Thistle one coat - two coats?

[vengenerator]

Hi there,

At the risk of a stupid question...

I've used thistle one-coat to plaster around a window reval. Can I apply a second coat of one coat over the first? In some of the thistle product literature it says you can build up with several coats but doesnt say how you should do this.

Would I need to PVA or wet or can I just skim directly over the first coat?
I put the first coat on yesterday evening would I be able to plaster over it tonight?

Thanks very much for your help
V

 

[roy c]

Thistle one coat can be built out to 2" but you have to build it out in stages, you can lay a thickish coat on and scratch it, let it pick up and firm up them lay another coat on and so on till thickness is achieved. But it is not always practical to build it out to such a depth. You should be able to lay your one coat on to the existing coat without pva or wetting down (I used to use it a lot when it first came out in the 80's) but plasterers did'nt seem to accept it so it didn't catch on as a vioable method as opposed to all the other backing plasters and float and set. It was used alot on big contracts (especially in Europe) and was put on with an elephant pump and the spreads followed behind. But what you have to do is put the top coat on and rule it off and when it firms up a bit (not changes colour) and you get a sponge float(this was what the sponge floats were for when they came out!!) and dip it in a bucket of water and take the excess off on the corner of the bucket and start floating your wall up with it . You will find that it will bring a lot of white bits to the surface leave it for a while then go over with your trowel and you will find that it will flatten out , leave it again then flatten again. You should be able to do this before it changes colour, it should come nice and firm and a good paintable surface ,last trowel you can wet your trowel if you want, sometimes you dont need to. Now this is the method we were taught by a representative from BG who went around showing spreads how to use it. It was basically a renovating plaster we always used to put a sand and cement waterproofed scratch on before we used it. Maybe a "belt and braces thing ". But I did actually like using it but it was never cost effective and was part of its down fall. Also it is called one coat because even tho you can build it up you can bring it to a finish ,so you dont need another plaster on it....

 

[joe-90]

Didn't know that about the sponge floats.

 

[roy c]

They weren't actually sponge joe they were rubber and a bugger to clean out after using them,,,

 

[vengenerator]

Thanks very much for the detailed response, much appreciated!

 

[joe-90]

Whatever you do, don't click the 'thanks' button on his post - he's trying to catch up with me.

 

[vengenerator]

Opps I slipped!