Forge build, (WIP?) Advice Please

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AlaskanHunter

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After my last forge melted down due to a homemade refractory mix that wasn't able to withstand welding temps, I am building a new forge. This time I'm trying to research it carefully and build it correctly. I'm going to build a horizontal forge lined with Inswool HTZ, satanite, bubble alumina, and ITC-100. The part that makes this a not-quite-so-standard build is the burner. Due to the extremely high cost of propane, and relatively low cost of waste oil and diesel, I'm going to build a "Hot-Shot" burner found @http://backyardmetalcasting.com/oilburners10.html. After crunching the numbers, I figured this should be sufficient BTUs (or maybe a bit much). There seem to be a fair number of guys using oil fired forges, but very little info on design and construction. With that, here are my current quandaries:
I found a recommendation for location and angle of a propane burner here (post #11): http://www.bladeforums.com/forums/showthread.php/1370502-advice-on-my-Forge-WIP. Are these figures universal for all burners, or should I be doing something different?
Does any one have info on recommended BTU to cubic inch (or foot)of forge volume? I found one of the propane burner shops with a ratio, but could not find any other source to compare, and now can't remember where I found the data.
I'm planning on an external size of 12" diameter x 24" length. This should give me an 8" x 20" chamber. Since I have never worked with an enclosed forge before, I'm wondering if this is a good size.
I'm planning on a 4x4" rear port and a full diameter front port, but would like to be able to close it off a bit when working smaller projects (knives aren't my only work). Has anyone built a vertical sliding "door" out of hard firebrick for their forge ports? If any of you have can you post a pic or design suggestions? If any of you have tried and found them to be more trouble than they were worth, or didn't work as planned, please explain.
When installing the refractory, the standard procedure (as I gathered from the forge stickies) seems to be Insulating Blanket>Satanite>ITC-100. Where in the process do I apply the bubble alumina? Does it go over Satanite or over the ITC-100?
Thanks For your advice. I'll post pics as I build.
 
Per Ron Reil's website, 400 BTU per cubic inch, 700,000 per cubic foot.8x20 chamber is a very large knifemaking forge. Really, you just need a little bigger than the knife blade, with the 2.5" x 11" chamber of the Atlas Mini Forge being very efficient for knifemakiing.
 
Atlas Knife Company said:
Per Ron Reil's website, 400 BTU per cubic inch, 700,000 per cubic foot.8x20 chamber is a very large knifemaking forge. Really, you just need a little bigger than the knife blade, with the 2.5" x 11" chamber of the Atlas Mini Forge being very efficient for knifemakiing.
Click to expand...
Thanks for the BTU info! I have recently had requests to make forged "household decor" - towel bars, TP and paper towel holders, cabinet handles, fire pokers and the like. Some of that won't fit in a smaller forge. Yes it is overkill for strictly knifemaking, but I do more than just knives.
 
I'm using an old 100# propane tank. I filled it with water (to prevent unnecessary excitement) and used a cut-off wheel to open it. If you don't know, garlic oil (the odor added to propane) settles to the bottom of old propane tanks. I heard complaints about the smell from neighbors at the far end of the runway!:o
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The tank was too big around, so I slit the side, rolled it tighter, and welded it together again.
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I got my stuff from High Temp Tools yesterday, so Today I installed the Inswool and put on the first coat of satanite.
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I did something a little different than usual with the openings. We'll see if that idea was either brilliant or really stupid when I fire it.
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Do I need to let the satanite dry/cure naturally, or can I speed up the process by gently firing it with my burner? Can I do the same for the bubble alumina and ITC-100?
 
Haven't had a chance to update this thread due to my work (maintenance at a summer Bible camp). The waste oil forge is a success! Once adjusted, it runs smooth and clean. I can turn it down so that it runs steadily just under non-magnetic, or I can crank it up till I get sparklers (too hot) and just about any temp in between. I can run it a tad rich or lean, so controlling the mixture isn't a problem. It does smoke a lot when first heating up or if I don't dilute motor oil thin enough with gas or diesel, so running it indoors is not an option.
First time firing it! Running a bit too rich.
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Running at a relatively high heat.
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And soaking along at a low heat.
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I don't have any other pics of running it yet, but this came out of it.
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Nice job forging that revolver! Way beyond my abilities, but then again so is the knife... [emoji12]Nice work!


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Ha ha! Just a prop. I wondered if someone would crack a joke like that.


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It works pretty slick. It not only allows larger projects, but helps with high and low temps. If I open both while running on low, it helps me stabilize the temp just below non-magnetic. If both are nearly closed on high, it gets really hot. I never guessed that controlling the escaping heat would make such a difference in temps. Next step is installing a TC to help me with my temps. Setting and holding any temp doesn't seem too hard, but knowing what that temp is a bit of a bear when you live in the land of the midnight sun.


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Are thoes wood stove fire bricks for the door (hard fire bricks) if so I would be a little cautious because when you crank the forge to max for a welding temp and thy will melt (don't ask me how I know). I thought thy where rated higher then thy are which is only like 2000-2200°. Your forge looks good, any info on you oil burner you can share. I'm going to be building another 1 or 2 forges coming up here in a little while and need much larger openings. I'm thinking about doing a ribbon burner forge on a table so the forge body can be what ever shape I want or need. I also need a verticle forge with a larger opening. I'm at 3"x3" now and need more room for larger Damascus billets. Let's see your burner
 
The bricks are the hard fire brick sold by hightemptools. I can't remember off the top of my head what they are rated for, but I'm confident it's better than 2000*F. I can give more info later, but the burner is a slightly tweaked "hot shot" burner from backyard metalcasting's website (link in first post). The key to getting it to burn well is "cutting" the waste oil to a thinner viscosity. Diesel works ok, gas works better. If I had a larger inlet port or a higher pressure blower, I think it would burn the thicker stuff better- my limiting factor seems to be the velocity and volume of air I can move with the blower (came off a Becket oil gun that was set up for .5- 1.75 gallons per hour).


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When I first fire it up it always spits out a fair bit of dragon's breath. Some of the local guys have jestingly threatened that they're gonna paint "Smaug" on the side of it.


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