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Post by Deleted on Sept 14, 2009 16:47:29 GMT
I do believe that they are the same, Chris. They are (or were) made of pulverised fly ash, a by-product from coal fired power stations. As we are mostly gas powered now I'm wondering where they come from currently! But of course, someone here will know........ JB
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simonwass
Part of the e-furniture
Cecil Pagets 2-6-2 of 1908. Engine number 2299. Would make a fascinating model....
Posts: 472
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Post by simonwass on Sept 14, 2009 23:38:04 GMT
I havent a clue ;D OTOH, only 40% of UK generation is gas, 33% coal, 20% nuclear, rest are piddly things. By 2016-20 most of the coal stations will shut due to difficult to achieve nox emission levels, there will be blackouts unless the men in charge have the balls to say 'as you were'. For that 33% coal generation 50 million tons of coal needs to be burnt and at 10% ash contect (varies wildly) you get 5 million tons of ash where 80% will be pfa (pulverised fuel ash (fine)collected in electrostatic precipitators), the other 20% is fba (furnace bottom ash (coarse lumps) which is fused slag ash which drops out the bottom of the furnace). Theres still plenty of ash about!
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kwil
Part of the e-furniture
Posts: 383
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Post by kwil on Sept 15, 2009 8:03:39 GMT
drjohn,
But they do not throw heat away, if they reflect it then it ends up where we want it, in the copper tube. We are not after an oven which retains heat for evermore.
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Post by cupalloys on Sept 19, 2009 9:55:18 GMT
The main requirement of a brazing hearth is to get the heat into the work not to heat bricks. The best materials are light so they have little thermal mass and do not absorb heat but reflect or radiate it. Bricks from storage heaters are the worst because their role is to absorb heat and release it slowly later. Keeps the workshop warm but does little to help your brazing! Vermiculite blocks and plates are much better. Or if you want to create a hearth that is not square, or you want to insulate your work to keep heat in, then use kaolin wool say 1" thick. All these products are available via www.cupalloys.co.uk. Look at "Heating Products" in the model engineering section.
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Post by Deleted on Sept 19, 2009 13:25:15 GMT
Many years ago I acquired (from a fellow club member) a box of highly reflective fire bricks labelled 'Fosalsil'. With the main structure of the brazing hearth lined with conventional fire bricks, these can be placed close to the job, helping to raise the copper to brazing temperature very quickly. Unfortunately they are quite fragile and deteriorate fairly rapidly. I am now coming to the end of my supply and cannot find a new source. Googling Fosalsil gets me a lot of references in Japanese which doesn't help me a lot. Anyone any ideas?
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Tony K
Elder Statesman
Posts: 1,573
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Post by Tony K on Sept 20, 2009 8:20:25 GMT
Many years ago I acquired (from a fellow club member) a box of highly reflective fire bricks labelled 'Fosalsil'. With the main structure of the brazing hearth lined with conventional fire bricks, these can be placed close to the job, helping to raise the copper to brazing temperature very quickly. Unfortunately they are quite fragile and deteriorate fairly rapidly. I am now coming to the end of my supply and cannot find a new source. Googling Fosalsil gets me a lot of references in Japanese which doesn't help me a lot. Anyone any ideas? I got as far as finding they were made by Moler products in Colchester, but found the following which suggests they went to the great fireplace in the sky.... "Outline planning consent to redevelop the large site of the former Moler Works for a mixed use scheme has been granted."
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Post by Deleted on Sept 20, 2009 8:49:55 GMT
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Post by durhambuilder on Sept 20, 2009 19:55:58 GMT
I bough a 3ft x 2ft sheet of 25mm thick vermiculite board from my local agricultural merchants for about £15, the idea being you cut it into the sizes you need to line your woodburner.
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simonwass
Part of the e-furniture
Cecil Pagets 2-6-2 of 1908. Engine number 2299. Would make a fascinating model....
Posts: 472
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Post by simonwass on Sept 20, 2009 21:23:16 GMT
That would be a useful find. I think I might take the blocks out of our log burner whilst they are still in good shape and draw around them to make templates for the future. The two side ones are an odd shape and about £40 a set.
