Jump to content



Photo
- - - - -

Not hot enough


  • Please log in to reply
9 replies to this topic

#1 JAKA

JAKA

    Junior Member

  • Members
  • PipPip
  • 25 posts

Posted 07 March 2011 - 07:32 AM

I was fortunate enough to have some friends make a propane forge for me several years ago. It heats up just fine but only has a small sweet spot in the forge for the iron to get hot and at that it's never hot enough to weld with.

As you can see from the attachments I think I need something more than the two inch pipe for a burner head but I'm not sure where to start. It runs right off the propane bottle with just a small fan for an air blast. I have a sliding plate in the inlet line to restrict air flow if needed. Any suggestions welcome. Thanks.

Attached Files



#2 ThomasPowers

ThomasPowers

    Senior Moment Member; Master Curmudgeon

  • Members
  • 17,760 posts
  • LocationCentral NM/El Paso TX Area, USA

Posted 07 March 2011 - 11:07 AM

I have a propane forge that looks a lot like that one, only not as much insulation in it and we were melting steel in it yesterday....not on purpose but students don't seem to realize that leaving their piece in the forge too long can be a bigger problem than leaving it in too short---no matter how many times you point it out to them!

Are you tuning the air-propane mix for maximum heat? Do you re-tune it after it warms up?

Does your insulation really insulate or it it a harder more durable material with less insulation properties? Harder less insulative forges often require long pre-heats before they will forge weld. (Some may take several hours to come up to temp and then weld like a fiend for the rest of the day.)

How much propane are you piping in? Are you using a high pressure regulator and NOT a low pressure one like most gas grills use?

Is the distance between the gas inlet and the flame retainer long enough to get a good mix of the air and propane?
Thomas Psychotic Psychobabblonian Powers

#3 beslagsmed

beslagsmed

    Advanced Member

  • Members
  • PipPipPip
  • 72 posts
  • LocationDenmark

Posted 07 March 2011 - 11:57 AM

Looking at your setup, I believe your gas orfice(spl) to too big, thus not having the right fuel/air mixture. I got a gas forge for my farrier rig and the orfice is about .5mm and I can burn up steel!!

#4 JAKA

JAKA

    Junior Member

  • Members
  • PipPip
  • 25 posts

Posted 07 March 2011 - 12:19 PM

I was fortunate enough to have some friends make a propane forge for me several years ago. It heats up just fine but only has a small sweet spot in the forge for the iron to get hot and at that it's never hot enough to weld with.

As you can see from the attachments I think I need something more than the two inch pipe for a burner head but I'm not sure where to start. It runs right off the propane bottle with just a small fan for an air blast. I have a sliding plate in the inlet line to restrict air flow if needed. Any suggestions welcome. Thanks.



I don't really have a gas orifice other than the ring spacers on the end of the 2" pipe. I also do not have a gas regulator. I'm really pleading ignorance on this one. I've always used a coal forge before so this is virgin territory for me.
What looks like insulation is actually refractory such as that used in furnaces.

#5 JAKA

JAKA

    Junior Member

  • Members
  • PipPip
  • 25 posts

Posted 07 March 2011 - 02:11 PM

I've started reading some of the other posts and see that there are those who take offense at questions without adequate research before the questions. I can understand the frustration if questions are asked over and over.

In that light, I think I'll hold off on asking advice on just where to get started until I've learned more on my own about forges. beslagsmed and ThomasPowers,
Thank you for the info you've freely shared. It's appreciated.

#6 ThomasPowers

ThomasPowers

    Senior Moment Member; Master Curmudgeon

  • Members
  • 17,760 posts
  • LocationCentral NM/El Paso TX Area, USA

Posted 07 March 2011 - 02:39 PM

Refractories vary greatly in how insulative they are. Since temp in a forge is a balance of heat in vs heat out how much heat the refractory soaks up or transmits out is an issue.

Having a regulator on that propane line is a *must* IMNSHO makes tuning the forge a whole lot easier. Talk to a local propane dealer about getting a "redhat" regulator or other type that will run between say 0 and 25 psi. Getting friendly with a Propane dealer is like being given free money! Lots cheaper to get tanks refilled than to use an exchange service! (and my local dealer has a frequent filler program where I get one tank free for every 4 I fill---a 20% discount!)

