Getting a smooth texture

[boatbuilder]

Just wondering if anyone has any tips for getting a smoother finish on render?. I'm getting a rough finish - i.e. bits of loose sand on the surface - maybe its just that the sand is too coarse? I'm using plastering sand from a builder's providers. Its very sharp, in fact you'd slit your hand open if you ran your hand over the finished surface.
I've done a bit with 4:1 scratch, then 6:1:1 topcoat, floated with plastic float, then sponged over with a yellow sponge. Not sure what else I can do?

 

[S a plastering]

Change the sand it sounds abit too sharp my friend
Also using a sponge will bring bigger grain to the surface
I only float up my render I never sponge also it can weaken
the surface

 

[Rigsby]

If you cannot change the sand then replace one of the 6 sand with 1 of soft sand.

if it is still course then rub up and flatten with a steel or plastic trowel then sponge again preferably with a finer sponge. I use upholstery sponge. Some local upholster will sell you an off cut.

Too fine a finish will show slight shinkage crazing after rain if not painted.

 

[malc]

you rub it up a second time with a float and a splash of water , [to get water back in to the render], then sponge finish.

 

[User___removed]

Madmonk your finish must look **** without a sponge.also it won't weaken the surface.

 

[malc]

Madmonk your finish must look **** without a sponge.also it won't weaken the surface.

there was a lot of rendering done before sponges came out in the mid 60s.
we had to rub up with a hessian bag filled with sand

 

[Arti]

i defo prefer the finish of a diamond float to the sponge

 

[LongstrokePlastering]

Must agree, it all about the rubing up with a float for various reasons but even tho i know its wrong i love using a sponge instead. #reversepsycology

 

[Arti]

All that sun last week has sent you do lally marra

 

[User___removed]

yeah to be fair malc it probably looked shocking!!

 

[mplasterer]

I use a revolving machine float, does a superb uniform finish. I have the same kind of sponge float for the more awkward bits the machine can't get to.