Welding Tips and Tricks

For some reason, I couldn't figure out why I couldn't get my table saw to cut accurately. Did every conceivable adjustment and nothing. So, I took it apart and found the culprit. One of the tabs that hold the trunion to the table was completely broken off. It's cast iron as mentioned before. I feel comfortable welding most other metal but have never tried a high stress weld in which a very heavy motor and table will be counting on to not snap again. Any suggestions like type of rod and technique? Do I need to heat up the mating surfaces first to a certain temp? I just feel lost at this point. Thanks to anyone who can offer any help.

Welcome, 5150cliff,

I'll copy your topic to "shop talk", where it'll be seen by all.

Steve S

There are a few issues, the cast iron fillers can be a bastard and not machinable once they get hard. You can use silcon bronze filler and tig weld it.

Grind the area out with a carbide burr, nd brush it very good. You need to peen it while the weld is still very hot, so I weld small areas at a time. Preheat is a must and a very slow cool down is critical, guys like to bury it is sand or even lime....works very well.

Wat type of welding equipment and experience do you have? You could also braze it...

Rick_H wrote:There are a few issues, the cast iron fillers can be a bastard and not machinable once they get hard. You can use silcon bronze filler and tig weld it.

Grind the area out with a carbide burr, nd brush it very good. You need to peen it while the weld is still very hot, so I weld small areas at a time. Preheat is a must and a very slow cool down is critical, guys like to bury it is sand or even lime....works very well.

Wat type of welding equipment and experience do you have? You could also braze it...

Rick,
I might respecrfully disagree with the peening while TIG brazing. Peening would only be need when welding the cast iron and not brazing. Correct me if I am wrong.

5150cliff,
Welcome to the forum. Before further help can be given by myself I would like to see a pic of the part in question.
-Jonathan

Another option before you get to carried away is check the price of the part new. I had a cast collar for the base of a drill press brake. I was gonna weld it also just to see out of curiosity what the part cost I looked it up. Brand new part was $12 with either 5 or 7 dollars shipping. So basically under $20 bucks was worth buying a new piece instead of messing with the welding on a crappy cheap cast part.

Just an option that might save you some time and money especially if you use nickel rods to fix it.

Superiorwelding wrote:

Rick_H wrote:There are a few issues, the cast iron fillers can be a bastard and not machinable once they get hard. You can use silcon bronze filler and tig weld it.

Grind the area out with a carbide burr, nd brush it very good. You need to peen it while the weld is still very hot, so I weld small areas at a time. Preheat is a must and a very slow cool down is critical, guys like to bury it is sand or even lime....works very well.

Wat type of welding equipment and experience do you have? You could also braze it...

Rick,
I might respecrfully disagree with the peening while TIG brazing. Peening would only be need when welding the cast iron and not brazing. Correct me if I am wrong.

5150cliff,
Welcome to the forum. Before further help can be given by myself I would like to see a pic of the part in question.
-Jonathan

Correct sometimes I take stuff for granted...yes peening is only needed when welding.

I've had some success with JB Weld. I'm not sure if it is suitable for your situation.

Thanks guys for the quick responses and suggestions. For the comment about my equipment and skill level.....I'm a recently retired federal law enforcement agent and am really just trying to self teach myself. I've got a Lincoln 180 mig unit and a Lincoln 225 "buzz box". Not real experienced but a quick learner. I'll send a photo of the part soon for further clarification. The replacement of the part is something I can consider but I figured that I would like to exhaust all repair possibilities first.

Just an update on my situation. First, I think that this site is great. I decided to do some further reading here and got a ton of information on welding cast iron. With that knowledge, and with the fact that the replacement part for the saw is over 250 bucks, I went to my local welding supply, bought some "Nickel 99" rod and went home. I heated the part up to about 700F and welded it up. What an amazing (well, at least to me it was) weld. I let it cool down slowly by wrapping it. After checking it in about 2 hours, I was happy to find that I had no cracks. Put the saw back together and am a happy camper. For all who have had input into this site, I thank you. Cliff.

Cliff,

I'd advise you to monitor that repair for cracking adjacent. It's just a precaution. The interface between the filler metal and the base metal will be fine, but the area "just" outside that is a different matter. There's a reason everyone recommends pre- and post- heat, and your high-vibration/high torque situation is one of those cases.

You might be golden... It may last for the life of the saw. Don't bet the farm on it, though.

Steve S

Otto Nobedder wrote:Cliff,

I'd advise you to monitor that repair for cracking adjacent. It's just a precaution. The interface between the filler metal and the base metal will be fine, but the area "just" outside that is a different matter. There's a reason everyone recommends pre- and post- heat, and your high-vibration/high torque situation is one of those cases.

You might be golden... It may last for the life of the saw. Don't bet the farm on it, though.

Steve S

Right on