# Silver Solder - removal of Soft Solder



## thumper (Jan 31, 2009)

I have an O gauge Bassett Lowke mogul that was originally soft soldered, and not very well at that.


I would like to reassemble the loco using silver solder, but I need to make sure all soft solder has been removed. I'm thinking of using a low pressure sand blaster to do the job [all paint has been stripped].


My question is: is there a better way to remove the soft solder?


Thanks,


Will


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## Greg Elmassian (Jan 3, 2008)

If you can heat and wipe or blow the molten solder off with air pressure, that's normally my first step. 

I'm not sure that a very thin film of the old solder would cause problems, but the silver solder experts would have to answer that. 

I wonder if blasting with walnut shells would not be safer than sand blasting. 

Regards, Greg


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## chuck n (Jan 2, 2008)

A machinist friend of mine once showed me how he removed solder. He had a wick made out of fine copper wire. He heated up the solder he wanted to remove and the wick. The solder flowed into the wick. Once the wick was saturated with solder he cut off the the solder/copper and repeated the process until all the solder was gone. Using a variation of this technique I have removed solder using a stranded fine copper wire. Much like that found in speaker wire. 

I think that the capillary action of the strands of the copper wire help suck up the solder.

Chuck


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## Greg Elmassian (Jan 3, 2008)

Yes, and you can buy that product at Radio Shack, called (surprisingly) "solder wick" .... not cheap though... 

If you can find a surplus place, you can find woven copper braid of fine wire (often used for grounding or tubular for shielding) and use a little flux to "suck it up". Way cheaper. 

Regards, Greg


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## fkrutzke (Jan 24, 2008)

Will: 

The best way for the bulk of the solder is to use "Solder Wick" available from your electronics supply store. Radio shack has some, comes on a flat spool, usable but not very wide, but the elec. supply store will probably have a spool of wider material. Lay it on the joint and heat with your soldering iron. I try to use an iron that is at least 75 watts. Also a little flux on the wick can help. After the bulk is off and the joint has been broken open, use sand paper, emory paper is best, to remove* ALL* the visually remaining solder. For the outside pieces I sometimes use the foam emory board womens finger nail buffers. For inside joints use 300 grit emory paper. You can wrap it around a piece of balsa cut to fit inside the pipe joint. The trick is to remove all the solder from the joint so that it does not oxidize when you heat to resolder using easy flow 45, and contaminate the joint. 

Torry


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## Shay Gear Head (Jan 3, 2008)

Will,

Just be careful that the sand blaster does not deform whatever metal you are working on. The thinner the more likely it will deform.

Maybe do the sanding first and finish clean-up with the blaster.


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## iceclimber (Aug 8, 2010)

Posted By Greg Elmassian on 11 Jul 2011 08:37 AM 


I wonder if blasting with walnut shells would not be safer than sand blasting. 

Regards, Greg 



Careful you don't let the squirrels know what you intend on doing with those walnut shells


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## Chris Scott (Jan 2, 2008)

Will wrote:
"I have an O gauge Bassett Lowke mogul that was originally soft soldered, and not very well at that. I would like to reassemble the loco using silver solder, but I need to make all soft solder has been removed."


2 Cents:
If you are talking about taking the O scale loco completely apart (hopefully you have not already)- STOP THE PRESSES !!! Fixing a joint that breaks, when it breaks, maybe proactively fixing a couple joints that are under constant stress, is one thing. Hard to conceive the agony and frustration beyond that tackling the whole loco.


Removing soft solder to resolder w/silver is tricky at best. The first time soft-to-silver resolding attempt if in the context of the whole loco, for me personally would scare the ba-geeezzzz'us out of me. I know I'd be sacrificing the loco on the alter of improving things. You may be braver. Listen to the wisdom of the gods, if it aint broke don't fix it. 


Ignor this minor rant if I misread you original post.


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## HeliconSteamer (Jan 2, 2008)

Will, 
I'm with Chris here. Unless the loco is having problems now or is exhibiting signs of impending problems, I would not bother removing all the solder and then silver soldering. 

These locos were designed with soft soldered boilers and have run successfully for many decades with said boilers. I've got two B-L moguls, one of which dates to around 1925, the other is immediately post war. The 1925 vintage loco has been run a lot and has given me no problems at all. The newer loco has run much less, but is in great shape. Its obviously never been run low on water and is an absolutely stellar performer. I watch the locos closely when running them, but the lack of brazed boilers certainly does not stop me from steaming them. 

The one thing you don't mention is if this loco is a Northampton Bassett Lowke or a Corgi reproduction. It really should not matter, but from friends' experiences, the Corgi repros are not necessarily as well built as the Northampton made models. 

Good luck, but I might reconsider redoing all the solder if its not causing problems. Again, if it ain't broke, don't fix it.


