AirCrete Form box
@upwinger I have experience using acrylic dividers in aircrete molds. We wrap our acrylic dividers with saran wrap. If the dividers are separated from the aircrete after 20 - 30 hours, there is no issue removing the saran wrap. The longer the aircrete is allowed to cure beyond 30 hours, the more work it becomes to remove the saran wrap. Separating the acrylic dividers away from the aircrete has never posed a challenge regardless of how cured the aircrete is.
Our dividers are 40 inches by 12 inches. We found it necessary to use spacers to lock the acrylic in place in the middle at the top and bottom of the dividers to prevent warping/deforming/bending.
These dividers are flat sheets separating rectangular blocks. We simply remove the outer form, then the blocks come apart easily thanks to the acrylic dividers. Our setup is the same as the one shown in the photos above, but on a larger scale.
@Zander Thank you! That is encouraging info about the use of acrylic.
Whats your experience with aluminum sheet? I was thinking that using 1/8" thick aluminum for a larger mold would not flex out from the aircrete pour, for use with my 4 arm compass idea. I have a TIG welder so I can weld on support tabs to attach 2x4 supports as the molds move up the wall.
Imagine a 4 armed octopus! A quadripus!! LOL
@upwinger I have no experience using aluminum. It sounds pricey, but it could prove to be a worthy investment.
I don't fully comprehend your vision. Are you expecting the aircrete to drop out of the form, or will you disassemble the form?
@Zander I suspect it will need to be broken apart to be moved to the next position.
I have the next few weeks off to dive in head first. I plan on making some big aircrete mushrooms
using aluminum bowls to find out if it sticks to aluminum. The mushroom stipes will be made out of pvc pipes so that I
can run some wires up to the caps and embed some colored lights into the mushroom caps. Big psychedelic aircrete shrooms!!!
@upwinger I built a second box (twice as big). This one has dividers. I wanted to make long blocks for building the arches. 5 1/2 inches thick x 11 1/2 x 30 inches long.
The dividers are made from 1/8 ply wood (underlayment). Everything is painted with an exterior latex paint. I wipe the interior down with vegetable oil prior to pooring to release the air crete.
@Jon-Bagpipes This is so amazing! Thanks for posting this and the images. I've been thinking about this as well but using a 3d routed mold so I can have flat sides and a curved side in unique shapes (thinking specifically about triangles for a bucky ball structure).
It's inspiring to see this - do you think that larger blocks or more unique shapes would cause issues? I was also thinking about using styrofoam and then lining it with an mold-release of some type... styrofoam is just so easy to cut and work with, and light, and it's easy to create layers for deeper structures on something like a 2.5D 8' x 4' CNC table... seemed like a good idea.
Haven't done a lot of work, mostly thinking so would love any thoughts.
If you use epoxy and fiberglass to make the stryrofoam shapes into a mold would be the way to go with that idea.
Its not a bad idea! You could really get jiggy with it!!!
@Jon-Bagpipes Those are some good looking aircrete blocks. Congratulations.
@upwinger I really want to try this out this summer... I need a staycation from work to do this work
We have an awesome makerspace (makerworks) nearby, and I'd like to build a dome which is a buckyball shape (strong, repeatable) with the largest blocks that 2 people could easily lift (perhaps adding metal inserts into the blocks to be liftable with a metal bar or something), where the outside is rounded but the inside has flat walls. This (hopefully) reduces the noise issue and creates vertical spaces on walls to install standard things like tables or hang pictures.
So the thought is use styrofoam sheets to build (from multiple sheets) a mold which is round on one side but flat on the other (the top facing side is flat, the bottom facing side is round).
I do think I'd need to use something like epoxy or something on the styrofoam to keep it from tearing off every time, but paining on a thin but strong layer definitely could work.
The action on here really keeps me motivated
@gbathree We know what's tried and true... the cool thing is that somebody may stumble on by accident a different way that may work as well.
Aircrete is a labor intensive, time consuming process. Experimentation is a requirement to get the recipe and process fine tuned.
It is a learning experience
I remember buying Portland cement 94# bags at less than $5.... now they are $16 per bag!!!
@Jon-Bagpipes awesome! Do you have an update on how it is holding up? How many batches have you made with the mold so far?