The StudioBuild Buffon residence project is underway. Unfortunately the mixing paddle broke on the first spray coat and by the time we got a new one from the hardware store it had been mixed too long. I ended up shooting a face coat that was way too wet and kept clogging in the gun. We stripped the forms, polished and fill any holes, but it just wasn't perfect. So here is take two.
This is a dark grey GFRC countertop. The face coat is sprayed and the backer coat is hand packed. The face mix uses Type S mortar, portland cement, and latex from home depot/lowes. The face coat also uses black pigment from the local decorative concrete store, high range water reducer which you can get on the internet, and metakaolin clay also found on the internet. The backer mix only uses Type S mortar, portland cement, latex, glass fibers, and water reducer.
The nice thing about the GFRC mixes is that they aren't full depth so you can fill the mold with water during curing.
The fresh concrete is placed over the side of the forms and then ground off flush after 1 day.
This is not the best picture, but here is the top. The white swirls are the paste wax we used as form release. After curing wet under plastic for 7 days, it will get a light polish 400-1800 grit before sealing.
What kind of consistency do you need to get it to flow through that gun?
ReplyDeleteI've been trying to pour tops for weeks and everyone I do has bug/pin holes all over. I've vibrated them. I've added a defoamer densifier, superplasticizer, and tried packing it down by hand in a drier mix and letting it flow out in a wetter mix. I am losing my mind but I guess that's part of the process... Right? I've had ok luck just filling the holes with slurry but there are so many it takes more time to fill holes than it does to do anything else.
I have read your entire blog twice, and probably everything else I can online and I'm still having trouble with a solid cast. Is spraying in a face coat the way to go? I like the idea but I'm afraid to try it and fail at it too.
Thanks for sharing your knowledge. Trial and error is starting to get the best of me.