Soldering without tears

[Cedge]

Here are a few tips on soldering that came to me the hard way.

#1... Never melt the solder under the flame. Heat the metal until the solder will melt when it touches it. This is when the solder will flow evenly into the joint. Melting it under the flame only makes nice ugly lumps you'll have to file away later.

#2... Flux... it's not just a cleaning agent. Flux being liquid, transfers heat to the solder and allows it to melt more quickly. It also acts to wick the solder into the joint.

#3... carbon... Solder dosen't like it and won't stick to it. After you've prepped your solder joint and fitted it, take an old cigarette lighter (think Zippo) or your handy dandy acetelyne tourch and smoke it up a bit, using the open flame with no oxygen added to the mix. Solder overflow and off target contacts don't stick and clean up is a breeze.

#4... Tinning is a great way to almost avoid that clumsy solder roll altogether. When two pieces need to be held togther where you don't want an obvious solder joint, apply a bit of solder to both surfaces before fitting them together. You want a nice thin even coating of solder here. You can always file a bit of it off if you get too much on a surface. Less is more in this trick.

Now put a bit of flux on one surface and fit them together. Use tip #3 as a precaution and heat the work until the solder melts in place. If more solder is required, the existing solder will wick it easlily into the joint.

#5... is an alternate to the last tip. hammer the solder out flat so that it becomes a very thin ribbon. Place small pieces of the thinned solder strips into the joint and proceed as in tip #4.

#6... When possible, fitting pieces as male and female makes for nice clean joints that look like one piece of metal. I needed to fit steam chest onto a set of cylinders and didn't want an obvious joint. I cut a notch in the outer cylinder wall that fit the steam chest quite closely. I then tinned the two pieces, and heated until the solder melted. The results looked like a single piece of metal. It was clean enough to cause a 30 year professional machinist to ask me how I managed to make such a complex cut on my chinese iron.

#7... Never solder work while on your lathe or mill. The vapors from the flux are highly acidic and will cause rust on any bare iron they happen to settle on. You can rust coat a whole lathe with only a drop or two of the stuff. Ask me... I know this one well....LOL


Best
Steve

 

[rake60]

Great tips Steve!

Soldering is certainly NOT a strong point for me.
I wish I had read this before I went to the shop tonight.
Your tip #3 could have helped me avoid this.

It sure doesn't come back off as easily as it goes on....
We'll be trying the smoking up, on the next one.

Rick

 

[Bogstandard]

I don't use soft solder at all, except for a bit of electronics.
All my joints are silver soldered, but as Steve said, solder doesn't like carbon, so I use a pencil (ok it might be graphite) but I find this drawn around the joint does the same thing, to form a barrier that the solder won't run past, tippex works as well.

John

 

[ksor]

Try this link and watch the videos - fantastic !

http://www.easyweld.com/

 

[IanN]

Hi Steve,

The process you describe in tip number 4 is called 'sweating' in the UK. In books and magazines (such as Model Engineer) it is quite common to see instructions such as '... sweat the brass diddly onto the support bracket....' with no further explanation as to the method recommended. Great if you know what they are talking about, very confusing if you don't.

Ian.

 

[Cedge]

Ian
It's called sweating here in the US as well, at least i know it is in the plumbing trade. It's hard to know just how technically correct to be when posting on a board where many users are just beginning to work metals. I figured it was better to be descriptive and hope the mental picture I'm trying to paint is somewhat clear....LOL.

Just one more thing on the list of things no one tells you until its too late to help....(grin).

Bog...
I get stuck having to use solft solder from time to time when restoring old European and early american to steam engines. I'd use silver solder then too, but the heat required melts the old solder out and makes one mell of a hess.

I, along with you, highly recommend using silver solder on any engine application, especially where steam pressure is likey to be introduced to the joint. It take a bit of practice to get to where you get more in the joint than on the work piece, but once you get the hang of it, its no more difficult than soft solder, as long as you are careful not to melt the work piece. Go ahead... tell me you've never ..(grin).

Rick...
Timing is everything.... I wish I'd posted it when I first thought of the idea. It might have saved you a bit of pain. Sorry about that, Boss.

