How to sand plaster?

Malia · Postby **Malia** » Fri 03 Apr, 2009 12:03

I'm new to this forum and after exhausting internet searches I've yet to come up with a method of sanding calcium deposits off without harming my plaster. Has anyone here ever successfully done this? I originally planned to get a pneumatic orbital sander to remove it and then do a light acid wash. Is this the right method and if so, what kind of sanding disk should I use?
Thanks for any help.

Malia · Postby **Malia** » Sat 04 Apr, 2009 10:33

Hmm...Guess I'm on my own.

Postby **Larry** » Sat 04 Apr, 2009 12:02

We have never had any success with sanding despite trying a variety of disks and brushes. An acid wash can be tricky and dangerous, but it is the sole method we use for removing scale deposits.

Although it can harm the plaster, an acid wash causes less damage than the sander or sanding disks/ brushes, which tend to dig into the plaster and gouge out chunks at times.

I have heard that sandblasting can successfully be done but we have never tried it.

Larry

Aquaclear-NZ · Postby **Aquaclear-NZ** » Tue 14 Apr, 2009 03:39

as Larry said there is no easy way
last season we had an experiment with a Lo-Chlor product called Nail the Scale, with mixed results, in about 50% of the cases it worked well, 25% little change and 25% no change

the ones that worked, worked very well with large deposits softened to a point where brushing with a wire algae brush removed the softened deposit

DiamondBrite was experimenting with an additive to help soften the deposits as well (Lo-chlor blended this proprietary product in with another of their calcium scale removers)

Sulphumic acid is also very effective on calcium

blakeusa44 · Postby **blakeusa44** » Sun 15 May, 2011 11:32

You can wet or dry sand the plaster using 220 grit + and a soft backed buffing pad. Use a 7" polishing tool with a low speed. Just take your time. There is no other way to remove heavy scale.... acid only gets the top surface. Acid wash after. Wet sanding is best to keep the dust and heat down. Also wear a respirator.

A diamond wheel is the best but expensive... and it needs to be flexible- not rigid. Use baking soda blast on the tile line.

Kiwi Pool · Postby **Kiwi Pool** » Sun 19 Jun, 2011 01:40

You will never get this sort of problem if you use Pool Quartz which is a 100% Quartz plaster

kiwipool · Postby **kiwipool** » Sat 06 Aug, 2011 00:18

Anonymous wrote:You will never get this sort of problem if you use Pool Quartz which is a 100% Quartz plaster

Re the Calcium Build Up. There are several reasons the water and the type of plaster one manufacture recomends the adding of Calplus every 6 months.

There is one chap who Grit blasts (using glass beads) but this is mainly on the water line tiles, using acid well to suggest that you would need to be a total idiot because it will possibly do more harm than you have now.

I would like to know what type of plaster you have on the pool.

You give now indication to where you are, if you are in NZ call me. I may be able to help you.

pg · Postby pg » Tue 20 Sep, 2011 18:00

I have sanded using a 220 grit red oxide sanding pad on a pole with the pool full. It was hard to keep in contact with the plaster surface due to the hydro dynamics of the pad shape wanting to "fly' the pad above the surface but worked very well in the shallow areas where the kids toes get worn down to a nub. But the scale came back faster it seems. I have color quartz plaster, 2 yrs old and a salt system in the los Angeles area.

Postby **czechmate** » Wed 21 Sep, 2011 11:55

It is a shame to experience calcium build-up in a 2 year old quartz based plaster.
First year it is almost impossible to get CH so much out of whack. It means it was severely neglected for the second year.
Use the POOL CALCULATOR from now on to monitor your CSI.
It will protect you from future problems.
You can try to use pumice stone fashioned in a holder for the deep. Any abrasive will have an impact on the surface surrounding the spot brushed.
But that is the price you pay for leaving the maintenance to a unqualified pool guy or not taking time to learning it yourself.
BTW, always double check the "friendly advices" you receive, when it concerns adding chemicals to your pool.
(The Kiwi guy is a prime example. If you have calcium build-up you do not want to raise CH. and quartz plaster is NOT 100% quartz. There is still a portland cement holding it together).

pg · Postby pg » Wed 21 Sep, 2011 15:24

Thank you for your responce .
I do my own testing and check 2 time a week 7.6 ph was my target but now I am shooting for 7.2 as the plasterer said since I check so often.
What do you mean "POOL CALCULATOR"
And yes I am disappointed in the calcium buildup.

Postby **czechmate** » Wed 21 Sep, 2011 16:58

You Google POOL CALCULATOR website real easy. It will turn out to be your necessary and also simple, most efficient tool in taking care of your pool.
If you have a little time 3 times a week you can maintain your pool yourself with no problem. I would be weary about PH levels below 7.3 unless it is aimed at special short term goal. Pool calculator will tell you how it affects Calcite Saturation Index.
CSI is also the number that pretty much determines the lifespan of your plaster.
If you want to keep your PH more stable look into adding borates via boric acid or even by plain borax.
It will also have other benefits, like more algae resistivity, softer water and sparkling shimmering water on top. In colored quartz surface it has remarkable effect.

Good luck!

kiwi · Postby **kiwi** » Sat 24 Sep, 2011 23:22

So you have a Quartz Plaster or you think you have, it is possible that the Plasterer/Builder told you that you were getting that but you possibly ended up with a mix of maybe Marble with some Colored Quartz added along with a few other things to make up the mix, that may be silica sand, oxides just what is any bodies guess.

I guess you will just have to live with the problem, The adding of salt will not have helped in the early stages.

Really its like phoning the doctor and saying I have a lump whats inside. So live with the deposits.

Postby **czechmate** » Sun 25 Sep, 2011 21:46

"any bodies guess"???
You crack me up Kiwi. You should write for Jay Leno. In English

pg · Postby pg » Sun 30 Dec, 2012 00:53

Kiwi Pool wrote:You will never get this sort of problem if you use Pool Quartz which is a 100% Quartz plaster

Yea right, thats what they told me too. My plaster is 3 yr now. 100% Quartz plaster. It feels like 80 grit sand paper now. Our water is hard and I added a salt system that I am turning off after I sand the surface and refill. I used a pad and red oxide 220 grit on a pole and it worked well on the seats and shallow end. I am planning on draining, sanding with a wet 7' sander then light acid wash. I was told if you dont acid wash you can get the hard water to be attracted to the scratches the 220 can make.
I hope by not going salt on the refill and changing 1/2 the water every year I can avoid this in the future.
FYI I looked in the plaster truck and he only had cement, color and color quarts bags.

EW · Postby EW » Sat 06 Apr, 2013 10:30

I have a salt pool. Has anyone ever heard of using pool salt as the sand blast medium? It would be easier to have the salt dissolve in the pool then worry about clean up of beads and glass.