Thinking of going to blown burners.

[Robert Simmons]

I have been trying to get atmospheric burners to work in my new cast forge, they all flame out in the forge and its getting in my nerves in the extreme. Balancing this and that and the wind and air pressure in shop since I have a top evacuation fan is getting on my nerves. It lacks simplicity and effectiveness. Any slight change in the atmosphere can sometimes blow the burners out or change their burn ratio to go yellow. There is a constant fight of venturi vs back pressure that i am sick of fighting. By closing a door or altering the size of an opening I change the pressure and sometimes put out the burners. I am thinking it is about time I go to a blown burner and simplify my life. There is just one problem. I don't have a blower.

Not only do I not have a blower, i don't have $500 to spend on buying a blower. I had thought of adapting my leaf blower which has a rheostat but the problem is IT IS REALLY LOUD AND WOULD MAKE WORKING IN THE SHOP A LOUD AFFAIR. I think ya get the point. A hair dryer doesn't seem to be a great alternative either as it is also pretty loud. What I need is a blower that can work fairly quietly and yet provide the air that I need. I want the loudest thing in the shop to be my hammering.

I need to get a solution soon because I haven't been hitting metal for two weeks now, instead tinkering with forges. I ditched the charcoal rig to go to propane and half of me is regretting it.

-- Robert

[edge9001]

bathroom fans might work. I've found the cheapest one run around 50cfm and are wisper quiet. some of the more expensive ones have a higher airflow. My solid fuel runs off of one of the cheapies.

[pkrankow]

Go to your local second hand store, Goodwill or Salvation Army. Buy a hair dryer. If it has a "cool" setting bonus, if not then you may have to remove or bypass the coil.
Phil

[Nakedanvil - Grant Sarver]

$500!!?? Blacksmiths Depot carries a couple of nice ones that have not disappointed anyone. The ones that say "Off Center Products" (just get the small one). http://www.blacksmithsdepot.com/Templates/cart_templates/cart-detail.php?theLocation=/Resources/Products/Forges_and_Parts/blowers/112_CFM_Blower

[HWooldridge]

Atmospheric forges are often a PITA to tune but you don't need much air for the average sized forge. I put a 60 cfm squirrel cage from WW Grainger on my Sandia style aspirated forge for no more than about $35 (this was a few years ago but WWG is still a pretty good source for little blowers). Add a needle valve inline to control the fuel and your problems should diminish substantially.

[Nakedanvil - Grant Sarver]

OK, i know, I got a dog in this race. I know what a forge needs and I have these blowers specially made and they sell at a reasonable price. Will something else work? Maybe. Will you ever be disappointed with this blower? Never! Small squirrel cage blowers suffer some of the same sensitivity to back pressure as atmospherics. Good products only cost you once. Get a blower with enough cfm and pressure!

Yeah, I got a dog in the race, but I think everyone knows I never give anyone a bum steer.

[Robert Simmons]

OK, i know, I got a dog in this race. I know what a forge needs and I have these blowers specially made and they sell at a reasonable price. Will something else work? Maybe. Will you ever be disappointed with this blower? Never! Small squirrel cage blowers suffer some of the same sensitivity to back pressure as atmospherics. Good products only cost you once. Get a blower with enough cfm and pressure!

Yeah, I got a dog in the race, but I think everyone knows I never give anyone a bum steer.

Yeah I dont carei f one is advertising good products then that is the american way. TBH I am thinking of buying one. The question is, how loud is it ? I also have to fuel three burners for the size of forge. I have forged a 1 inch pipe in the castolite that is about 4 or 5 inches long. What I was thinking is if I can go to a blown design then I might be able to weld 1 inch pipe to the outside of the forge around the burner holes and inject the gas right into those holes and use those cast holes as the burner mixing tube itself (in addition to the pipe welded to the outside, and then I wouldn't have problems with heat melting the burner. One possible complication is that the burner holes are flared by half an inch or so where they break into the chamber.

