Now we go back to the "don't use too much pva" You have a porous surface and you seal it so much it becomes non porous so you have no suction
But you don't use pva on walls with no suction! You use bond it etc. If you have no suction you plaster tears when your troweling up
The pva is to close up some of the holes in your sieve (seal them) so you don't have too much suction
Not to do with plaster, years ago I had to replace a terracotta tiled floor, we took the old tiles up, clean the existing concrete base ready for new tiles, the customer who was a scientist told us in no uncertain terms not to use PVA on the existing concrete and to only wet it using water and then bed the tiles, when we questioned this he explained that PVA was not a glue as such and would not aid the skicking down of the tiles, he said it would have the opposite effect and form a barrier between the concrete and the tile adhesive of which neither of them would stick to, were as water would evaporate slowly allowing the adhesive time to bond with the concrete. ???
No. Yes you do use pva on non-porous walls. It gives adhesion where there is no suction. Yes you use pva on porous walls. It prevents too much suction and aids adhesion. The grit in bond-it further aids adhesion. You know it makes sense. Mr. HandyAndy - Really
Exactly Phil, so by pvaing your sieve you are only sealing some of the holes, this allows some suction to adhere the plaster but not so much that there is no suction
No, pva is only for controlling suction. If you have no suction you have nothing to control If you have no suction you have no key So you use bond it to create a key which doesn't require suction
I feel like a fish in a bowl, I'm going round and round in circles. But you are understanding more the dizzier I get.