Waste-oil burning stove/heater

[Jesda]

I always forget that cold weather exists in MS.

[PapaSmurf2k3]

Update - I've been running it on the colder days this winter and did a clean out of the bucket. A few of the donated oil jugs had some chunks in them that I got to scrape/wipe out of the bottom.
I painted the whole thing black to class it up as well as promote heat transfer.
I never did get the alternate burner made. The plasma cutter dude still kinda owes me one though so we'll see.

[PapaSmurf2k3]

BUMP!
New shop, new heater.
I sold my place in MS, and the waste oil heater was actually a pretty decent selling point.
I've been playing catch-up on projects here since moving almost 2 years ago, and my shop was finally built at the end of May. Long story short, with the other stuff going on, I elected to not build a heater from scratch this year, and to just try and modify a wood stove that I was able to pick up locally for cheap.

I now have my own plasma cutter and wired in a 220V outlet in my shop. It blasted a hole through the wall of the wood stove with no issues at all.
I welded on a small oil feed line coming from the side because there's some flaps and baffles and other wood stove weirdness going on at the top. I had to extend the feed tube pretty far so the oil would get to the center of the burn chamber, and as such, I have concerns with the oil burning and coking up while its still in the tube. I'm adding an air feed line to hopefully help push the oil through quicker and also keep it somewhat cool. We'll see.

Being that the woodstove size and surface area is considerably less than my old barrel style heater, and adding fins is fairly impractical, I'm going to maximize my chimney surface area and use that as a big heat exchanger.
The plan is to zig-zag a big with some of those clamp-on fins before going out the side of the wall. I'll have to support the chimney with some brackets. I ordered a couple of these:
https://www.amazon.com/gp/product/B09HC ... UTF8&psc=1
I also ordered some M10 threaded rod to secure to a weld nut or something to my metal wall studs.

I'd like to thank 2021 James for pointing out the various bulkhead/needle valve options outlined previously in this thread. I picked some of those up from Amazon as well.
https://www.amazon.com/gp/product/B07D7 ... =UTF8&th=1
^Ideally I would have liked an angled bulkhead fitting, but I couldn't find any that output to a 3/8" barb.
https://www.amazon.com/dp/B0BPXMNK7J?re ... title&th=1
^This needle valve is a good bit cheaper than the McMaster one I ordered. We'll see how well it works.

I still have some insulating and cement boarding to do before she's ready for prime time. I have some leftover 2" R10 foam from when they insulated under the concrete that I put immediately next to the heater and on the ceiling above. Cement board will be going over that to prevent it all from getting melty.

[float_6969]

IDK if this will help, but it can't hurt to try.

I used to work for a pool and spa company that also did fireplaces. One of the main thing about fireplace is how and where the air is introduced in relation to the burning wood/pellets.

They called it primary air and secondary air.


Primary air is right at the fuel source. Ideally underneath it, but since you're burning a fluid, that's not really an option. I think your rotor should be serving that purpose well enough.

Then you need secondary air. The combustion process will create a lot of unburned gasses that need more air to burn, but if you just try to introduce that air at the fuel source, it cools the combustion process off too much and can put the flames out. So the secondary air needs to be up above the fuel source, ideally just above the level of the flames. Because of the flue effect, once the system is heated up, everything should be under a vacuum, so you won't have flue gasses coming out of that.

Smokey flue gasses is a sign of poor secondary air supply.

If it were me, I would add some sort of valved pipe near where the SS pot meets the barrel. Or maybe set it back on the jack and start slowly lowering the pot away from the barrel until the burn cleans up. You might even be able to add secondary air in the drum, but I'm not sure if that will have enough heat to allow the unburnt gasses to combust.

Looks like a good setup though, you just need a little tweaking.

If you don't get the flue gasses cleaned up, eventually you'll get creosote build up on the inside of the flue pipe. I've seen a flue fire from creosote burning and it's SCARY. Sounds like a jet engine and the entire flue pipe turns cherry red. You can imagine the carnage that follows.

It's probably too late now, but you'll get a better draft if you have a solid few feet of straight pipe coming out of the barrel before you make a turn. Ideally, the pipe goes straight up and never bends. Those setups always burn really well.

[PapaSmurf2k3]

Sounds like you're commenting about my old setup - none of that really applies to this setup, but it does make sense. I'll keep it in mind if I end up changing this one out next year.

