Sweat soldering

Hi everyone, please can you tell me what the difference is between soldering and sweat soldering, and when would you choose sweat soldering. Thanks.

Typically I use sweat soldering when putting together two flat pieces of metal, where I want there to be a complete seal holding them together with no gaps around the edges. When doing this I will flux the smaller of the two pieces first and place multiple tiny solder chips around the surface. When heat is applied and the solder melts, I then use a titanium pick to spread out the solder so that it covers the entire surface in one thin layer. After this piece has been cooled and pickled, it can then be placed on the second piece of metal (after both have had generous amounts of flux added). Both pieces are then heated to temperature so that when the solder flows again, the two pieces are joined. There are others here who are much more advanced than me who might explain this more eloquently!

2 Likes

The brass piece in this cuff I made several years ago has been sweat soldered in place.

1 Like

Thanks so much Sally. I haven’t needed to use this technique so far but I may need it soon as I have an idea for cufflinks. Appreciate you taking the time​:blush::hammer:

1 Like

Standard Soldering

Flux and then place the solder underneath or on top of the join itself and then heat until the solder flows up.

This is the basic way to solder that is most widely used for different kinds of jewelry pieces.

Sweat Soldering Jewelry

Two-step heating process. First, flux and melt the solder onto the first piece of metal then pickle and quench it. Second, place the 1st piece of metal (solder side down) onto the second piece of metal that you’d like to solder it to. Heat both pieces until the solder flows and joins the two metals together.

Sweat soldering is ideal for joining an embellishment to flat metal sheet or other jobs where you don’t want the solder to be visible on the jewelry piece.

Pick Soldering

Heat the piece of solder until it melts into a ball, pick it up using your soldering pick, place the ball of solder on your join and heat it until the solder flows.

Pick soldering is ideal for delicate pieces that you could overheat or melt all together.

2 Likes

Thanks William.

I do normal soldering but I haven’t tried swear soldering. I have a project which would benefit from sweat soldering. Great to get the benefit of your advice.

Many thanks. Katie

Hi Katie, I am sure that it was a typo, but swear soldering is a fourth type of soldering technique known to many of us. It seems to occur for me when a complex, frequently multi step soldering project is in process and then, for obscure reasons, the piece slips or a pallion flips out of place for the sixth time… swear soldering.

8 Likes

Ha ha! I love it!:joy::joy::joy:

Hi Katie,
Soldering is one of the techniques that I concentrate on demonstrating in detail when I teach because it is a mystery to so many people. It is not difficult and if you are methodical in the way you set things up. You should have almost no clean up when you are attaching one polished pieced to another. Pieces involved should be finished and look the way you want them to appear when the piece is completed. The aim is to not have a mess that you have to file, sand and re-polish. For example, when you are attaching a wire, tube or jump ring to another surface, flux and melt a small piece of solder to the the part that is meant to touch the other piece and pre melt that solder. Then set the two pieces next to each other making sure that they are touching and heat and re-melt. It is essential to flux solder joints. I things looked black when you heat them they are not fluxed. They should appear protected and not oxidized. Solder does not like to jump air gaps. The pieces must touch! You can make more complex things by preparing multiple elements and heating them all at the same time. Solder reflows when it is brought up to melting temperature again… I find many people get nervous and over heat things. Stay calm and practice on less valuable projects first. Another tip… As long as you have fluxed the piece and there is still signs that it is fluxed you do not have to pickle in between… I lot of pickling is a waste of time because if the piece is already fluxed it is protected. If you pickle you have to clean the surface and flux again and again. It is totally unnecessary!
Sally, the jeweler with the beautiful and technically well done cuff bracelet, gave a very good description of a technique called overlay. It is used in Native Am. jewelry a lot. I can add something that will help you keep the solder from creeping up on smaller pieces. I use white out [type writing correction fluid.] It prevents soldering from flowing on surfaces where you don’t want it… [ there is another jewelers brand called Stop Flow that is more expensive] Both are basically acrylic paint and do not dissolve when coming in contact with water based flux.
[Yellow ochre and rouge applied with water can bleed into flux and ruin your solder joint.] W

hite out totally prevents solder from flowing on surfaces that you want to protect… I use it in moderation because as it heats up it makes fumes are not good to breath. It is important to work in and area with good ventilation. The type of flux you use is important too. Some flux like Handi-Flux have dangerous fluorides in them. Dandex and Superior do not have fluorides that cause raspatory problems.
Learn good habits…I feel upset when I come to the end of a project and have to do a lot of clean-up. If you work carefully and make sure surfaces are clean and look the way you want them to appear in the end you can avoid having to remove fire scale and scratches etc. It saves a lot of time and frustration!!! Marilynn

2 Likes

Hi Marilynn,
Thank you so muck for your really detailed and generous information. I realise I’ve been using the technique with jump rings without knowing this is sweat soldering, though I avoid it because my hand shakes. However I would like to try it with a larger piece so I’ll practice on a few old bits until I get it right!
Thanks again
Katie