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Post by Deleted on Sept 23, 2009 15:37:51 GMT
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Tony K
Elder Statesman
Posts: 1,573
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Post by Tony K on Sept 24, 2009 7:53:49 GMT
Hey Loco, looks like a bargain - and it works - visual proof! Looks as though he has moved to here
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Post by Deleted on Sept 24, 2009 13:53:46 GMT
Thanks, Tonytrans, for the information on Fosalsil. Another useful supplier bites the dust. Anyway, it looks as though vermiculite will fill the bill.
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weary
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Member is Online
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Post by weary on Sept 25, 2009 8:36:55 GMT
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chiptim
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Posts: 270
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Post by chiptim on Sept 26, 2009 21:42:29 GMT
Hi JB, I was lucky and found some angle iron in the skip at work so knocked up this. I've got 4 small vermiculite blocks that are good but the rest are Celcon blocks as in the photo. They're OK but for me the real winner is the Kaolin Wool blankets. Sometimes I spread them flat over the Celcon blocks and place the work on top, sometimes I wrap them around the work either in direct contact or form a hood and wire in place. They're great and make a huge difference. ALthough I've got a shield around 3 sides, sometimes this restricts access. In this case I lift the blocks off and work on the ground. Having the whole thing on casters is useful - just wheel it out! Regards Tim
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simonwass
Part of the e-furniture
Cecil Pagets 2-6-2 of 1908. Engine number 2299. Would make a fascinating model....
Posts: 472
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Post by simonwass on Sept 26, 2009 23:08:25 GMT
Now thats just showing off I can 'get' ceramic wool from work, its used when welds are being heat treated. The stuff's just binned after use! It used to be classed as a carcinogen once heated but is now 'body soluble' so apparently not dangerous.
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brozier
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Post by brozier on Sept 28, 2009 9:44:38 GMT
Hi Tim,
Is that an Oxy-Propane setup you have there?
What do you use it for when boiler making? What bits do you need?
Would you recommend it?
Cheers Bryan
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Post by ilvaporista on Sept 28, 2009 14:25:14 GMT
I have the same nominal set up as Tim's Low density blocks reflect the heat very well, good use of the blanket, I must find some to try. The oxy propane is great for concentrated heat, stays being a prime example BUT remember that the hottest part of the flame is well over the melting temperature of the material. Go on ask me how I know that!! I found that the trick is to keep going towards the work slowly with the torch until the solder starts to run then move back, check, go back in again if necessary, then move to the next joint. Keeping the normal flame playing on the firebox sides kept everything hot an just allowed me to touch the stays. Before I had pools of molten solder all over the stays and was never sure if I had disturbed anything. Once I had got the hang of it everything turned out great. Practice first before you ruin an otherwise good boiler. ;D
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chiptim
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Post by chiptim on Sept 30, 2009 14:36:48 GMT
Bryan, yes it's oxy propane that a friend has lent me. I'm trying to build the whole boiler using just the propane so haven't had to use the oxy propane yet. I've tried it on some scraps and you can melt copper so I'm a little hesitant although I must say this is much less likely to happen on the boiler because its thermal resistance will be so much less than an offcut! Also the nozzle is a little small - looking in Alec Farmers book he uses No 11 -18, an 18 being suitable for 6mm thick steel, but copper takes far more heat. I'm expecting that I might need the oxy propane for some of the later stages, foundation ring and possibly stays although I'm step soldering so I'll see how it goes but it is a 7 1/4" boiler albeit a small one. Regards Tim
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Post by stovebrazing on Jan 14, 2011 19:52:50 GMT
Hi, I have lots of vermiculite fire bricks listed on ebay. It is heat resistant up to 1100ºC /2012 ºF Can be cut and shaped using standard DIY tools It has no ceramic fibres, its non-irritant and odourless See link below:- stores.ebay.co.uk/stovecareandrepair?_rdc=1Kind regards Mark Attachments:
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Post by stovebrazing on Jan 14, 2011 19:55:44 GMT
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