I started a couple cauldrons/cooking pots, the smaller one ended up a nice enough shape, just need to put a handle on it. 

The larger one didn't go so well, it went sorta Pringle shaped, and I had a hard time getting it to even out. After that I worked it to thin and split the bottom, oops. I also had a hard time bringing the edges in to get a more closed shape.

I was using a ball peen and a piece of heavy wall pipe with the edge rounded over, about 2.5" or 3" diameter, to sink them.

I started in the center and slowly spiraled my way out, making a little ridge and pushing that ridge to the outside edge. I was working cold, and relaxing the metal with a torch in between passes. The smaller one was also a little thinner, about 1/16", and the bigger one was maybe 11ga. 

The smaller one went a lot smoother, no Pringle shape, didn't feel like I had to go over the same areas as much.

Would a larger tool help with making larger dished shapes? 

How do you prevent your work from getting that Pringle shape, and if you do get it, how do you get rid of it? Working around the edge seemed to help, but trying to stretch areas within the workpiece didn't seem to do much for me.

The next attempt on the larger size I will be doing hot instead of cold, it was rainy today and I didn't feel like catching any 120v from my blower controller again so I tried getting a way with doing it cold.

Any other advice for more drastic dishing? I wanted to get the rim to be a smaller diameter than the belly on the larger one, but didn't get a chance before I split it.

 

Good Morning,

Weld the cracks with Oxy/Acetylene Torch. By the time you are finished, you won't hardly see the weld. Enjoy the Journey.

Neil

Well the real experts on dishing are over at the armourarchive.org as a lot of armouring involves dishing and raising.

You may notice that in earlier times large cauldrons were formed from multiple pieces that were riveted together and then "gunked".

To pull in an edge you need to shrink it or  start with it thicker at the circumference you want and then dish out the rest to make it balloon out.  Raising may be more applicable than dishing for large items.

Ball peens are usually much too sharp to do a good job of dishing; you want a very smooth curve ) on the face of your dishing hammer! So grind or forge the flat face to be ).  I make dishing hammers from dome headed RR bolts, not spikes, bolts; but then I do most of my dishing hot and use a large solid ring, (think ring and pintle hitch), or the base of a scrapped oxy tank to form into.

Stop by the metalworkers guild event Saturday as I will be teaching how to make dishing hammers there!

I'll either weld it up or do something more abstract and maybe go for a few more splits. All out of acetylene right now, so leaning towards just having some fun with it.

I'll definitely have to check and see if I have any rr bolts kicking around, the other problem I had with the ball peen is it's a little short to get into the deeper areas well. Might have to ask a gas supplier for an old tank next time I swing by as well.

Make sure they know you want to chop it up!  We once got 3 full sized pickup loads of tanks that failed hydrotest from a Hydrotester; but we had to cut them up onsite.

Currently I have 6 tanks that went through a fire and then to the local scrapyard.  I just need to get them cut!  (Stocked up during the lockdown to help keep the scrapyard in business.)  

When working with a RR bolt  you can put the handle eye in the threads near the other end and so have a deep dish hammer. I also found that putting a slight curve in the body of the bolt allows you to hit dead on when working the sides.  The curve should match your swing arc.  You can harden in oil and temper or normalize too.

 Tow ring, commercial boilermaker's sledge, bottom of a welding tank

  RR bolt dishing hammers: curved, straight, center handle

I'll be trying to pass on some of my "scrap to make armourmaking tools" this weekend.  I seem to find it faster than I can use it!

Great post. Now I know what to do with the RR bolts I have kicking around my shop! 

it's posts like this which illustrate why we miss Thomas so much.  Johnny, we lost Thomas earlier this year to brain cancer.  He was one of the great ones.

I see where Thomas used a bolt to make a hammer. Even though he's gone he gave me the idea to pull out a giant bolt (1 1/4" x 14") I've had for a few years and see if I can make a small hammer out of it. I suppose I'll see if I can salvage the nut and do something with that as well. Even though his anvil rings no more his wisdom rings loud for those who care to listen. I can only hope I might inspire a single person half as much as he has inspired so many.

Be careful with the bolt. Many are plated with other metals that are toxic.  If it's just steel go ahead, but if it's a different color, you might want to reconsider. 

 

 

Nothing to worry about there Brian. The bolt is rusted pretty bad and the building I got it out of was a 150+ year old railroad depot. I don't think it was ever galvanized. It seems to me that years ago we lost a member here to welding galvanized metal. If I remember correctly it was 10 years ago or more and it was somebody who obviously knew the dangers because I seem to remember them sending everyone out of the shop before he started. I could be misremembering but I'm sure some of the old timers here remember who it was or if it even happened the way I remember. I haven't used galvanized metal since. 

Glad to know the warning wasn't needed and it sounds like your bolt is safe. 

I have a bucket with some largish bolts with a golden colored plating which I think (but am not sure) is cadmium.  I got them off some old equipment racks that were being dismantled many decades ago.  They don't rust.  I'd never put them anywhere near a forge or welder. 

 

Put them in vinegar for a few days. If the plating isn't too thick it might eat it off without damaging the underlying metal. 

Keep in mind that using acid to dissolve coating that may be hazardous make the acid itself hazardous waste.

If the coating is cadmium, it could take a lot stronger acid to dissolve it off. If it does the waste created is much more hazardous than if it was hexavalent chromium which is your typic yellow zinc plating that is pretty nasty in it own right.

Keep it fun (and safe),

David

I only use vinegar to deal with rust on things I want to restore but I've seen people use it to take off zinc plating. I don't use vinegar on things I'm making simply because I don't need it. I just don't use coated materials, it's simpler and there isn't much that is plated that can't be found unplated. 

5 hours ago, Jason L said:

I'm sure some of the old timers here remember who it was

Yep... That would be Jim Paw Paw Wilson and here is his story.

I can't control the wind, all I can do is adjust my sail’s.
Semper Paratus

 

That's the one Irondragon. I knew one of you guys would remember. I remember lots of talk about metal fume fever and warnings galore. He taught me a lesson for sure and I haven't let flame touch zinc since.