A lot of carburetor bodies have cracks like this. I gather silver solder is the recommended fix. Is there some way to clean the inside of the crack so the solder will stick?
Would JBW be acceptable here?
I do not believe you can silver solder cast iron if that is what the parent material is.You can lead solder it. I was always told you couldn't silver solder cast iron,but I've never tried it just to spite my mentors
Old cast iron seems to have a lot of carbon in it and it must be very clean before attempting any bond using heat,and during the heating process a good flux material must be used to prevent oxidization.
Also, you can use a tiny abrasive disc in a dremel tool to groove out the area to recieve the filler metal.
#1.If the casting has swelled at the crack, and bowl threads are too loose, forget about it. Bodies are still too plentiful to worry about it...I'd leave it for the next generation.
2. If the castings haven't swelled at the crack, it is possible, but difficult to silver solder, and when you do, the casting will swell at the crack and you'll be back to #1. Binding with wire prior to soldering may or may not keep the casting from moving, but is worth your time to try if you're intent on doing this.
3. If the threads are OK, and bowl can be snugged up, then drill a small hole at the end of the crack to stop propagation and forget about it. Those cracks are not in a place that seals anything.
I think my first choice on the cracks would be to "v" then out, pull the crack closed and braze or silver braze them. Then because it is obvious that the area is weak, make a steel band to fit snug around the outside and braze or solder sweat the band on. Or if you can machine the carb and band to get it to fit close enough, you could heat shrink the band on. You would end up with a better then original part.
Unless you don't consider "your" time valuable Steve, there are too many cores still available. Regardless of the attempt to repair - it's still a "repair" - in MHO.
Fix it steve, just because you can! i dont throw anything away.
why not braze it? check to see if the threads are loose and if they are squirt a little brass in there grind it down and tap it!
If the OD of the piece is round enough, and the pieces line up well enough, then turn a ring from steel with the ID just a couple thousanths shy of your tightest OD measurement. Prepare a driver of some kind (piece of pipe?), support the work, heat the ring red hot and hammer it home. This worked so well for me that I was able to chase the threads with a tap, right down to clean metal.
I wasn't working on a carb, though; it was a heavier casting.
Steve, I had a cracked inlet from tightening the elbow too tight, I V'd it out and brazed it with success. After grinding it back flush and painting there is no sign of being repaired. Should work as well on the body.
Harris Safety Silv 45 will braze cast iron just fine, as will a plain bronze brazing rod. silver braze melts about 1150 F while brass will melt about 1250 F or so. with a good flux the silver braze will flow very nicely.
I also had a cracked inlet on my 54 Ford tractor carburator and repaired it pretty much the same way that Gordon Byers fixed his.
It worked fine.
I would try to fix it and its a good way to educate yourself in using brazing rods and controling the heat on cast iron.
You can do more than you think with brass and flux.
What have you got to lose in trying to repair it and the expeirence you gain only helps.
Bore an accurate sleeve from a pice of pipe on your new lathe, and tap it on to close the threads. Measure an uncracked carb frame for the size. Braze the end joint closed. the cracks make no difference. Make sure the sleeve clears the float. Id dip the end in some muriatic to clean the loose rust out of the crack. troop
Hey Steve, that stuff's junk. It'll only split again when you run in the fitting.
Try it and tell us how it works out. Brazing might work well too.
I have repaired carbs like that before with JB weld with no problems. A dremel disk to clean out the crack works well but do not V it out as you will lose threads.
Clean well with acetone (VERY important !!!) air dry, and then use the JB weld.
Look at it this way. Its easy, its cheap, and it does no harm if it fails and you need to repair a different way. The carbs I've done this to have only been working for 10 years or so.....so your probably good for at least that long.