Comments for "Propane Burner"

19th February 2008 11:02

Alan Yates wrote...

Probably. You didn't specify how wide and long the piece is, but iron is not particularly conductive so the length shouldn't be too critical.

Some fire bricks to contain the heat around the region you wish to bend should make it more practical to heat wider pieces. Basically you'd assemble a rough forge with the bricks around the region and just heat the hell out of it with the torch running rich to minimise scale production.

The mechanical properties of the heat affected region will likely be changed significantly. My understanding is that most common steels shouldn't be forged below about 900 C. Steel softens to about 1/5 of its yield above 650 C, but working it in that region will probably damage it. However, I make no claim to having a clue about metallurgy!

Some back of the envelope calculations suggest it takes about 370 kJ/kg to heat steel to 900 C (ignoring conductivity losses). I have no idea what the burner rating is, I didn't measure the fuel flow rate and couldn't begin to assess its efficiency, but Propane has an energy density of about 46.6 MJ/kg. This means a 9 kg tank has the energy to heat about 1100 kg of steel to 900 C assuming no losses! (Melting an engine block with a tank of Propane sounds remotely feasible...)

The burner runs for quite a while on a full tank, but I haven't timed it, so I can't really say if the thermal output will be sufficient to do the job. It sounds quite reasonable that it should be up to the task if the heat is well controlled and losses are minimised.

19th February 2008 09:32

John Baker wrote ...

Will the burner make 6 mm steel plate red hot so it can be bent?

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