silver solder for cast iron?

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this is a little off topic, but i figure lots of you fellers use silver solder, so maybe you can help...

i have an old hand router plane (for wood) that cracked on the frame...it's a pretty clean crack, and very thin, all the way through a section measuring probably 3/8" x 1/2" square...i estimate the width of the crack at somewhere between 1/32 and 1/64"...i can probably push it together to where it's closer to 1/64"...

would silver solder be good enough and strong enough to fix this? and would it fill the crack or is it too thick to fill? and if so, is there a particular kind that is best for cast iron?

i THINK it's cast iron...not positive...and no idea what kind of cast iron...

i've thought about brazing, but that requires a much higher temperature...i'm not experienced and don't want to mess with heating up cast iron that high...i understand it can be tricky stuff...

thanks in advance...
 
or can i use some other kind of solder? it'd be great if i can use something that i can pick up at home depot, rather than having to order silver solder...

i DO want it strong, but this joint isn't going to have a lot of stress on it, so it doesn't have to be super strong...
 
I guess that the solder would not 'wet' (a term used that means that the solder alloy combines with the alloy or metal being soldered) with iron. However, I am not expert in silver solder or its uses. I hope you, and am sure you will, get expert advise from someone here that knows better because it sounds dangerous to me if that router could fly apart on you under hard use.

Roger
 
I believe he's referring to a router plane (the original router, not the new fangled kind) so there's no danger of flying apart.
 
Short answer: Buy a new plane.

Long answer:

There are methods that will repair gray iron castings but they all have serious disadvantages.

1. adhesive bonding - Epoxy is recommended. Low strength, will probably just fail again.

2. brazing - Special filler and fluxes needed, specialized pre and postbrazing heat treatment required to avoid repeated failure due to stress set up by the heat source. Will be about half the original strength of the part (at best), will probably warp the casting.

If you choose to have the casting brazed make sure that the shop specializes in cast iron repair (typically iron engine heads, blocks etc.). Do not deal with any shop that will not warranty their work. Do not have this done at a standard welding shop.

3. soldering - Extreamly difficult but possible. Similar strength to epoxy bond.

4. arc welding - Some welding hacks (usually the ones specializing in farm equipment) will do this. Not recommended.
 
yeah it's an old hand plane...no danger here...

thought about JB Weld, but the crack is too small...i can't get it in there without forcing it apart...unfortunately, the way this thing is shaped, i'm afraid doing that would cause the opposite end to crack...

serves me right for shopping on ebay, i guess...oddly enough there was no mention of the crack in the ad...still more oddly, i haven't heard back from the seller...(that's a very sarcastic "oddly", by the way...)
 
Actually you can weld cast iron well if you follow the proper procedures. That said most welding shops prolly won't. First the end of the crack needs to be found. wipe the cracked area down with kerosine. Wipe dry and then rub powdered chalt over the crack. This way you can see where the crack actually ends. Drill a small hole at the end of the crack. Preheat the whole piece till it's a dull red. Weld using a nickle rod. Cool the whole piece as slowly as you can (50deg/hr or less). Basicaly not hard, just a royal pain.

WS
 
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