Darjit                  

Q&A

Q: Would PVA sealer work as acrylic bonder?

Q: Will Darjit handle sub 0 weather?

Q: How would we calculate how much or how large a surface, sculpture we can make with one bag?

A: PVA sealers do work, regular PVA wood glue will deteriorate over time when used with cement, But many PVA's are moderfied to work with cement products now.

A: It has handled sub 0 weather in the situations I have tested it in, I do use higher recycled paint contents 15-20%.

A: One bag an even 1/4" layer will cover about 40sqft. It depends on how thick you put on your plaster layers, when sculpting shapes, you can build shape with stiff plaster up to 3".  

A: A bag weights about 26 pounds.

A: It will keep at least 2 years. It does get smelly and discolors after a few months, but that dosn't seem to affect it once it is mixed up and used. You can dry it out and rehydrate it when you want to use it and that way it will keep indefinitly.

A:Out of the sun is best.

A:One reason the second coat doesn't bind to the first is if the first layer is to dry, you get a moisture transference from the fresh wet plaster to the dry older surface. When your applying most plasters to dry sub surfaces apply a coat of concrete bonding adhesive/sealer, it looks like Elmer’s wood glue but it's made for concrete based products. I water it down 30% with water and sponge, brush or spray it on, this will also extends your working time when your sculpting detail into your second layer.

Another reason for cracking in the second coat is because the first coat to smooth or the second coat is thick in some places and thin in others. Where it gets really thin, is where it's prone to cracking.

Remedies for this depends on your surface treatment, if your finishing with paints, metal powders, oxide washes, mosaics etc you can fill the cracks if they are not structural and put your finish on. If you’re having a plaster finish you can cut back the plaster to a place in your design where you can hide a cold joint, or the edge of the repair patch, be sure to coat the areas to be replastered with the adhesive/sealer.

For fine cracks I often find the most effective fix is to rub more darjit into the crack, then sponge it clean like I was cleaning grout off tile. When the darjit dries the crack usually disappears and I don't have to worry about cold joints.

The most common problem though is your mix not being right, some part left out, not being mixed thoroughly, letting the mix sit to long with the cement mixed in and then remixing it after it has gone off to much.

If your work is in the sun, or it is really hot and dry with a moisture sucking breeze blowing, that’s bad!! It can cause cracking/dehydrating.

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