cant get welding temp

custommachineman said:
I am working on building some new burners that should work better. I have built Reil EZ burners before and they worked great. I am working on something like the T-REX burner right now.
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You will be very happy with that burner. Great T-REX style design. Very efficent.
 
This is a test burn with a 1 in 12 flare 1.5" long. The mix looks to be about right. But I dont know much about it. I am thinking that this burner will be a little large with 2 in the forge so I am going to build a 5/8" id one to see how it works.
burnertest1.jpg
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burnertest2.jpg
 
Where are the air chokes on those modified burners???
The needle valves are fine for balancing the burners, but without chokes, I would think it won't work well at all. If you remember how they were before you modified them, there was a metal plate on each burner,that you could adjust to draw the air at the right ratio. You need to make some new ones. Or you can modify them again and make a blown burner.
Stacy
 
My vote is; you have the orifices set too far down the throat of the venturi tubes. Use the original configuration as example.

Venturi burners are amazingly sensitive to length of burner tube and the gas air mixture. They have to be adjustable to get the best atmosphere inside the forge.
Fred
 
I have a full machine shop so I cut my own flares out of SST bar stock.
I am going to go with my new burner. It is smaller than the one I posted pics of but it works well.
If I have a 9/16 bore how long should my burner tube be? The new burner is 9/16 and I think I made the tube too long although it works as is I am going to make the next one 5" instead of 7" to see if it works better.
 
custommachineman said:
I have a full machine shop so I cut my own flares out of SST bar stock.
Click to expand...

Did you cut the 1 in 12 on a lathe? If so, can you explain how you went about getting the proper cut for 1 in 12? I have a lathe but have not been able to figure this out...

Thanks, Eric
 
i'd junk them nc tool burners, they suck, this is all personal preference, but i hate them, they charge so much for them forges, and you can built one for less than $30 that will weld all day. if you dont know how, PM me and ill fill you in.

18 psi, spen $12 on some black pipe fittings, $8 on a cheapo blower at the flea market and you'll weld at 4 or 5 psi, successfully.....nice looking new burner your building.

andrew
 
This is a picture of the attachment you use on the lathe. You loosen the nut by where the arrow is pointing and rotate the head. You will also have to rotate the tool holder by loosening the screw on top. This is a metal lathe and I dont think that you could do it on a wood lathe if thats what you have.
The way I did it was to drill a hole the size of the out side of the burner tube and then cut an angle with the setup pictured. 1" in 12" angel works out to 4.7XXX degrees on the dial.
lathe.jpg


This is a pic of the 9/16 burner I made running at about 8 psi. I used the top from the first one and put the smaller tube on it. It does huff a little. What causes that? They seem to work well and I will try them tomorrow.

5625Burner1jpg.jpg
 
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Thanks for the lathe pics. They are worth a thousand words. Yes I do have a metal lathe. Your pictures made the process all clear to me.

Your burner looks fantastic.

Eric
 
BTW, I think you will get rid of some of your huff and refine your flame by adding a sliding choke over your air intake ports like the T-Rex has.
 
This picture shows that it has a rotating choke. That's 2 tubes with the same holes milled in them and I rotate the outer one. If you look at this picture of the two burners I made. One is longer with a smaller flare and one is shorter with a larger flare. The longer one does not huff but wont hold a flame at as high of pressure (max about 10 psi). The shorter one huffs but holds a flame up to about 20 psi. What is causing this difference?
5625burnersjpg.jpg
 
Don't know what the issue is at that psi. I never run higher than 7psi to get welding temps with propane and a venturi forge. My current welding forge is using natural gas at residential pressure (about 1/2 psi) using a blower and easily gets to 2600F depending on gas volume and fan speed.

How does your burner work at under 10 psi? That is the range you should be using for propane. With your burner design you should get a much higher efficiency that may allow you to go down as low as 3-5 psi.

BTW, the maker of T-REX went away from rotating chokes and went to sliding chokes since he found that worked much better. Maybe part of the problem with a rotating one is what you are experiencing... I do not know. You could shoot him an e-mail and ask why he shifted.

Eric
 
the kiln &forge book
gives some guidlines on Burner tube size, length and tip size

tip .023 tube 1/2" length 4-1/2"

tip .023,.030 tube 3/4" length 6-3/4"

I have 3/4" side buner with an .045 tip, I can weld in it.

BUT, it eats more gas than my blown forge.

I've found longer burner tubes work better for me.

One of my best was a 3/4" tube swadged out 10 1-1/4" the burner tube was about 11" long. dead simple the mounting collar in the forge does two things, it allows more to be drawn in and it keep the end of the burner tube cool, the tube is just carbon steel.
Yes I do have to choke it back some, I usally use a wad of newspaper or piece of gray tape.


Here's link to it.

http://www.forgemagic.com/bsgview.php?photo=472&cat=&by=Sweany
 
oh yeah, I found the ball valve to be of little use to me. Heat is controlled very nicely with hte needle valve.
 
I did some experimenting with the longer and shorter one using a .024 orifice and they both ran better. I found that if I moved my flare back a little so that there was a bigger step from pipe to flare it also ran better something about turbulence. I made a flare that looked more like a bell shape like a rocked uses and it wouldn't hold the flame. Thanks for the suggestions.
 
Are those lengths from orifice to flare tip or to where the flare starts? I assume that if the tube is too long it would slow down the gas flow and not long enough would not allow for proper mixing or compression.
From what I have read I think he went away from rotating chokes because they were harder to make.
 
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I'm not sure about the length but I assume it does not include the flair, as the flair is a separate piece.

I just swedged the end of the 11" tube slightly,.

I built a t-rex clone and used a checkerboard pattern of holes instead of the slot, as I am not a machinist. I used apiece of .022 SS that slides over the swedge as a choke.

http://www.forgemagic.com/bsgview.php?photo=548&cat=&by=Sweany

not areal good pic of the burner but You get the idea.

I find the air choke system isn't too picky, it's just how much effort do you want to put in it.

In a bell reducer i suspect a SS srubber pad would work as a choke.

Once I get the choke set, I really don't mess with it much anyway.
And yeah very nice looking burner

my .02
 
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