While I am at it, anyone have an idea of a good way to cut soft firebrick without spraying powder all over and being able to make a curve?

[fciron]

While I am at it, anyone have an idea of a good way to cut soft firebrick without spraying powder all over and being able to make a curve?

Water-jet?

Do they still sell cable saws? I think I have seen omni-directional blades for coping saws but you might have to build your own extra deep frame to reach the work. Hole-saw in a brace?

Grant, nice looking blower, but I didn't see the OC name mentioned anywhere.

[Francis Trez Cole]

Granger has a blower number 2c647 catalog 398 page 3053 $56.85 and less if you use your abana number Dayton also makes a round flange blower about the same price mast grangers carry them in stock. I have used one for 10 years works great I use a damper to regulate the air flow not a reostat

[HWHII]

$500!!?? Blacksmiths Depot carries a couple of nice ones that have not disappointed anyone. The ones that say "Off Center Products" (just get the small one). http://www.blacksmithsdepot.com/Templates/cart_templates/cart-detail.php?theLocation=/Resources/Products/Forges_and_Parts/blowers/112_CFM_Blower

I have two of these blowers and they are all that. They have worked flawlessly.

[eric sprado]

Old Genaire(sp) stove blowers work great.

[Marc]

eBay could be a good source of used blowers.

Cutting soft brick - they do still make cable saws. Look in the H/W store in the plumbing. They're for PVC, but soft brick is so soft I suspect it will work fine. I just used a wood coping saw with a narrow blade. That would work fine for all but the tightest curves.

[kcrucible]

Jeweller's Saws would cut firebrick.


I've ordered a lot from Rio Grande over the years... here's one example from there.

[Robert Simmons]

Well, I think I might have the wrong pour to go with blown burners. They flame out too fast when using a hair dryer as a blower. I suppose I need to get a gate valve to control the air flow.

All in all it is frustrating. I took up the hobby to hit metal, not spend 2 weeks trying to heat it. I now wonder if I shouldnt have stuck with charcoal. What good is a propane forge if one cant use it.

Singed ... Frustrated.

[edge9001]

Well, I think I might have the wrong pour to go with blown burners. They flame out too fast when using a hair dryer as a blower. I suppose I need to get a gate valve to control the air flow.

All in all it is frustrating. I took up the hobby to hit metal, not spend 2 weeks trying to heat it. I now wonder if I shouldnt have stuck with charcoal. What good is a propane forge if one cant use it.

Singed ... Frustrated.

Dont get discouraged, I too am new to gas forges. IT looks like fun once you get the hang of it. so far mine is. it is faster and cleaner than charcoal, you just gotta work out the bugs.

I have run across an interesting thing with mine The burner seems to stick too far into the forge, when its been burning for a while the burner starts glowing red inside the forge. Yesterday I cut the fuel when I pulled my project out of the forge. When I turned it back on the burned wouldn't light properly, the besty way I can discribe it was the forge barrel became the burner, the flame jet coming from the burner was gone and wouldn't return. However, the jet flame came from the front of the forge instead and the forge got a lot colder.

It seems to be the burner neesds to be pulled further from the forge. My burner tube sits in a collar that is welded the the side of the 10x18 pipe.

good luck with yours.

[Nakedanvil - Grant Sarver]

You got a great shell, you just gotta get the fire going. Without any air control you're getting way too much air. You can't exceed a certain velocity without the flame detaching. There are many different designs of "flame retention" tip. A simple one is to hacksaw 6 - 8 slits down about a 1/2" in the tip and close the tip JUST A LITTLE. The added turbulence will keep the flame attached, you'll still need to control the air, all you need is a piece of paper over the hair dryer inlet. As long as it's running the suction will keep it there, easy to adjust.

[Nakedanvil - Grant Sarver]

Reading back over your other threads I see you're using 3/4". I would prefer 1" with a blower and the end crimped in to 7/8".

Boy, that thread went south too, didn't it? Might try to make it a little more clear when you're stating your opinion, you often have a way of making it sound like it's absolute fact.

