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Post by milspec on Mar 27, 2022 11:32:03 GMT 10
As one of the steps towards building myself a wood gasifier I have decided to make myself a 500mm wide sheet metal roller/bender. There are some pretty neat and simple builds on YouTube. My design is being influenced by what scrap metal I had lying around.
I've never used a sheet metal roller and my question to anyone with experience with these machines is: what governs the desired spacing between the two lower rollers ?
I will be bending 2-3mm sheet and flat bar up to 5mm. I may also machine some grooves into the rollers to accommodate rolling tube.
This is a bit of a niche question so I won't be surprised if there isn't much feedback.
Picked up a pair of old 45kg lpg bottles for $80 today. That means the gasifier project is underway.
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hd1340
Senior Member
Posts: 330
Likes: 426
Location: WA
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Post by hd1340 on Mar 28, 2022 0:55:24 GMT 10
As one of the steps towards building myself a wood gasifier I have decided to make myself a 500mm wide sheet metal roller/bender. There are some pretty neat and simple builds on YouTube. My design is being influenced by what scrap metal I had lying around. I've never used a sheet metal roller and my question to anyone with experience with these machines is: what governs the desired spacing between the two lower rollers ? I will be bending 2-3mm sheet and flat bar up to 5mm. I may also machine some grooves into the rollers to accommodate rolling tube. This is a bit of a niche question so I won't be surprised if there isn't much feedback. Picked up a pair of old 45kg lpg bottles for $80 today. That means the gasifier project is underway. Look forward to seeing updates on your progress
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Post by graynomad on Apr 1, 2022 17:46:42 GMT 10
I don't know what governs the spacing, but I have both a slip roller (no I don't know why they are called that) and a ring roller and I can measure them if you want. My slip roller is only good for about 1mm though I think, that may affect the spacing. Actually it's a 3-in-1, roller, break and gillo.
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Post by milspec on Apr 2, 2022 6:05:32 GMT 10
I don't know what governs the spacing, but I have both a slip roller (no I don't know why they are called that) and a ring roller and I can measure them if you want. My slip roller is only good for about 1mm though I think, that may affect the spacing. Actually it's a 3-in-1, roller, break and gillo. Thanks Graynomad, no need to measure though. I've decided I'll make a couple of positions that the rollers can be installed in. One question you may be able to answer is how important is it to be able to incline one roller? Is that a necessary feature to enable rolling conical sheet metal forms? None of the many videos I've watched address the roller inclination side of things. Cheers.
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Post by graynomad on Apr 2, 2022 22:11:01 GMT 10
Yeah inclining is used for rolling a cone, this video briefly shows how it's adjusted on a roller, mine is almost the same but a larger version. I've never rolled a cone though.
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Post by milspec on Apr 3, 2022 12:12:42 GMT 10
Yeah inclining is used for rolling a cone, this video briefly shows how it's adjusted on a roller, mine is almost the same but a larger version. I've never rolled a cone though. Thanks. Yeah I also concluded that the roller spacing will govern how long that flat piece will be before the bent section commences.
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Post by milspec on Apr 7, 2022 18:35:29 GMT 10
Well it's not quite finished yet but it is functional aka functional enough to roll the 'wheel' which meets the tips of the spokes. Since it seems to work I will go ahead and go over the tack welds with more durable worlds and then give it a lick of paint. Now I will tackle building the gasifier but I anticipate that will take some time as it will be fit in amongst other jobbies.
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Post by graynomad on Apr 7, 2022 20:36:28 GMT 10
Wow, that's an impressive piece of work, inspires me to get back into fabricating. I assume you used it to roll the wheel.
What have you used for the rollers?
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Post by milspec on Apr 7, 2022 20:55:03 GMT 10
Wow, that's an impressive piece of work, inspires me to get back into fabricating. I assume you used it to roll the wheel. What have you used for the rollers? Thanks. Yes, did a test roll, then rolled the wheel. I used some extra heavy duty pipe, the walls are 5 or 6mm thick. Then I machined a bearing carrier for a 40 which rides on a 17mm shaft. I machined solid ends for the upper roller because it is Welded to the shaft so that it can turn via the wheel but the shaft for the upper roller sits in sintered bronze bushings in the carrier assembly. The carrier assembly is machined for snug tolerances so that is isn't sloppy but still has sufficient vertical play to allow for an inclined set to the upper roller.
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Post by Joey on Apr 8, 2022 19:38:04 GMT 10
Looking good, can't wait to see a thread on building your gasifier
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Post by milspec on Apr 8, 2022 20:21:38 GMT 10
Looking good, can't wait to see a thread on building your gasifier My plan is to go ahead with the Ben Peterson design. I have his book which really explains a lot of the details. His design is more complex than some of the simple builds that can be seen on youtube but I Think that additional complexity stems from a design which is tuned from his considerable experience to deliver a quality gas with minimal undesirable by-products. I'm kinda in the build it once build it right school on this project. My build will be based on some old propane tanks I've picked up from Gumtree. I haven't measured them but they are probably slightly different to the US equivalents his design is based on. No doubt I'll have to create a spreadsheet to convert all those imperial measurements of his design into s proportional metric equivalent. Not looking forwards to that chore but ya gotta do what ya gotta do.
