So I tried to make a forge by cutting the top off a propane tank, lining it with ceramic insulation and coated it with furnace retort cement. Have one 3/4 brass inlet pipe and have been trying to use a benzomatic twist flame torch from home depot. But it is not getting hot enough. Is the hole to big? I mean it is a big hole and I made a lid but still not enough heat. Or is the flame not enough? or both. Should I just rip the wool out an start over? Or is there no way to use that torch to get hot enough?

Sounds like you have to much volume in the forge for that size torch. A small plumbers torch like that is better suited to a small soup can forge than something the size of a propane cylinder unless you have a massive amount of insulation in it to cut the volume.

Build a venturi burner and run it on a regular propane tank. Actually you'll probably need to manifold two 20# tanks together or get a larger tank so it doesn't freeze up. I think you might get away with using your 3/4" opening.

 

How thick of insulation did you use?

Welcome aboard Knife Guy, glad to have you. If you'll put your general location in the header you might be surprised how many IFI guys live within visiting distance.

 

What you're trying to do with what you describe will NOT work, probably less than 1/10 the burner out put you need just for general forging let alone welding operations.

 

If you take a look down the Iforge front page you'll find the gas forge section, there are hundreds of posts about gas forges including good instructions for building and lining forges, building and tuning several kinds of propane burners, etc. Pack a lunch, something to drink and pull up a comfy chair, just the gas forge section is a LOT of reading.

 

Once you get a handle on forge and burner building you'll enough enough knowledge base to ask questions that will actually help you out and better still, understand the answers.

 

Frosty The Lucky.

It was only 1 inch maybe a little more for overlap.  So I just looked up the Ray Rogers dirt simple venturie burner and is it just a matter of the 10 psi being pushed thru a brass block into a long pipe  with a reducer fitting on it? Do you lite it on the inside or right there and it sends the flame all the way down the pipe? could I just saw the whole tip off a cheapo benzomatic and just run a hose to a valve and then a 10 psi regulator then tank and just plug it in the side? Is the leant important? 

BTW when you said propane tank; you did mean the big gas grill tanks that a lot of folks use for propane forges and not the small hand held plumber's torch right?

 

And could you explain what you meant by "ceramic insulation"  Did you mean something kaowool or inswool or did you mean a castable refractory?

 

Re reading this I started to get the feeling that we were not using terms the same way.

No your right on. Regular Propane tank like for a grill is what I cut up and yes kaowool but not the same brand so just ceramic insulation.

ok you need bigger burner(s) pushing more BTUs in.  You could do it with one blown burner but would probably want two aspirated ones

First, I'm no expert on this stuff. I just got done doing bunches of reading on another site before I came here, and I built a larger forced air forge, but from everything that I have read, you want 2" of the ceramic blanket. That will still give you about a 8' ID on your forge. That's a large area to heat. Even with a venturi burner, I don't know if you could get up to welding temps.

I'm going to back out of this conversation now, because I'm really too new to be giving any advise. I just suggested the venturi burner thinking it would be an easy fix for your forge, but I forgot that venturi burners need a flared/bell/cone shaped piece at the end of the burner in the forge, and your insulation has to be formed around that. So it may not be that easy to change anyway. Plus, I really think you need more insulation.

Knife Guy with no home (location)

 

The knowledge base here is HUGE. If you add your location, there is probably someone very close to where you are, that you can learn from.

The burner you have, MAY be enough to create a Forge with one or two fire-bricks. Small burner = small forge.

Good for you for trying, that is how you learn what won't work. Leave the door open and lite the forge with a piece of burning newspaper, on the inside of the forge.

A bar-B-que lighter also works. Strike the flame BEFORE you turn the gas on, otherwise you will not need a haircut for quite a while!!!!!! :) :)

 

There are lots of different burners. Some work better with a small blower, some work well with a venturi as the air draw.

DO NOT USE A PROPANE FORGE IN A CONFINED SPACE!!!! YOU NEED FRESH AIR!!!!!!

Propane forge makes Carbon Monoxide. Not enough ventilation = forever sleep!!!!! :( :(

I'm trying to do it on my back porch. I live in an apartment so it is low on space. I maybe should have started smaller. I live in Durham Nc. I did update my profile to include location. Thanks for the tip and the warm welcome. If anyone lives close and wanted to show off their stuff I would be more than interested. Thanks.

Have you looked in the forum for information, we have an entire subsection for gas forges.