3” boiler project.

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Steamchick

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Hi DJ.
This morning I mocked-up the 3in. Round ceramic by taking the burner out of my 25 year old 3in. Vertical boiler... I hues it with butane, usually in warmer weather, so pressure is nearer to 15psi. But today is quite cold - mate 6 or 7 C? In the garage, butane in a small canister started at 10psi and drops to around 5 or 6psi. The burner is OK, but a mid to dull-orange, as pressure drops. With butane propane 30%mix, the canister can hold 28 psi max. But that is too much for the burner. But as it is designed for 15psi butane it actually works OK with 15psi mixture. So I reckon on Propane, you'll be OK at somewhere between 10 and 20 psi max. The burner has a no 8 jet, 0.25mm drilling. The mixer tube is 8mm (5/16" ) bore, with 2 x 6mm air holes. The 0.30 mm (no 12) jet is too big for the higher pressure. Basically, it doesn't draw enough air at low pressure with butane, but the pressure above 15 psi draws in cannot get enough air as it chokes by being too small, so the top flame is too big and will send CO as unburnt gas up the chimney.
Hope this helps give you a starting point?
K2
 

DJoksch

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Looks good! Now: BEFORE you stick the ceramic to the tin....
  1. Is there a small hole in the centre of the base of the "tin"? - I'm sure you solder a blank over it if there is...
  2. Does the ceramic sit inside the spinning, or just on the top edge? If on the top edge, it will need to be affixed with silicon to allow for differential expansion between the ceramic and copper. If "half-inside" the copper spinning, then you will need a good 1mm or 1/16" clearance for sealing with silicon paste and allowing for differential expansion.
  3. The outside can be "smoothed-off" with an application of Exhaust Sealer paste from the Automobile shop.... Cheap but high-tech sealer that is much better and neater than firebrick cement. But not good on skin, so wear Nitrile gloves when doing that job!
  4. But don't stick it together yet!!!
  5. First have a look in the larder for a tin of peas, beans, soup or whatever you are having for tea.... The tin needs to be the same size (or maybe a tad bigger) to take the ceramic. If you don't have a suitable tin, I have managed with a plastic tub, or heavy aluminium foil from a pie case and made a mock-up. You will probably destroy it later, so that's why I use these materials. They are not as strong as the ceramic, so they can be hacked off carefully with scissors or something if necessary.
  6. When you have the "Mock-tin"... Make the proposed gas-air delivery tube and jet and fit it into the mock-tin with silicon seal. Fit the ceramic - I use masking tape as it will be on and off a few times! The outside (Your machined surface) of the ceramic is all pitted and won't seal, so you can fill the bottom 1/8" with silicon seal, smoothed so it fills the grooves, or you can fill the side grooves completely using the exhaust assembly paste. ALLOW TO SET.
  7. Put a 1" ball of pan-scourer stainless wire wool about 1/2" away from the end of the inlet pipe. (Not tightly compressed, quite open as bought from the store). Sit the ceramic on the mock-tin and seal it (This is where I use masking tape...).
  8. Connect to the gas canister, and try the burner. Only for a half minute or so, and not "full gas". Maybe photograph or sketch the surface colours so you can keep track of changes. Then turn OFF and allow to cool.
  9. It is likely that the burner will have some hot spots and grey areas. (cold spots). Lift the (Cooled) ceramic and try a bit more, or less wire wool until you get and even burn across the face of the burner. Taking photos I find useful as it enhances the colour so it is easier to spot cool spots and hot spots. These variations must be eliminated as much as possible, as otherwise the ceramic will crack with differential expansion and contraction, after a few cycles.
  10. When you have an even burn, try the pressure variation from "just lit and stable" to a "mid-orange to bit brighter" - AND RECORD the PRESSURES. If the burner roars or sings, you probably have too much gas, too lean combustion, or a particle of something you may spot as a black dot or yellow to white dot on the surface. TURN OFF THE GAS BEFORE YOU BURN-OUT the ceramic and get a flash-back. Turn the gas down a touch to a good mid-orange - and call this setting "Maximum".
  11. Now try it in the boiler, and study carefully. The different conditions (constraining the exhaust, back pressure, heat loss to boiler metal) all affect the combustion. Most noticeably, any back pressure that changes the gas-air balance and mixture. Too much flame - trying to escape rather than going up the flues will mean you have to turn down the gas and set a new maximum. If all looks good, check the exhaust from the top of the chimney, by "grabbing a handful and smelling it". DON'T stick your nose over the chimney. If there is a lot of CO, you won't smell it, just poison your blood. carefully try to move a lighted flame into the updraught of hot exhaust gases. (I use a barbecue lighter 6" long so my hand is well clear). It should extinguish without any flaring with a dark blue (Ghostly) flame.
  12. When you are happy, strip-down the mock-tin burner, and rebuild into the proper tin, sealing between the ceramic and copper spinning with silicon sealer, and covering that from the flames at the top of the ceramic with the auto-exhaust paste.
Sorry this is long-winded, but necessary for me to do on every new burner, to be sure it is right. I think you'll find it works for you too?
Enjoy modelling! - I do!
K2
Thanks for the list. I ordered another piece of ceramic just in case. Have a tin that should work nicely for a mock up. My work space is well ventilated and with a CO monitor for the reasons you describe. You answered the question about what adhesives to use. I am designing a door with a glass to lite and monitor the flame when the burner is complete. Thanks again.
Doug
 