[float_6969]

Yeah, I see that now. Somehow I missed the 2nd page. Sorry!

[PapaSmurf2k3]

I finally got up on the ladder and cut back some of the insulation to see where to put the chimney pipe out. I actually had another section of pipe, but if I used it, it would put the chimney through the wall in an awkward spot, right where the C-channel brace thingy is.
Once I cut the insulation, I found a flat spot to put the pipe through. Unfortunately this isn't in the center of the circle of insulation I cut, but whatever... I'll probably end up throwing another piece of insulation up there to cover it up anyway.

I threw a cap on there in hopes that rainwater wont make its way in. I'm sure it will.
I also sealed the pipe going through the wall with some roof caulking I had leftover from a solar install at my house. Not sure what the temperature rating of that stuff is, but I'm sure I'll find out
So once the chimney was installed, I was able to fire the thing up. I wanted to go slow at first, so I only added a little oil to a mostly wood load.
Once it was going, it got kinda smoky in the shop. I figured it was just the oils and Chinese kid fingerprints burning off from the pipe factory, but then it proceeded to get more and more smoky.
It turns out the roof overhang is open to atmosphere where it meets the wall, and the smoke was coming out the chimney and going straight back into the shop
I shut her down and sealed up the roof line with a couple cans of great stuff. Ghetto? Perhaps. Do I give a s***? Absolutely not.

Anyway, once the smoke situation was handled, I fired it back up and cranked up the heat a bit. The results were pretty disappointing. The majority of the heat was going right out the chimney, even with those pricey snap-on heat exchanger collar things. I guess the fins I welded on to the old one really did work well... and that got me thinking... I have scrap steel, I have multiple welders... let's fix this.

I plasma cut a bunch of strips out of scrap steel and went to town.

By the end there I was getting pretty f*** drunk, and there were some gaps to fill, so a couple of those fins got a little wonky. I'll paint it black and not give a s***.

I cranked the heat back up on it, put a fan on it, and its much better, but I still have a ways to go.
Reading the chimney right before it goes outside, I was still getting above 220F. I'll weld more fins on the pipes, consolidate the snap-on heat exchanges to the upper pipes, and figure something out for the base woodstove unit as well.

[PapaSmurf2k3]

So my shop reeked like smoke from burning wood. I decided it was time to start burning some of my oil reserves. I drilled a hole in the bucket, installed the on/off valve, got some 3/8" transmission hose from Autozone for $3 per foot, and hooked the needle valve on the end. All I needed now was a shelf to put the oil bucket on to assist with the gravity-feed.
I had some brackets kicking around but they didn't have a triangular support, so I took some flat stock and made some. Even kicked it out at an angle a bit so it should be stronger when loaded in different directions.

The little Titanium flux core welder is great for stuff like this and actually makes some decent looking welds.

Here's the whole setup:

I picked up a 9x9 stainless pan on Amazon for like 10 bucks to serve as my burn pot. I have to angle it to get it through the opening, and its a bit high on surface area for the airflow available, so I'm going to pick up an 8x8 as well and see how that works.

Once burning oil, I broke all the temperature records I had previously set with wood. With an outside temp of about 40 degrees, the shop was a toasty 68 inside. I moved the fan to the back side of the stove where it was hottest. The surface of the back of the stove was up in the 870 degree range, and the air temp of the stove pipe just before going out the building was high 200s... more fins needed!
To loosely quote the Ambition Strikes youtube channel - This isn't a "how-to" thread, this is a "what I'm doing" thread.
Waste oil heaters are great because you can essentially use whatever materials you have laying around to accomplish the goal. In this case, I have a bunch of lawn mower blades that came with the house. I fired up the plasma cutter and went to town cutting them up into chunks so I could weld them into a plink-o-style arrangement on the stove to promote better heat transfer.

I tested THIS setup down to 32F outside, and inside was still up at 68 degrees.

I mentioned earlier there wasn't enough air for the given oil area... so I can either reduce the oil area (with that 8x8 pan), or add more air. I'm thinking for those super cold days, more air will make for even more heat. I'm going to try and develop some kind of fan forced-induction
More to come.

[Beancooker]

Looks pretty awesome, James. It’s all about the surface area when it comes to extracting the heat from the stove box and into the room. The plinko fins are a good idea. I can’t wait to see how it turns out.

