Fasted58's Propane burner build

My first burner build.

About ten years ago I began researching internet sites and YouTube on foundry builds, other projects took precedence though. Spent many hours researching and taking notes of where I wanted to go w/ this build. Every builder has their own style and application whether forge or furnace work. Didn't answer all my questions though.

Pipe fitting vs machined or fabricated. Materials. Orifice size and placement. Hot end flare. Primary air choke or not. Adjustability, etc.

I chose a pipe fitting burner for ease of swapping out components, also happen to be a pipe fitter. This could be a test mule of sorts.

Ordered parts online rather than chasing around locally. Online build consensus was 7-8" Schedule 40 black nipple w/ 1-1/4" to 1-1/2" max BMI reduced coupling for the air inlet side. 1" x 3/4" reducer for the flame side, ordered that in SS.

Chose a 2" x 3/4" BMI reducer to add a primary air shutter for adjustment, may be room for a diffuser also, we'll see.

Import casting is OK for regular piping duty, rather irregular though as I'll soon find out. Domestic may not be that better btw.



Ground the threads out w/ a carbide burr and tried to smooth the lumps and casting lines. Inside is more oval than round. Porting kit cartridge rolls didn't do much to smooth. Surfaced the fitting faces on a pedestal disc sander.



Paint stripper wheel oughta help smooth that out. Stumbled across the HF kit for $7.49. Chucked it up in the drill and ground the diameter down and radiused the edges on the bench grinder to fit inside the bell. Wow, made short work of it.

Gotta, gotta recommend this for small metal finishing:

http://www.harborfreight.com/2-in-conditioningstripping-kit-69777.html



Result:



Also used on the SS 1 x 3/4" hot end flare.



Most would consider this step unnecessary. Why did I do it? Because I could.

Centering tool made from a long 3/8" bolt, hex head removed and w/ two 5/16" washers w/ 3/8" ID. Soaked in muriatic acid to remove cad plating before welding. Shaft chucked in drill and spun against bench grinder till washers slip fit inside pipe ID. Had to hone the nipple bore w/ home made flap wheel on a rod to fit the guide, tool shown above.



Result:



Start of carrier for nozzle assembly. 3/4" x 1" stock from the shelf. 3/8" drill thru, squared and radiused on pedestal disc sander. Drill and tap 1/4-20 NC for bolt as a handle during forming, later to be used for set screw for nozzle pipe assembly. Used 3/8" OD tubing bent 90° for pivot during radiusing against disc sander to save my fingers.



Missing pics in this segment. Finished carrier block w/ 3/16" x 3/4" flat stock welded on center. Corners radiused w/ burr, contoured w/ porting cartridge roll. My Dykem went MIA so wide tip black Mark-X for layout and scribed.



Transferred scribe marks down each side. Pilot drill then 3/16" drill at bottom of slot. Cutoff wheel to complete the slots.



Allowed a little block stick up above face to be surfaced later. Trim ends, MIG weld sides and face.



Carrier welded in, bell face and OD have been surfaced on the pedestal disc sander.

Made a radius scribe tool from flat aluminum stock and a TIG tungsten. Mark-X Dykem FTW.



Laid out 6 hole pattern on a paper template and transferred to the bell face. Slight compensation for two holes because casting being irregular, it's not as round as it looks. Drill and tap 10-24 NC.



Start of primary air shutter:
I had flat stock and auto body metal on the shelf but came across these box covers at HD for 60¢ each. Nice and flat and had slots for hold downs already. Screw onto flat board and hole saw cut.



Used same radius scribe and paper template to layout shutter base plate. Cutout OD was larger than bell diameter so ground it flush on the disc sander.



Drilled the corners of opening first for radius, cutoff wheel next and carbide burr to rough in, file to finish. Lotta file work on midnight shift. Being rather conservative w/ the opening, could always remove more out of the center later if needed.



Shutter wheel next. Another hole saw cutout w/ OD ground to fit.



Pared down w/ drill for radius, cutoff wheel and filed to finish.