[Robert Simmons]

In the poured shell I have three tubes running from the side into the forge at an upward angle. The idea was hopefully to create a swirl but that might have been a bad Idea. I dont know at this point. Anything that goes through into the forge chamber might be subject to melting so I thought I might use the tubes themselves as the burner tube. The idea would be to weld 1 3/8 pipe (the size of the holes in the castable) to the side of the forge and then install the propane directly into that pipe as well as the blower. (note I want to get a real blower but I dont have the finances now). Basically I would be using the pipe as well as the cast walls of the tubes for the 3/4 ID old burners to create the actual burners. One complication might be that the end of the burners in the forge are flared slightly. I dont know if that will cause a problem or not. The whole idea of casting the flared cone where the old burners were to enter was to use that flare as flame holder and not risk melting something.

I have heard others use the water type gate valves to regulate the air. Would that work for me?
Would I want to avoid venturi type narrowing designs?
Finally do I need to use a propane jet, such as the MIG tips I was using for venturi designs, or some other configuration?
If I wanted to enlarge the holes cast in the castolyte could I use hole saws that just barely are bigger than the current holes or would that potentially crack the castolite?

[youngdylan]

Atmospheric forges are often a PITA to tune but you don't need much air for the average sized forge. I put a 60 cfm squirrel cage from WW Grainger on my Sandia style aspirated forge for no more than about $35 (this was a few years ago but WWG is still a pretty good source for little blowers). Add a needle valve inline to control the fuel and your problems should diminish substantially.

H. Is that the Sandia recuperative style forge. I keep mulling over experimenting with one (one day). The heat from my 3 burner gets unbearable in 400 sq ft. It should also cut down on fuel cost at run the forge hotter. A win win win ..... if I can find the time.

Got any pictures/ info?

[fciron]

The very first thing I would do is choke off some of the air. I have used the 'piece of paper' choke technique and it works great. This will let you experiment with your air fuel mixture and get some ideas for your final design. It should also let you get some metal hot so you can have a go at hitting something. It sounds as though you are well and ready to do that.

A forced air burner is a very simple and robust thing. Provided that you have a way to control the amounts of air and gas you should be able to get a stable flame out of just about anything. Flame retainers and permanent chokes on the air are necessary refinements for down the line but right now I'd concentrate on getting something hot.
This page has the old Hans Peot gas forge plans from that ABANA used to distribute. I think the flame holder is a little complex, but you can see that the whole thing is pretty simple. You could make a manifold to feed the large tube to your smaller burners.

Edge, I try to avoid using residual heat for a relight. If you do run into that trouble again try putting your hand over the burner intake to choke it back, this will temporarily reduce the velocity at the burner end and the flame may burn back into the forge to your burner.

My couple of thoughts.

[kcrucible]

Well, I think I might have the wrong pour to go with blown burners. They flame out too fast when using a hair dryer as a blower. I suppose I need to get a gate valve to control the air flow.

All in all it is frustrating. I took up the hobby to hit metal, not spend 2 weeks trying to heat it. I now wonder if I shouldnt have stuck with charcoal. What good is a propane forge if one cant use it.

Singed ... Frustrated.

I notice on your burner picture that you're just using a 3/4" to 1" reducer for the flare.
http://www.iforgeiron.com/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=23848

Flares have been reported to be important for flame stability outside of the furnace, but apparently many run without inside. That reducer probably is still threaded, so you'd be getting a lot of turbulance at the ends. You could try running "bare" and see if things change. You could also get a proper flare from Zoeller. Ron Reil swears by them. Here's what he has to say about flares....

http://www.abana.org/ronreil/design2.shtml#premade

The following four factors are, in my opinion, what a flared nozzle does to contribute to burner performance, and why you should use one of your own making, or one of the stainless flares offered here.

1) The flared nozzle acts like the "impedance matching device" found on radio transmission antennas. It creates a "pressure transition" to balance the internal pressure of the burner tube to the lower pressure of the forge chamber atmosphere.

