I got mine off ebay. 5 to a package for around 10 bucks. Mine have only about 9/16 or 5/8 hole which seems to run my 10 hp B&S engine just fine. I think Dave and Gary use around 1 inch.
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Thierry,
The standard pistons in 1976 were dished. My replacement pistons are the older style flat tops. With the flat pistons and about .040 shaved off the head, I think I can reach 12:1. Most of these old MG heads are cracked, so a head replacement may also be needed. Iām actually hoping that I can squeeze about 45 HP out of the existing engine. I think that may be enough for playing around in the flatlands.
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Hi Kyle , The Tig nozzles were shipped from China to Australia , took about 2 weeks from memory , I guess if you want them straight away you can get them local from welding suppliers ,ect , I did that for my first one , but I paid $10 price for just the one .
Dave
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Iām out of town for a few days.
So, no more tinkering.
But I have my laptop with me. So, I ordered a few things off Amazon and EBay.
(1) A couple of those ceramic kiln firebrick (the lightweight carveable kind).
(2) Some refractory cement.
(3) A high alumina ceramic pipe.
(4) Some ceramic ākaowoolā style insulation.
(5) Some 1/8" hardware cloth, so I can get my screening right.
(6) A gear motor (for a shaker, maybe?)
I can hardly wait to get home and play with that stuff.
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Oh oweā¦ Kyle has the bug something baaaad.
I should not go on Amazon after 9 pm bad things happenā¦
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Like my wife always used to say when she went to the shoe store: āIt was on sale, so I had to buy it.ā
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I didnāt see TIG nozzles on your shopping list Kyle , are you going to try the tubes instead ?
I tried the tubes ,but ended up buying TIG nozzles after they all broke and also TIG nozzles were less than a 1/4 of the price for 5 .
It may be my connection but I am not able to see the latest video ,has anyone else had a problem seeing it ?
Dave
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I was going to try to pick up the first TIG nozzle locally. That way, I can look at the various styles and sizes before making a decision.
I am getting enough stuff together to try several different nozzle types.
I kind of think that the simplest nozzle might just be a firebrick with a hole bored through it. Has anybody tried that?
What happened when you tried the ceramic tubes? You say they all broke. Do you think they broke from the heat, or from mechanical abuse / stress ?
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I have used a hole through a firebrick on several different gasifiers. Easy to make with a diamond coated core drill bit and water on the drill press. I have tried many different nozzle ideas and this firebrick method is the one I have frequently returned to because of its price (once you have the drill bits) and availability. One time a firebrick nozzle split on me so I just wrapped some wire around it to hold it together and was back in business. That said, the TIG tip is going to be hard to beat for price, and durability. Gary Gilmore is the simplicity guru for gasification and he likes using stainless steel pipe and views it as a readily available consumable. I like trying new stuff and am optimistic about the thick-walled copper tuyere. If its ability to conduct heat away from the tip really stops the corrosion, it will be strong and will handle the stress of water drip.
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Bruce - Did you use the hard (dense) firebrick, or the lightweight kiln style? I was thinking that the lightweight kiln style might work - maybe if you put a thin coat of refractory cement on the outside. It is very easy to carve / drill.
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I use 1/2 of a full size hard firebrick. Let me know how the light stuff works. There is also an aerated cement building block material that can take 800C. It might also work with a coating of refractory cement?
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Bruce,
the heat dissipation of the nozzles also comes from the shape of the generator.
if the nozzle is near the generator walls should stay fresher? (As gasifiers Koen)
Contradict me if Iām wrong
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I have used kiln type fire bricks in one of my systems I used a 1 inch TCT hole cutter to bore down 1 inch into the fire brick and cemented a tungsten carbide nozzle into brick . the tungsten was 25MM OD with a 12mm ID , i then drilled through a 12mm hole the rest of the way through the brick ., I ran this nozzle for some time , cant remember how long as its been some time ago now , but I can say for the hours it did run ,that the surface of the fire brick turns to glass , the Tungsten not a mark on it ! it worked brilliantly , I would continue to use if I could lay my hands on more with a larger hole at the price I paid = free from the scrap bin !
TIG nozzles are swap and go now for me , takes a few minutes to change when i burn one out ,and at a couple a $ a throw its a no brainer .
The high alumina tubes for some reason , maybe because they didnāt transfer the heat away from the tip or me being to rough when cleaning the slag off them just didnāt last .
Here are a few pictures of a tube that just snapped off in my hand when I was cleaning the slag off the front , looking at the break you can see its dirty all the way around apart from a small part that was all that was holding it together , meaning it must have fractured while running
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Wow.
Makes me wonder where all that slag comes from.
I thought it was the gasses reacting with the metal.
But itās hard to imagine they would react that strongly with the alumina ceramic tube.
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PS: It doesnāt look like it would be that easy to swap TIG nozzles. Donāt you have to make a new one of those assemblies each time?
The slag comes from the impurities in the charcoal , nails ,dirt ,ect but isnāt a big problem really long as its not covering your nozzle hole ,and even then it can be gently tapped out of the way .
The nozzles are so easy to make I try and make 2 at a time so I have a spare , all I do is stand a nozzle in a tin can rest the tube on top and fill around with a refractory cement @70% alumina content
In winter or cloudy days I run my engine 4 or 6 hours a day and may only change the nozzle once a month , all depends on if I had a water drip or not .
Dave
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Dave,
150 hours on a homemade refractory nozzle sounds good to me.
If someone wants to get the perfect tuyere maybe they can have these guys make one:
http://foundrymag.com/meltpour/ceramic-protection-copper-tuyeres
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Bruce those nozzles look the beeās kneeās compared to my attempts ! Mine are never as smooth looking as those ones , still for the cost of what I am using and the life I get out of them I think I will carry on trying to improve slightly on what I have come up with so far .
I have over 2/3rds of bag left of this refractory cement to use up before it goes out of use by date , so I better get casting plenty of spare nozzles for years to come or start to make a pizza dome shell .
Ps I found a piece of 25mm dia copper about 100 mm long with a 12mm hole through it and thought hmmm that would make a nice nozzle , then shook my head and chucked it back in the scrap bin , after though was might have been worth a play
Dave
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Perhaps silica in refractory cement has a protective effect on steel up to 1177C, above that it could make oxidation worse:
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