naturally aspirated burner

You mean I dont have to try and counter the worlds rotation after all?

 

Rasper and I both run the Bucket Vacum, I actually wore one out, but I cast more then most

https://www.homedepot.com/p/Bucket-...ible-with-5-Gal-Homer-Bucket-BH0100/202017218

 

Do you use anything to adjust the flow or do you just use it at factory setting? I see a lot of folks on here using speed controllers and such. That is pretty cheap for that and heck I could use a better vacuum in the shop anyway.LOL

 

I have a speed controller, but dont use it. I got Very Lucky when I built my burner, and Got alot of things perfect totally by accident , but with my orafice size , and 22PSI that vacuum running all out , I get all But perfect burn in my furnace

 

It's up to you. Proceed at your own risk!

 

I'll just have to give it a whirl.lol

 

If you don't want to use a speed control you can restrict the inlet to a hair dryer with a piece of cardboard. Restricting a fan lower's it's horsepower so no harm is done. But run it on the cod setting or clip the heating element. Being able to adjust the air flow lets you know you have it right. On propane, yellow is too little air, green is just right, blue is too much air.

When your flame went out sometimes it just burns outside the furnace because of not enough air and the furnace is too rich to burn.

 

This is a perfect explanation. The only thing I would like to add is if you do not have control for a variable speed Electric fan blower. Just add a in line exhaust that is a ball valve. This can reduce some and all of the pressure being put into the furnace. It is just a valve that exhaust some of the air to atmospheric air. I learned this a little bit the hard way. Adding more air provides a hot or flame, if you can give more fuel.

I went a little overboard on my blower. But I also went a little overboard on making a small burner. My burner air is variable speed at the twist of a potentiometer.

Propane as a fuel will not get you the same temperatures as diesel.

I have two tanks with fuel in them. They are both 2 1/2 gallons. I felt one of them up with pure diesel and the other one with mainly recycled vegetable oil, old two-stroke fuel, diesel and vegetable oil mix and old gasoline... This tank gets or white animal fat sludge in it. I use 200 W magnetic heater. I'm not exactly sure what the whole mix is. But I pressurize the tanks for feed.

I have a switching handle that pulls off the individual tanks. I can fill one tank while the other one is being used and it takes about two minutes.

 

An inline exhaust absolutely dumps excess air. However the blower is still running at full capacity. A suction restriction, on the other hand, also slows the volume going to the furnace but also unloads the blower. I'm using a leaf blower with a knife gate in my burner to limit the air going into the burner, that works well too and unloads the blower motor. The easiest is a piece of cardboard over the inlet to a blower. The blower suction holds it in place and it will slow the flow nicely. Of course the shape of the blower inlet grill may dictate using a piece of cloth or plastic sheeting to conform to the shape if you really want to slow the flow way down. And a suction restriction is very cheap.

 

And this is another perfect situation. If you reduce the suction, it reduces the amperage on the blower and creates less volume of air. This is absolutely ideal as well! But… It will raise the RPM of the motor and noise. In the big scheme of things, the blower noise is not a problem.

 

If Billy, the OP of this thread is only thinking of using LPG, a soft blower like an air mattress or hairdryer blower would be perfect. Tweaking it to be perfect is a whole different animal.

 

Im not going to say I am only thinking about using propane, but that is the easiest for me to obtain with the exception of kerosene. I imagine there are a few quick lube places around here in town that I may possibly be able to get used oil from in the future as well but that will be later. I have a few options for the blower and after get the furnace lined I will play around with some of them. Right now I am sticking to what is the easiest and fastest way for me to get going.

 

Billy,
After you finish this iron duty furnace, you might find it useful to build a smaller, low mass, aluminum duty furnace.
Running propane only in the high mass furnace is going to use quite a bit of gas to get the furnace to temperature.

 

I plan on using this one for aluminum first and then get into some bronze and iron. I actually was thinking about building a bigger one later so I wont be so limited on mold size but that is quite a ways into the future. So..just curious if anyone has done any cost analysis for propane vs kerosene or diesel fuel? If it is a considerable cost savings I certainly would be interested in saving money.LOL

 

If you're interested in saving money, jump to waste motor oil. There are lots of methods, but I start on propane, switch to motor oil, then back to propane before I shut off to avoid smoke. Motor oil burns hotter in my furnace. People seem to have different results. Propane is the easiest and most forgiving. A drip burner is the simplest and works with any liquid fuel. An atomizing burner requires well filtered fuel and either a high pressure pump or compressed air. A drip burner just needs a valve and a blower.

People use different burners due to individual preferences and situations. They all work well once you get set up and running.

 

Yeah...I could see that being much cheaper....as in free vs. 11$ a propane bottle. I have not really looked at the drip burner too much, because I knew I needed propane to get it up to temp first anyway, but that does sound pretty simple. Thanks!

 

Not to belabor the point, but an 18" piece of 1-1/2" pipe with a hose off one end to a blower and a propane port in the side makes a great propane burner. Then a 1/4" tube running down the middle from an elevated oil tank makes it a drip burner. Pressurize the tank with 5 psi air and you don't have to elevate it and can open the valve to blow out gunk when necessary. I used an ell through the side of the pipe and a piece of old brake line for my drip tube. Anything works.

K.I.S.S.

 

I am fond of the K.I.S.S. methodology. Sounds pretty simple! I will have to look around and find some more alternate fuel sources. I think I might have a lead on oil but not sure how often he can provide it. Have you guys ever had any issues with mixing the oils...like synthetic and such or will any used motor oil suffice?

 

It certainly doesn't get any simpler than a forced air propane burner, just a straight pipe, a blower and a propane feed, the only slightly complicated bit is controlling air flow. That said however, I really like having a naturally aspirated burner on my furnace because my foundry area is about 100ft away from the nearest electrical outlet and I don't feel like stringing out the long extension cord.