Spraying with the papercrete pump/sprayer setup 2/1/2009

This is a video of me using a commercial grade texture pump fitted with a home made nozzle and a 100 CFM air compressor to shoot papercrete onto a styrofoam board. This is a test run for the "scratch coat" that will be applied to an airform dome I made from parachute cloth. In this test, I could put the papercrete on about 1/4" thick before it would start to slide off, adding latex to the mix should improve the thickness per coat. I may also add a "lath" of bird netting to give the first coat something better to adhere to. This test papercrete was a mixture of paper, water, and portland cement. I was pumping from a 5 gallon bucket so it ran dry pretty quick, for production I will be shooting from a 50 gallon hopper or larger. See www.papercretedomes.com soon for all kinds of info on how to make a super efficient and strong dome out of paper and mud.

Category:

Science & Technology

Tags:

• papercrete
• dome
• construction
• homes
• green
• building

[sklarm]

Nice Work, Dave. Thank you for sharing your setup. I'm looking forward to seeing the airform receive a few coats. What mix will you use.

[AquaponicDave]

Thanks, Mikey. Back at ya.

I'll be using a prepared papercrete mix sold by Mason Greenstar, so I don't really know exactly what's in it (it's proprietary, although I have some ideas about what's in it). Their blocks are awesome, and I had a million other things to deal with so I wanted to reduce the number of variables by using a mix that has been proven already.

[sklarm]

I have seen the Mason Greenstar blocks and they are indeed impressive. I believe they are using a "tree sap" as the sort of resin bonding/sealing agent which is their secret ingredient.

[AquaponicDave]

I'd be interested to hear what mix you would recommend. I've had decent results with a 1:16 mix (16 parts thick paper slurry to 1 part portland, measured by volume). Haven't tried latex yet, but I can get recycled latex paint around here for free so I will definitely try it. I will also be going to a clay-based mix as soon as practicable, since portland is such bad stuff ecologically.

[vutEwa]

cool beans dude.  hope that works out for you! how much time do you think it will take to spray on 1/4" layers before you get a dome of the proper thickness?

[AquaponicDave]

The first layers will be thin, but subsequent layers should be thicker. The airform is slippery so the first coat can't be too thick or it will slide off. I have another pump which will put out more material but it has to be thinner in consistency, after the first 1" is hard I'll be able to put on layers of about 1" thick. Final thickness will be about 1'.

[kenwinstoncaine]

Hi Dave:

What commercial texture pump are you using? Do you think one of those allegedly 2800 psi paint sprayers that you can buy at Home Depot would work to spray a slighly sloppy papercrete slurry if you changed the tip to 5/8" -- thus avoiding the need for a compressor altogether?

Also, can you describe how you modified the texture sprayer tip?

[sklarm]

I'm used to measuring by weight so it is hard for me to convert to volume measurements. My new favorite mix is paper:clay:lime. I constantly adjust the quantities, but I love the smooth texture and low cost. This is a week mix compared to Portland. It is only used for infill. Prickly pear is fun if you have a chance read up on how to brew it.