Jump to content
I Forge Iron

Can't get my propane forge up to welding temp


wildvortex

Recommended Posts

I have built a propane forge based on Wayne Coe's design using a propane cylinder except I used 2/3 of a forklift tank.

http://www.waynecoeartistblacksmith.com/site/mobile?url=http%3A%2F%2Fwww.waynecoeartistblacksmith.com%2FForge_Supplies.html#3002

 I also used 2 modified sidearm burners

http://www.zoellerforge.com/sidearm.html

Yesterday I tried working with it for the first time besides to heat treat. I could not get the steel past a medium orange.

What could be some factors causing it not to heat to welding temp?

 

Link to comment
Share on other sites

I'm guessing you are using the .045" MIG tips for jets and have a lot of Dragons Breath?

If so, try the .035 MIG tips instead (the Zoeller page gives both sizes as suitable). While you are buying tips, it might even be worth picking up a couple of .030 tips in case you've still got lots of DB with the .035s.

The .045s should be "better" for HT: less sensitive to small adjustments of the choke and therefore easier to set a precise temperature with, but I don't think they are likely to go lean enough to get the flame temperature up to welding levels. 

Link to comment
Share on other sites

You need to share some details or any advice you get will just be wild guesses. For example I say, "my daily commuter only gets 13 mpg. What's wrong?"

With that little info what possible reply could be useful?

Frosty The Lucky.

Link to comment
Share on other sites

7 minutes ago, Frosty said:

You need to share some details or any advice you get will just be wild guesses. For example I say, "my daily commuter only gets 13 mpg. What's wrong?"

Nothings wrong, that's like double what I get. :lol:

Link to comment
Share on other sites

1 hour ago, timgunn1962 said:

I'm guessing you are using the .045" MIG tips for jets and have a lot of Dragons Breath?

If so, try the .035 MIG tips instead (the Zoeller page gives both sizes as suitable). While you are buying tips, it might even be worth picking up a couple of .030 tips in case you've still got lots of DB with the .035s.

The .045s should be "better" for HT: less sensitive to small adjustments of the choke and therefore easier to set a precise temperature with, but I don't think they are likely to go lean enough to get the flame temperature up to welding levels. 

Nah I am using .035 tips and am getting a good flame. With the choke I am able to go from dragons breath to an oxidising flame. One question though, what are you using on the bottom to set your steel on so you can grab it with tongs?

 

Frosty I am not sure what more I can say. 1 in. Kaowool on the bottom 2 in the top. Topped off with Refractory cement and metrikote IR sealant. I have tried all pressures from about 3 to 20 psi.

Link to comment
Share on other sites

That's better. What's the chamber volume? and what size burners are you using. PSI doesn't really mean that much, there are too many variables between your shop and anyone elses to mean much.

A couple pics of it running will let me see what it's doing. one pic in the door before the forge is warmed up, one after it's warmed up and another across the door so I can see the dragon's breath.

If you have a full range of fuel air adjustment with the choke tuning is handled something else is going on or not.

Frosty The Lucky.

Link to comment
Share on other sites

2 hours ago, wildvortex said:

Nah I am using .035 tips and am getting a good flame. With the choke I am able to go from dragons breath to an oxidising flame. One question though, what are you using on the bottom to set your steel on so you can grab it with tongs?

 

Frosty I am not sure what more I can say. 1 in. Kaowool on the bottom 2 in the top. Topped off with Refractory cement and metrikote IR sealant. I have tried all pressures from about 3 to 20 psi.

Just how much refractory cement did you use in your forge?  If you only used it for a rigidizer and put it on thin then it is probably o.k. but if you cast a thick wall of it that might be part of your problem.

 

Link to comment
Share on other sites

No sweat I might hold you to your no promises though. :rolleyes: The volume of the forge to the size and number of burners is probably the most critical ratio to account for. Insulation and basic burner type are factors too but it's the amount of heat generated in the volume that really counts.

There are tricks for helping to contain and retain the heat say insulation, chamber layout and shape but those are for a little later. Give me a shout when you have time.

Frosty The Lucky.

Link to comment
Share on other sites

The volume of the chamber is less than 577 cu in. I say less than because it is d shaped. I measured the radius with a approximate center between the base and top.

The burners are 3/4 and are 2 of them.

The first pic is choke closed the second is choke wide open across the front.

The third is when first started

Fourth is after 15 min.

The one thing I have figure out is that the ambient temperature outside would have an overall effect on flame temp. But the day I tried welding with it it was 70 deg out.

 

IMG_20160104_084302878.jpg

IMG_20160104_084240207.jpg

IMG_20160104_084441274.jpg

IMG_20160104_085833782.jpg

IMG_20160104_090032614.jpg

Link to comment
Share on other sites

Two 3/4 burners should do nicely in that volume forge. Your doors are WAY too large, close them up till the back pressure starts to log the burners down and open them back up a little.

A little kaowool to seal the burners off in the holders can't hurt but for now I'd say it's the too big, wide open doors keeping it cool. Once you get a good air fuel ratio STOP messing with the chokes. With them closed  like the first pic your forge is just a CO generator. Wide open it's probably just a scale reactor. While iron scale is good for making roses really red you can sweep up plenty at the anvil no need to make a scale reactor.

Frosty The Lucky.

Link to comment
Share on other sites

Lol Frosty I had the fire brick doors open wide so you could see better inside. I normally have them just open enough to get my steel in and out. The back is totally closed off. 

I don't however have the burner holes sealed off. I am guessing that I should pack with kaowool?

Once I got it running right I was planning on leaving the choke alone. you are right I do need to fill around my flooring material and where the log for my anvil comes through the floor but I don't need to fill it with scale.

I hope to get out there and mess with it the end of the week. I will get back on this then.

Link to comment
Share on other sites

With the back being totally closed off if you put a couple inches of kaowool then the hard fire brick it will heat up quicker. The hard brick takes a little while to get to temp but once it is it really helps hold the heat.

I could not tell from the pictures, have you coated the interior with a IR reflective coating, ITC-100 or equivalent? That will help if you have not done that yet.

Link to comment
Share on other sites

Yes frozen it has a coating of metrikote on it. So I should keep kao on the back opening as well as the fire brick unless working with something long. Will try that have plenty of kaowool. I bought 20 feet of it.  Cheaper that way if I get my butt in gear and put some up for sale

Link to comment
Share on other sites

  • 2 weeks later...

How about your forge floor?  Is it also hard brick without any insulation between it and the outside?  With that and the large rear door not being insulated (hard brick is an awful insulator on the scale of things) you could be losing a lot of heat.  The insulation layers can either be inside the hard brick, as Frosty suggested above, which keeps the brick cooler, or outside the brick, where the brick will need to warm up as a large thermal mass.  The latter will take a lot more time.

 

Sorry, read in the above that you have a layer of 1" on the floor.  Not sure why you aren't getting up to temp, try insulating doors.

Link to comment
Share on other sites

Naw, don't give up you just need to learn a new tool. Next time you're making a welding run in it try poking a piece of iron wire in. If the end doesn't melt and drop off then you have a forge problem. I'm betting you have a soak time issue, a coal forge heats much faster. Every tool has it's idiosyncrasies, up and down sides.

Frosty The Lucky.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...