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Help needed with new forge but old burners...


p.grigorakis

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Hi all, I was hoping I could get some help with my new forge. As you can see in the videos, I am having various issues with the burners not lighting up, sputtering and flaming out. I can run one of them on a very low pressure, but not both of them. 

The weird thing is that the burners were running more or less fine in my old cylindrical forge (standard 11kg propage gas tank) and I recently decided to build a newer one, because the kaowool insulation was starting to show and it was a health hazard. I also changed the mig tips, but used the same type, 0.8mm. I use the standard Frosty T burner, with 3/4" pipes.

I have uploaded some videos on youtube: 

https://youtu.be/bfH0cJ-rJ8A

https://youtu.be/JadlPS0j02s

https://youtu.be/9wS_3ByUAJs

https://youtu.be/Gf95-lzm_Iw

https://youtu.be/Iw4BTFeITaQ

I am not sure exactly what is wrong, but I am hoping that your collective expertise will help me out. If there any info about the forge please let me know and I will reply. 

Thanks in advance!

 

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Welcome aboard, glad to have you. If you'll put your general location in the header you'll have a better  chance of hooking up with members living within visiting distance.

Did you actually follow MY plan and build instructions posted here or something else? 

How long is the mixing tube? 

Lighting burners at the air intake is like putting the spark plugs in the air cleaner. It's not quite heating the water after getting out of the shower but close.

How far is the output nozzle inside the forge liner? It should be barely inside the steel shell.

Thank you for posting the <shudder> videos on youtube rather than wasting bandwidth on the forum. I won't even gripe about having to watch videos. 

Frosty The Lucky.

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Thanks for the replies both and sorry for the late response, life in the way etc.

Frosty

I followed your plan, which I found here. The tube is 150mm, which is a hair under 6in. The construction of the forger is 2mm steel shell, then 2in or so of kaowool and 1in refractory bricks. The nozzle is just barely inside the refractory brick. Does that mean I have to pull them up? Wouldn't that blow fire right on the kaowool, which would be a terrible health hazard?

Also, the channels where the tubes are in, are narrower than in the previous forge. Would that perhaps reduce the airflow? Although, now that I think of it, there are two huge openings, larger than in the previous forge front and back...

Mikey

Hmm, I don't think there are any obstructions, but this is a good point. I will check this when I am next in the shop.

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Are those the plans from the interview I did a few years ago on Blacksmither? Those are kind of dated but they'll work okay. The plans in the gas burner section of Iforge are more recent. 

Yes, pull the nozzle of the burner till it's just BARELY inside the shell. widen the kaowool burner port enough to line it with hard refractory and kiln wash it. This will allow you to form the entire refractory liner into a flare and improve combustion air induction.

What do you have on the output end of the mixing tube?

Did you use teflon thread tape on any fittings? If so a shred may be blocking the jet. Regardless, Mike is right debris can easily be blocking the jet. Even propane isn't completely clean ad the capsasin oil used to oderize can leave waxy residue. 

The jet doesn't need to be blocked, all it takes is a little change in the shape of the orifice to throw the jet off and reduce induction.

Frosty The Lucky.

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The forum plans look like they are the same as what I have used. I don't have a flare at the end right now. I did have a 3/4 to 1in fitting in the previous forge and I also tried it in this one, without success. Also, I forgot to mention that the burners are doing the same thing even outside of the forge, during testing, with or without flares. I will check if any teflon tape pieces are causing the issue and see if moving up the burner tip solves this.

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I use a 3/4" thread protector, available probably free at any real plumbing supply, they're screwed onto the threaded ends of pipe for shipping so they don't get damaged. Thread Protectors, Yes? They're like a coupler but WAY cheaper.

Are you lighting them at the air intake like in the video? Don't do that, light it at the outlet, flame nozzle. In the forge put a piece of burning paper or a burning torch flame IN THE FORGE so the burner lights where it's supposed to burn.

Are the mig tips aligned as close to STRAIGHT down the CENTER of the mixing tube as possible? This is the most important construction detail.

I use gas rated paste joint compound in my propane plumbing, never tape. No matter how careful you are there's always a chance of pealing a tiny bit when you screw a joint together and any loose bit will eventually find the mig tip jet orifice.

