Suction

[Gimpy]

As I'm not a spread, the only suction I have in my life is when the other half has her mouth round my cock ;D ;D

Been reading a load of threads on the forums about suction. Reading how spreads use a coat of PVA, or 2 coats of it etc etc.

Now how does a spread know there's suction on a wall? How does one know if suction is strong or weak, how does a spread find this out??? Is it purely experience or is there a technique?

Might be a silly question, but I'm very curious

 

[beddy]

pretty much experience mate. it all depends on what paint is on the wall already etc. for skimming or for floating what the wall is eg thermalites. just give it a coat of pva and see how it pulls in. if it sucks it straight in then you will need to give it another good coat. if it stays wet for a while before going tacky. one coat would do

 

[olie501]

put pva on let it dry,flick watder at the top of the wall , if it runs all the way to the bottom , another coat of pva , when it goes tacky fire it on, if the water doesnt make the floor ,another coat needed.

 

[Gimpy]

Cheers chaps. What does WBA do then? Does it do the same job as PVA? And how about Thistle GypPrime? Do they all do the same job or do they do a totally different job all together?

 

[RMK]

WBA and thistle bond-it are the same. Think theres even a Knauff version too. They say that they prime the wall, control suction, provide a mechanical key ready for plastering.
In reality... they are rubbish for priming, the bits of sand in them create problems if you're doing any patching etc, and they recommend to apply the stuff 24 hours before plastering.

I used to HAVE to use it allllllll the time cos the gaffa insisted on it. Now I use pva for around 90% of jobs. Priming coat, then bonding coat, sometimes a scratch if wall needs it.

Hope this helps!

 

[lucius]

Interesting comment RMK personaly i find bonding agents far superior than PVA only prob is that they are overpriced.

 

[The Apprentice]

Test for suction by gently flicking water on to the wall, the further it runs down the wall the lower the suction. Personally, unless on aircrete blocks when I give it a couple of coats of PVA at 6:1, only use water to control suction unless plastering over plaster, artex, tiles etc and never on old brickwork or blockwork.