new propane--shell, length/burners questions

[SwingsSharpObjects]

Hello--this is my first one here. I have a few questions about my new knife-ish forge in the making. The planned shell is stainless steel (kitchen trash can). The outside dimensions are 24" x 12"--going with 2" insulation (refractory?...still getting used to the language) that leaves me with 20/22" length and 8" diameter or 1000 cu/in to 1100 cu/in to bring inside to forging temps. This length requires at least 2 burners (3?), but what size (1" required or will 3/4" work?) and what type and spacing distance? My other questions are whether the shell is fundamentally up to the task and what's the best way to door, close or cap this off (thinking original lid on one end and fire bricks, a temporary start, on the other? Thanks! Ryan

[pkrankow]

Welcome aboard Ryan.

I am making my first forge too, and came up with some extravagant plans from a 16 gallon barrel. My plans became much smaller as I took stock of various thoughts.

Are you making swords? Do you need such a long forge? Would it be better to cut it down some, open up the cutoff and flatten it out to get metal to make ends? Firebricks on angle iron tracks are often used as effective doors. Is the lid metal too? You can make a front door by cutting this up. 1/8 inch steel or stainless steel pop rivets are nice, cheap, and effective, but be careful about breaking drill bits. Can you buy a second trash can to get more metal if you really require the length?

One 3/4 inch burner working correctly heats 200-350 cu inches of volume to welding temperature. Having more heat available means you can turn down your pressure and not use all of it. Not having enough will always be not enough. You need openings in your ends to let hot exhaust out, figure at least 4x4inch or equivalent. I am unsure if this is per burner or not. You can always use a firebrick with a notch cut out of it sized loosely to the chamber at the back to reduce volume and change exhaust gas flow.

Large forges are going to consume large volumes of fuel. Energy used to heat the forge with is never reclaimed to do work with. Reducing a large forge with a movable back wall, and turning off burners helps some. Unused burners can be damaged by heat or other factors, there is a report of a rodent getting cooked in one.

You can also double the metal thickness where your burners will be, or use separate supports if the walls will not hold the burners. Drilled or welded angle iron, or punched legs from inexpensive steel shelving is effective for bracketing.

Read Ron Reil's website, Forge and Burner Design Page #1 , and check out the blueprints section here. You should also check out the freon bottle forge on Ron's website or the simple gas forge on Zoeller Forge. Just call up your local HVAC company and ask for a few spent freon bottles, you can probably get them for free, but they may be punctured for recycling. This is not a big deal, just line up the hole for something and cut it away, plug it with a bolt, or ignore it.

I probably should have gone that route for myself (I did think about it), but I wanted something that had a wider floor area for hot bending metal. Remember that there is more than one way to do anything and your brain is your most powerful tool.

Phil