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A little knowledge welding the venturi head


Pigsticker

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Many thanks Sirs. I've been adjusting only the tank valve and the cutoff. I'd never put it together that it should be open always and just using the regulator. So how hot can a propane forge hit? I knew mine was having trouble hitting a welding temp before but I thought there was a limit to propane's heat maximum. Can I hit 2600 degrees with bricks up at 12-15 psi or am I being crazy? Here's another one, can I air dry my rigidizer solely? It be a real mod 42 to wait for inbound forge metal parts. I have kastolite ready to go but if Ive  gotta wait til I get forge parts that adds like 5 days. I saw old postings from both you guys on rigidizing  and heat curing it or not. I've spent too much time and loot on all this to have kaowool concerns. I really coated it in a lot of rigidizer ( I'm rebuilding my newly built forge from a heavy crumbling and 1/2 lb of melted cable on the floor encountered on initial firing. And they should have something in 101 on metal pipe sizing and achronisms.

thanks again for helping

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After all reading previous correspondence, I realized my pipe and reducer are marked as 3/4" pipe on the t fitting on original venturi setup. Am I definitely wrong? Side note- I have a brand new 1"x8" stainless pipe threaded and a 1"x2" unthreaded reducer if anyone wants to start the bidding war on my erroneously ordered 1st attempt. Let's go $80 and up, reserves exist and boy, this is shiney metal.

Thanks 

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Ditto here, I tune by eye and ear I just haven't taken the gauge off my regulator, it's been there for maybe 35 years +/-. I'll use it occasionally in the NARB forge for heat treating and yesterday it came in handy. I could see the pressure begin dropping so I could keep ahead of the slushing up propane curve though that's easy to hear and see by burner performance but staying ahead of it is better. It was 15f. in the shop and I use hot fire brick door baffles to keep the tank warm . . . enough. I stand one on end almost touching the tank and swap them out about every 15 minutes at a guess. Once I had an idea of how often to swap bricks the gauge resumed it's usual duties. . . nada.

Frosty The Lucky.

 

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Is the deftly hidden message above about: you heard pressure go down as your tank emptied then you upped the regulator because hiss equaled the temp regardless of pressure adjustments on dials? This is all w tank wide open right? Are fire bricks referred to henceforth about2.5" thick or the 1.25" bricks? You keep your propane tank heated??? We've already got down in the 50's but I'm not gonna hold a lighter to the tank to heat it. I used to tell people how they could scramble eggs by shaking it and putting it in the microwave 3 min. I'm not sure if or when my proofreader will return from brunching in a vest with squirrels , cheeses and fruit (fruit is plural EVEN without an s) so let me wish you all the merriest of Christmas and 2023 gonna rock. 

Thank you 

(Above was no cussing, ribbing of Frosty, nothing disrespectful intended)

 

 

 

 

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Wait. You're calling dials and gauges In reference to just the gauge part. No one is saying no regulator. Glad I caught that. I wasn't even reading when it hit me like a bolt of lightning. That's why I just lay my trash in the can instead of dropping it to the juicy depths.

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21 hours ago, Pigsticker said:

So how hot can a propane forge hit? I knew mine was having trouble hitting a welding temp before but I thought there was a limit to propane's heat maximum. Can I hit 2600 degrees with bricks up at 12-15 psi or am I being crazy?

Two different IFI members, with the necessary equipment, have recorded forge  temperatures of 2750 F. Welding temperatures are only around 2200 F Most forges easily reach 2300 F.

However, attaining high forge temperatures not only requires a properly built and tuned burner, but a properly built forge, which is correctly set up; this means the burner is kept well inside its forge portal, and A baffle wall is kept at the right distance from the forge shell, with its opening kept just large enough to pass the work piece back and forth. Additionally, the amount of secondary air passed between the burner's body and the its portal is moderated with a secondary choke on the mixing tube, or ceramic wool between the mixing tube and the portal.

In fact, there are more and ever more commercial burners on the market that are more than capable of doing the job, And greater care in forge design, and better understanding about how to run them well are the greater need these days.