[PapaSmurf2k3]

Not a huge update here, but I did weld some more fins on to the main woodstove body as well as on to the next stove pipe. This section is a little smaller because there's a collar there that fastens it to a local stud, so I went a little taller with the fins.

I'm getting pretty good with making nice straight cuts with the plasma cutter.

I went outside to silicone the connections so rain water can't creep in and down the pipe, and found that at least one of my burns was QUITE rich.

I cleaned the joints up and siliconed them inside and out.
In an effort to correct the rich condition, I'm adding some forced air (or a turbo, if you will). Specifically, this one:
https://www.amazon.com/gp/product/B0C7Z ... =UTF8&th=1
I ordered it 2 weeks ago from Amazon (when it was still listed as Prime shipping), and it still isn't here. It should allow me to dial in the airflow to match whatever oil flow (and type) I'm using to get a clean, hot burn.
To prove the concept, I put my leaf blower up against one of the air intakes and pulled the trigger on its lowest setting. It immediately increased the temperature of everything pretty substantially, but also blew carbon and ash out of the slip joints on the stove pipes and on the stove unit itself.

I welded it up and it pretty much immediately cracked in a few spots, but that's ok as long as its a tighter fit than what I had. Carbon and ash could/should seal it up the rest of the way.

[Beancooker]

If you heat the stove with a torch prior to welding it, it’ll be less likely to crack. That goes for pretty much all cast iron.

[PapaSmurf2k3]

It was heated with burning oil on the inside. Surface temp was 500-600F and had been at that temp for a while. I'm not really worried about the crack TBH... I just wanted to choke down on potential flow (and carbon) from coming out of the seams.

[Beancooker]

TBH... I just wanted to choke down on potential flow

Somehow I’m not at all surprised that you want to choke down on the flow.

[float_6969]

[PapaSmurf2k3]

Somehow I’m not at all surprised that you want to choke down on the flow.

Look...
.
.
.
I have no rebuttal.

[Beancooker]

So how’s the stove working out? Did the forced air arrive from Amazon?

[PapaSmurf2k3]

Yeah it arrived... finally!
I had a reducer and welded a cross-tab in it to mount it to the stud on the stove. I also cut some slots in the reducer so it would slip inside the blower (because of course they were both the same OD/ID).

Threw a couple aluminum beer cans with some water in them on top to further promote heat transfer.

Had a good mixture going and got some new high scores on the ol thermometer.

After that pic was taken I think I hit about 870 max. Evidently I didn't have my fan oriented quite correctly, so it started to melt the insulation.

I rectified this by getting a better position on the fan to cool this area, as well as added a sheet of cement board.
More to come.

[float_6969]

Nice!

[PapaSmurf2k3]

I built a fan array out of old 120VAC computer fans that work was throwing away in mass quantities.
I lined it up with the chimney and mounted it to the stud coming out of the wall. It dropped the exit temperatures by 60-80 degrees

The addition of the forced air made me realize just how many nooks and crannies there were on the stove. Smoke would come out of all of them as soon as the fan was kicked on. Lots of welding later... and I still get smoke sometimes coming out of the oil feed line. Quite the annoyance. I also have traditional waste oil feed issues with different viscosities and changing viscosities as things warm up, making it pretty labor intensive to just keep it somewhat optimized.
I picked up a diesel heater and will try running waste oil through it with a 50/50 mix, and see how the wood stove does with just dry wood. I also might add an exhaust catalyst to it to boost the efficiency.
Also, the forced air fan thingy decided it didn't want to work anymore. Looks like it developed excessive shaft play and the fan is contacting the housing.

All in all not a great year for this compromise of a waste oil heater. In the end I should have just built my own from scratch, similar to the last one I had.

[Beancooker]

While it may not be the most successful, you can take what you learned from this one, what worked and what didn’t, and make the next one even better.
Would there be a way to actually incorporate a turbo? Have a very large hot side impeller so it would spool up a very small compressor? When I say large and small, I’m thinking like a Kenworth sized hot side to a Juke sized cold side.

