Can you silver solder cast iron

[Leigh Betsch]

Anyone know if you can silver solder cast iron. I figured I'd try to repair my broken No 7 since it is pretty much shot anyway, but I couldn't get the silver solder to flow. Either my flux is bad, or I can't get enough heat with my small propane torch, or it just can't be done. Anyone know if it is possible?

[Dave Beauchesne]

Leigh:

My guess is not enough heat - that being said, cast warps badly if things are not right.

I have brazed cast heat exchanger ends, but packed them in dry sand so the cooling is more controlled - you need lots of heat!! Also, cleanliness is paramount.

Perhaps Harry can wade in - - - - -

Dave Beauchesne

[David Christopher]

not sure about SS but you can use brass,... you can get it with flux already on it at the BORG but I dont think your little propane torch gets hot enough.....I have a #5 that I fixed with brass and it works fine

[harry strasil]

Most people get the parts too hot when Silver Brazing. (once you get it too hot, the flux burns off and no matter what you do, the silver brazing will not adhere to the base metal) and you will have to shine up the cast, its iffy even under perfect conditions because of the free carbon present in Cast Iron.

Take a small glass, fill if full of marbles and then pour in black pepper till its completely surrounding all the marbles, that is what cast iron really is, nodules of iron surrounded by free carbon(the pepper) and that's why it breaks so easily the nodules are not completely cemented (joined) to each other, when machining or grinding cast iron your hands get black from the free carbon.

FWIW, Soldering, Brazing and Welding are just heat ranges.

Soldering is using a filler material that usually melts at 600° F or below.

Brazing is using a filler material that melts prior to the base metal melting, this varies with different materials.

Welding is using a filler metal that requires the melting of the base metal.

The new breed of technicians call forge welding, cold welding because you don't really melt the base metal, just bring it to a plastic stage where you can force it to join together by hammering on it.

[harry strasil]

You might take it to a good welder and have him TIG weld it, they have compatable filler metals out now that make this process workable on Cast Iron. Just don't let some one cobble it up using Nickel rod, Nickel rod is for people who really don't know how to Torch Braze. And in my opinion is a waste of time and effort, I have lost track of how many, probably thousands of times, that I have had to remove nickel some one cobbled on cast iron and fix it right, Its not really hard to remove, just take a real small ball pein and tap the edge of the nickel and it falls off easily.

[Jon Toebbe]

I bought a #7 from a seller on fleaBay, and the plane's cheek cracked in shipping. Just a little one, nice and tight. I was able to very carefully JB Weld it back together, and it ended up working just fine.

With a shattered body though... yikes. Keeping everything aligned during welding would be a real problem. I'd be quite surprised if the plane ever really cut with the same ease as it did before its mishap. I'd be think about salvaging the usable parts: tote, front knob, frog, iron, etc. to sell on the Bay in order to fund a replacement. Solid planes can be had pretty cheaply, and original parts can command quite a premium. You may, more or less, break even that way.

Good luck with whatever route you choose!

[harry strasil]

I don't want to burst your bubble, but JB welding something is about the same as daubing on some Bondo Body filler, it has no holding power on metals. And when whoever has to fix it right, its a real bear to get it all off so as not to contaminate the weld.

There is a much better chance of it holding if you would use the glue that door hinges and body panels are glued onto the new cars now.

[harry strasil]

FWIW, one of the best uses of JB weld is if you spend a lot of time working on your knees and you abraid the leather off the toes of your steel toed boots, It works great by just mixing up some and smearing it over the toe of the shoe and it wears excellent too.

[Jonathan McCullough]

Yes, you can solder cast iron, but how strong the thing will be is open to question. Bob Smalser shows how he soldered parts together for a high-angle frog on one of his planes:

http://www.cianperez.com/Wood/WoodDocs/Wood_How_To/INDEX_How_To_pages/Smalser_on_FiftyDegreeFrog.htm

and part II:

http://www.cianperez.com/Wood/WoodDocs/Wood_How_To/INDEX_How_To_pages/Smalser_on_FiftyDegreeFrogII.htm

[Bob Smalser]

Anyone know if it is possible?

Yes, but there are so many complications with cast iron, you'll be better off parting out your broken #7 and buying another.

Brazing a frog is relatively easy, but brazing a plane body isn't at all.

The problem with cast iron is warping, and the problem with plane bodies is it doesn't take much warp to ruin the mouth trying to flatten the sole after it warps even slightly. And the longer the plane, the greater the problem.

Any silver braze worth using will melt in the vicinity of 1100 degrees (with brass and bronze brazing even hotter). Reaching it should be done slowly in an oven....not with a torch....and the body should be packed in a bucket of lime or the equivalent to cool even more slowly.

You'll never get enough heat with a propane torch to braze anything relatively large. The cheapest alternative for those without a gas welding setup is MAPP Gas. TIG offers many heating/cooling advantages, but it'll be a 90-dollar job or more in a welding shop.

[Matt Radtke]

It can be done and done easily. My dad works in a small job shop and one of his welders was able to fix up a number 3 I picker up cheap. The break was very similar to yours, just only one side. Came back as flat as it was went I sent it, though it is a little ugly now. As I understand it, it only took 15-30 minutes-ish.

[Jon Toebbe]

I don't want to burst your bubble, but JB welding something is about the same as daubing on some Bondo Body filler, it has no holding power on metals.
No bubble to burst, Harry. It was a cheap, fast "fix" to see if I could avoid having to part it out and find a replacement. Because of the location of the crack, planing pressure tended to close it rather than pull it open -- so Bondo probably would have done fine, too. The other cheek was sound, so the whole thing held together.

I've since sold the plane (had to downsize drastically when I went back to grad school), and the new owner reports that it's holding up fine. Of course, I suspect he mostly uses it as a decoration in his power-tool centric shop. C'est la vie. :) The bottom line, for me, is that anything more involved than that is likely to be a waste of time and/or money for most folks -- Jim Koepke and others can advise you on how to price salvageable parts, and you could probably nearly break even by finding another usable plane. It's not like Bailey's in good working order are scarce.

As much as I respect the ethic of repairing what's broke, rather than tossing it, sometimes the end result isn't worth the effort.

[Leigh Betsch]

Thanks for the input guys. I had the silver solder and the flux and a propane torch so I figured I wasn't out anything to try it. No sense in putting any real money into it. I'll probably just keep it for parts and look for another plane to replace it.
Back in the day when I was a mold maker I did a bit of TIG welding, fantastic machines. I was never real good but the good guys would weld mold inserts under a microscope. They could easily lay a bead on the edge of a razor blade. I think the rods were .015 diameter. Most of us "elitist" toolmakers scoffed at anyone that would resort to welding. Usually welding meant that you screwed up the machining and had to find a way to fix it. But there were many cases were a precision weld would save a $10,000 mold cavity from the scrap pile.

[george wilson]

I'm not much of a welder,but my journeyman Jon is quite expert. He has always brazed cast iron. We had quite a few jobs in the shop that needed brazing.

I had for many years a Stanley #1. It must have been dropped early on,because the decal on its handle was mint. I got Jon to braze it. It was broken from the throat right up both sides. I re jappaned it,and after grinding the sides flat on my belt grinder,I aged it to look like the rest of the body.

You could still see where it was brazed,but it wasn't glaring. You had to look. I made no secret of it at all,and when the EAIA visited my shop a few years ago,I showed it as a restoration. I took it to their tool flea market(which I ALWAYS love!!!!). Walked around with it taking offers,and got $700.00 for it. Non broken ones get over $1200.00. I guess the decal on my #1 accounted for some value,but I am glad I got around to fixing it before I retired,and was still in circulation.