Spray Washer Papercrete
(Spraypercrete)
Almost all of the pictures on this site are 3D Crosseye View
Obtain one of these:
These vary in price from $150 to a couple of thousand dollars. I try to get the best tools I can afford, knowing that better tools do more of the work for you, so I got this mid range Karcher
4000 PSI 3.8 GPM with a 50' hose so I can work a fair distance from the truck without even unloading. Actually, the method I chose for this project is to park the truck right next to the slip form and mix on the flatbed so I don't have to unload anyway. This will work for the first half of the project and a little adaptation should get me through the second half.
Karcher pump, Honda engine, more than enough pressure and flow to make some good papercrete.
Slip forms don't have to be complicated. This one is made from an old swimming pool ring. Plywood works well also. The other side of this form is a piece of stucco mesh, which can be peeled off and reused elsewhere once the papercrete sets.
One end of this pour will tie into a big column, so the extra metal made a convenient stopping point.
I'm mixing in a plastic drum with a hole cut at the bottom of one side. I cover the hole with a plastic rectangle strapped into place. This barrel gets between 1/3 and 1/2 full of paper, depending on the type of paper. I'm recycling a couple of piles of scrap and waste from other projects into this one, along with newspaper and other donations. Using the power sprayer I can turn this into nice smooth pulp in just a few minutes, adding 25 pounds of portland cement during the process.
This is a video of PC dumping out of the barrel
Here's the form a little over half full.
Almost full. This section of 30'x3' varied in thickness from 12" to 30", and consumed 25 drums of papercrete, containing six sacks of portland cement.
The remainder of the dome will be poured 12" thick and will be faceted like the geodesic frame underneath.
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Update 20081016
(pictures in "X" view 3D)
Another couple of days of work and that form was topped off. The metal form was moved up to the top of the pour and resecured for the next pour. The bottom pour has some wide places that will act as shelves for plants, etc., but the remainder of the dome will be restricted to 12" thick.
We had an uneven top, but that's no problem with papercrete. We just plugged the gaps with chunks of pc that were lying around.
It's easy to see the layering from each day's work. I considered rubbing the wall smooth but I like the texture. I'll possibly go ahead and rub it. The slight undercut was caused by a bend in the metal form. At that point the wall is close to 24" thick, so that slight undercut won't have any effect.
Here's the mixing barrel being filled with recycled pc chunks.
(no, that's not me, it's this guy who helped me out for several weeks on this project)
This is a view of the platform that we made for the back of the truck to get the mixer up above the form. I hate lifting wet papercrete, and just dumping is a whole lot better.
The platform is based on four bus seat frames wired together (someone stole my welder) and then a couple of pallets strapped down to the seats. It is amazingly stable with a full barrel and a couple of workers on top of it.
Here's the barrel in mixing position and ready for some spraying. The sheet of tin extending to the right acts as a chute to direct the dump into the slip form.
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Update 20081027
Some of the formwork surrounding the door. On the left I am using triangles that were cut for a 20' dome and never used. They make a nice shell 12" out from the dome.
The buttresses are for extra strength in the area around the door frame.
The slip form was moved upward about 1' to match the bottom of the next row of triangles. It easy to see the shelf formed when the slip form was allowed to move. After this pour is complete then I will use more plywood triangles to match the other side. The plywood triangles will be removed after the pc sets up.
The form for one of the buttresses, and the front stoop.
The other buttress form, and stoop area.
Higher angle with the end of a poured wall visible. This end will be encased in the door frame.
Looking into the buttress form showing the pipes that were driven into the ground to act as anchors.
A closer look at the end of the wall. This was encased in the door frame column, and I'll have more pictures early next week.
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20081106 Update
Got a few pictures yesterday, though not too much work done as it was windy and generally unpleasant with a cold front blowing in. I spent a while working on forms around the door.
My helper had to leave, and I realized that I needed to improve my methods so I could work solo. After a little thought, I decided to make a filtering system to prevent pump clogs, and start using the trash rated pump again. I put a plastic drum on it's side and cut a 8"x30" hole in the side. I covered the hole with some 1/2" hardware cloth, and another drum with a matching hole. I cut a 10"x30" hole in the top of the top drum to dump papercrete into. Since the drums are 24" in diameter, the stack is 4' tall. A few pallets on the flatbed truck get me high enough so I can continue to mix and dump, but not have to get increasingly higher as the forms move up.
I tested the system on Monday with a few loads, and it works well in spite of a couple of bugs I will work out tomorrow. One is the seal between the barrels, which has enough gap to leak a lot of papercrete onto the ground. I think a can of spray foam will take care of that for me.
The piece of metal acts as a splash board when I dump into the barrel, so that almost all of the pc ends up inside the top barrel.
You can sorta see the 1/2 mesh in the bottom, along with the two cans of spray foam I temporarily put there until I get back to it. That gap has to be sealed.
Peeling away the metal form to expose the newly poured wall section
Part of the uncovered section, about 7' tall so far.
The production system, spray washer and trash rated pump.
Part of the formed section waiting for pc. These triangles were originally made for another project that never happened.
The wall with the filter barrels in front of it. The barrels are tilted so the pc will flow towards the pump.
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20081216
I've been working off and on, have had a few distractions with the holiday season and studying for exams so I haven't taken the time to update here. I did put together a quick slideshow of progress right before Thanksgiving, and put it here. There are comments on the pictures that give a little idea of what I've been up to. I also redesigned the filter barrels but didn't take pictures as I did it so words will have to suffice. I wrapped the top barrel with 1/2" mesh and screwed it in place. Then I cut a wider opening in the bottom barrel and attached the top barrel so that its bottom opening was well within the opening in the bottom barrel. No more leaks between the barrels. I do have to spray wash the papercrete through the mesh, otherwise it just sits and drains. Larger mesh would probably lead to more pump clogs.
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I'll update as progress and pictures are made.