As far as the issues with the different viscosity oils… get a drum and mix them. Store them all spring and summer so you have a reserve. Give it a good mixing and have it come from the drum. That way it’s more consistent.
Pressurize the fuel. That’ll make things more consistent as well.
Now you’ll want to get an o2 sensor for the chimney. Then you can have a little raspberry pi that calculates the air fuel ratio based off the o2 sensor readings.
Thinking it through, skip the turbo part. Just go back to a better fan for forced air. Maybe a longer tube feeding the air so the fan isn’t so hot. Then the raspberry pi has better control over the air fuel as it can adjust the speed of the fan, along with the fuel pump.

Raspberry pi controller is the way to go.

[PapaSmurf2k3]

It sounds like you're making this quite complicated haha.
This particular stove doesn't like being pressurized... it has some ports and covers and stuff that can be removed, so if you add much or any pressure, you get smoke/leakage out into the atmosphere. I can certainly weld them shut and it has crossed my mind.

The more I work with it, the more I can narrow the performance of this thing down to 2 things:
1 - Not enough air
2- The air comes in through the front door only

I think I can remedy both of these things by plasma cutting a big f*** hole in the middle of the floor and welding in a 4" (ish) exhaust pipe with some ports in it. I could then add a bundt cake style pot for waste oil catching and burning. There's a few videos online of these things in action and they look pretty good, although they typically all utilize electric air pumps to get a good clean burn. I think if I'm running just wood, I wouldn't need any additional fan, but if I want to burn oil I most likely would.
Adding the fan (and an elbow or something) from the bottom would get the thing more away from the heat and also promote a 1-directional flow path.

[PapaSmurf2k3]

Oh I also ordered a stovepipe catalyst to turn some of the exhaust smoke into heat. We'll see if it works.

[Beancooker]

It sounds like you're making this quite complicated haha.

You’re trying to f00king under-complicate things. That’s not how it’s supposed to work over here at Nicoclub.

You make it the biggest pain in the f00king a** as possible, and then post pages of rants in the style of Konata (Grant) complaining about “Stance”.

Seriously disappointed in you, James. You need a mango-tomato beer.

Any why, for the love of God, in 2025, do we have a f00king swear filter? Can’t we swear like men in a car forum?

[VStar650CL]

Forget swearing, the filter here turns tran-sfer, tran-spose, tran-sact, tran-sexual, or anything else that starts with tran-s into "transmission". Try it.

I hate filters, whether they f00k or not.

[float_6969]

We can thank the Oppressive Google Overlord for all the swear filters. Can't we get Trump to fix that? I feel like Making the Internet Great Again is way more important than renaming a mountain or the gulf.

[PapaSmurf2k3]

James. You need a mango-tomato beer.

Update - Fired the b**** up the other day and smoke was just POURING into the shop. Worse than its ever been by far. I got to thinking the only thing that can do that is a s*** of outside wind, or a severely blocked chimney. I went outside and removed my chimney cap that was supposed to keep birds and s*** out. It was quite clogged and crappy. The fire started choochin WAAAYYYY better, to the point where I'm gonna hold off on plasma cutting a hole in the bottom of it to re-engineer the whole oil burning thing.
I'm leaving the cap off. f*** the birds.

[IanS]

Update - Fired the b**** up the other day and smoke was just POURING into the shop. Worse than its ever been by far. I got to thinking the only thing that can do that is a s*** of outside wind, or a severely blocked chimney. I went outside and removed my chimney cap that was supposed to keep birds and s*** out. It was quite clogged and crappy. The fire started choochin WAAAYYYY better, to the point where I'm gonna hold off on plasma cutting a hole in the bottom of it to re-engineer the whole oil burning thing.
I'm leaving the cap off. f*** the birds.

Yah, I've never liked those caps. When I was still heating with wood and waste oil I tried one to keep pine needles out of my chimney, hated it. Never worried about critters, all the spot/ash seemed to do that for me.

[PapaSmurf2k3]

Its been warming up around here but we still get chilly nights. I took the opportunity on a warm day to lay some paint down on the exposed metal bits. I used 2000 degree high temp primer and black paint.
Getting full coverage on the pipes with fins took A LOT of paint, which just goes to show how much surface area those things have.

I'll ultimately most likely remove the "snap on" heat exchangers in favor of welded fins at some point, but this is likely the final form until next fall/winter.

[Beancooker]

That paint should smell quite nice the first time you fire it up, high-temp or not…

[IanS]

That paint should smell quite nice the first time you fire it up, high-temp or not…

Yah, I've never found a paint that doesn't stink/smoke the first few heat cycles.