DJoksch

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Hi DJ.
This morning I mocked-up the 3in. Round ceramic by taking the burner out of my 25 year old 3in. Vertical boiler... I hues it with butane, usually in warmer weather, so pressure is nearer to 15psi. But today is quite cold - mate 6 or 7 C? In the garage, butane in a small canister started at 10psi and drops to around 5 or 6psi. The burner is OK, but a mid to dull-orange, as pressure drops. With butane propane 30%mix, the canister can hold 28 psi max. But that is too much for the burner. But as it is designed for 15psi butane it actually works OK with 15psi mixture. So I reckon on Propane, you'll be OK at somewhere between 10 and 20 psi max. The burner has a no 8 jet, 0.25mm drilling. The mixer tube is 8mm (5/16" ) bore, with 2 x 6mm air holes. The 0.30 mm (no 12) jet is too big for the higher pressure. Basically, it doesn't draw enough air at low pressure with butane, but the pressure above 15 psi draws in cannot get enough air as it chokes by being too small, so the top flame is too big and will send CO as unburnt gas up the chimney.
Hope this helps give you a starting point?
K2
Yes, it does. I am drilling out a mixing tube to 5/16”. I will start with .25mm for the jet. I ordered a propane regulator which should arrive tomorrow. Maybe I should install the view port in the boiler so I can see the flame in it’s working environment.
 

Steamchick

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I hate the smell checker! I can hardly understand Water I have rotten after Giggle has car ruptured it!
Blame the tools!
K2
 

Steamchick

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Hi DJ:
My write-up: with pics. I think. (Hope I picked the correct version for you!). The boiler is around 25 years old. The burner at least 5, possibly more like 10? - Everything rusts when made from tin-plate and cooked in the firebox! - So time to make a new burner tin? Maybe I'll silver solder a brass or copper "tin", or even try my hand at spinning? Am I right you started with a large circle, clamped against the former at the centre, then carefully stage-by-stage press the sticky-out rim down to the sides of the former? - Starting at the former edge and working outwards? - What rotational speed? Any Lubricant? And how often do you take it off and re-anneal? This could be a new string to my fiddle!
The layout on the boiler board is the boiler with burner, Steam exits the super-heater coil low down at the rear, as the engine is usually behind the boiler, facing Joe Public when on display. Hot whirly things hissing steam are a great attraction for kids, but the steam puffs help keep them back from the display. Also it means the really hot thing (me? - no, the boiler and burner) is behind the engine on the Display side, and further from prying fingers. Water gauge at left hand side, Pressure gauge above boiler facing the fireman. Safety valve is shrouded so steam blasts upwards, though this never happens on my watch! - Most unprofessional! BUT I do test it when first raising steam every shift! (Before public arrive if at a show). Front right corner is where the gas connects to the gas valve (Round knob), the gas-valve then connects to the burner at the back. This is because the Gas cylinder is usually on the floor below the bench, so the hose comes up over the edge of the bench to the front right-hand corner, away from hands that are pumping water, or adjusting the gas-valve, or Joe Public with little childrens' hands that play with everything! The water tank is on a flexible pipe so I can locate it anywhere at the back of the boiler or either side. I usually move it to the right side so it is convenient for topping-up. The engine exhaust has an oil collector and vertical exhaust pipe that sprays condensation with oil drops onto the roof of the tent - helps deter Joe Public from coming too close! I don't like venting up the boiler chimney as it is unnecessary with gas and just makes the boiler dirty, and smelly as the vented engine oil migrates down to the burner! Anyway, it usually rains, and the oil mist helps waterproof the tent to keep me dry!
The Club provide a 3-sided tent, where the public view from the open side. So it is out-doors, which is nice safety for any gas leak, but I avoid those, as to escape a fire I would have to hurdle the bench - possibly the location of the fire! (or drop to the ground and roll under the back-flap. But I normally avoid anything that forces me under a back-flap! - That's when you know you are in the S£!t).

Bit my tongue on that one it was so far in my cheek!
Enjoy steaming!
K2
 

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DJoksch

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A photo helps. Basically building a carburetor from scratch. I am finishing the mixture tube and should be ready to test as soon as the regulator shows up. After I get the current burner working, I plan to make another using an internal tube as in your second version. I use copper because I have a 3 foot square I found clearing the shop. I am really a novice at spinning and found the thick copper sheet required annealing after each couple passes. I basically replaced hammering to fit with spinning. I also need to clean up the mandrel. The hole in the middle is not needed. I use an older SouthBend 10L lathe that I run as fast as it will go and grease the metal before hitting it with the tool. I did have a casualty due to a sneeze. I wear cut resistant gloves due to my 9 fingered friend who showed me how to spin. I use a simple square bar in my tool post and have “make a proper bar” on my things to do list. I did not take pictures when I made the boiler caps or the burner cups. Here is a YouTube video of what it looks like.


