1justin

I am working to build a forge and I have experimented with a few ideas on paper but havent started the construction. I figure I need to get a good burner up before I can think about the forge itself. So, to that end I have been doing some research and would like to ask some questions about burner construction. As a preface I have read most of Reil's pages on burners and gleaned a great deal of information but there are some holes in the knowledge.

I am considering building a burner with an inline Jet made of a MIG tip tapped into a brass end cap which is screwed on to a brass nipple that is, in turn, hooked up to the propane tank or manifold plumbing. For the burner tube I had thought to use a 1/2" diameter 12 inch black iron nipple with a 12" to 1" bell expander on each end to get the venturi effect to pull more air into the burner. For mounting the jet injector I have a couple of ideas but haven't made up my mind. Given that I have some questions.

1) First of all, is there anything I am doing that you can think of might be dangerous or just not work?
2) Two methods of mounting the jet are to leave the back open and hold the jet in place with three set screws or to tap a hole in an end cap screwed onto a nipple between the bell reducer and the end cap and then cut 1 inch holes in the nipple to allow air in. Is there any inherent advantage or disadvantage in either idea?
3) I noticed that Reil has a Nono-mongo prototype that is entirely out of brass, wouldn't there be a problem with heat given that brass melts more easily than iron? What parts of the burner will get extremely hot?
4) Again with the nano-mongo burner, I gather the brass tube was expanded with a flare, wouldn't that weaken the pipe? If not, how much could the metal be flared out without damaging it to the point of being useless? Could the same swaging be done on black iron if heated orange or would that not be advisable?
5) When it comes to side vent holes, is there any advantage to one large 1 inch hole over several 1/2 inch holes that have the same open area as the larger hole? I am concerned about structural stability of the nipple as I cut metal off of it.
6) Is there an upper limit to the venturi reduction that I need to keep in mind or could I mate my 1/2int to 1 inch bell to a 1" to 2" bell and get more airflow?
7) If the jet tube is brass will that be a problem or will I need black iron? How hot does the jet tube get?
8) If there anything i should look out for that might cause something catastrophic like an exploding tank?
8) If I can rig the jet tube so it can be adjusted not only by centering in the tube but also by its depth in the burn tube, will that be an advantage or is it a waste of time?

Thanks a bunch in advance.

We are gonna need pictures now. Having a non-standard burner means you need a non-standard answer.

All fired bricks are "ceramic"in the sense that they are fused clays and fillers, however the difference is moot for now. In any case the alternative is a ceramic wool, which is very lightweight. The wool has a higher insulating value than the bricks, but at a sacrifice of durability. There is products like duraboard which are rigid.

Phil

What Phil said. The T-Rex is a great burner and definitely gets hot, but there's nothing magical about the design; it's just better made than a Reil or the like and that amounts to better performance. Smooth flow is more efficient than turbulent flow, the angles are optimized, etc.

Yeah, mine has the sliding choke.

When you say ceramic blocks, do you mean soft firebrick? I'm just looking at the weights on the NC Tool forges online, and wondering if they're using hard firebrick on the interior.

*A friend of mine runs NC forges. He uses his 3 burner for making welds in. The knifemaker forge on NCtools page is a 3 burner and has damascus making listed as an attribute...

Is it blacks spots in the weld, or delaminations? Maybe a longer soak time would help?

Personally if you want to make a lot of damascus, get a blown forge design like Jymm Hoffmans.

*my .02,other results may vary

https://dg.box.net/shared/static/s3pjhjalji.pdf

This design is by Daniel Gentile, a very talented Swiss bladesmith, toolmaker, machinist, etc. I own a T-Rex. The T-Rex is similar to any venturi style burner (not sure venturi is quite the right word, but that's the common parlance), it's just better made and they did quite a bit of experimentation to optimize everything. As best I can tell this design is pretty much the same as my T-Rex. Of course Daniel uses metric measurements, so you'll have to convert everything. Sorry about that.

By the way, how's that NC Tool forge insulated?

Hi, I'm a machinist and a damascus knife maker, too. I was using the coke forges at my school to make my forge welds, but have since graduated, so no more access to them. Two years ago, I bought a new two burner forge from ebay, before I got into machining and realized I could have made it better and way cheaper. The guy I bought it from boasted how "easy" it was to forge weld with, however it has NC burners that really don't get it hot enough to do any kind of a decent weld at all, even at 20 psi.

Does someone here use T-Rex burners? Can you tell me more about how they work? What pieces are involved, that sort of thing? Like I said before, I'm a machinist and am interested in designing something similar to use in my own forge. Because, the NC burners just don't cut it with making damascus, I get little spots in the middle of my billet where the weld didn't quite take. These spots later expand during the heat treat. Any help would be much appreciated, because I don't have the money to buy one of these burners myself. Does anybody know if hybridburners sells these to vendors? Or are they the only place you can buy one?

Thanks, Justin