Q: Would PVA sealer work as acrylic bonder?
A: PVA sealers do work, regular PVA wood glue will deteriorate over time when used with cement, But many PVA's are modified to work with cement products now.
Q: Will Darjit handle sub 0 weather?
A: It has handled sub 0 weather in the situations I have tested it in, I do use higher recycled paint contents 15-20%.
Q: How would we calculate how much or how large a surface, sculpture we can make with one bag?
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".
Q: How many lbs per bag?
A: A bag weights about 26 pounds.
Q: How long can the material last unopened?
A: It will keep at least 2 years. It does get smelly and discolors after a few months, but that doesn'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 indefinitely
Q: Any restrictions (out of the sun etc...) for storage?
A: Out of the sun is best. If you want to keep it indefinitely, open the bag and let it dry out completely, when you want to use it, soak it in water for a couple of days before mixing.
Q: What do if the coats don't bind or I get cracking
A: One reason the second coat doesn't bind to the first is if the first layer is 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, spray it on, this also extends your working time when your sculpting detail into your second layer.
Another reason for cracking in the second coat is having the first coat very smooth, and the second coat thick in some places and thin in others. Where it gets really thin it is 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 your 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 re-plastered 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 drys the crack usually disappears and I don't have to worry about cold joints.
The most common problem tho 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, thats bad!! can cause cracking/dehydrating
1. May I use concrete acrylic additive and ground cement pigments in lieu of the paint for the mix you prescribed. Do I use the same proportion of additive as the paint? YES
2. To adjust the consistency of the mix do I use water? YES
3. How thick should each coat be? First coat can be as thin as 1/8” to as thick as a couple inches to build up areas. Second coat should be at least ½” to 2” thick. ? Should I apply the first coat with a notched trowel? I like using the atlas brand gloves or tight fitting rubber gloves to apply both coats of Darjit. You can use a notched trowel if you desire. On finished coat you can use a piece of sheet metal to make a smooth texture or stamp it with leaves, rubber stamps, pine cones and whatever else you can find.
4. How long do I wait between coats? Until it stiffen up but not completely dry. It depends on the weather. I will guess with the way the weather in here about 8-10 hours. MAKE SURE YOU WATCH OUT FOR COLD JOINTS. Plan on one if you stop in the middle of you project and come back a day later. Only way to fix this is to create a crack effect or recover the entire finish coat with another layer.
5. Can Darjit be polished with very fine sandpaper? Yes, I don't like sanding because of the dust, I often do carving with wood carving tools to refine the fine details. You can buffer with a bees wax type product. If you want a polished smooth surface, my favorite tool is the back of metal spoon as the Darjit is setting .