Neil,

I have been researching cast iron welding so I can weld with gas (or braze, silver solder?) my exhaust manifold on my TWENTY. I have spent some quality time viewing YOUTUBE with guys welding cast iron with gas, MIG and stick welding with CI specific rods. If I understand your problem, part of the hole (has split away from the rest so you can see the threads in there?) I would try this. Clean all surfaces with a wire wheel. Try to vee out where the weld will be made but leave a small section where the bolt will screw into the broken part un-veed so that the part goes back exactly where the threads are. I have no idea how much area you have to work with so maybe that is poor advice. It saves drilling it out and re-taping. You still would need to run your tap into the brazed area if the braze runs into the hole that far.

I think the pre-heating and post welding cool off in the grill is a good idea. If you stick weld you can peen it with a small hammer after you weld a bit to get rid of the stress. If you braze it, I'm not sure the stress builds up as bad so peening maybe not necessary especially if you cool it in the grill. (Bye the way, I like grilled D2 bottom tanks best when eaten with Dijon Mustard!)

Sorry, I'm no expert on this and still learning. Another option would be to take it to a professional welding shop and let them have a go of it.

Good luck with it and let us know how it came out. That's my 1.25 cents.

Jan

Hi Jan, that sounds like a plan (and thanks for doing the research and sharing : ).
Fatcat - I'm more of a waste-not/want-not guy : ), and am interested in how well this works as well as actually ending up with a working bottom tank.

"drujinin" wrote:

Jan idea matches mine, so I would call it valid!
Braze it, don't even try to weld it! Those guys on YouTube vary from knowledgeable to just plain lucky it holds! Ask the guy with 30 years plus of O/A, Stick, Mig and Tig that's what he will tell you!

Thread Sealant Tape is indeed Teflon Tape found in the Plumbing section of Stores.

Jeff,

Let's just call it the "Cattaraugus County Cobble-ass Fix"! It should work up in Monroe County too.

Yes, I am aware of the varied knowledge (or lack of it) from those who make the YOUTUBE vids, but in general, you pick up some good stuff. Anymore when I have need for a "fix", I go there to see others doing exactly what I need to do. I find it amazing how much is on there. Just recently my wife came home with a problem- "I can't get the window to roll up" on her Honda. I went on there and there was a guy installing a new driver's door power window unit. I went to NAPA and picked up a new one and had her going again in 3 hours. Just saying-

Jan

I'm the same Jan. I'm about to replace the timing chain adjusters on my wife's car, which has a 5k labor charge at the garage. I've watched a couple of youtubes, have the manual, and the tools and am ready to go. Did one on the other car which was also expensive and the video shows me how to do it, and especially what to watch out for. With some pre-existing mechanical sense, I can tell which videos are worth watching. There definitely is a lot of crud out there though.... like that lame D8 vs. 20 jeeps video