Rust Bluing tank project - advice needed

dilly

dilly

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Hi folks. I am building a rust bluing single tank set-up with a propane burner and am looking for some wisdom or advice from anyone who has experience with the burner part. First off, I made a tank from regular steel and tig welded the ends. It holds water just fine without leaks. Here is what it looks like on the stand.
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The burner set-up is just cobbled together. I took a regulator off an old Morrone turkey fryer and cut the big cast burner off the other end with a hacksaw. I inserted that into a piece of black iron pipe keeping the air intake system intact.
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The burner is just the pipe with a series of paired 1/8" holes drilled 1" apart along its' length.
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Close-up
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So, I know that the propane regulator can deliver tons of BTUs. When used with the turkey fryer, it jets out a 3' flame on high. When I try to do that with this setup, it blows out. I can manage to get flame and can regulate it to a nice clean blue, but it wont heat the water past 85 degrees.
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The other issue I have, is when I place the tank over the burner, the flame become erratic and travels back and forth on the pipe. I suspect this is due to it not being able to exhaust adequately because of the wind screens I built in. I think the environment in there gets oxygen deprived and it starts to choke. So, right now I am considering drilling some breathing holes around the perimeter of the windscreen to allow for exhausting and air flow. What I don't know is, if I enlarge the holes in the pipe, will it give me more flame and heat? Anyone care to weigh in?
 
Yes, you will need exhaust ports.
You will need to determine the actual gas pressure in the manifold. For propane you will need at least 6"wc at low fire. 10"wc at high would be a good place to start. With the size of the burner tube you have, odds are the reg isn't providing enough pressure.

Balancing a burner is a trade all by itself, air fuel ratio, pressure and burner volume all have to work together to provide the btu's for a given application. Above all check for leaks at all connections, gas isn't a joke and after 20 years in the trade I have seen things go bad in a hurry.
The burner air will have to be adjusted by eye.
If you are using a standard regulator you can't adjust the pressure output, so the only option would be drilling out the orifice. If you have to do this, you're looking at thousands of an inch at a time.

So you will have to get either a water tube manometer or another manometer capable of low pressure reading, drill and tap a port to check pressure. Or find an inline gauge with inches water colum or kilopascal to get the pressure you need to run the burner.

Good luck and play safe. I would test fire outside before using it in a garage.
 
I appreciate the advice and the cautionary statements. I did run it outside first until I was comfortable with the little flame. I sorta understand what you are saying too. Just wonder if the pressure is insufficient, could I go the opposite direction and start taping off holes until I get higher pressures? The regulator "seems" to put out tons of propane, so much that the flames go out when I turn it up.
 
Combustion it touchy, the air/fuel adjustment on the burner is sized and designed for the original burner, without doing a Combustion test or seeing it in person its hard to say for sure why its flaming out. But knowing the gas pressure pre burner is vital. You have to start there. Once you KNOW you have enough gas, you can set up the burner balance.
 
If you can see the flame separating from the burner tube as you increase the flame, there is too much pressure, if it just goes out, its an issue with gas supply(low pressure or mixture is no good). LP is only combustible in the 2.5-9% range, so the air mixture is very important.
 
It's definitely the flames separating from the holes. I suspect the pressure is too high. Once the flames get about 3/8" from the hole and it is really whistling, she goes out.

I also taped off the air intake a bit because it was sucking in a ton of air.
 
Hi
You need a variable propane regulator and gauges.. look at propane blacksmith forge supplies to find that
http://blacksmithsupply.com/catalog..._supply&DeptID=148174&ItemID=6156951&detail=1

I would have went with a blower on the burner... then its much easier to tune the air to psi of fuel

Yes indeed the exhaust has to easily escape.. or the exhaust will be a problem... also remember that this should be done with alot of outdoor ventilation or may cause operator to take a permanent nap !

having a hardtime to see where the exhaust vents... is it just those two little holes by the burner?
 
You could try placing the tank a bit off center - a bit forward, so there is a gap along the back. That would tell you if you need to provide for exhaust.

