Another newbie question

[troglodyte]

Merry Xmas everyone. Great xmas. Loving wife gave me a 2x42 belt sander and a 8" buffer. Here's my newbie question. Building my little forge out of a 5gal. air tank from HF. I was given bunch of new K-23 brick and shape to fit and have a 5" dia x12" chamber. Plan to coat with satanite to seal seams and coat with itc100. vol. of chamber approx.190ci. will a 1/2 burner suffice to heat with. Any advice greatly appreciated. Happy Nw Year guys and God Bless.

[Ray Rogers]

I see you have done a lot of work already but you may want to start over. First, you have a fair sized container, then filled it with brick. From the description it sounds like the interior is now a rectangle. If so, you have a number of problems.

First, brick is relatively heavy, which means it soaks up a lot of heat, which means it will heat up very slowly and use a lot of fuel before it gets hot enough to be useful. Next, you have a non-round interior which means you will have serious hot spots somewhere in there depending on where and how you mount the burner. If you intend to heat treat simple carbon blades you can probably get the job done with this forge arrangement but if you intend to forge your blades this is far from the best design.

What is a 1/2 burner? A half inch forced air burner? Might work but probably won't be fast.

I'd get rid of the brick and reline the forge body with a couple layers of 1" ceramic wool (cheap, fast, and simple). You could use the brick on the forge bottom and for doors at the front and rear. With a more or less round interior and the burner mounted correctly you'll have a lot better performance than with an all brick rectangular interior ...

[troglodyte]

Hi Ray. Thank you for the advice and you are correct, but brick Ihave and it was free. During my reading I noted many smiths agree with you about square chamber forge, but mine is round. Brick was easy to work. I made a very small chamber and rounded it out with a carbide wood carving burr. I was led to believe that ITC 100 increase heat reflectivity back into the forge chamber. As to the 1/2 in. burner it's a T-Rex burner that was a christmas present from my brother in law. Would this suffice, if not I can build a 3/4 in Reil type burner. You stated this was a fair sized container. Its only 11in dia. To big? Thanks again for your advice. I need all I can get.

[Ray Rogers]

The only way to know for sure is to try it. A round interior will help the gasses to flow if you do your part and get the burner in there at an angle that will start the gasses off in the right direction. Venturi burners can be touchy, some work very well and some aren't that impressive. The brand you have is a good one but it might not like the altitude you live at or the back pressure it finds in your forge body, etc. Just have to try it.

But, even if it works very well you still have a considerable mass of brick to heat up. It may be slow but eventually get there or it may not be able to get there at all. Or, it might get hot enough very quickly - possible, but doesn't seem likely. Again, try it and see. The ITC-100 will help but it's only good for a few percentage points and it only works for as long as it takes to burn it off or chip it off - with brick it probably isn't as helpful as it is with wool. But again, you've got it built and paid for - nothing to lose by trying it. We might be pleasantly surprised...

[Crex]

Not sure about the designation K23 on the brick, is this the "soft" brick you can work with moderate hand tools (hacksaw, rasp, knife)? If so, it is more of an insulative brick and will heat up quite rapidly much like the K wool fiber. My experience with the soft brick has been ok (not quite as good as the wool). The ITC should stay put if diluted well before application. I have welded up damascus in one of these, but flux will eat them up like styrofoam.
The 1/2" is probably undergunned for that size chamber, but the T-rex is a good torch and may do ok. As Ray said, try it. Nothing to build a larger one if need be.
Doubt altitude will be an issue in KY with the venturi burner. I regularly use mine at 2500 to 2700 (NC) with no problems, higher maybe a little touchy.
Looks like you are close enough to just fire it up and see how it does. Just make sure you take the time to dry it out properly before going mid to full load fire.

[troglodyte]

Hi Crex. Hope you had a great Christmas. In response to the type of brick. The k23 brick are the soft insulating type. Very easy to work. You said that flux will eat them like stryofoam. Will the satanite and itc 100 coating protect them enough. Took Rays advice and started construction of a 3/4in burner today. I'm trying to incorperate the best features of several different different burner types I've studied. Such as adj. air flow via asliding choke, adj burner placement and adj flare placement on the burner tube. Hope I'm not trying too much, but as my wife says that I'm an incurable tinker and wont leave well enough alone. Have a Happy New Year TROG

[Doug Lester]

I don't believe that Satanite is very flux resistant. You might get a small bag of a castable refractory like Mizzou and coat the bottom of your forge with it. Check with High Temperature Tools and Refractory. I think that they carry it in 5 lb bags. I have found that even if you don't forge weld in a forge lined with soft brick that it's a good idea to coat them with something to keep them from breaking down.

Doug

[Crex]

Doug's correct on the satanite, flux will eat right through it, ITC100 is the same. Been told that the "bubble alumina" can stand up to flux but have no experence with it. I found it easier and more economical to make a verticle forge for welding.
What I'm sort of hearing is that you plan to do some forge welding as well as straight forging, correct?
Recommend that you take the time to learn the basics of forging, thermal cycling and control well, before complicating things with welding. Yeah, damascus is pretty and neat, but if you haven't learned to forge and finish a knife correctly and with competent skill, you are making the whole learning process way more difficult.
By the time you gain the necessary skills, you will also have the skills to build up a nice vertical forge to dedicate to welding.........instead of spending fun forging time relining badly abused forges.