For those who want to learn to Weld

[ThrottleJockey]

welding cast is a PITA if you don't have a furnace or oven to bake it in. you need to know what kind of cast it is and what filler metals will bond to it. lots of info on welding online weldingtipsandtricks.com its good stuff.

as for even cooling, you can bury it in sand, flame cool, bake it cool or wrap it in heated fire blankets like reliant gear (welder powered heating coils). the important thing is to heat / cool it evenly to prevent stress cracks or weld failure.

as for identifying cast iron types, file hardness, metal color and acid testing are good simple and easy to do at home. ring testing if you are very damn good (not I). do not taste test the metal to ID it, welders say you can taste the different kinds just to see if ppl fall for it. its funny as hell but very wrong.

i have seen it welded with GMAW, GTAW and SMAW. even Oxy-Act welding. all very cool. i prefer GTAW root with SMAW cover passes, that is with metal preheated to 350degF, cracks and joints cleaned and beveled, welded to 3/32 above surface for weldment. if i can access the back side i will back gouge the root and weld up to surface. all the while keeping the temp above 350degF but not welding between passes if the temp is over 500degF (called interpass temp). a lot of juggling heat and hot parts.

PITA!

but i have fixed a few cast parts for the LSD i was stationed on a few years ago. I also fixed some tractor and equipment parts for my Dad. another PITA procedure is doing hard surfacing on equipment or contact parts.

most of my experience is Navy based welding not shipyard or industry there could be a thousand more ways to do what i have described. this is just what i know and i'm always learning more.

GMAW - gas metal arc welding - mig
GTAW- gas tungstun arc welding - TIg
SMAW - shield metal arc welding - stick
LSD - landing ship docking variant

Thank you for that! Very informational and it appears you know your stuff! My pops was a welder at the StPaul shipyard for many years before it was closed down and my uncle welded drive gears for Steiger CAT in Fargo at their reman facility for a long time also. The drive gear welding sounded like quite a PITA too as it had to be xrayed at every 1/4 inch and if it failed it had to be ground out at least 1 inch on all sides....WTF? Not for me! I heard a lot of complaining at family dinners.

 

[Steveca]

Far from being a pro but I have learned little bits and pieces from various people.

One job I had required building up and hardfacing water well drilling augers and bits. The owner showed me how to do it and I went from there, The machine was a miller with a big crank on the top. I was able to diagnose some problems (with help of forumites) and get even nicer welds than him. Major problem was the 7018 rods were for DC and this was an AC welder. Another problem was 'someone' was doing the filling AND hardfacing all with the hardfacing rod, not good and the welds would break and chip away. I also found some really nice hardfacing rods that, once I got accustomed to, were as easy to use and get beautiful welds with as putting a bead of icing on a cake.

As for cost of metal, a trip down a few back alleys can render all manner of free material; bed frames, fence posts (I don't mean steal somebodys fence) I found a section 8'x12' of chain link that someone had left in the alley after converting from chain link to wood fence, after 3 weeks of sitting there I went and grabbed it, it was leaning against a vacant properties fence, across the alley, not even the yard where it was removed from. It was close enough that I just walked home with it; too big to fit in a vehicle.

At the shop we have 480V units both mig and stick with a gun for aluminum and bronze, stainless, etc..

The bronze wire is pretty amazing, believe it or not I had an application where I needed to weld copper to steel and the bronze wire in the mig gun did it... pretty slick. You have to get the copper really hot so the bronze will stick to it, as copper is a great conductor but other than that it works fantastic... Start welding on the steel real close to the copper so the copper gets lots of heat and it will start sticking.

 

[Steveca]

OK, without pics it didn't happen...

Here is a pic of an anode basket for zinc balls. The 1/4" copper rod is welded inside the V of 1/2" angle iron.

 

[FixItMan64]

A little more info on the cast iron subject. I'm also a professional welder by trade (for more than 10 years). To start off, I agree 100% with everything that 'the_whingnut' wrote.
My welding school instructor had an interesting story about fixing a cast iron engine block from a fishing boat. It had cracked over the winter from a hard freeze (not winterized properly or at all). It was striped down to just the block & the crack was notched, ground out, & prepared for welding. Then a "box" of fire bricks was dry stacked around it & about 20 bags of charcoal briquettes were poured around the block (it was from a commercial size boat). A couple of scraps of 3/4 inch steel plate made a lid. They lit it up & waited for the whole block to get dull red. The plates were slid apart just enough to reach in and weld it up. After he was done the plates were slid back together & they let it burn out (took about 12 hours). They even cooked a a bunch of burgers & dogs on top after the job was done.
Yes this was on a very large scale, but the idea can be scaled back for doing smaller parts. When you don't have access to big expensive equipment, you can McGuyver things in a pinch. The charcoal preheats your work piece. You don't have to worry about inter pass temps because the whole thing is uniformly hot & expands all over at the same rate. Then, as the charcoal burns out it lowers the temp of the whole item slowly over several hours (as a post heat cool down oven would). The part cools & contracts all over at the same slow rate, thus preventing cracking.
It's an old trick learned from an old welder (he was 86 when I took his class). He had more experience in his life time then I will ever get.

I'd also like to add- my hat is off to all of you people that are 'self taught'. Welding is a difficult skill to learn even when someone is teaching you. When you say you learned it out of a book by yourself, I say: bravo, well done.

Tasting cast iron to identify it? That is a good prank (I'll have to remember that one). The guys I worked with would always dare the newbie to bend 3 welding rods around the back of his neck (like a horse shoe shape). The kicker is, yea you can do 1 or 2, but 3 is too much to bend at once. Then the new guy grabs 3 rods & bends them with little effort. Only to have all the coating material crumble off & fall down the back of his shirt. Followed by a chorus of laughter from the old timers.