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New propane tank forge v1.0 and burner


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Hey all I don't think I've posted here before so here goes.  I started with a 20# propane tank for the body. I used a 2300f 3/4" blanket in two layers with over lap at the bottom and in the back of the chamber.  I made the mistake of not using rigidizer before applying a thin layer of 3000f resistant mortar cement to the blanket and the floor of the forge. 

My burner is the simplest perhaps hap hazard design I could come up with that is influenced by the principles of other designs I've seen.  I have a 20 psi regulator with a 3/8th outlet running to a 1/2 gas rated ball valve.  The other side of the valve is a reducer to a 3/8th nipple with a 3/8th hex sided cap that I tapped with a #6 1.0 to accommodate a .30 miller mig tip.  This sleeves, after some light filing on the corners of the cap and reducer, into a 12" long 3/4" ID sc40 pipe nipple that I drilled a series of 7/16th holes into for the venturi effect. I have a 1" ID sc40 section of pipe filed enough to sleeve over the mid section of the burner which acts as the choke.  I welded a 4" long piece of sc40 with a 1" ID coming past the wall of the shell about 1/4". This along with the blanket and 3000f cement form the cone for my burner.  So far I am able to bring 3/4" mild stock to easy forging temp in about 3 to 4 minutes after a 5 or 6 minute warm up of the forge, I should mention I am using a full 3ft rod for this as I am making my own tongs and currently have none to accommodate 3/4 stock, this I believe is a large heat sink being mostly outside the forge. I have not timed this precisely but i can. I do not have a way to read temp aside from scale formation, the feel of the hammer blow and the initial glow brightness. I am color blind so this is what I rely on. I do not yet have a needle valve or a pressure gage in line but may add these. I usually forge steadily for 2 hours or more the last few evening and have no ice or even an overly cold touch to the 20# supply tank though it is freshly filled. I have questions to follow and thank you for your time gentleman and ladies.



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

There are a couple ratios you missed or didn't understand when you were looking at burner and forge plans. The most important relation is between burner output and forge volume. One properly tuned 3/4" burner will bring 300-350 cu/in to welding temperature. Insulating refractory is also important to forge and fuel efficiency.

Another set of ratios that obviously weren't discussed in the "plans" you read have to do with the burner itself. The burner tube length as measured from the narrowest dia. of the air intake end to the output end should be L= 8-9xDia. a 3/4" dia. burner tube needs to be 6" long or skin friction will seriously degrade performance, shorter and it doesn't have time to properly mix the air and fuel.

Take a look around and pick ONE set of plans then follow those. Mixing and matching when you're not really tuned into how these things work isn't going to improve things. There are people out there who have been building similar burners for quite few who are doing a pretty good job of making poorly designed and inefficient burners to look like they're burning well.

Look, I'm not trying to come down on you, you've done a pretty decent job for having picked poor plans. I don't want you to quit the craft in frustration or devote huge amounts of time and effort trying to make so so tools work for you. If you spend a few dozen hours reading the gas forge and gas burner sections here on Iforge you'll gain a good grounding in how these things work, what questions to ask and what the answers mean.

Honest I'd really rather see you successful practicing the craft and there are a lot of us here who'd like to help.

Frosty The Lucky.


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Frosty, I'm not sure how to take you so here goes. 

First, I have no idea where you read that I have a set of plans, or that i read plans or me even typing the word "plans" in my entire post. I haven't "picked poor plans". I have seen videos and read the "help me" forums on the various sites and arrived at this design because of available material and minimal set up time.  I realize there are lots of forges having difficulty getting to forging and welding tempts, I do not know why you have presumed I am having trouble with my burner or forge setup in those areas. I did not build a forge to do it all, I built this one as a successful test run and to forge tongs, fullers drifts and punches.  I haven't even attempted to scarf anything as of yet, but i also haven't cranked up the flow. I'm not here to make another knife, or a katana or a yard hook.  I make tools, I started with wood, many of my tools in daily use are 100 or more years old and the ones I make are based off of these, but now I am in metal as a way to further my knowledge.  There are only a handful of principles at play in these forges and burners, they are also very easy to apply so long as they are not over thought.  The only goal I see for any of these forge and burner builds is to get X stock hot enough to move around under a hammer.

What I'm most frustrated by though, is inferring that I would "quit the craft in frustration" like I'm a teenager wanting to make his first sword cause I'm the biggest Vikings show fan. I've been a carpenter for 20 years, picked up my first hand saw up at 6. I'm hardly a stranger to difficult tasks involving your brain and brawn. I began blacksmithing in a homemade charcoal forge with a hairdryer and a horrible tuyere.  Gas allows me to forge sooner in the evening with less prep. If I were going to quit blacksmithing it would of been well before now. 

My current forge, is reaching yellow heat on 3/4" round bar in acceptable time, and once removed from the chamber my work scales and squishes easy enough under my hammer, though I am using a 7 pound hand sledge to draw out. I have no intentions of working wrought iron so I do not need white heat temps, once I have enough forging tools I may build an even smaller forge as higher carbon steel forges at lower heats but this is not the topic at hand.  I am only having an issue with the refractory slaking off the walls and ceiling. I posted here to find out the preferences of castable refractory and any useful recommendations.  What I've received is being told that I've mix matched components to a system that I don't understand, even though my build is accomplishing what I have set out to do with it, push hot enough metal around under my hammer.

I see we are off on the wrong foot Frosty, if you take offense to my words then so be it. I do not mix well with thin skinned folks anyways and I will intentionally throw a congeniality contest when it comes to forum moderators.  If that gets me banned so be it, as I am not currently impressed by being told out the gate of how wrong my forge and burner setup is even though I am only having an issue with refractory slake.

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