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Post by keithturtle on Feb 7, 2019 23:00:45 GMT -8
This is a good source for fine graded Lye and KOH, been buying form them for years. THis deal is so good I use it for drain cleaner too
KOH is flakes and not finely sized, or uniform but still pure stuff
Shipping can add up at those weights; depends on how bad you want it
Turtle
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Post by JonS on Jan 27, 2020 10:18:09 GMT -8
Hello,
1st of all, thanks for sharing all of this information. In a day or two, I should have all of the ingredients arriving to make a test batch of KC#1. After reading up on KOH, I am getting a little nervous. I am planning on wearing eye protection and gloves but do I need to take additional precautions? Does the mix off gas? Is it safe to make it in the kitchen or do I need to find a more ventilated area?
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Post by sksshel on Jan 27, 2020 12:28:03 GMT -8
Hello, 1st of all, thanks for sharing all of this information. In a day or two, I should have all of the ingredients arriving to make a test batch of KC#1. After reading up on KOH, I am getting a little nervous. I am planning on wearing eye protection and gloves but do I need to take additional precautions? Does the mix off gas? Is it safe to make it in the kitchen or do I need to find a more ventilated area? I wear a respirator as well. Yes, it emits gasses. I assume they are harmful out of an abundance of caution. Well ventilated, yes. There is considerable heat and a fairly robust reaction. I mix them slowly. Good luck. |
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Post by JonS on Jan 27, 2020 15:58:01 GMT -8
Hello, 1st of all, thanks for sharing all of this information. In a day or two, I should have all of the ingredients arriving to make a test batch of KC#1. After reading up on KOH, I am getting a little nervous. I am planning on wearing eye protection and gloves but do I need to take additional precautions? Does the mix off gas? Is it safe to make it in the kitchen or do I need to find a more ventilated area? I wear a respirator as well. Yes, it emits gasses. I assume they are harmful out of an abundance of caution. Well ventilated, yes. There is considerable heat and a fairly robust reaction. I mix them slowly. Good luck. |
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Post by JonS on Jan 27, 2020 16:24:14 GMT -8
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Post by sksshel on Jan 28, 2020 4:52:59 GMT -8
Looks good though I am not an expert. |
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Deleted Member
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Post by Deleted on Jan 28, 2020 10:10:31 GMT -8
If a chemical reaction releases considerable heat wearing a respirator is always a good idea.
The chemical reaktion of mixing monopotassium phosphate with potassium hydroxide:
KH2PO4 + 2 KOH = K3PO4 + 2 H2O
The released gas is water vapor.
The actually harmless steam can throw small lye particles and droplets into the air.
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Post by JonS on Jan 31, 2020 9:41:25 GMT -8
Thanks for the feedback. I should be ready to make my 1st batch this weekend!
My end goal is to cast a half barrel shaped dome for the top of a batch box pizza oven… I have made a mold by bending ¼ inch plywood into the half barrel shape. Should I be concerned with shrinkage in a non-flat shape and the mix cracking? Would it be beneficial to build it up slowly with several coats of geopolymer instead of one thick one? Also, is it possible to cure the material faster in the oven (say 200F) or is that a bad idea?
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Post by sksshel on Feb 1, 2020 8:17:58 GMT -8
Thanks for the feedback. I should be ready to make my 1st batch this weekend! My end goal is to cast a half barrel shaped dome for the top of a batch box pizza oven… I have made a mold by bending ¼ inch plywood into the half barrel shape. Should I be concerned with shrinkage in a non-flat shape and the mix cracking? Would it be beneficial to build it up slowly with several coats of geopolymer instead of one thick one? Also, is it possible to cure the material faster in the oven (say 200F) or is that a bad idea? Yes, shrinkage will be an issue. Cracking could be also. Another issue is the semi-cured material can break when moving into it's final place. The mold might be able to be used to sturdy the structure during movement. Others will give their opinions on here, but if I were you, I'd make the dome very thick. 3-4" is my guess. I also would put some "chicken wire" in the middle of the thickness. What is the diameter of the dome? How long is the dome? |
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Post by JonS on Feb 1, 2020 8:54:43 GMT -8
Wow, that is thicker than I expected. The inside of the dome is 15 inches wide x 7 inches tall x 24 inches long. It will be sitting on firebrick splits on 3 sides (4.5 inch height) with a door on the front. I wish I could figure out how to send a picture...
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Post by DCish on Feb 4, 2020 12:14:50 GMT -8
Wow, that is thicker than I expected. The inside of the dome is 15 inches wide x 7 inches tall x 24 inches long. It will be sitting on firebrick splits on 3 sides (4.5 inch height) with a door on the front. I wish I could figure out how to send a picture... Space to host pictures is full. You have to upload your picture somewhere else, like Google photos, Share it from there, then embed a link. Annoying first time or two, but once you get the hang of it, it goes pretty quickly. |
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Post by JonS on Feb 5, 2020 17:51:34 GMT -8
Full disclosure, I didn't have rockwool. I made a round sample omitting that ingredient and it seems to be curing very hard. With that success, I tried casting a mini dome over a cut in half yogurt tub. That cracked after a day... Has anyone else had experience not adding the rockwool? I think I remember a post where Karl said it adds elasticity but not hardened strength. I noticed that the mix takes about half the water without the rockwool which seemed like it would help with shrinkage but might not be as insulating. My new plan is to cast the half circle ends and then make 6, 4x27 lengths to place side by side to form a dome.
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Post by sksshel on Feb 6, 2020 6:22:26 GMT -8
In my testing the rock wool greatly reduced cracking.
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Post by JonS on Feb 8, 2020 8:33:53 GMT -8
Wow, that is thicker than I expected. The inside of the dome is 15 inches wide x 7 inches tall x 24 inches long. It will be sitting on firebrick splits on 3 sides (4.5 inch height) with a door on the front. I wish I could figure out how to send a picture... Space to host pictures is full. You have to upload your picture somewhere else, like Google photos, Share it from there, then embed a link. Annoying first time or two, but once you get the hang of it, it goes pretty quickly. Thanks for the tip. Let's see if this works. If the link works it shows the general idea. I initially was trying to make a refractory/vermiculite mix to cover the wood dome but it was very week... photos.app.goo.gl/C23rWkvZCVg17yr16 |
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Post by DCish on Feb 10, 2020 17:05:28 GMT -8
Link works. If you want to embed a single photo so that it shows up in the post, you can do so by pasting the direct link into the "Image URL" field of the "Insert Image" button. You find the direct link by opening just that shared photo in the browser, right clicking, and selecting "copy image address". Like this:  Nice project!  |
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