kkp
Junior Member
Posts: 55 
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Post by kkp on May 19, 2018 14:34:19 GMT -8
Over at permies.com they are adding perlite to premix refractory mix to make it go farther. Maybe that's my solution considering I already have 3 bags of premixed refractory Perlite is a great insulator which you probably don't want in your bell. It also makes things weak. It is horrible as a grog. It can be used in the outer portion of insulated burning areas. You are working on the bell for your build. The top of the bell has to be the hardest part of the design. Think about it; 1 It has to be refractory 2 cover a wide span 3 hold up weight 4 handle heat cycling 5 ?.... I think if you could come up with a good cast lid then its just bricks from there right? Is that what you are planning? I think this is why rockets with the steel barrel setup are so popular, it is a simple and cheap solution. I'm thinking of going the non exposed steel bell route. I would love to just make a bell out of steel and cover it with cob. Still researching that idea. I have concern with possible moisture buildup though due to a new design change that would be lower internal temps and causing rust through. I have a large sheet of 3/16" steel plate I would weld up and use instead of a barrel for longer life. Cheap, Strong and Last forever... Pick two Yes that's my plan.
I have 3 bags of pre-made castable refractory now.
Also, for anyone in the Spokane WA. area - White Block carries 2600F castable refractory. I was in there a couple days ago to get fireclay and the sales guy told me they have it, $73 per bag.
Right now gadget, I'm working on a way to dilute the hot gasses coming out of the top of riser to reduce thermal shock. I have a couple ideas so far. I asked the question to an expert in fluid dynamics actually - he hasn't got back to me yet.
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Post by gadget on May 19, 2018 19:39:22 GMT -8
Perlite is a great insulator which you probably don't want in your bell. It also makes things weak. It is horrible as a grog. It can be used in the outer portion of insulated burning areas. You are working on the bell for your build. The top of the bell has to be the hardest part of the design. Think about it; 1 It has to be refractory 2 cover a wide span 3 hold up weight 4 handle heat cycling 5 ?.... I think if you could come up with a good cast lid then its just bricks from there right? Is that what you are planning? I think this is why rockets with the steel barrel setup are so popular, it is a simple and cheap solution. I'm thinking of going the non exposed steel bell route. I would love to just make a bell out of steel and cover it with cob. Still researching that idea. I have concern with possible moisture buildup though due to a new design change that would be lower internal temps and causing rust through. I have a large sheet of 3/16" steel plate I would weld up and use instead of a barrel for longer life. Cheap, Strong and Last forever... Pick two Yes that's my plan.
I have 3 bags of pre-made castable refractory now.
Also, for anyone in the Spokane WA. area - White Block carries 2600F castable refractory. I was in there a couple days ago to get fireclay and the sales guy told me they have it, $73 per bag.
Right now gadget, I'm working on a way to dilute the hot gasses coming out of the top of riser to reduce thermal shock. I have a couple ideas so far. I asked the question to an expert in fluid dynamics actually - he hasn't got back to me yet.
I would think adding an increase in volume should cool down the gases some. Let us know what you hear back. I'm doing a heavy steel plate bell to pull out some heat right after my burn chamber and had concerns over steel erosion. I was thinking about having a sacrificial plate of steel the gases could hit that sat just an inch or so under the bell top. The gases could work there way around it to transfer heat. Maybe something similar would work for your setup. -Gadget |
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Post by gadget on May 19, 2018 19:49:03 GMT -8
Hey karl and sksshel, This sounds very interesting, especially on the low cost. My stove design has changed such that this could be useful. I'm interested in some material that could handle moisture that may linger around the floor or other areas of a vertical double bell. Any thoughts on how well the geopolymer you are using would hold up as a hot face, say inside a firebox covering ceramic fiber board? Say 1/8" - 1/4" thick? Any info on expansion rate / heat cycling toughness?? I'm guessing this cement is a permanent phosphate bonded? I'm going to have to dig through some threads and find a recipe to experiment. -gadget I recommend you read the thread on Kansas City #1. Let me know if you have questions after reading it. Yep, read through it and some other material karl posted. Problem is now I have some serious gears turning upstairs. I came up with an idea using geopolymer/slag I posted in the sub forum. Geopolymer is very fascinating. -Gadget |
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kkp
Junior Member
Posts: 55
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Post by kkp on May 22, 2018 16:41:09 GMT -8
Yes that's my plan.