You can cause obstructions with paste too if you use too much or put it in the Female side.

ALWAYS apply joint compound, paste or tape to the MALE side and hold it back a couple threads from the end.

Frosty The Lucky.

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I have to clear obstructions once or twice a year it seems.  Never really can find what it was but a coup!e times saw something that looks like a speck of dust or something. 

Its the first thing I would look for. 

Not proud of it but I have even taken the hose off and sucked on the fitting and have cleared an obstruction by vacuum power..., once.

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Talking about NOT sucking on hoses unless you really have to. One spring there was a lot of runoff and the gozintas in my shop were all full of water so I grabbed a short garden hose and with one end in a gozinta and the other at the low end of the fill the shop sits on I started sucking. Between breaths a bunch of little SPIDERS :o came boiling out of the hose!

NEVER going to do THAT again!

Frosty The Lucky.

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So you can suck on them when you unscrew them? Hmm, I thought my solution works just fine and better yet, I get to watch bugs squirt out of the hoses in spring. One of these days I'll remember to run it through a colander and do a hose bug count.

Frosty The Lucky.

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  • 1 month later...

So, weather was cold so didn't get to spend much time in the shop. I finally managed to do the checks and the modification mentioned by Frosty in this thread and I am happy to report that the burners work fine now. However, it seems I am having a couple of different issues right now: first, the flames are shooting up from the burner openings. Second, and definetely more importantly, my CO alarm is beeping like crazy, with the old forge. Up to 150ppm but most of the time it stays around 50-60ppm. My "shop" is a half container and while the air circulation is not perfect, I kept the doors open when I run the forge and the CO detector was just above the forge and it has never registered any values above 5-10ppm. Not sure why the change now.

I have already moved the forge (conviently on caster wheels) right at the entrance and I am looking at ways to move it outside while it is running, but need to keep it protected from rain. Any suggestions for a ventilation system would be welcome. 

(the glow is from the fire bricks. While I did remove some firewool from around the hole opening and covered the exposed one with refractory cement, the fire bricks still have the original diameter, so the flame is basically hitting a part of it before entering the open forge space -> /_ _\ basically the _ parts )

Video 1 

The flame shooting up from the openings. Also, the back burner seems to have a different flame color. Any ideas why?

Video 2 

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"This video is private"        Is the forge set up to recycle exhaust back through the burners?  That can spike CO production, often a problem for systems that have the burners mounted vertically at TDC as the hot exhaust rises from the openings and gets sucked in the air intake.

Doors at one end do not do a lot for ventilation!   I have  10'x10' roll up doors at either end, 10' high walls and open gables and the shop is aligned along the general wind direction.  Too much ventilation is the issue in my shop!

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6 hours ago, ThomasPowers said:

"This video is private"        Is the forge set up to recycle exhaust back through the burners?  That can spike CO production, often a problem for systems that have the burners mounted vertically at TDC as the hot exhaust rises from the openings and gets sucked in the air intake.

Doors at one end do not do a lot for ventilation!   I have  10'x10' roll up doors at either end, 10' high walls and open gables and the shop is aligned along the general wind direction.  Too much ventilation is the issue in my shop!

Oops, should be good now.

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How large are the burner ports through the refractory? They need to be larger than the tube or flare diameter, 50% larger isn't too much. I use thread protectors for nozzles, their IDs are approximately 1" and my port through the liner is 1 1/2". The flame doesn't run into any resistance going thro ugh the liner and in fact draws air into the forge chamber where yours is blowing flame out.

This is on burner mounts made from pipe like yours are. My main forge uses floor flanges so there isn't a significant space to pass air into or flame out of the forge. If it WERE blowing flame it would show it's not an air tight mount.

Frosty The Lucky.

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Have you tried turning down the pressure?  The local university had a propane forge for their Fine Arts Metals class; but nobody wanted to use it because of excessive dragon's breath. I was teaching an intro to forging class and went over and checked it out---yup several feet of dragon's breath. So I checked the regulator, no gauge, but it had been marked with a sharpie for the correct setting.  Right. So I turned the regulator knob 3 complete turns backing off the pressure. Sharpie mark lined up and forge was usable.  They used to say that a Marine could break an anvil with a rubber mallet; students are close behind!

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