[TheForge] Sidearm burners

Wed Feb 14 01:27:18 EST 2007

Here is Jerry's burner article posted on the NWBA web site.

http://www.blacksmith.org/drupal/forge_burner

Darrell

----- Original Message ----- 
From: "Jerry Frost" <frosty at customcpu.com>
To: "Sponsored by ABANA" <theforge at mailman.qth.net>
Sent: Tuesday, February 13, 2007 6:19 PM
Subject: Re: [TheForge] Sidearm burners

> 
> -------------------------------
> If it ain't forged
> it ain't real.
> Wrought iron is.
> The FrostWorks
> 
> Meadow Lakes, AK.
> 
> http://www.artmetalradio.com/
> 
> 
> From: "Steve Smith" <sos at alum.mit.edu>
> 
> 
>>
>>
>> I'm responding to Frosty's comments, but welcome 
>> replies from all.
>>
>> I'm still messing with burners in a very slow 
>> fashion. I've made maybe a dozen Reil burners and 
>> have been very happy with their performance. I make 
>> the jet out of 1/8" brass pipe, aligned with the axis 
>> of the burner, jet hole drilled in the brass end cap.
>>
>> I was pretty interested in sidearm burners when they 
>> were first discussed. I followed in Frosty's 
>> footsteps and experimented with a 4 way pipe fitting 
>> instead of a sidearm. It was ok, but not as good as 
>> the Reil burners, which I chalked up to not having a 
>> smooth transition to the 3/4" body.
>>
> 
> More likely you're trying to use the same size jet 
> orifice as you do for one of Ron's. Try stepping it 
> down about 30%, a jet ejector type burner is about a 
> 30% more efficient inducer. Alignment is still 
> critical, no change there.
> 
> There isn't a significant difference in the transition 
> from a Bell reducer to a nipple than there is a "T" or 
> Cross to a nipple.
> 
>> Then I saw that Larry Zoeller had added a sidearm 
>> 'kit' (all you have to do is tighten things up). I 
>> bought one of these. It came with a tapered mig tip 
>> for the gas jet, pretty nice setup and for not much 
>> more than the fittings would have cost me. I recently 
>> compared the performance of this sidearm burner to a 
>> Reil burner. Both are 3/4" body with Larry's 
>> stainless flares on the end. I measured with a 
>> thermocouple, both in the same, single burner forge.
>>
>> The sidearm was almost as good as the Reil burner. 
>> Final temp was maybe 100 degrees lower. This makes me 
>> think that the sidearm is just an easy way to put the 
>> same burner together, and less impressed with the mig 
>> tip. Sounds like this isn't correct--what am I doing 
>> wrong?
>>
> 
> If both are properly tuned there will be no significant 
> difference in performance, a neutral burn is ging to 
> put out the same BTUs for the same amount of fuel. 
> Tuning a sidearm requires taking into account the 
> single air intake and how it deflects the propane jet. 
> You need to offset the jet slightly to make up for the 
> single air intake.
> 
>> I'm at maybe 300' above sea level, neither burner has 
>> a choke. Pictures could be done if important to the 
>> plot.
>>
>> Thanks,
>> Steve
>>
> 
> A little (recent) history may be in order:
> 
> The "sidearm" configuration for a jet ejector was 
> Robert Grauman's innovation. The summer of 98 or 99 
> Robert and his wife were visiting Alaska and stayed 
> with us for a few days. Deb and I were in the middle of 
> building the house and I didn't have much of my 
> smithing stuff unpacked. Certainly not the propane 
> forge, we had heaps and piles of wood so that's what I 
> was using for the little smithing I needed to do while 
> building.
> 
> Anyway I described the "T" jet without making sketches 
> and Robert misinterpreted the description. The first 
> time I saw a picture I nearly E-mailed a correction but 
> reading further realized he'd made it work just fine so 
> I filed it in my "learn something every day" file. One 
> of Robert's casting buddies made a 1 1/4" bore sidearm 
> and melts up to 25lbs. of iron at a time with it.
> 
> Another good example of well tuned sidearm burners is 
> Ralph Sproul's variable volume forge. 
> http://www.bearhillblacksmith.com/
> 
> Ron's criticism of the sidearm was about it's off 
> center flame. This is easy enough to correct by 
> tweeking the mig tip towards the air intake a LITTLE 
> till the flame centers properly. It's a minor thing.
> 
> Then there's the whole mig tip for the jet thing. I'd 
> given up on making a linear inducer to my satisfaction. 
> Oh, I'd made a couple but they took more tinkering than 
> I liked to get tuned properly so I tried a jet ejector. 
