[TheForge] Sidearm burners

[schade at acegroup.cc]

thanks Darrell. And Jerry.

Bob
_____

On Feb 14, 2007, at 12:27 AM, Darrell wrote:

> 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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