My forge

[Forgehermet]

I am putting my gas forge together and I only have ribbon burners. They are three connected together each being about 17 inches long. My forge is a  8x8x28 inch square tube that I plan to insulate with refractory cement and one inch of kaowool.how thick should my cement be and how should I arrange my ribbon burners to prevent melting and get maximum heat? I am fin with using less than three burners if I should.

[ThomasPowers]

What is the intended use of this forge.  Those setups look like you are trying to make a tempering oven not a forging forge. Those burners do not look like any ribbon burner I am used to for forges. 

What pressure do they run at and natural gas or propane?

[Forgehermet]

I'm not sure about the pressure but they use propane and I hope to be able to do general bladsmithing 

[the iron dwarf]

I presume that they were from a forge and not something designed for much lower temps like an oven, otherwise you may do a lot of work for nothing.

what do the makers say about their use?

[ThomasPowers]

Also a 28" forge for "general bladesmithing" is like buying a dump truck as your daily commuting car because you expect to buy a load of gravel a couple of times a year.  Even for swordmaking you don't want that much hot at one time save for heat treating; the rest of the time you are throwing money away or damaging your steel!

[Forgehermet]

It was given to me and I hope to use it whole and not cut it

[mutant]

I think it can be very versatile if you can use the burners separately. If not, don't worry, it's pretty easy to make a propane burner. You would need a high pressure regulator anyway. That would be the most expensive part.

[Buzzkill]

It's your time, effort, and money, but 28 inches is easily double (more than double my forge) what you need.  You'll spend more time and money in up front construction cost and a significant amount more in gas cost over time.  Unless you know your ribbon burners were used in a forge or something else that gets over 2000 degrees F you may be asking for a lot of headaches trying to make your original idea work for you.  We typically recommend 2 inches of ceramic fiber blanket plus a thin hard coating over that.  Suddenly your 8x8 pipe is less than 4x4 inches with the insulation and hot face coating in place. Even if you only go with 1 inch of kaowool you've got a very long and narrow forge.  Figuring out how to protect the burners from overheating and/or erosion is another challenge.

I know you want to use those pieces.  Been there, done that.  I've even forced a few things to work - kind of.  In the end I would have been better off finding people like those on this site who have experience in what they are doing and know of at least one way that will work well.  If you haven't done so already, it would be worth your time to read through some of the many forge construction topics here and/or head to Wayne Coe's website for a good way to construct a small forge.

[Forgehermet]

Thank you for the advice buzzkill

[ThomasPowers]

My advice:  cut it in two and make two forges that you can put inline for when you need the extra length.

However using a 28 inch forge when not needed will end up costing hundreds of dollars extra in fuel use to heat the unneeded space. (I keep mentioning swords because back in the early 1980's i spent a year apprenticed to one of the top US swordmakers and so strange as it may seem I know a bit about them...)

[Forgehermet]

Ok good idea never thought about that I also plan on being able to shut gas off to burners if they are not in use

[Irondragon Forge ClayWorks]

Those burners came out of a home heating gas furnace. I doubt they will work in a forge for heating metal.

[Frosty]

I think everything has been touched on so far. The stuff you've collected isn't going to make a forge. It just isn't. As Buzz says by time you insulate that piece of pipe your forge would be less than 4" x 4" in cross section. It's a perfectly usable piece of pipe, put it on your resource pile. 

Those burners were designed to burn INSIDE those long tubes and heat air or maybe water. They just won't heat a forge, no way. More for the resource piles. (Yes, sort your resources it really REALLY helps)

It's going to cost a bit but if you build a proper gas forge it'll serve you for many years and pay for itself. Some things aren't worth the time and effort not to mention the risk. Propane forges are those kinds of things.

Frosty The Lucky.

[John in Oly, WA]

If you had the means and the inclination to cut your 8" x 8" x 28" square tube, and cut it in half, then cut one piece lengthwise on the corners and the other piece down the middle of the sides lengthwise, so you essentially had two 4" x 4" angle iron, you could weld it up into a bigger box that would get you the room for the needed ceramic blanket and castable refractory. Something like this -

Then you'd just have to figure out more suitable burners.

[Forgehermet]

Would one inch kaowool work is is two inches a must? And I looked at your t burner designs, frosty and I think that is what I will try if you think that will work.what else would you recommend for a forge outline that would replace the tubing.

[John in Oly, WA]

In my first forge, I used 1" of kaowool and 2" of cast-o-lite 30. It works fine. When I build my second, I'll reverse those numbers. I think it'll work even better.

[Frosty]

I recommend two layers of 1" 8lb. ceramic fiber refractory, we all call it Kaowool as it's probably the most famous but there are a lot of  good makes of the stuff. I find 1/2" of hard refractory is plenty thick unless you're rough on the forge. Be a little gentile and you do't need a thick hard flame face.

You want to figure one each 3/4" NA burners for every 300-350 cu/in of volume. Shape is a factor in the number and placement of your burners as well, a chamber can be 350 cu/in but long and narrow so one burner can't heat it evenly. Two 1/2" NA burners is roughly equivalent to one 3/4".

Figure out what size and shape forge you want. THEN determine how many  of what size burners it will need to do what you want. 

Take it from an old guy and don't build a BIG forge. Build a moderate to small forge, say 250-350 cu/in. and get the feel for using a gas forge. It's an economical size to build and operate and it's plenty large enough to do real work. If after you've used it a while, say maybe a year it's not large enough you'll have earned enough off it to build a larger forge and you'll still have the first one.

Frosty The Lucky.

[Forgehermet]

Thanks I ended up with two inches of wool and Putin refractory but I guess I put in the wrong refractorysince it was firebrick repair