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Post by Joey on Apr 8, 2022 21:51:10 GMT 10
If you're going to be welding pipes together, use this website for your notching calculations. I've given this website to a few boilies I've worked with over the years and it's made their life easier. You enter your pipe diameters, and the joining able and it gives you a printable template that you cut out and wrap around the pipes to cut your notches to join the pipes together neatly without having to to everything out manually. www.blocklayer.com/pipe-notcheng.aspx
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Post by milspec on Apr 9, 2022 6:43:01 GMT 10
If you're going to be welding pipes together, use this website for your notching calculations. I've given this website to a few boilies I've worked with over the years and it's made their life easier. You enter your pipe diameters, and the joining able and it gives you a printable template that you cut out and wrap around the pipes to cut your notches to join the pipes together neatly without having to to everything out manually. www.blocklayer.com/pipe-notcheng.aspxThanks Joey, that's neat. That'll get some use for sure. I can use that for my fence end assemblies as well as I do them in steel mainly.
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malewithatail
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Posts: 3,338
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Location: Northern Rivers NSW
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Post by malewithatail on Apr 9, 2022 8:23:13 GMT 10
Many years ago I built a vertical downdraft gasifier. It worked well enough, and I even coupled it to my ute to have a drive around the farm. The unit wasn't quite big enough for the vehicle, but ran the 8.5 kva Honda generator well. Unfortunately, it was destroyed when the tractor battery shorted out and burnt down the shed years ago. Am collecting stuffs to make another, probably the same design, but a bit bigger hearth to allow for more air flow and higher gas output. I used a centrifugal filter as well as a heavy duty cartridge filter to get rid of particulates as they will destroy your engine very quickly. I experimented with water injection, but the whole contraption was prone to backfiring when the water was disassociated into hydrogen and oxygen by the heat, so was too dangerous and I reverted back to a straight gasifier. Tar buildup is the biggest issue, and by using a wood chip filter, almost all the tar was removed, and the filter could be burnt in the stove, giving a useful recovery of heat as well as being easily replaceable. Cooling the gas is also essential, as the cooler the gas,the more oxygen it can absorb and the greater the power output you get. I used a Caterpillar bulldozer radiator as a heat exchanger and it worked very well, apart from the aforementioned tar buildup.
Take your time about getting even, there is no rush as the creep will be too busy shafting others. Enjoy it.
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Post by milspec on Apr 11, 2022 18:28:56 GMT 10
Many years ago I built a vertical downdraft gasifier. It worked well enough, and I even coupled it to my ute to have a drive around the farm. The unit wasn't quite big enough for the vehicle, but ran the 8.5 kva Honda generator well. Unfortunately, it was destroyed when the tractor battery shorted out and burnt down the shed years ago. Am collecting stuffs to make another, probably the same design, but a bit bigger hearth to allow for more air flow and higher gas output. I used a centrifugal filter as well as a heavy duty cartridge filter to get rid of particulates as they will destroy your engine very quickly. I experimented with water injection, but the whole contraption was prone to backfiring when the water was disassociated into hydrogen and oxygen by the heat, so was too dangerous and I reverted back to a straight gasifier. Tar buildup is the biggest issue, and by using a wood chip filter, almost all the tar was removed, and the filter could be burnt in the stove, giving a useful recovery of heat as well as being easily replaceable. Cooling the gas is also essential, as the cooler the gas,the more oxygen it can absorb and the greater the power output you get. I used a Caterpillar bulldozer radiator as a heat exchanger and it worked very well, apart from the aforementioned tar buildup. Take your time about getting even, there is no rush as the creep will be too busy shafting others. Enjoy it. There is plemty of temptation to build a simple gasifier but I'm pretty sure thats when tar and water materialise as significant issues and grate agitation is probably also an issue. The Ben Petersen design evolved over quite a bit of time, research and experimentation on his part and he is still active so I figure its prudent to run with what he put so much energy into (no pun intended). His design includes a relatives simple 1.75" pipe based heat exchanger, that in itself should be fairly resilient against tar buildup. It has crossed my mind that an IBC full of water could also serve as a heatsink for the heat exchanger but its probably unnecessary.
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malewithatail
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Location: Northern Rivers NSW
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Post by malewithatail on Apr 11, 2022 19:55:49 GMT 10
Tar was taken care of with a wood chip based filter that was just burnt in the fire when it got too blocked with tar, Water wasn't an issue, in fact, some water is good as it adds to the caloric value of the gas with hydrogen and oxygen, especially if injected straight into the hearth and it dissociates with the heat into hydrogen and oxygen, but be careful, it can backfire ! The lid hit the roof a few times ! The gas cooler was an old 2 inch thin pipe bed frame and worked well for small engine/generator, but wasn't big enough for running a vehicle. A water bath would be better. To kick the thing off, a heater fan was started to draw the fire, then that was turned off and the engine vacuum did the rest. The fan was steel though as a plastic one would probably melt. The gas was tried to be cleaned by bubbling through a water bath, but the back pressure was too much for the 8.5Kva Honda generator, however, it did show promise for vehicle operation though.
There are some people one should never screw with, there is always someone better than you at revenge.
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