Propane with forced air burner

My current propane burner is a naturally aspirated, venturi style. I've tried forced air with it, limited success. I'm thinking of building a 2nd one, similar to this one by luckygen1001. I'll probably use a variac controlled air source.
Thoughts?
Higher temps or not? Fuel savings?

 

I used a hair dryer, still have it somewhere. But when I used it, it was injecting on a branch (iron wye) but not mixing with injected propane until the combustion chamber. Sinice I've got no plans for melting iron, maybe that sleeping dog can lie.
I rarely take my regulator much over 30. Flame gets a bit unstable. My jet is centered in the large end of a 2" x 1" bell reducer, aiming down a 1 foot length of 1" iron pipe, no flare. Maybe I'll add a flare. I do have an adjustable gate over the 2" opening, starts mostly closed during warm up, mostly open during the melt.

 

I think that is an excellent solution. That's how I do brass and bronze.

http://www.alloyavenue.com/vb/showthread.php?7953-Reil-Blower-Combo-Burner

Robert

 

Hi all. Been a while since I've posted here. Thought I'd share my experience with adding a blower. I started with a naturally aspirated 3/4" T-Rex burner. Worked OK for AL but took a long time with brass. Forget iron. Then I added an inline blower using a pineapple juice can. Worked great! Cut AL melt times almost in half. Later I got hold of a bounce house blower and it got me to brass and bronze temps easily and iron OK. What I found was as the hotface heats up you can turn up the air and gas even more. The inline blower had some issues with back pressure, I think because my burner tube is only 3/4", and the bounce house blower was way overkill at full throttle. Each fan liked to be controlled in a different way. The folks who know electrical issues can explain it but the inline blower liked being controlled with its own speed controller which is more than just a light dimmer some how. The bounce house blower didn't like to be electrically controlled at all. It likes to just have its air input or output restricted. I also have an old shop vac which likes a good ol' light dimmer on it. Later I added some dryer duct quick connects for easily switching blowers and breakdown. I use the inline blower for AL as even the restricted flow on the bounce house blower creates so much turbulence in the furnace it over oxidizes the melt and sets up standing waves that sloshed over the crucible. But on heavier brass, bronze & iron the bounce house blower is the ticket, though a smaller one would work just as well. This monster is just what came my way.

 

Thanks for the suggestions everyone. Early on, I debated myself about 3/4" vs. 1". Despite all the 3/4" burners I had seen, I justified 1" as bigger = better. Not always so.

Ill check out Robert's link on AA.

CactusDreams, glad to see you're on here as well. I remember a lot of your stuff on AA. You're in Mexico right? Hoping to make a trip to Ajijic sometime. But I really miss Baja. Used to surf a lot down there when I lived in San Diego. Kept my taco addiction fed as well. Thanks for the pics.

Edit: Sorry Cactus. Just looked at your profile. Canola Park, not Mexico. I lived in Rowland Heights breifly, not that close to Canoga Park. But, closer than where I am now.
I cannot remember who that was in Mexico that was on AA. But I do remember your stuff.
[end ramble]

 

http://www.alloyavenue.com/vb/showthread.php?12550-HT1-s-Moya-Burner&highlight=burner


Here is my build thread, very simple, i'm running almost the same setup as Rasper, save I never hook up the oil fun it on propane all the time... be forewarned furnace design is more of an issue then people thing, My new Hemispherical lid proved that

http://forums.thehomefoundry.org/index.php?threads/making-it-a-hemi.320/

V/r HT1

P.S. play with how far you insert the Burner into your furnace... there is a big fall off on mine if it is too far in, but my furnace burner opening has a bell mouth on the inside... also I let my furnace warm up with the lid open as idt sputters a little till it gets hot ( like 2 minutes) then quiets down I close the lid and melt

 

That is really clever.
I have a propane burner like that, but never figured out how to add combustion air to it.

 

I've gathered the parts for a new burner, planning on a forced air connection like Cactus shared. New model will definitely have a flare on the end. Hoping to reduce the propane consumption a little.
My 100 lb. tank acts like it's endless, but we know better than that. Last time I filled it, I was alerted that the inspection was overdue. Best $75 worth of propane ever .

 

I only use forced air burners. I have posted my little burner before on other forums. I drilled a hole in an exhaust pipe from Autozone, bent a piece of 1/8" copper tube to go into the hole and then point down the tube, hooked it to a high pressure propane reg. My large blower is a squirrel cage and I have to keep it closed down or there's too much air. The highest gas pressure I've run is about 10 pounds. In these pictures I have a small computer fan. Yes, I was surprised it work but I have to keep it shut down also, I use about 5 to 7 pounds of gas for Bronze and aluminum. Less than $30 just because of the regulator.
Yes duct tape and hose clamps. 12 volt fan and I hook it to a charger while melting.

 

More good info. Thanks guys.

 

My regulator only goes up to 20 PSI. I think I may do better with 30. Any one got a link to a good quality item?
Robert

 

The pottery kiln supply people should have a suitable flow regulator. The propane furnace a friend uses on a regular basis has one: http://www.e-weld.co.za/product/regulator-lpg-high-pressure-red-devil/
The burner is simply a length of 1/2" copper tube connected to the regulator that carries the fuel into the forced air stream.

 

I've got a Fisher FS-67CH-150, bought at a nearby welding supply, $65 almost 3 years ago. Can't find it online, but other models come up. It has an outlet pressure gauge. Spec says 30 -60 operating range, I rarely go over 30. Hoping to go lower with this new burner.

 

There ya go Frank. That's a quality regulator. https://www.emerson.com/en-us/catalog/fisher-67c-lp-gas

 

Thanks for that! You've inspired me. I'm going too splice in a propane line into my oil fired furnace to start it up.

 

This is a fab thread thanks. It has made for a very entertaining Sunday afternoon for me. I've successfully upgraded my waste oil burner to now also burn propane for preheating the furnace to then switch to burning waste oil. Here is a video short of what I've done and the results. Cheers.

 

Nice work Jimmy.