|
|
Post by firewatcher on Oct 2, 2016 9:44:39 GMT -8
Likely your zeolite is not milled finely enough. Or did you got more milling media for a better result ? I'm waiting on additional milling media from my free source...so I haven't gotten the zeolite any more fine than previously. Mine is very fine, with 50 micron for the largest particles and most are a lot smaller. Another factor is your rather coarse aggregare. As I have suggested before you could try to add about 20% very fine sand to your aggregate to fill the space wetween the coarse particles. I have some silica sand available. I'll give that a try in my next mix. Yep, ash works quite well. |
|
|
|
Post by firewatcher on Oct 2, 2016 13:20:43 GMT -8
Here's a side-by-side sand size compared to slag size...there doesn't appear to be a very large difference. Do you think it's worth adding this particular sand or should i start looking for something that's indicated as "extra fine"?  Supposedly there is another finer grade of the slag that i bought...not sure if tractor supply carries it though. The material that i have is marked as a 30-60. The finer grade is marked as -60 (extra fine). |
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Oct 3, 2016 2:54:07 GMT -8
The sand is to coarse.
Ssomething around 100 mesh would be required.
You could look at a pet shop for very fine sand
for aquarium or birds.
The finest from ATI Black Diamond is 40-80.
Blackblast has an extra fine with 50-150,
which is very similar to the one I use.
|
|
|
|
Post by firewatcher on Oct 5, 2016 12:21:12 GMT -8
Just a quick update on the "replacement" perlite geopolymer brick that i had to remake due to my first one cracking upon unmoulding due to my impatience...looks pretty good so far. I'll have to "low temp" cure this brick before "camp fire" curing to use the same method on all test pieces that I'm trying to compare. I decided to increase the slag/pozzolan ratio (5/1) so I won't be able to directly compare results to the other test pieces where I used 4/1 ratio, but i had a previous test piece which turned out very well except for cracks which occured during "camp fire" curing so I thought that I'd retry that recipe with a low temp cure firstt and see what happened.  |
|
lawry
Junior Member
Posts: 113 
|
Post by lawry on Oct 6, 2016 8:45:04 GMT -8
Just a quick update on the "replacement" perlite geopolymer brick that i had to remake due to my first one cracking upon unmoulding due to my impatience...looks pretty good so far. Yup this one looks far better. If I remember correctly your plan is to cast the firebox and riser.... What is your plan for final curing the complete firebox? Are you going to use the Camp fire? |
|
|
|
Post by firewatcher on Oct 6, 2016 9:07:33 GMT -8
I've been thinking about your very question for the past few weeks. Most likely the "camp fire" cure of a casting would not work well as even my camp fire ring has a small footprint. One way I've been considering to "controlled" low temp cure the casting, would be to place some sterno canisters in the fire box, vent the riser just a little to allow the heat to build up, and allow it to slowly dry out to start.
Then start with a few small short normal operation burns and work my way up to full temperature burns for full firing of the material.
Any suggestions or ideas with regards to this are welcome.
It may change, but my plan at the moment is to cast a 3" batch box (to keep material cost/quantity down and try the material i end up chosing to use on a larger scale than just test pucks). There is most likely a learning curve in this phase of the project as well and I hate wasting money, so the best that I figured I could do was to at least minimize any potential waste if something doesn't work out.
If my math is correct, it should only take about 1/4 of a cubic foot of refractory to do so (both fire box and riser...only 1inch thick)
|
|
lawry
Junior Member
Posts: 113
|
Post by lawry on Oct 6, 2016 12:45:16 GMT -8
" firewatcher" I tried to modify my 6" cookstove oven to fit the casting and mold in there, but I couldn't.... Bad planning and design I guess. After that failure I decided on the black curing box. The density of my wet mix is 1984 kg/m^3 (123.8 lbs/ft^3) for 50mm (2") thick casting of a volume of 0.01958 m^3 (0.6917 ft^3) Just as a reference. |
|
|
|
Post by firewatcher on Oct 6, 2016 13:18:37 GMT -8
" firewatcher" I tried to modify my 6" cookstove oven to fit the casting and mold in there, but I couldn't.... Bad planning and design I guess. After that failure I decided on the black curing box. The density of my wet mix is 1984 kg/m^3 (123.8 lbs/ft^3) for 50mm (2") thick casting of a volume of 0.01958 m^3 (0.6917 ft^3) Just as a reference. I do have access to some larger rigid black sheets of plastic. The 3 inch batch box would probably fit into a "black box" made of that material. Unless i really hurry up and decide on a mix to use (and make my mold), i'll probably not be able to cure outside until next spring/summer and I'm still not completely satisfied with any mixes that I've tried to date. The latest LTGS brick that i tried was pretty impressive though. Depending on the results from my second LTGS brick (this time i actually made the mix correctly), i may just use this mix. It looks like it's VERY promising and the low cost is a benefit as well. Temperatures are already starting to get cool and it's anybody's guess as to when temperatures will really start to drop significantly. My guess is that i probably only have about 4-6 weeks before it's not going to be feasible to cast anything outdoors due to colder weather. As always, I'll be happy to share any information on my progress / or lack of progress along the way. |
|
|
|
Post by firewatcher on Oct 6, 2016 17:02:52 GMT -8
After two hours of "low temp" cure over the flame from a can of chafing fuel, the opposite side temperature of the brick is 198F (92C). I'm hoping to "camp fire" cure the brick tomorrow. Before...  After...  |
|
lawry
Junior Member
Posts: 113
|
Post by lawry on Oct 6, 2016 22:18:58 GMT -8
Here is the bricks that I cast last time. The grey looking one is the conductive one with aluminum oxide and silicon carbide. The large one cracked while I was handling it when it was still wet? After the geopolymerisation the crack didn't propagate. The brick can support its own weight and I can't break it with my own hands, I thought it would have weakened from the crack  these large ones will be bench caps.  |
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Oct 7, 2016 1:32:16 GMT -8
|
|
|
|
Post by firewatcher on Oct 7, 2016 3:33:41 GMT -8
Lawry, your bricks look fantastic...glad to see that you're having success in making your bricks!
|
|
lawry
Junior Member
Posts: 113
|
Post by lawry on Oct 7, 2016 6:00:40 GMT -8
Lawry, your bricks look fantastic...glad to see that you're having success in making your bricks! Thanks firewatcher. A friend was telling me that they were around a firepit enjoying the fire. While chatting, the firepit (normal concrete) exploded and sent hot coals 6 feet high and around. The explosion exposed the rebar! My point being Geopolymer concrete should be THE solution for such applications. I haven't had a puck explode on me while in the fire curing... |
|
|
|
Post by coastalrocketeer on Sept 23, 2017 0:23:46 GMT -8
Just went back and your geopolymer board is gone :-(
Sad to see the wealth of advice you'd put up gone, as well as the advice you so kindly gave me. Hope you are well Karl?
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Sept 23, 2017 6:23:21 GMT -8
The genetic lottery made me to the biggest winner and the biggest looser, all at once.
There's no hope of escape, there never was.
|
|