I have 3 bags of pre-made castable refractory now.
Also, for anyone in the Spokane WA. area - White Block carries 2600F castable refractory. I was in there a couple days ago to get fireclay and the sales guy told me they have it, $73 per bag.
Right now gadget, I'm working on a way to dilute the hot gasses coming out of the top of riser to reduce thermal shock. I have a couple ideas so far. I asked the question to an expert in fluid dynamics actually - he hasn't got back to me yet.
I would think adding an increase in volume should cool down the gases some. Let us know what you hear back. I'm doing a heavy steel plate bell to pull out some heat right after my burn chamber and had concerns over steel erosion. I was thinking about having a sacrificial plate of steel the gases could hit that sat just an inch or so under the bell top. The gases could work there way around it to transfer heat. Maybe something similar would work for your setup. -Gadget What about stove top glass instead of steel, or would that melt? It also might be too fragile, for the area you want it. Or too big. |
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Post by keithturtle on Jun 28, 2018 17:55:49 GMT -8
I finally found a supplier that will sell alumina cement by the bag. It is not high grade stuff but should work for some comparative builds against the kastolite 26 www.calucem.com/products/lumniterefcon/lumniter.htmlThe seller globaldrilsup.com/This is used in well drilling applications for its underwater setup qualities I paid $53 USD in Ohio for a 94 pound bag. Also got some fine bentonite clay (200 mesh) which I don't know if I can use instead of fireclay (what I'm finding on the foundry sites is, no it can't be used) Turtle |
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Post by Sidney on Oct 19, 2018 3:33:32 GMT -8
Hi guy's,
I'm getting ready for some experimenting this winter and I was looking for a cost effective method of construction for the experiments and I cam across this recipe:
"From http://www.delftclay.co.nz/how-to-make-refractory-cement-3-recipes/
Refractory Cement Recipe #1
What You Will Need:
● Portland cement (You can purchase a 94 lb. bag at your
local hardware store for less than $10.)
● Perlite (Can be purchased for $10 to $25.)
● Silica Sand (A 50 lb.bag costs less than $25.)
● Fire clay or Well drillers mud (A 50 lb. bag averages less
than $10.)
The Formula
1.5 parts Portland cement + 2 parts Perlite + 2 parts silica sand + 2 parts
fire clay
What to Do:
Using the portions listed measurements listed above, mix the Portland
cement, Perlite, and silica sand together thoroughly.
Combine the mixture with 2 parts fire clay.
Once the mix has the consistency of stiff cookie dough, pack it into the
preformed form. You may need to add a little bit of water to get the
right consistency.
Allow it to dry for several days."
I got all but the clay mud but the land here is all clay (the type that makes your boost 6" think after 4 steps when wet). I was just going to collect some in the yard.
I was wondering if anyone ever tried this before ?
Sid
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Post by coastalrocketeer on Oct 19, 2018 9:07:10 GMT -8
If the area is not going over 500C then that would work... above that I would replace silica sand with lava sand, Mullite grog, or another material that does not have crystalline structure.
Karl, our chemistry, geology, and mineralogy guru has stated that the quartz in silica sand changes size above 550C or so, and causes break down of refractory mixes.
He has suggested (in this thread, I believe) ways to make Portland cement mixes refractory to 900C which would be good for most any NON hot-face/flame-path zone in a stove. Still not enough for burn tunnel and riser, or the area directly above the riser.
And perlite is a weak material, so the more you add for insulative value, the weaker the resulting cured material will be.
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Post by coastalrocketeer on Oct 19, 2018 9:19:18 GMT -8
Karl’s suggestion for a high heat Portland based mix is on page two of this thread.
MKP is most cheaply obtained from Ag suppliers as a fertilizer. Buying it online is rediculously priced, as far as I have found. A fertilizers supplier in my state of Oregon told me that he deals in it by the truckload, and when I told him I just needed one bag (50+lbs) he said he had a mostly full one in his garage at home he would give me for experimentation purposes.