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## Phippsburg Eric (Jan 10, 2008)

I geuss I would agree witht the above posts...with the Exception that you could build a new boiler without wrecking the old...you could use the old for measurements and arrangements, even convert it to butane if you wanted...the old boiler would still be there for you if you fail or get side tracked. 

I have learned that approch with some of my own modeling efforrts by wrecking something that worked sort of to something that didnt at all. Plus the cast off parts are a good history lesson. 

Aside from those ideas, you will probably end up with a better and safer product than you would by trying to clean out and old boiler. 

--Eric


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## Charles (Jan 2, 2008)

Posted By Phippsburg Eric on 11 Jul 2011 02:31 PM 
I geuss I would agree witht the above posts...with the Exception that you could build a new boiler without wrecking the old...you could use the old for measurements and arrangements, even convert it to butane if you wanted...the old boiler would still be there for you if you fail or get side tracked. 

I have learned that approch with some of my own modeling efforrts by wrecking something that worked sort of to something that didnt at all. Plus the cast off parts are a good history lesson. 

Aside from those ideas, you will probably end up with a better and safer product than you would by trying to clean out and old boiler. 

--Eric 
Add to all that has been said, the skill and expertise to re-solder a boiler if the material can withstand the addition heat necessary for "proper" solder job. I would think a new boiler would be a better outcome.


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## xo18thfa (Jan 2, 2008)

Having done it several times myself, the best way is to heat and remove the soft solder as much as possible. Then sand the part until fully clean of soft solder. You can easily tell, the soft solder is bright silver against the copper or brass. It has to all come off by mechanical means. Wash clean in soapy water. Clean the entire inside of the barrel to ensure no leftover soft solder flux is in there. There is no chemical way to remove it as far as I know. Sandpaper, #220 grit will do the job.


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## bob80park (Jan 2, 2008)

You might want to consider using a silver bearing soft solder 4 to 6 % such as "Stay Bright". It work well over an existing area that was previously solder with soft solder 50/50, 60/40 etc. Many of the silver bearing solders are flux-less and require the use of flux.

Bob


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## xo18thfa (Jan 2, 2008)

I was just going to say if it is vintage O gauge Bassett Lowke, you might consider resoldering to original condition with soft solder. The 4% will work. If you go with regular solder use 50/50 solid wire with acid flux. Match the flux and solder per manufacture's instructions. The parts are already "tinned" so resoldering should not be too difficult.

As an editorial comment this water based flux they sell now is absolutely worthless. For 50/50 use the nasty, smoky, brown acid paste.


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## thumper (Jan 31, 2009)

*THANK YOU, THANK YOU, THANK YOU!*

First, let me provide a few facts to let you know why I'm where I am in this project.

I purchased the loco from a U.K. seller on Ebay who thought he was doing me a favor by crudely stripping the paint. In the process, scratched the sheet metal, so I'm going to refinish it completely. 

Before doing anything, I tried to test it on air [+/- 25 lbs.]. Not only did the loco not run, the front of the boiler blew off revealing the fact that the original joint was only about 80% complete. How it ran in the first place, I don't know other than to say the back of the boiler front was packed with crud. Some of this same crud has plugged the steam lines so that has to be cleaned out too.

As for soldering, I was not thinking of disassembling the entire loco and then reassembling it with silver solder, only reattaching the boiler front with silver solder. From the above, I think I will not go the silver solder route, but I will use a high quality solder with a proper flux.

As for the project, can anyone tell me where I might find a replacement whistle and valve?

Thanks again for the many good suggestions.

Kind regards to all.

Will


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## xo18thfa (Jan 2, 2008)

It sounds like a good plan to me. Using the flux matched to the solder is a big deal now-a-days. And getting everything clean as possible.

If the fix does not work out, the old boiler can be the pattern for a new one. But hopefully the original will get back to new condition. 


The engine would not turn at 25 PSI?? Wonder if the piston packing and/or other gland packings are "gooped" In the old days packings were with asbestos graphite yard. Graphite yard can deteriorate, get "icky" or break down over time. Maybe it needs an overall tear down, overhaul and clean up. Can't get asbestos anymore, but regular graphite yard works. Plumbing shops have it.


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## Phippsburg Eric (Jan 10, 2008)

I would bet that the front of the boiler was only the weakest link, probably other joints are deteriorated as well. I would say that you should at least clean what you have down to bare metal and resolder all the joints...not an easy task I am sure...again maybe starting from new with silver solder? It might be easier to replace steam lines than trying to un-plug them? 

soft solder can deteriorate by chemical corrosion especially if water is left in the boiler. Silver solder is more corrosion resistant as well as being much stronger and having a higher melting temperature.


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