Steve

 

[Bogstandard]

Hi Steve,
For the last twenty years or so, since I was taught how to do it properly by a chap who has long gone to a better place - NEVER.
My way of doing it is to assemble everything first with silver solder and flux in position and 'sneak' up on it with the torch until the solder flows into the joint, the job doesn't overheat as it does when trying to 'feed' in the solder with your spare hand. I use 0.5mm silver solder wire for all my small jobs, the large 1.5mm rods just take out too much heat from the area as it is being fed in, and so more heat is applied to get it to melt and so the small parts end up as 'blobs' of metal. A range of blowtorches is essential, it is no use using a big plumbers torch on small parts and a micro torch is no use for a lump weighing a couple of pounds. I have four ranging from a micro pencil torch to a brute of a thing that runs from an 8kg propane tank.
Plus the most important part of silver soldering is the flux. No compromises on this one, crap flux, crap joint. I have used for many years a flux designed for SS but works great on almost everything and it is called Tenacity 4a, I don't know if it is available in the US, but if you can get it use it.
http://www.jm-metaljoining.com/onlinepdf.asp?chartid=16&id=77

John

 

[mklotz]

Sloppy joints can also be avoided via a technique used by jewelers.

Take a length of wire solder and pound it into a flat ribbon on a clean anvil of some sort. Cut tiny pieces (jewelers call them pillions - tiny pillows) from the ribbon with a pair of very fine diagonal cutters. Coat the pillions with flux and stick them to the (fluxed) joint. Now heat the whole assembly gently (so as to not blow the pillions away) until the solder flows.

By carefully controlling the amount of solder available to the joint this way, you're assured that most of it will flow into the joint and not create the kind of blob so common when applying the solder wire directly to the joint.

 

[deere_x475guy]

All great info here and I am glad I did search. I was avoiding a built up crank for my Siamese Twin engine because of the soldering mess I always get. With the tips here I hopefully can aviod it.

Thanks guys!!!!

edit due to fat fingering and NOT proof reading :roll: :roll:

 

[Mcgyver]

I agree, Kozo's method is the best, like John says just warm everything up and and bingo, perfect, clean joint. Kozo went to great lengths to pin and screw everything together - my preference was to make decent third hand so you don't have to....I know Marv has made some nice tooling along these lines as well....

http://i20.photobucket.com/albums/b201/michael0100/3e5f7733.jpg

http://i20.photobucket.com/albums/b201/michael0100/Mcgyversthirdhandcloseup.jpg

http://i20.photobucket.com/albums/b201/michael0100/McgyversthirdhandcloseupII.jpg

http://i20.photobucket.com/albums/b201/michael0100/universal swivel/silversoldering.jpg

there are five ss joints in this adjustable tooth rest:

 

[jgarrett]

Good advice and good work.
You can also "walk" solder with heat. If fluxed properly it will follow the heat also never let an open flame touch your joint as it will burn the flux and makes for messy and bad joints. Like Rick said heat it untill it flows.
Julian G.

 

[rake60]

Try this link and watch the videos - fantastic !
http://www.easyweld.com/

Somehow I missed this post...
The video on that page of aluminum welding with their product at:
Durafix Video is pretty impressive. I'll be looking for that!

Rick

 

[tmuir]

Sloppy joints can also be avoided via a technique used by jewelers.

Take a length of wire solder and pound it into a flat ribbon on a clean anvil of some sort. Cut tiny pieces (jewelers call them pillions - tiny pillows) from the ribbon with a pair of very fine diagonal cutters. Coat the pillions with flux and stick them to the (fluxed) joint. Now heat the whole assembly gently (so as to not blow the pillions away) until the solder flows.

By carefully controlling the amount of solder available to the joint this way, you're assured that most of it will flow into the joint and not create the kind of blob so common when applying the solder wire directly to the joint.

I do a bit of silver smithing and rarely gold smithing and use this technique all the time.

I used it here to solder the wick tubes to the feeder pipe and although there is a bit of solder creep its would of been a lot worse if I used a rod of solder.
I also have silver solder for my jewellery that is only 0.6mm in diameter so great for that really fine work.

In case your wondering it is a replacement burner for my Bing loco made around 1915.
No where nearly as interesting as a lot of other stuff shown here but we all have to start somewhere.