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Post by Karl L on Nov 27, 2020 10:20:27 GMT -8
The onset of colder weather means I've been using my new DSR2 heater every day for around three weeks. I've noticed that the small mild steel deflector plate -- the 'cobra head' on top of the vertical square tube -- has largely disintegrated.
I was expecting the floor channel to last a bit longer - around 1 year at least.
Is there something I am doing that might be making it disintegrate faster than normal? Some of the burns have gone into 'thermal runaway', before I figured out the kind of fuel load that would avoid that.
Thanks for any thoughts.
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Post by josephcrawley on Nov 27, 2020 16:06:37 GMT -8
That seems very fast. What gauge of steel is it? I had fast degradation on a floor channel but that was due to undersizing the floor channel leading to poor air flow.
I always use 3/16 steel for the cobra and it's head. Thicker would be better but that is the max my welder will handle.
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Post by Karl L on Nov 27, 2020 23:56:49 GMT -8
Thanks. Yes, I was also wondering if it was low air flow. But the tube is scaled correctly from Peter's core drawings, I think.
This is a 125mm/5" core. The scaled internal width of the square tube should be 25.2 mm. My tube is 27.2mm internal - i.e. 16% oversized. The Horizonal tube is 2% oversized (It's made from 60x30mm, 3mm wall tube).
The cobra head is 2mm mild steel (~80 thou) - so that's a lot thinner than yours. The vetical square tube is only 1.6mm (1/16") - but that's not disintegrating so fast.
I wonder if the horizonal tube sometimes gets so hot that the air expansion restricts the flow rate? I once had a fire so hot that nearly the whole length of the horizonal tube was glowing red when I looked down it! But that doesn't happen with smaller loads of lighter wood, which is what I've been mostly using.
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Post by peterberg on Nov 28, 2020 4:02:27 GMT -8
Hmmm... I'd recommend to leave a good layer of ash on the feed part, only take some out when it's really in the way. Desintegrating of the cap is mostly due to poor cooling but in case the air is already overly hot in the feed cooling of the stub wouldn't be sufficient, I'd say.
By the way, I recently had my floor channel changed out for a new one. The old one had a cap of just 1.5 mil, was eaten away and severely curled up but still there. The fuel is predominantly soft wood species but the cap has been like that for three seasons I'd think. Having said that, your feed/stub proportions aren't ideal. In order to have this right, the feed should be twice as much internally csa as the stub. My feed, also in the replacement cobra, is just 2mm wall thickness. I fully intend to re-use that part next time, just switch out the stub.
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Post by Karl L on Nov 28, 2020 5:14:40 GMT -8
Thanks, Peter, I'll try leaving some ash over the feed tube and see what happens.
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Post by Orange on Nov 28, 2020 11:05:17 GMT -8
I wonder if painting the floor channel with waterglass or mud would pronong its life..
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Post by belgiangulch on Nov 29, 2020 6:56:40 GMT -8
Matt Walker just checked the floor channel in his cook stove. 2.5 years and the RA330 high heat stub is as good as new! I am currently making secondary channels with Peters Cobra design. I opened an account with rolled alloys and have an order in for RA33. I will be offering these for sale by the new year. I currently do not have an open store. Contact Matt at Walkerstoves to reach me.
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Post by josephcrawley on Nov 29, 2020 9:46:28 GMT -8
Matt Walker just checked the floor channel in his cook stove. 2.5 years and the RA330 high heat stub is as good as new! I am currently making secondary channels with Peters Cobra design. I opened an account with rolled alloys and have an order in for RA33. I will be offering these for sale by the new year. I currently do not have an open store. Contact Matt at Walkerstoves to reach me. That ra330 runs about $10 an inch. I would rather spend my money on a welder and the versatility that comes along with it.
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Post by Karl L on Dec 16, 2020 2:12:02 GMT -8
Matt Walker just checked the floor channel in his cook stove. 2.5 years and the RA330 high heat stub is as good as new! I am currently making secondary channels with Peters Cobra design. I opened an account with rolled alloys and have an order in for RA33. I will be offering these for sale by the new year. I currently do not have an open store. Contact Matt at Walkerstoves to reach me. That ra330 runs about $10 an inch. I would rather spend my money on a welder and the versatility that comes along with it. Thanks, but I'm not sure that would be a good way to go for me right now as I'm experiementing with many variables and may need to change the floor channel size/shape or not need one at all. Also I'm in the UK.
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Post by Karl L on Dec 16, 2020 2:12:50 GMT -8
Does anyone know what happens to readily available stainless steel when used to construct a floor channel vertical tube/cap?
(One of the annoying things about the top portion of the cap/head disintegrating is that lumps of charcoal falling off the burnt wood can now easily block the secondary air.)
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