I would be cautious running it indoors.
 
dimeN said:
Hi
You need a variable propane regulator and gauges.. look at propane blacksmith forge supplies to find that
http://blacksmithsupply.com/catalog..._supply&DeptID=148174&ItemID=6156951&detail=1

I would have went with a blower on the burner... then its much easier to tune the air to psi of fuel

Yes indeed the exhaust has to easily escape.. or the exhaust will be a problem... also remember that this should be done with alot of outdoor ventilation or may cause operator to take a permanent nap !

having a hardtime to see where the exhaust vents... is it just those two little holes by the burner?
Click to expand...
There are no vent holes. Those two holes in the end were so I could watch the flame. I will be punching a bunch of vent holes around the perimeter to let it breath. Also, the regulator is adjustable now. It's one from a turkey fryer and I can adjust it up and down with quite a bit of range.
 
tiriaq said:
You could try placing the tank a bit off center - a bit forward, so there is a gap along the back. That would tell you if you need to provide for exhaust.

I would be cautious running it indoors.
Click to expand...
You are bang on with your idea. I ran it with the tank off centre and it breathed way better. Just can't get high power out of it. Just blows out.
 
dilly said:
You are bang on with your idea. I ran it with the tank off centre and it breathed way better. Just can't get high power out of it. Just blows out.
Click to expand...

You could cut a vent along the top of the rear skirt.

You only need to boil the water - not like hot caustic bluing that requires a lot more heat. See if you can get a boil - you might not need high power.
 
This is a burner I built. Same idea as you using a turkey fryer regulator.
I used 1 1/4" EMT pipe.Holes are 1/16" spaced at 0.300" cc. 110 holes per row.
I have no problem boiling water with it.

 
freddygotarf said:
This is a burner I built. Same idea as you using a turkey fryer regulator.
I used 1 1/4" EMT pipe.Holes are 1/16" spaced at 0.300" cc. 110 holes per row.
I have no problem boiling water with it.

Click to expand...
Got it. You have way more holes than me. Good to know. I enlarged mine to 11/32". Getting better flame now. Going to keep fiddling with it.
 
Well I made my own burners for hot bluing, so maybe I can help. I didn't do any fancy calculations, just trial and error. I don't have too many pictures, and some of the details might be fuzzy as it was a few months ago I made the burners, and I'm away from home so I can't just go and look at them right now.

My burner tubes are made out of 1-3/4" DOM with 0.120" wall. Maybe overkill, but they shouldn't rust out. For the burner holes, I tried drilling holes, but didn't have much luck. Flames seemed to blow out easier, so I went with just sawing a slot in the tube with the sawzall (hacksaw would work too). The width of the blade is all I cut, and I cut to a depth that allowed an arc of about 1.5" length on the tube's circumference. I cut the slots every 1", enough to cover the length of the tank. I think I have 38 slots on each burner.....?

My air intake and fuel feed are pretty self explanatory in the pictures. I just used plain old iron fittings from the local parts store, nothing fancy. The whole gas orifice section is made to slide on the burner tube, to adjust the air intake size. Once I found a good spot for burning, I haven't adjusted it since.

The actual gas orifice is made out of a brass plug. Just drill a small hole, this takes some trial and error though, to find the appropriate size. I think I ended up with 0.070" holes, but I can't remember for sure.

I think my burners sit about 1" - 1.5" from the bottom of the tanks. The flames will roll out from the sides when I really crank them up. No shields on the sides, but I have my setup in a tent in my backyard at the moment. Some draft, but no serious wind to blow anything out.

The brass needle valves are my actual flame adjustment. Nothing fancy, but they are the valves typically used on tiger torches, so they are meant for propane burners.

When I was building and testing everything, I was able to get water from 50F to a boil in 15 minutes. This was in the shop with no wind, but my backyard tent isn't much different.

Burners have been working fine for all the bluing I've done so far, and they will burn well enough to get my bluing tank up to 300F, I haven't tried to go over that yet. They also light super easy.

No fancy regulators or valves. In fact, I'm using an old saddle tank from my truck that was 3/4 full, so I had to flip it over and jimmy rig a regulator and valve setup.

Hope this helps......let me know if you have any questions.

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Nice setup ssapach. I like your vent design. I am going bigger with the holes in hopes of getting into the realm of your slots.
 
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I found with mine that there was not enough secondary air until I vented it. You can't just have the exhaust gasses spilling out from underneath the unit. You need to induce a draft across the burner. It takes me about 20 minutes to achieve a boil.
 
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