2) It slows the gas stream to a velocity below the burn velocity...its flame holding and stabilizing function.

3) It creates a low pressure in the nozzle step that, in effect, invites more gas down the burner tube, allowing a slightly greater output than would occur without it. This factor is not proven or provable with our crude testing equipment, but I can clearly see its contribution in my mind.

4) The last function is to initiate the burn earlier so as to prevent the injection of cold gasses and free oxygen into the chamber of the forge or furnace....the result is a hotter chamber and less, or no, scaling.

If you would like to buy premade burner flares that have a perfect 1:12 taper, and made of stainless steel no less, there is now a source. Most of the problems that I deal with when helping guys with burner problems relate to the rate of flare of the burner flares that they put on their burners. If the flare is not made correctly the burner will not function correctly. I was astounded when Larry Zoeller sent me one of his "press formed" stainless steel flares to try. I removed one of the old forged flares from the number one burner on my four burner forge and installed Larry's stainless flare. My old mild steel flare came off in fragments, as it had totally corroded through in only two years of use. The best I had been able to do for "idle" pressure with my old forged flare was 2 psi. Below that the flame would start to pulsate or huff. When I put Larry's flare on the burner it easily held the flame steady all the way down to a little below 1 psi! His flare just doubled the "idle" economy of my forge! I have ordered 7 more from Larry, they are that good. I can certainly make my own flares, but to obtain the precision that Larry has achieved I would have to set up a hydraulic press as he has done.

If you would like to obtain some of these superb flares, contact Larry at the address shown below, or at his e-mail address. I am sure you will be very satisfied with the results of your purchase. You may initially think that his price of $6.50, plus shipping, for a burner flare is steep, but remember that he not only makes them from stainless steel, but they are drilled and tapped, and come with two stainless set screws installed also. They are ready to just tighten into place on your burner. BTW, I get no payment of any kind for this "add." I just think that these flares meet a big need out there in the metalworking field and should be made available to the forge and foundry community. Please be aware that these flares can melt and deform if used on the Micromongo Burner when its run at high gas pressures. In the case cited in the linked document, Fred was running them at 25 psi.

[pkrankow]

The MIG tip is acting like a metering nozzle, and is not needed in a blown burner. A port dumping the fuel into the burner is all that is needed, say 1/4 inch tubing, or even a plug in a Tee.

Switch out to larger pipe like Grant (Nakedanvil) suggested, and get the forge glowing before doing too much to it as adjustments go. Once the forge is radiant hot it will auto-ignite fuel in the cavity, and it will be easier to control.

For air control you have many choices, but it looks like using a choke on the fan like Grant suggested is most popular. This way you only need one fuel injector into the manifold to the 3 burners.




http://forums.dfoggk...14112&hl=burner

http://www.anvilfire...20anvilfire.com

you can look at Jymm Hoffman's proven design
http://www.iforgeiro...8-blown-burner/

Phil

[Nakedanvil - Grant Sarver]

Hold everything! If you haven't been able to run it, then it hasn't gotten cooked out has it? You have to get it cooked out 100% dry before the burners will work right. Any steam screws things up fast. If you can get any kind of steady burn, put it outside and cook that sucker out good.

[Robert Simmons]

Hold everything! If you haven't been able to run it, then it hasn't gotten cooked out has it? You have to get it cooked out 100% dry before the burners will work right. Any steam screws things up fast. If you can get any kind of steady burn, put it outside and cook that sucker out good.

I have been able to run it and steam it somewhat but it needs more. It has been drying since i poured it last thursday. I can only run it from a burner comming in the back door with the current venturi burners I have.

[edge9001]

Edge, I try to avoid using residual heat for a relight. If you do run into that trouble again try putting your hand over the burner intake to choke it back, this will temporarily reduce the velocity at the burner end and the flame may burn back into the forge to your burner.

Thanks I'll try that next time i fire it up. any ideas on a pilotlight? is this even possible?