.com/watch?v=oSUOeT2dBg0&list=PLRhWJddSvPkTATsq1yUnXdfAKhqFXo3T0&ab_channel=Brownells%2CInc.

Hello all

I am unable to find old 50/50% tin lead wire, but I have found and bought the following:

SN 30% Pb 70%, I suppose SN is tin, and of course PB is lead




and SN 97% , 3% Cu, Cu is for copper








I have read people using 2% silver, which I find extremely difficult for the ribs as the temps must be very high

Can someone tell me if any of the above solders I have found are suitable??

I also have strong acid flux for the tinning (residues will be cleaned after very well), and rosin flux for the final soldering of the ribs on the barrels

Hope someone can help me as I plan to do the job in Easter holidays

Hello Paco,
I have found that solder that melts at a higher temperature does not work well with rosin flux. You certainly can use an acid flux and the neutralize it before joining with rosin, I do not do it that way, I use rosin flux for the whole operation. The key with rosin is to not get it too hot, once it burns you have a problem. I would look for 50/50 myself before attempting to join the ribs, my fear being that the solder you have on hand will become wet at a temp above which the rosin will burn. Of course, you could try on a piece of scrap and see if the combo you have will work. I hope that helps.
Steve

Sn is tin.

The 30/70 tin/lead solder works fine in my experience.
I used it a few times as I didn't have any 50/50 around.

It melts at 361°F , Working temp - 491°(flow temp?) according to a couple sources that sell the stuff.

Looks like it was a favorite dent filler in the days of repairing sheet metal like car fender dents.

Rosin flux works with it and some of the solder offered is Rosin Core.

I've always just used a simple paste flux available in most DIY stores for any soft solder jobs. They usually have some Zinc Chloride in them,,the dreaded 'Acid Soldering Flux'
I tin the surfaces with it and also solder them together.
A very thorough rinse/neutralizing wash is used and I've never had any after rust issues.

In regard to the excellent comment by Cutter and especially his comment on a very thorough rinse to neutralize acid, I refer you to the Eastwood Co. (find them on the web). Some barrels are really difficult to "tin" and in that case I use Eastwood's tinning butter to set a base of lead/tin on the barrels. Wash the barrels completely and then finally coat them in a bicarbonate of Soda paste and wash that away to neutralize the acid. Eastwood has tinning butter in lead/solder and also pure tin(or they did the last time I bought products from them) They also have 30/70 tin/lead solders that Cutter refers.

I also buy rosin powder from Diamond G Forest Products in Georgia.

Kind Regards;
Stephen Howell

Rosin flux should be available in Spain. It is a natural resin extracted from pine tree stumps or bark, known as rosin or colophony. I Googled the Spanish translation for rosin, and it is "la colophonia". It consists largely of abietic acid, which acts as a cleaning agent when heated to remove oxidation. It is very commonly used as a flux for soldering electrical circuits, and a lot of electrical solder has a rosin flux core.

The 97% tin/ 3% copper solder you bought is intended as a lead free substitute for copper water lines and fittings. It won't work well for relaying a shotgun rib. The Oatey No. 95 Lead Free Tinning Flux shown on the bench in one of your YouTube videos is great for tinning, as it is infused with tin particles. It works very well with regular tin/lead solders. It is corrosive, and any residue must be cleaned and neutralized.

I'd strongly advise that you find a set of junk double barrels to use for practice before moving on to your Scott barrels. You can learn just how much heat you will need to unsolder the ribs, and you can then learn the entire process of cleaning, tinning, and soldering, while also finding an effective way of securing everything in position while doing the actual soldering. Just jumping in with good intentions is likely to end up badly.

The rosin powder referred to by Steve, above, is a product of pine tree sap, or rosin. In the South it is referred to as pine tree fat. It ignites easily and burns very hot when impregnated in the pine wood. When I used to cast a lot of lead bullets I fluxed the molten lead with small pieces of the rosin.

It is also used by baseball pitchers to get a good grip on the baseball. And, I have been told, by gymnasts on the rings and the balance beam.

I use liquid rosin flux, Kester 1544.

https://www.newark.com/kester-solde...Nk2LM9PHMI21SDybiBMHDSGRrzhoCkqcQAvD_BwE

When tinning I let the soldering iron do most of the work and use a torch sparingly, mostly toward the breech end. I try to heat ahead of the area I am tinning with the torch and keep the flame away from the flux. I made up some soldering coppers to fit inside the bore as well, turned on the lathe slightly under bore diameter and mounted on a rod, they can be heated with a oxy acetylene torch then inserted to where you need the heat.

It has already been mentioned that cleanliness is key to success, I have found that a media blast cabinet is an excellent way to prepare the surface under the ribs for tinning, especially if any corrosion has taken place in the past. I use fine glass beads or my blasting media.