Is Acid Washing Recommended For Pebble Plaster?

[mrsfluff]

Hi all,

I am here to gather a consensus of opinions from the veteran pool guys of TFP.

Acid wash pebble plaster? Is it recommended for routine maintenance? Do you have any personal experiences to share?

 

[AQUA~HOLICS]

Routine maintenance, no.
Any type of acid wash removes surface product including the plaster that holds the exposed aggregate in place, in turn creating a more aggressive feeling to the surface.

 

[mrsfluff]

Routine maintenance, no.
Any type of acid wash removes surface product including the plaster that holds the exposed aggregate in place, in turn creating a more aggressive feeling to the surface.

Thank you for your input! I was told that once the acid is applied, it "resides" in the plaster, slowly eroding it away. Not only will pebbles fall off, but the plaster will eventually, too. Even when done properly, it is contraindicated for pebble. I gather it is a very delicate process that one must be experienced in performing. Is there any time an acid wash would be recommended for pebble plaster? I cannot imagine it would be recommended for anything considering the damage it could easily cause.

 

[AQUA~HOLICS]

I have done acid washing of pools and yes with time comes experience of the process and mixtures that are specific to your finished outcome.
The washes I have been involved with had typically two reasons for the wash, removing calcium or stains.
Exposed aggregate finishes do not show these two situations as vivid as a Marcite finish.
The existing visual problem has to be weighed against the hopeful outcome of the wash.

 

[mrsfluff]

I have done acid washing of pools and yes with time comes experience of the process and mixtures that are specific to your finished outcome.
The washes I have been involved with had typically two reasons for the wash, removing calcium or stains.
Exposed aggregate finishes do not show these two situations as vivid as a Marcite finish.
The existing visual problem has to be weighed against the hopeful outcome of the wash.

Pretty much as I figured based upon my research. I have read that the plaster must be on its last leg before resorting to acid, that there are other, less aggressive means for stain removal, AND to NEVER use acid for maintenance.

 

[mgtfp]

Pretty much as I figured based upon my research. I have read that the plaster must be on its last leg before resorting to acid, that there are other, less aggressive means for stain removal, AND to NEVER use acid for maintenance.

If on its last leg, then you'll really be cutting that last leg off with an acid wash. Any acid wash will reduce the lifetime of any plaster based surface. Especially with old plaster I'd rather put up with stains than doing an acid wash.

For metal stains, there are other treatments (like ascorbic acid for iron). An acid wash will simply remove a layer of plaster, taking the stains with it.