> The first "T" jet. I suppose I should call it a "T" 
> intake but what the hey. If I'd been smarter I would've 
> gone ahead and spent the time to hunt down a pipe cross 
> but having a lathe I just used a pipe "T".
> 
> What I knew from the general information I have on 
> inducers is; a jet ejector will be about a 30% better 
> inducer than a linear but I'm not good enough at math 
> to calculate the ratios. So instead of going to all the 
> headaches of drilling a bunch of pipe caps till I got 
> it right, I drilled and tapped one, 1/4"-28 and bought 
> a handfull of mig tips. that's when I learned a brass 
> cap isn't thick enough for a mig tip to thread into 
> securely so I found a brass fitting with 1/8" FPT to 
> something with a hole smaller than I needed for a 
> 1/4"-28 tap and chased it out.
> 
> So, I spent about an hour lighting it up and changing 
> mig tips till I got my first "T" jet tuned to my 
> satisfaction and called it good. I still have a little 
> baggie with half a dozen different mig tips. The one 
> that worked was a 0.045" Miller mig tip in a 1 1/4" x 1 
> 1/4" x 1" pipe "T" and I'm still using it some 12 years 
> later.
> 
> Having met with acceptible success for such little 
> hassle I haven't bothered to replace it with a better 
> one. I have made half a dozen since and fine tuned the 
> "design". I've shortened the mig tip considerably to 
> move the introduction of the gas jet higher in the 
> intake's cross section. This improves induction 
> considerably so a simple 1" x 1" x 1" pipe "T" works 
> quite a bit better. This is how I made the burner for 
> Rich Fizzell, host of the first (now) annual ArtMetal 
> Shindig.
> 
> What I didn't realize when I started using the mig tips 
> for jets was just what a genius I was. I thought I was 
> doing it the easy way and it wasn't until Mike Porter 
> straightened me out that I realized I was using the mig 
> tips for something else entirely. <grin>
> 
> What Mikey uses the mig tips for is an "accelerator". 
> Basically the same thing as the nozzle on a hose. It 
> "conditions" the propane into a laminar stream which 
> performs much better as it enters the burner's 
> induction zone. Being a smooth conical stream (rather 
> than the turbulent vortex a simple drilled hole causes) 
> the propane expands smoothly and enters the the throat 
> of the tube uniformly. All this increases both the 
> device's induction and disperses the propane uniformly 
> in the intake air column. It also allows a natural 
> vortex to form in the burner tube which enhances 
> mixing.
> 
> Here I thought I was being expedient (lazy) and all 
> along I'd come up with a simple solution for a complex 
> problem. <grin>
> 
> So, there is a good reason for using mig tips though 
> they don't have to be full length. I've found 9/16" 
> works just as well as full length and I'm sure shorter 
> will work as well though I don't know how short is too 
> short. I haven't had much time to experiment this 
> winter like I'd planned.
> 
> It doesn't matter much which configuration you choose 
> for a naturally aspirated burner, tuning it is what 
> counts. Some (jet ejectors) are easier to tune by their 
> nature but once tuned there won't be any difference in 
> heat output.
> 
> Tuning is where gun (blown) burners really shine, 
> they're easy as adjusting the gas valve till you like 
> the fire. You have to retune every time you turn it up 
> or down but it's still very easy. Building a gun burner 
> is pretty easy if a lot more expensive. You simply 
> plumb a blower's output through at least 1 90* turn 
> with a gas fitting either in the elbow or just in front 
> of it. Attach it to your forge as you like and begin 
> tuning.
> 
> A properly tuned naturally aspirated burner on the 
> other hand needs no further fiddling. The intake air is 
> induced in a direct ratio with the propane. Turn up the 
> propane psi and the air induction rises with it. The 
> only time you might need to choke a properly tuned 
> naturally aspirated burner is for lighting. I simply 
> put a palm over one of the intakes on my "T" jet and it 
> lights right off. It'll light anyway but it sometimes 
> blows the newspaper out of the forge before it lights. 
> Like THAT'S a big problem. <grin>
> 
> I haven't put an electronic igniter in it though one is 
> on the board for my next forge.
> 
> Frosty 
> 
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