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Post by photoman290 on Apr 17, 2014 6:16:00 GMT -8
going to have a play with castable refractory for my burn chamber. i have spoken to someone who sells it here in the uk,and he recommends 2inches thick. i should get a whole burn chamber out of one 50pound bag. it comes in different densities and temperature ranges. the idea is to make a mold using matt walkers mix of fireclay perlite and fire cement mixed with rockwool as the outer part and the burn tunnel and ski ramp out of castable refactory. i have a choice of 1600c 1700c or 1800c. any one know which one i should go for? the price different isn't huge but not sure if the properties change much with the temperature range. i am also hoping to make the trip wire from the same stuff as well. i am sure this has been covered but i cant find any threads.
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Post by matthewwalker on Apr 17, 2014 6:40:56 GMT -8
I like the lower temp mixes as they are typically more insulative, but there are a LOT of different refractories out there, so you will have to look into the properties of the specific product. If you are going to use a refractory anywhere I strongly recommend you use it for the feed as well since my mix is quite soft and gets abraded quite easily in the feed area.
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Post by 2tranceform on Apr 17, 2014 6:41:48 GMT -8
Should be good with any of the three. Probably be best using the most insulative to keep the heat in the burn chamber. I have been told that the refractory that I have should be cast at least 2 inches thick as well.
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Post by smarty on Apr 17, 2014 8:27:01 GMT -8
kilnlinings give a discount if you quote code KLWOF10 they also do a castable that can be cast in thinner sections. KL16F. Althjough it says to cast it in 2" or more it works fine at 25-30 mm. These are products designed for industrial use so they hold up ok for the kind of stuff we are up to. Always remember to cast things up in two halves. this allows the stuff to move around a bit more and avoids cracking. you need to get hold of some ceramic fibre paper for a gasket between the two halves and then use some means of clamping them together. stainless steel strapping metal bars down the sides with a threaded rod bolted across top and bottom, or something like that.
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Post by peterberg on Apr 17, 2014 10:22:10 GMT -8
Smarty is right, this 2" figure is way too much in a domestic environment. Thirty millimeter or 1 1/4" is about as thin as one can go in my experience because of trouble to get the air out properly using a vibrating table when going thinner. Avoid casting high and narrow walls, try to cast it flat if at all possible.
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Post by photoman290 on Apr 17, 2014 10:42:31 GMT -8
ok will stick to 30mm 25kgs should be plenty in that case. i was wondering about the vibrating table. it was suggested by the person i spoke to to use a vibrating poker. had a look at the hire cost and decided it is way to much for what i need. peter can you give me some idea of the frequency to use as i can knock something up for less that the hire cost. i did work in a foundry many many years ago so i know a bit about how foundry equipment works.
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Post by satamax on Apr 17, 2014 11:01:05 GMT -8
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Post by photoman290 on Apr 18, 2014 12:45:26 GMT -8
www.youtube.com/watch?v=GWImU7CCU8ghad a look in the pile of junk i call my workshop and found a small diaphragm compressor that looks like it will do the job. got feet as well so should be easy to bolt to a piece of ply. that design is very simple. i stiil like the chuck key in the drill idea. but only have one chuck key.
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Post by independentenergy on Apr 27, 2014 0:54:01 GMT -8
I like to use the vibrator using a jackhammer , a metal table above the mold
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