Blown burner question, large flame out the front: what do I do?

[Railrider1920]

Hey Folks,
I made up a small 2 coffee can (end to end) forge a while ago. I finally got a burner into it tonight. I made up a blown burner using 1" pipe. It might be over kill for the coffee can furnace. I'm going to try it in a larger furnace tomorrow.

I was kind of nervous lighting it up. After playing with it a little, I got it to burn kind of like a burner probably should. I probably had the propane at maybe .5 to 1 psi or somewhere there abouts. The gate valve I used to regulate the air was wide open. There was a flame coming out the can and then going up into the air about 2 feet. Maybe an orangeish color. I stepped away so I could look into the can. The flame coming out of the end of the pipe was blue, not too light and not too dark. It also sounded like a jet engine from an F-16. I was encouraged by the sound and the blue flame inside. The flame coming out the end however, was almost enough to make stick with charcoal.

I'll try to get some pics of everything tomorrow. I have the blower attached to some PVC piping to get it down to 1", then gate valve, then a piece of straight pipe, a 90 deg elbow to straight pipe then into the forge. The propane comes into the elbow via a welded on brass pipe. I couldn't find any larger pipe locally to make a mixing chamber after the elbow. The blower I am using is the one pictured in the link below, the one on the left.
http://www.bladeforums.com/forums/showthread.php/887418-Questions-about-blowers-for-a-gas-burner

Off of this little bit of info, can anyone suggest what to do to tune it better so I do't have 3 feet of flame out the front? More propane, less air maybe?

Thanks for any suggestions,
Rob

 

[Salem Straub]

Sounds like you need to tune your propane way back. And your air, accordingly. There should be a needle valve as well as a regulator to tune the gas or at least a reg and shutoff valve. If your burner doesn't have a gas orifice providing some restriction but just tubing or whatever, 1 psi is still a lot of gas for a small forge. But really, you probably need a bigger heat chamber anyway.

 

[Stacy E. Apelt - Bladesmith]

Did you ever watch the "Home Improvements" show where Tim Allen put a huge motor on a lawn tractor? It didn't work out well ........for the same reason your 1" blown burner isn't working on a coffee can forge. Your burner is way too big for such a small forge.

You can turn down the gas pressure and choke off the air until it is a more tame animal, but that is only using 10-20% of what the burner is capable of.
Do that for now, but when you get the chance, build a suitable size forge with a good liner. The burner will be quite happy in that new home.

 

[jawilder]

If you just had the burner lit without being connected to the forge, it will burn like that. Once you put it on the forge, it should burn better. Mine did the same thing. As I held the burner in my hand the flame came out more like a bic lighter but when I put it on the forge, it turned into more of a torch flame.

But if it is already connected to the forge then get a bigger forge.
Jason

 

[Rick Marchand]

Stacy knows more than I on blown forges and the burner/cavity ratio does seem off..... but I do have one question that hasn't been addressed yet. How long did you let the forge run? I remember Wally Hayes' blown forge would shoot 2ft flames out both ends until it got to heat. After it reached a certain temperature the whole burner characteristic changed in an instant. It was like someone flipped a switch. My venturi forges do the same thing on a smaller scale.

 

[Railrider1920]

Guys, thanks for the replies. I think Stacy is spot on, Salem too. I changed it around today and it's working much better, I think so anyway.

jawilder- It was inside the forge at the time. The coffee cans were too small.

Rick- Thanks for mentioning that. I'll keep that in mind when I get to using it on a regular basis. The concrete (refractory) has been drying for a few months and this is really the first time I lit up the bigger forge. It ran for maybe 5 min then 5 more later in the day.

I moved that burner from the coffee cans over to a different forge made out of a can for spare air. I got it lit and started to add some air to it. It quickly went from just burning propane orange flame to having a nice looking blue flame coming out of the pipe. Still have some orange flame but it is staying mainly inside the forge. The blue flame comes out, hits the wall and follows it down to the floor and then stops. The orange flames do swirl around the inside of the forge. The bottom is soft fire brick. I figured if I ever needed to replace it, this would be easier to cut out. It started to glow after the burner was on for about 3 minutes.

After looking at a thread on ribbon burners, I'm almost wishing I went with one of those instead. Maybe on the next one.
http://blacksmith.org/forums/threads/509-Ribbon-Forge-Burner

I took some cell phone video which can be found at the links below. If you look at them, turn your sound down some. It's kind of loud. in one of then I was trying to talk over the blower. Pretty sure that one is the one when it was getting dark out. I had turned the air down really low and it kind of started to sputter.

If you watch the vids, please let me know what you think about how it's working, how its set up or anything else. Does it look like the mixture is ok? Do you see any potential problems later on down the road? Have any suggestions? The burner is just sitting there in the hole. I will be putting on some "mounting brackets" of some kind to make sure it doesn't move or fall. I'll also weld on another piece of pipe with some screws in it to hold it in place.

I'm probably going to move the burner to the back hole and make up a plug for the other hole as well as make and attach a back door.

Please let me know what you think, good, bad or ugly
Thanks,
Rob


Video during the day. One min 45 sec
http://s77.photobucket.com/albums/j74/railrider1920/knife stuff/?action=view&current=Picture083.mp4

when it was a little bit darker out. 4 min or so.
http://s77.photobucket.com/albums/j74/railrider1920/knife stuff/?action=view&current=Picture098.mp4

Day light no fire
http://s77.photobucket.com/albums/j74/railrider1920/knife stuff/?action=view&current=Picture084.mp4

This is the info sticker on the blower motor

Home for the forge. I'm going to have to cut out a slot for the burner to clear the lid when it is closed. I figured I'd put it in an old grill for a couple of reasons. It won't be out in the open if anyone ever looks in the junk yard I call a back yard. It will be easy to move around like this. One of the main reasons I'm planning on putting it in here is the rain. If It ever starts to rain while I'm forging, All I'll need to do is to cut off the propane, turn off the blower and close the lid.

Side view, well, mostly any how....