[SEL] Silver Soldering Failure

[Dave Croft]

----- Original Message ----- 
From: "Luke Tonneberger" <flywheelin at hotmail.com>
To: <sel at lists.stationary-engine.com>
Sent: Monday, April 18, 2005 5:00 PM
Subject: [SEL] Silver Soldering Failure


> Hi Everybody,
> 
> Well, I tried my hand at silver soldering Saturday and didn't have any 
> success. I tried for about 4 hours and just couldn't get it.  I practiced on 
> a piece of steel. Got it red hot and touched the silver solder to it. It 
> melted and made a nice little blob. After it cooled I smacked and whacked on 
> it and it wouldn't bust loose. I thought hey that's pretty easy so I tried 
> it on my crankshaft.  Put my flux on and heated it with my oxy/acetylene 
> torch with a brazing tip in it.  Got it red hot and touched the silver 
> solder to it. It melted for about 3/16 of an inch and quit melting. I heated 
> it up again and as it got red hot, it started to blow out my other solder. 
> It would just not stay hot to apply my solder long enough. As soon as I got 
> it red hot and started to apply the solder it would cool off and not melt 
> the solder. I tried the cutting tip to get it hotter and that didn't work 
> either. Actually started to melt the steel in a couple spots, then quick 
> started to apply the solder and same thing, just 1/8 to 3/16 and it would 
> cool off and not work. Then reheat and it would melt the other solder out of 
> the way and have to do it over again. I messed around for about 4 hours and 
> didn't get anywhere. I was not a happy guy! After almost throwing the whole 
> damn model in the scrap bin from being so frustrated, I figured I'm not cut 
> out for model making. After sleeping on it for a day I took the welder and 
> welded the crankshaft. I did a little at a time so it didn't get too hot. 
> Not sure if it will be distorted or not, I didn't really care at that point. 
> I did put it in the main bearings after welding and it still turned over and 
> didn't bind. So that's my silver soldering failure story.
> Luke Tonneberger

Hi Luke, Silver soldering is something I learned a good number of years ago
but I still remember a fair amount.
One thing I have just found while Googling for a good site for you is how much
bullshit is on the web on the subject.
See http://easyweb.easynet.co.uk/~chrish/t-solder.htm for a basic guide!
You need the joint you are soldering to be clean & fairly tight.
I use a powder flux which has to be melted on the joint with a very hot gas flame 
until it turns into a thin liquid.
When the temperature is high enough apply the silver solder stick and allow it to flow into the joint.
The entire joint area needs to be very hot & as you move around the joint you need to keep the very 
hot area moving so that the solder stick keeps liquidising.
I advise practising on a few trial pieces before ruining a job.
It is a skill well worth learning.
Best of luck!
Dave Croft
Warrington
England
http://community.webshots.com/user/crftdv