Depending on your region MKP may be available at local farm and feed stores.
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Post by Sidney on Oct 19, 2018 15:52:11 GMT -8
Karl’s suggestion for a high heat Portland based mix is on page two of this thread. I saw that recipe, but I'm looking for the cheapest solution for running test burns. Once I find the right design, I'll probably use castable refractory if needed. I know this mix will not survive long in 1000C environment, but if it can last for 10 or so runs, I'd be done with it and on to the next test design. MKP is most cheaply obtained from Ag suppliers as a fertilizer. Buying it online is rediculously priced, as far as I have found. A fertilizers supplier in my state of Oregon told me that he deals in it by the truckload, and when I told him I just needed one bag (50+lbs) he said he had a mostly full one in his garage at home he would give me for experimentation purposes. Depending on your region MKP may be available at local farm and feed stores. One of the issues I have is there is not much locally. Everything is over 1 hour drive away for anything that is not standard/normal/common. I also work 6 days a week and I have to budget cleaning the house and laundry so time is also a every scarce commodity. I got some firebricks to build a known good fire box / batch box. I looking at different known good option for risers. I place on experimenting with the box riser area. I want to start with a 6" batch box design to the exact Peterburg's specs and get base line readings, performance and feel Then make changes and see what effects it has.
So if this mix can withstand 1200C for a few runs and not explode, I'm a happy camper 
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Post by coastalrocketeer on Oct 19, 2018 17:33:40 GMT -8
I understand... am in a similar situation... suppliers are 1.5 to 2 hours away for me for a lot of the stuff i’m Looking to experiment with making my own geopolymer refractories.
Let us know how it works!
Non-quartz masons sand may be better as aggregate than silica sand that is effectively pure quartz sand, even if it is coarser. What is available here for mason’s sand is the finest screened fraction of river rock. Might test a mix with each if you can find it locally.
Looking forward to hearing how it holds up.
What part of the world are you in? I’m on the coast of Oregon, an hour and a half from any level of industry and major highways.
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Post by Sidney on Oct 21, 2018 3:02:31 GMT -8
I checked again for fire clay or "slurry" in my area and no one has any. I do have oil absorbent at the shop and that is diatomic clay in granules. But I think just cleaning some clay from the yard would be better.
I just got thrown in tire season due to the weather sooner than expected. I'll make to collect some clay before hell freezes over till may lol
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Post by firewatcher on Nov 6, 2018 17:34:58 GMT -8
Monopotassium phosphate 10%, lye 5%, fire clay 20%, Portland cement 65%.
Hi Karl,
Can you provide some additional guidance on mixing together the components mentioned above?
For example: first mix MKP with water, then add lye, then add fire clay and Portland cement all at once...
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Deleted
Deleted Member
Posts: 0
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Post by Deleted on Nov 7, 2018 6:09:33 GMT -8
The acidic monopotassium phosphate would react far to strongly with the cement,
therefore it must be made more basic.
Mix the monopotassium phosphate with the lye and add just enough water for dissolution.
Depending on the lye the reaction will be as follows.
KH2PO4 + KOH = K2HPO4 + H2O
KH2PO4 + NaOH =NaKHPO4 +H2O
Then add the clay and more water to the mixture.
Mix the cement with water, then add the mixture of clay and chemicals.
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Post by firewatcher on Nov 7, 2018 6:55:55 GMT -8
The acidic monopotassium phosphate would react far to strongly with the cement, therefore it must be made more basic. Mix the monopotassium phosphate with the lye and add just enough water for dissolution. Depending on the lye the reaction will be as follows. KH2PO4 + KOH = K2HPO4 + H2O KH2PO4 + NaOH =NaKHPO4 +H2O Then add the clay and more water to the mixture. Mix the cement with water, then add the mixture of clay and chemicals. Thanks as always Karl! Hope you are doing well...it's good to hear from you. |
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Post by coastalrocketeer on Nov 7, 2018 10:47:17 GMT -8
As with GP mixes I'd expect that higher strength will be obtained by adding just enough water to make the mix workable.
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