There is one best air/gas mix to get the most heat out of the system FOR EACH LEVEL OF AIR OR PROPANE. So you can set the propane and adjust the air till you get the best or set the propane and adjust the air. Or you can work both up from some starting value till you get the heat input you want.

I tend to tune the air unless I need a totally different level of heat and even then I will usually start at what I'm used to and then add/subtract propane and then tune the air to the new value. Coarse tuning can be done by sound, the burn is best when loudest. Fine tuning can be done by eye, the burn is best when the refractory the flame impinges on is brightest---have to allow some lag time as it does take a bit to come up to a new temp.

If you are worried about decarburization in high carbon steels you may detune it so it runs a bit rich---HOWEVER this tends to up the CO output as well so MASSIVE VENTILATION is suggested. (Actually with a gas forge it's ALWAYS suggested!) My system tends to run a bit leaner when hot so when I notice that the scaling is a bit heavier I will tune it again.

Blown forges generally do not need a fancy gas orifice, they do need mixing---why the right angle fitting right before the gas inlet to provide turbulent flow.

Was this abrasive enough for you or shall I taunt you some more!
Thomas Psychotic Psychobabblonian Powers

#7 JAKA

JAKA

    Junior Member

  • Members
  • PipPip
  • 25 posts

Posted 07 March 2011 - 03:17 PM

Refractories vary greatly in how insulative they are. Since temp in a forge is a balance of heat in vs heat out how much heat the refractory soaks up or transmits out is an issue.

Having a regulator on that propane line is a *must* IMNSHO makes tuning the forge a whole lot easier. Talk to a local propane dealer about getting a "redhat" regulator or other type that will run between say 0 and 25 psi. Getting friendly with a Propane dealer is like being given free money! Lots cheaper to get tanks refilled than to use an exchange service! (and my local dealer has a frequent filler program where I get one tank free for every 4 I fill---a 20% discount!)

There is one best air/gas mix to get the most heat out of the system FOR EACH LEVEL OF AIR OR PROPANE. So you can set the propane and adjust the air till you get the best or set the propane and adjust the air. Or you can work both up from some stating value till you get the heat input you want.

I tend to tune the air unless I need a totally different level of heat and even then I will usually start at what I'm used to and then add/subtract propane and then tune the air to the new value. Coarse tuning can be done by sound, the burn is best when loudest. Fine tuning can be done by eye, the burn is best when the refractory the flame impinges on is brightest---have to allow some lag time as it does take a bit to come up to a new temp.

If you are worried about decarburization in high carbon steels you may detune it so it runs a bit rich---HOWEVER this tends to up the CO output as well so MASSIVE VENTILATION is suggested. (Actually with a gas forge it's ALWAYS suggested!) My system tends to run a bit leaner when hot so when I notice that the scaling is a bit heavier I will tune it again.

Blown forges generally do not need a fancy gas orifice, they do need mixing---why the right angle fitting right before the gas inlet to provide turbulent flow.

Was this abrasive enough for you or shall I taunt you some more!



I love it when you taunt me. Thank you for that wonderful information. I can already see where I need to go with my forge. By the way, I wasn't offended by those who would like newbies to gas forges like myself to do more research. I understand that one can get frustrated answering the same questions over and over which is why I feel it's on my head to corral as much info as I can. It certainly wasn't aimed at the two of you who replied on this topic. I just felt like I had touched a sore subject. Thanks again and I will trap my propane dealer next time he arrives and will visit about a pressure valve.

#8 Jack Evers

Jack Evers

    Member

  • Members
  • 308 posts

Posted 08 March 2011 - 12:14 AM

Having a regulator on that propane line is a *must* IMNSHO makes tuning the forge a whole lot easier


To second Thomas - Propane puts out 25 psi at zero degrees F and 130 psi at 80 degrees F. I can't imagine a system working W/O a regulator.

#9 beslagsmed

beslagsmed

    Advanced Member

  • Members
  • PipPipPip
  • 72 posts
  • LocationDenmark

Posted 10 March 2011 - 11:38 AM

I also agree with getting the regulator - SAFETY FIRST!! Also setup are very different if you have a blower and a natural asperated setup. I had a blower forge for a while, but changed it to natural asperated. This is where I had to come into getting a smaller orfice to get the best mix.

#10 Lee58

Lee58

    Newbie

  • Members
  • Pip
  • 1 posts

Posted 16 March 2011 - 05:48 AM

Lots of help thanks




0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users