Does anyone have any experience with inflation forging? .....IE heating an enclosed fabricated mild steel form to red hot and then injecting compressed air into it to make it expand. This method has been used in industry and I was thinking of incorporating it into my artistic language

I have never heard of this process outside of glass blowing. I would guess that it would take more pressure than any standard air compressor would put out in order to move steel. I have heard of explosive forming where an explosive charge working against water forms the part via hydraulics into a lower die.

The biggest problem I see with this is safety. A hydraulic leak isn't bad compared to an air tank failure = rocket propulsion. You could easily get enough air into a red hot vessel to create a very dangerous ( deadly ) situation. An air compressor tank failed at an auto shop. When the tank ruptured it propelled the compressor through the block wall killing the mechanic on the other side. A tire may only have 35 PSI in it, but when you figure out the sidewall surface area it adds up to tons of pressure exerted onto the rim. Compressed gases need to be treated with the utmost of respect.

Elizabeth Brim is noted for mastering this technique if anyone was looking to research this.

Master Metalsmith 2009: Elizabeth Brim

Our guild demoed that a few mos ago. Use 16-18ga sheet. 2 pieces weld together. Weld in a pipe about 2 foot long with a ball valve and air chuck. Leak test while cold(slack tub)
Heat to forging temp. Inflate. Wear face shield and leathers keep others back. Any weak
spots in the weld will blow out.
Ken

When I assisted Elizabeth Brim at Caniron in Hamilton she had a piece of pipe welded onto the 2 pieces welded together. She then just held a rubber tipped blow gun onto the end of the pipe and blew the air in. Doing it this way seems much safer as you cannot get as high a pressure just holding the tip into the end of the pipe and if anything goes wrong stopping the air is just a matter of letting go of the trigger on the blow gun or letting it out of the end of the pipe.

I can see now what you were talking about. I thought that you were wanting to work with thicker material.

there's a video on youtube of someone doing this type of operation but using a pressure washer instead of compressed air. much safer in my opinion. think they may be making an expansion box exhaust for a two stroke motor bike.

I've seen it done in Demo's using a bicycle pump. Gas forges where you can heat the entire thing up evenly are a big help!

Ahh putting water into a red hot enclosed form = safe???? That sound you hear is the steam explosion paging Darwin!

"IE heating an enclosed fabricated mild steel form to red hot and then injecting compressed air into it to make it expand"

Or do you mean they were using high pressure water into a cold system---not what was being discussed. I still think that low pressure into a hot system would be safer than high perssure into a cold system.

Edited October 27, 200916 yr by ThomasPowers

If I remember correctly they actually had that as a project in "The New Edge of the Anvil". The piece they show in the book is an artistic pillow with tassels

Ive watched this done, Eddy Raine demoed this for our OBG meeting some time ago, he cut, forged and shaped two halfs of a fish out of sheet metal, welded the two up with a small pipe maybe half inch attached, as said above he used a compressor with just a rubber tip, the fish blew up nicely. it was also mentioned that you could use something like a high pressure CO2 tank or Argon, anything none flammable.

Dave Mudge out of Louisiana inflated a fish and made a really cool lamp out of it on one of the old Modern Masters TV episodes. Come to think of it now, Modern Masters is where I first saw a young Danger Dillon working a 50lb little giant and a hossfeld bender...Good times!
-DB

Dave Lisch has done quite a bit of this type of work, You might send him a PM and pick his brain...