Forge won't get hot enough - advice?

[Frosty]

Hey Frosty - I just went and double checked - my 3/4" nipple is 8" long.  My mig tips are .035, trimmed down a bit and cleaned up with a torch cleaner.  I think I only deviated from your write up a little bit.  I tapped the 1/8 pipe nipple for the mig tip, instead of the brass 1/8" MPT to 1/4" flare, and then I threaded the outside of the pipe nipple about an inch up.  This way, I can just screw the pipe nipple up or down in the T to tweak it to where I want.  Seems to work well, although something isn't adding up.

 

Do you think I should try dropping to .030 mig tips?  Or pulling the mig tip back further in the T? Go to 9" nipples instead of 8"?  Yeesh - very tweaky little beasts aren't they

 

Spruce

 

Sounds like you're in the ball park. I was estimating your tube length off the screen and am not a bit surprised I was that far off.

 

.035" mig tip should work well and with the shape of the flame it's aimed correctly. What is the "T" size? The first couple I made I used 3/4"x3/4"x3/4" "T"s and they worked well but were a bear to adjust. now I'm using 1"x1"x3/4" to make it intake air more easily and they're a bunch easier to adjust and much less sensitive to  breezes.

 

About commercial burners: You'll see the tube is tapered it's full length at a ratio of just under 1:12 or a bit under 12*. This gives them very robust induction and they use larger jets and much lower psi. Tapering the tube full length is sort of outside the typical home shop unless a person wanted to build a spinning lathe and learn to spin OR buy a machine lathe and machine them from billets. Just WAY too much work for normal folk making about $200+ for a commercial burner reasonable.

 

There's no question a commercial burner will beat mine or Ron Reil's or Michael Porter's or a Rex easy. Ron and I spent a happy year brainstorming and experimenting with these things, not because we thought we could make a better burner but because we love to tinker and the early failures got out backs up. Ron spent a lot of time and effort developing an easy to build linear induction type burner and I went with an ejector type for it's more robust induction. Michael got involved after Ron and I stopped playing together with burners and he developed a good instruction set for making his version of an ejector.

 

All in all I have no idea how many hours we invested reinventing the wheel but it's been a fun ride and I get a bit of a rush seeing one of our burners on someone's forge or foundry furnace or whatever.

 

In all that time the biggest problem was getting them to induct enough air to produce a neutral flame. If we could taper the tube it becomes easy as the gradually increasing diameter requires the air fuel flow to fill a larger volume increasing the vacuum and draw. Using a smaller diameter jet and higher psi makes a stronger vacuum as well making for a lean flame so a choke makes for easy adjustment. This is a perfectly valid method and will make as hot a fire. However, we spent a lot of time going the way we did because a smaller jet means less fuel and fewer BTUs per second overall. A smaller jetted burner has it's upside, it's easier to adjust using the choke, no question so it's generally easier to build too. Good points. While it's absolute temperature is as high it doesn't make as much heat total so the size of the forge chamber is less. I use 0.023" mig tips in 1/2" burners for ban can forges with volumes around 150-175 cu/in.

 

Gee, didn't that turn rambly.

 

Frosty The Lucky.

[Spruce]

Cool.  I'll try some adjusting to see what I can achieve.  I think maybe I'll try .030 mig tips to see if that helps - maybe because my forge is so small, I'm dealing with more backpressure, so I'm just flowing too much gas into it?  I dunno, but I'll try adjusting one thing at a time to see if I can get it to work better.  I know my arm would thank me if I could get my metal a little hotter.

 

BTW, you say commercial burners are better Frosty - in all my searching around the only thing I've seen which is sort of a commercial burner are the T-Rex burners - are there others?  I just did some googling and didn't find any.

 

If one was to buy a premade burner, is there one which is hands down the best?  I kind of thought that was the T-Rex burners, but are there other options?  Hopefully I won't have to go that route, and I can get mine working just fine, but I'd like to know what my options are.

 

Spruce