What is this “paint” of which you speak?

Frosty did you ever experiment with pre heating the intake air? 

12 hours ago, JHCC said:

What is this “paint” of which you speak?

Isn't that what I asked you?

12 hours ago, jlpservicesinc said:

Frosty did you ever experiment with pre heating the intake air? 

Yes, a couple times but it's too easy to preheat it enough it pre-ignites in the mixing tube. In fact the NARB tends to preheat the mix to the point it burns back once the block heats up. I have to keep the psi up to keep it cool enough it doesn't backfire.

Frosty The Lucky.

Ever thought of adding some external fins to the plenum, to help radiate off some of the extra heat?

The reason why I asked is because in most metal heating operations on large scale they use heated air to inhibit the cooling factor of the incoming air.. 

I am going to be looking into a reverbaratory (not the right word but can't remember the right one.. long day) firepot design based on an old example in a book.. ((((the air being fed into the bottom of the firepot is heated by the sides of the firepot and then blown in to the bottom))  It would actually do several things which might be neat.. 

The only down side I can see if clinker sticking to the clinker breaker more so than usual..  

My NARB would run at 5psi for about 30 minutes and then start popping. At first I turned the gas up, and that worked, but then I got smart and just opened the doors up all the way. Now it runs @ 5psi for hours at a time, at a nice yellow heat.

18 minutes ago, JHCC said:

Ever thought of adding some external fins to the plenum, to help radiate off some of the extra heat?

It's not the air coming in through the driver it's the outlet block getting forge liner hot that causes the back firing.

Jennifer: It's a logical question and is indeed used on large furnaces but they operate differently at that scale.

The term you're looking for is "recuperative" and is what preheating the intake air with exhaust gasses is. Try searching the terms, "recuperative wall furnace." for a mind boggling bunch of ideas for efficient furnaces.

Where propane is concerned getting the unfriendly stuff to mix with air well is the real problem. The most effective method I've seen without going to the mechanically complex methods All States torches use preheats the propane to crazy hot. Picture a jet of 2,000 f. propane injected into an air stream. It doesn't instantly ignite because it isn't a flammable ratio and by time it is the entire mix has cooled below the flash point. However, by then the propane has become almost perfectly combined with the air.

The most common example of preheated propane burners are under hot air balloons.

There's lots of really cool stuff out there.

Frosty The Lucky.

Or really hot, as the case may be.

Warming up I see.

Frosty The Lucky. 

I’m just full of hot air.

Not JUST hot air.

Frosty The Lucky. 

Thanks Frosty, I knew you would not only have the correct word but have more info.. 

My pleasure Jennifer, info isn't the only thing I have more of. I'm just really happy when it's useful or at least interesting.

Frosty The Lucky. 

On ‎2‎/‎21‎/‎2018 at 10:37 AM, Jasent said:

I have only used kastolite but no leaks or cracks. I fired mine in the forge after curing for 2days if I remember right. 

did you fire it long enough for it to go entirely ceramic? If so, I am surprised and impressed  it did not shrink enough to loose the seal at the plenum, this is good to know.

In case anyone is wondering, this is what a NARB looks like without its refractory block:

(Or, What happens when curiosity meets impatience.)

13 hours ago, Howling dog forge said:

did you fire it long enough for it to go entirely ceramic? If so, I am surprised and impressed  it did not shrink enough to loose the seal at the plenum, this is good to know.

Fired till bright orange. Almost disappeared in the forge.  Pic of mine somewhere in this thread

ok, so, new here, but been reading up a bit.  still lost in the sauce, however, thinking about forge size.  Would two propane injectors feeding into one ribbon(multiport) burner manifold heat as effectively as 2 completely separate burners?

I haven't tried it, so I can't say for sure, but it occurs to me that it's unnecessary.  Unless you were using a very long ribbon burner and had concerns about the fuel/air mix reaching the end ports, any needed increase in fuel/air can be accomplished by using a larger diameter mixing tube with a corresponding increase in jet size.

If I were contemplating the 2 scenarios you gave, I'd opt for 2 separate burners rather than a single burner with multiple inputs.  It seems to me that there may be a number of unforeseen complications with more than one input.

The only thing I can see as probable, putting two inducers in one plenum is trouble getting one or both inducers to work properly. 

If you really must have a 40" long forge make two of them. I don't know if a larger home built inducer will deliver evenly down a long ribbon. 

Have you been making swords long? I haven't heard of many using a forge that long other than as heat treat kilns. 

Frosty The Lucky.

Frosty - it was more a thought experiment.  and i was thinking if you had a blank area in the middle to give turbulence a chance to settle from the mixing of the two streams it might not conflict too greatly.  I am not doing any forging yet.  just reading and had a weird idea is all.

Could a home made AGF type ribbon be made? Could it be made NA?

If so, would it be practical in a forge?

http://www.agfburner.com/home.html

I had to look at the AGF site. What shape AGF burner do you want to make? In a forge, why not?

The burners I've made are home builds and can't compete with the AGF burners in performance so I can't imagine one not working provided you follow the directions or specify what you want when you order.

Frosty The Lucky.

2 hours ago, Frosty said:

I had to look at the AGF site. What shape AGF burner do you want to make?

They are very "cool" looking flames, kinda velvety. I was thinking a whole wall of a rectangular forge could be a burner. Maybe the side for controllability. The face would be a challenge to get right. There are many outlets and getting that ratio would mean lots of tedious effort in testing. Especially for a NA. Even if ratios are balanced, what would the face be made of? I didnt find any info on materials. Ceramic maybe?  

 

Edited December 29, 20187 yr by 671jungle

Hi all,  here is my entry into the multi-port game.  3/4" with an AMAL commercial injector.  7" tube. Started with 19 @ 5/16" holes, got some backfires so ended up plugging 2 of them with furnace cement and it runs like a dream.  As an experiment/proof of concept I used a 3000 deg. insulating fire brick as the burner block.  Super easy to drill and cut, very precice holes.  I put a little countersink/taper/flare on the buisness end of the burner holes.   Only used for about 6 hours so far but the brick still looks lilke new.  Time will tell if it has the longevity needed.

Delivers a high yellow heat at 10 psi, starts to backfire around 3 psi.

Like everyone says, these things are nice and quiet.  The hiss of gas going thru the injector is louder than the noise of the burn.   

The smaller block was the drop from the brick I cut down, with hole spacing half as far apart.  I drilled it a little more aggressively, got it up to yellow in my other forge, and manhandled it a bit as a stress test.  When it didn't crack I felt like I was good to go with the hole spacing in the bigger block.  

Nice job, Judson! Another new idea: cutting a firebrick to shape and drilling it out to use as for the 

working end of the burner.  If you have the tools, it looks like a good option.  Hope it lasts, keep us updated.

 

Daguy

p.s. (how is the brick attached to the mix chamber?