fold forming

thanks roger, the library list is somewhat overwhelming. i see some familiar names, some from our group here in arizona. others, old friends from past ABANA conferences. let me throw out another technic i've had some fun with. has any body out there had any experience doing blow ups? i don't mean exploding propane tanks. i'am talking about inflating sheet metal at red heat. i first read about this in the anvil's ring. i think the article was eric zinner does fish. have fun, mark

Elizabeth Brim is big on this.

For example, see the pillow.

Pete Stanaitis

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Mark F> thanks roger,

I saw a video on the net somewhere of that being done as a demo. Maybe a video about the metal museum in Memphis? Looks like it would be fun to try. They were using low pressure compressed air, but I don't remember how they attached the air to the pillow-shaped object they had made.

Elizabeth Brim welded a 1/8" pipe coupling to one corner to get the air in. I think she only used about 15 psi or so to do the job. The biggest issue was to get the whole part heated evenly, as you might expect. I don't remember how she isolated the air line from the heat. Maybe she used a piece of pipe a couple of feet long. She demonstrated for our club, the Guild of Metalsmiths, some years ago. My wife and I bought the "pillow" she made during her demo.

Pete Stanaitis

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Curt Welch wrote:

I had a bit of a play with inflating a couple of years ago. I welded in a bit of pipe a couple of feet long, which also served as a handy handle, and rigged up a supply of low-pressure air. I was a bit afraid of the whole thing blowing up on me - probably heard one too many scary compressor stories.

For the piece that was too big for my forge, I just kept going back and forth over it with the biggest oxy-propane torch I had to hand, and it inflated gradually but very tidily.

There are a few pictures here:

Richard

Thats is neat looking!

My Dad tells a story of going to the state fair in Indiana as a wee lad.

The fair was all new high tech steam tractors and stuff. One booth was a steel box of heavy plate and he lit a newspaper in it. Said to be 6' on a side. It crushed under the vacuum as the oxygen was converted and air burned.

He said it was impressive to watch.

Mart> I had a bit of a play with inflating a couple of years ago. I welded

impressive work richard, or should i say inflative. i've learned a thing or two about blowups, and will now share this knowledge with the rest of you. as long as you inflate hot steel at low pressure you are safe. the worst that could happen is that your work will spring a hole, at that point inflation will stop. some of my early experiments i found that in larger pieces, ie. 6 inches or greater between welded edges, the work would inflate without heating (cold) . and as i increased the pressure ,work would inflate more. however without warning the piece being inflated suffered a blow out to rivel any truck tire blow out. to say the least, a stunning experience. so to sum it up , don't use more than

Mark - that does sound scary - I'm glad you survived! :-)

Do you have any pictures of the things you've inflated ? I'd love to see them.

Richard

Don't forget ice. A friend of mine makes bananas from 16 ga steel this way. After forming and welding all the pieces together, he adds a pipe coupling, fills it with water, plugs the opening and freezes it. The freezing gives the final, just slightly convex look to the fruit.

Pete Stanaitis

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Mark F> any tips, technics or old hands at this procedure? i made some christmas

that's a very good point pete. there's incredible power in water becoming ice. i remember a story about some one salvaging cannon balls that way. they had to be broken in half first, before being melted down to make sure there was no charge left in them. have fun, mark