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Thank you. I thought that propane only got about 2-2100 degrees. That explains a lot more of this mystery.  What would the max temp of near all blue flame. Does having metal in the forge allow a forge to run hotter? It seems like any solid bump on the blue flame would hold the fuels together long enough to achieve maximum hear. Right, maybe?

Thank you

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theoretically propane can reach 3600 F burning in air, if you have the time and know -how to build a burner as complicated as a jet engine, than you have 'a chance' at that :rolleyes:

As to how hot the flame on a burner in the real world gets; this is quite variable. I have only built burners that create a Nox spike twice; this happens between 2800 and 3200 degrees. Since this is way hotter than is needed in a practical burner, I don't pursue that goal. The secret of making a hot enough forge, is to look at every aspect of its deign; its burner is just one thing amoung many. Good enough is good enough in burner design.

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Thanks. couldn't process how propane could burn away cable if it only got to about 2000. Spent way to much effort on the temperature gun an not learning steps. From the factory my forge was supposed to be 2600 ready (with refractory and rigid). When I read how far off advertised vs actual temps were it made me realize the forge guys probably say reviews are just as judgemental and inaccurate. So, with such a rapid cool down, a forge with metal in it would be an obstacle to the 3000k cooling?

Wow 3000 degrees.

Thank you

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23 years ago, when I started hunting for correct information on flame heat potentials of various fuels burning in air, it took months to sort out earnest sources from biased information; some of it was merely 'massaged', and some of it was "as crooked as a dog's hind leg"; but most of it was just one ignoramus quoting other ignoramuses. When it comes to advertisements, those "birds of many feathers" have become a vast flock.

I watched sellers of butane lighters and (to a lessor extent) propane torch-heads raise their figures on flame temperatures to match each other, for the first twenty years, and they are probably still going up. You could probably dig up the now badly dated information on potential flame temperatures of fuels burning in air today, but they will all be buried in tons of phony baloney advertisements; maybe you could start searching on page twenty, and your search would only take months.

However, mathematically derived (adiabatic) flame temperatures of various LPG fuels burning in air would still be irrelevent. What the last two decades have repeatedly proved is that burner design will usually have more to do with flame heat than what LPG fuel gas is used; propylene being the only exception (since MAPP gas is no longer being made on this continent). I think you can still find MAP gas elsewhere in the world; but propylene burns just as hot, and is cheaper/safer.

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Wow, I was way off. Everyone, I thought, was saying propane doesn't get hot enough reliably to weld. I knew coal forges get up to 3000k but I've  "seen" coal scorch metal . I thought I read butane is in the 800's. I'm pretty sure my vague familiarity is with torch 's btu rating. I had tried to find a gas torch to tack together billets before I weld it. Does that mean there is a gas torch invented that goes up to 2500 degrees or so that I could tack with? I know it's not a great example, a bond made at 700 degrees to hold metal at 2200 won't work. Fascinating to know 3800 is possible. Is there anything commercially available over 3 k? As long as the forge stays hot, it would cut reheat times about 40%, right.

Side ?

What is minimum temp to hit cable being welded without separating it? Red seems way too cold. If you need 2100 to weld, and 1700 to forge, can you start each pass by hammering to weld and hammering to forge?

Many thanks guys. I think I must have been looking at cigarette lighters btu info.

Tx 

The only reason I'd be open to gas torches, it because I have the faintest experience w gas burners. I've never ig'ed anything(t or m) and have enough random skills. I'm really floored propane gets so hot.y old zippo never did.

Tx

 

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Well, yes. But then I am a complete geek about this stuff. Most other people want simple practical answers about flame temperatures and upper limits in forge temperatures. So, I try not to geek out on the subject :rolleyes:

But thank you for more facts that can drool over in private :)

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I assume the 3350 adiabatic figure is for natural gas (methane), becuase of the cooling effect of some of its hydrogen and oxygen content recombining to make steam. And probably the 3800 figure is for acetylene.

Don't forget to add an damantine crucible to melt your witches brew in :rolleyes:

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