Posted by Sherman in Idaho [209.33.95.254] on Tuesday, December 23, 2014 at 01:42:59 :
In Reply to: Re: Pto posted by jerryinidaho [24.49.176.137] on Monday, December 22, 2014 at 22:12:21 :
If you don't care what it looks like, no need to "V" out the crack. That's tricky with brazing anyway because the grinder smears the graphite around and makes it hard to get the braze to stick. I'm a lousy welder, but I've had good luck brazing various castings. All you need is a regular old torch, some brazing rod and borax flux. The PTO housing is small enough that you can get the whole thing fairly hot. Ideally it would be all red-hot to minimize warping and cracking, but I've never had a problem so long as I ran the torch all around the area to warm it up evenly and wait till I have a pretty good sized red hot area before I turn up the heat in one spot and start brazing. If you can solder water pipes you can braze cast iron. Ideally, the brass will wick down inside the crack and make a stronger-than-new repair. That seems to be asking a lot, though, so I usually build it up 1/8" thick or so by letting it get a little cooler until the rod is more in a mushy stage and then doing the build-up. Plenty of extra flux, besides what's on the rod, also helps. Once you're done, put it where it can cool slowly. You can even wrap it up in some scraps of insulation or cover it with vermiculite or sand to let it cool even slower. Before you put all the stuff back in it, paint the inside with something like rustoleum paint to seal the pores. Some castings are porous enough that they'll sweat oil right through the metal if you don't paint the inside.