 

Original plan was a MIG tip threaded in a Schedule 80 1/8 black nipple... dimensions were that close. Nipple had a big lump of a inner weld seam and while it did tap the threads were kinda shallow. Could have brazed the tip on but that would defeat the purpose of quick change. Almost abandoned that idea.

Found that a Schedule 80 brass nipple had enough wall to drill and tap 1/4-28. Typically, Miller and Lincoln MIG tips in 0.023, 0.030 and 0.035. Import tips are M6.

Brass polished up nice. The needle valve is an option but paid off in low pressure test. Rather have it than not.



3/8" shaft collar from Fastenal for $1.02, drilled to nipple size keeps spring tension on the shutter wheel. Fastenal, my new favorite store.



Drilled hole in the bell OD for allen wrench access, used the same hole to tighten bell to nipple w/ spanner wrench. Nozzle assembly unloads fast for MIG tip or shutter wheel change.

 

Needed a mount to chuck in a vise for testing. 1-1/2" angle iron and 3/16" flat stock off the shelf w/ Dupli-Color black engine enamel to finish.



1/4" NPT brass street ell to acclimate the gauge for easy viewing. 1/4" ball valve for quick shutoff. Chose a 10' SS braided propane approved hose for safety reasons also.

 

First fire. Lit at 20 psi gas, 1/2 air choke. Once warming could reduce pressure and adjust choke to compensate.

40 + psi gas and choke open full shown.



Cut another shutter wheel for the 0.023 MIG tip. New shutter wheel is on the right. Needs more finishing but was anxious to test it.

 

Changed out the 1 x 3/4" bell reducer for a straight 3/4" SS coupling on the flare end. The 1 x 3/4" bell would work well using it as a forge burner or for other shop use but not necessarily in the furnace.

Could have cast a socket with flare molded in the furnace refractory for fitting the 3/4" pipe end but the refractory would degrade over time and need replaced or recast. The 3/4" coupling will be used as a sacrificial/ consumable piece. SS was chosen over BMI or steel for durability. A 3/4 x 8" SS nipple replaced the previous black nipple.

At first the burner lit w/ the 3/4 coupling flare outside the furnace but burnt back in the pipe. First time that ever happened. Ground the threads out w/ a carbide burr, not happy yet. Ground a slight taper towards the end of the coupling and bingo, she lit but at higher pressure. Once warmed up some I was able to lower the gas pressure to 2 PSI and adjust the choke down.

There is about 12 hours run time on this SS coupling as shown.



Lowest fire I could get, that is with the 0.023 MIG tip and choke cut way down. I could never get the 0.030 orifice down this low. The refractory was warmed to over 185°F w/ lamps during dry out. Not throwing too much heat at it to start. The needle valve came into play also for fine tuning.



Primary air cut back at 2 PSI gas pressure.

That ain't a lot of primary air.



Shown in operation for curing refractory.

 

I'm rather pleased with this build.

Wanted to test orifice distance to 3/4" pipe in air inlet side. Nothing appreciable found by adjusting it's depth. Currently the MIG tip is 1/2" from pipe inlet and works well.

Quick-change is nice. I can change out the MIG tip and/or the shutter wheel in around a minute, even with the burner in the furnace.

Glad I can use the MIG tips in 0.023, 0.030 and 0.035. 0.023 for low fire as dry out and curing refractory, and later used for curing HTC100 HT. I may use the 0.030 for melts next year. 0.030 and 0.035 can be used for a forge, maybe look into that later. Shop use heating also. The needle valve came into play with low fire.

Would definitely run an air choke again. This air shutter may look like too much but I had plenty of time on my hands. There are many types shown out there, many more simplistic. It particularly came in handy for low fire.

The 3/4" x 8" pipe nipple works fine. I was going to build a weld fitting burner after learning the test mule results. This pipe fitting burner works fine and components can be changed out quickly. 3/4" coupling flare for furnace work or 1 x 3/4" flare for use outside.

Keg foundry furnace build is finished and cured. Will melt late this year or early next year. Will post a build thread in the near future.

 

Nice work, and a well documented build. Looking forward to some shiney liquid metal!

Pete

 

Mighty fancy burner. Looks good!