Sponge float sand finish problem

[Tman]

Hello,

I'm trying to match ten foot square area 1940 interior plaster sand float finish. From what I have heard, plasterers used to mix the aggregated basecoat 1:1 with gyp and apply that as finish coat and float it. Because of materials that are avIlable, I am using 1/2 structolite and 1/2 imperial veneer finish ( in USA) floated with fine green sponge float.
I can get the texture pretty close, but sponge
leaves light lines or trails in plaster from aggregate pulled or dragged down from sponge. Original plasterers work shows no trails at all, just a light texture of sand or perlite. What am I missing? Did those old timers also use a sponge, or did they use some sort of other float? Is my plaster mix ok u think? I am waiting to float until it's set up a bit, but always the same end result-- a sand float finish with lines that does not look smooth. Any ideas or help would be much appreciated.

 

[Loren]

I patch that stuff all the time. Thing that works best for me is I brown coat the patch level with the surrounding wall let it setup. Scrape the structolite so there isn't any overlapping onto the existing finish.
I then give the patch a couple of coats of all purpose joint compound, sand the surface so it blends into the existing finish. Next I take the thick PVA concrete bonder the white stuff, add to a scoop of all purpose compound and add a small hand full of super fine sand or #30 silica. Mix together so you have a consistency that you can use a 1/2 " nap paint roller to roll on a coat over your patches, vary your strokes & feather out towards the existing finish.

 

[leebo02]

i find foam (like the foam out of old settees) better than sponges

 

[malc]

sponge was not available to about 1960. in england the plasterers used a hessian bag filled with sand to give the final finish

 

[Tman]

Alright, I'll try that. Thanks for your time.

 

[Loren]

sponge was not available to about 1960. in england the plasterers used a hessian bag filled with sand to give the final finish

I guess I'm getting to be one now but when I was a LOT younger the old timers used to talk about using 'Carpet Floats' for sand finishing. I made one a couple of years ago and it can be pretty handy matching some of those old stucco textures.

 

[Tman]

I have come across a few mentions of carpet floats. Thinking this might be a good way to go and makes sense, I think, for the age of the house. I went down to the store and bought two feet of carpet I thought had a good texture (short and dense). Had no choice on looks, however, and will end up with a floral patterned float. We'll see how it goes. Thanks.

 

[jamesthefirst]

I would say the £39.99 a square yard off cut would be better than the £12.99

 

[Tman]

The carpet worked out. The problem before ( I now realize) was that the sponge did not quite allow enough time for the plaster to just almost set, whereas the carpet could be floated harder on the surface, thus bringing out the sand and giving that smooth texture without wet trail lines. The carpet float is all right. Matches nice, and only one purchase of carpet believe it or not.