I can see where I might make improvements on another boiler build. The boiler door to lite the burner will have a glass window facing the viewer to make it more interesting.

Doug
 

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Steamchick

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Thanks Doug. I'll watch a few utube vids before I start making the gear. - VERY interesting!
On lighting boilers, I just use a small hole, or a tube, through which I poke a flame or lighter. I must get better and make a door with a window...!
Thanks,
K2
 

goldstar31

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Ken2 and chaps!

I seem to recall that Tom D Walshaw writing as Tubal Cain did a series of articles in 'Enhineering in Miniature' regarding something small like the boiler in question.

It maybe worth 'looking at'

Cheers

N
 

DJoksch

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I ran a mock up this evening. At low pressure it pulsates and there is some yellow flame at higher pressure. I don’t think it’s getting enough air. I had a .35mm jet. I think it’s to big. I need to replace my smaller bits and try .25mm and see how that works.
 

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DJoksch

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Ken2 and chaps!

I seem to recall that Tom D Walshaw writing as Tubal Cain did a series of articles in 'Enhineering in Miniature' regarding something small like the boiler in question.

It maybe worth 'looking at'

Cheers

N
I will check it out. Thanks
 

Steamchick

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Sorry DJ, the JET IS TOO BIG! The gas goes up the hole, but there isn't enough diffuser CSA to allow all the air you are trying to draw-in. You are trying to push twice the gas up the hole and the extra gas is replacing the air you need for the correct amount of gas. You NEED a 0.25 jet, to get the gas-air mixture right and the intake mixture volume right for the size of burner. TOO MUCH WILL DESTROY THE CERAMIC. I have done it. Don't waste your time but please learn from our experience. I'm using capitals as I thought I had stressed this in my earlier explanations, but obviously I didn't do a good enough job and I am mad at myself for letting you go astray... - read my post #41 and your post #43 please. I thought you were doing it right..?
SORRY, I'll try and do better next time.
I get a bit upset, as you do such good work that I only aspire to, and I don't want it all being destroyed in a big bang - which is possible with burners in confined spaces. Also, I have seen photos of Flash burns and Scalding, and don't want anyone to try either of those. Victims scream uncontrollably and it can be a bit distressing... That is aside from poisoning from CO gas from a rich burner, poor mixture. I don't want to sound dramatic, but remind everyone that CO is a toxic gas that converts good blood into useless blood, which clogs the lungs and blood to the brain and kills people. So please use a 0.25 jet next time.
Gas burners, and Steam are both very dangerous if you don't follow strict instructions exactly.
So please BE CAREFUL and stay safe,
K2
 

DJoksch

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The jet is removable so I can change it out. I knew it was likely too big. Testing is always done outside in open air to be safe. I am waiting for replacement drill bits. Sorry for the scare.
 

DJoksch

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Update. I drilled a new .25mm orifice on the jewelers lathe. The burner is sitting in what will be the stand. I set the copper cylinder for the water feed tank to show that I intended to have actual boiler slip sit on top. It burns clean and even. I did make some adjustments to a packing of a stainless steel scouring pad material to get rid of a hot spot. The CO meter reads zero ppm.

 

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Update. I drilled a new .25mm orifice on the jewelers lathe. The burner is sitting in what will be the stand. I set the copper cylinder for the water feed tank to show that I intended to have actual boiler slip sit on top. It burns clean and even. I did make some adjustments to a packing of a stainless steel scouring pad material to get rid of a hot spot. The CO meter reads zero ppm.

Hmmmmm - - - - CO meter - - - - please - - make model and source (cost too if you would)?

TIA
 

DJoksch

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Burner is ready to go. I’m constructing a viewport with a glass window for the boiler to light and monitor the flame. The boiler just slips on and off. I am thinking about building a coal burning version.

Thanks for all the help! I’ll post the complete steam unit after I install the viewport.
 

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Steamchick

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Hi Doug,
Just re-reading this thread - I realise I have done some useful stuff in my explanations here, so "teaching you" has been very rewarding for me! - It organised the scattered ideas in my brain, so a big "Thanks" - and for teaching me! Seriously, conversing with you has been really helpful to me, and I shall now embark on some spinning trials, when I have made suitable tools and rest, and a former for making "cans" for ceramic burners. It took a day or more to make a 1 3/4" aluminium can for a burner last week, by making flat shapes and soldering together - or in some case melting the parent metal! I had to resort to a 3mm thick base as the 1mm base just frazzled with the heat on the first one I made. Your spun can is just the right process.
P4102383.JPG

My photography is rubbish as well!
Now I'll have to find the "finished boiler" pictures I thought were here somewhere. I'll be looking forward to the final pictures when lagged and clad in wood, with feed pump etc. on the mounting board.
Keep writing, more photos, your work is commendable!
K2
 

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