[SEL] Silver Soldering Failure

[Curt]

Luke,
I hope I am not repeating what has already been mentioned.....but two 
additional things come to mind.....
1) When I silver solder with a oxy/act torch I adjust for a slightly 
reducing flame so as not to melt or burn the metal as you mentioned was 
happening.
2) The principle with silver soldering is essentially wicking. Yes you 
have to get the entire area you are trying to get soldered hot, but the 
solder will wick or run to the hottest section. You heat the entire 
female area to be soldered early on until close to the melting temp of the
solder. Pick a side you will feed the solder to. Move your torch to the 
opposite end. Continue heating and once you cross the threshold into 
melting the solder it will suck right toward the hotter end.

This technique has served me well with regular solder on copper water 
pipes, with silver solder on HVAC tubing, and a host of other 
applications. You might buy a few copper fittings and some pipe and 
watch the wicking action before doing another crankshaft. If you are 
trying this with 3/4" fittings, apply your heat around the fitting only 
(never the pipe), about 3/4" away from the end. Keep heating, as the 
heat travels to the end of the fitting it will eventually melt the 
silver solder which you are holding in contact with the pipe at the edge 
of the fitting. Once you just exceed the melting point the silver solder 
will instantly wick towards the heat source completely filling the joint.
Hope this helps,
Curt Holland
Gastonia, NC

Luke Tonneberger wrote:

> 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
> Rockford, Michigan
> USA
>
>
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