Sealant = sealant Bonding agent = for BONDING Bond-it = bonding agent(from thistle's site) PVA = Sealant and Bonding agent. I cannot say more. Mr. HandyAndy - Really
No, that's not what I'm telling you. Not always. In the case of non-porous surfaces, yes. That is what bond-it does. That is what PVA does. In the case of porous surfaces, no. Prevent suction. That's what PVA does. Mr. HandyAndy - Really
That's what I've been saying!! Suction control!.......... It doesn't stick the plaster to the wall though. That's why you need some suction
Don't take the p. Read the info on the websites. They say it. You seem to believe everything the manufacturer says, I'm just repeating it. Mr. HandyAndy - Really
I don't believe everything the manufacturer says. If I did I'd be telling you not to use pva at all and use gyprime.
In the case of POROUS surfaces, yes. For NON-POROUS surfaces, you need ADHESION. There is no requirement for suction control here. That's why you PVA or Bond-it. For adhesion. There is no suction on non-porous surfaces. Mr. HandyAndy - Really
I'm glad you said that. So on non-porous surfaces, applied pva, what then creates the adhesion of plaster? Mr. HandyAndy - Really
Put a piece of paper in a sieve The piece of paper is the new plaster The sieve is the old plaster Get a Hoover on the opposite side of the sieve You will see how suction works The piece of paper (new plaster) will be drawn towards the sieve (the old plaster) by the Hoover (the suction) This creating adhesion
No try replacing the sieve with a bowl, this will be your non porous no suction background When you put the Hoover on the opposite side now your piece of paper (the new plaster) will not be drawn towards the Hoover because the no porous surface has killed the suction So this is when you use blue grit etc. to create an alternative key you wouldn't use pva on this type of background
Now line the sieve with pva and the bowl with pva. Then apply your paper(the new plaster). It sticks. Suction or no suction. It's called adhesion. Mr. HandyAndy - Really