How to vibrate a countertop made of expanded concrete?

[nybyggarn3]

Hello,
I'm working on my outdoor kitchen, which includes many meters of concrete countertop. I've cast a part that turned out quite well. There are some small pores in some areas. I could reach the underside of the form and tap it with a hammer.

Now I'm going to cast the next phase and need to set the form on the finished slab. This means I won't be able to tap the underside of the form. The question is, how do you do it then? My feeling after the first phase is that you don't get the same effect by tapping the sides of the form.

Any tips?

 

[FredrikR]

I vibrated with a reciprocating saw without a blade against the mold.
Worked well for me.

 

[nybyggarn3]

I vibrated with a reciprocating saw without a blade against the mold.
Worked well for me.

Thanks. Did you run it on the mold's sides?

 

[FredrikR]

Thanks. Did you use the sides of the mold?

On my mold, the bottom extended out beyond the side walls so I could reach and vibrate there.

 

[nybyggarn3]

On my form, the bottom stuck out beyond the side walls so I could reach and vibrate there.

It will do the same for me, and I can reach there. So you mean that was enough to avoid getting a lot of holes?

 

[FredrikR]

It will do for me as well, and there I do have access. So you mean that was enough to avoid getting a lot of pits?

I must have messed up when the first bag was mixed, it was much more solid than the other 2.
The surface became porous where the first mix was scooped out and good where the rest was poured out.

 

[z_bumbi]

A vibrating sander also works on the sides of the shape, run without paper.