Sanding Plexiglas/Acrylic of Shower Enclosure?

[ScotF]

We have hard water where I live and it has left deposits etched into the sides of the plastic enclosure.  No amount of chemicals or scrubbing gets rid of them.  I was thinking of trying to sand them out.  What sandpaper would work best for this purpose?  I was thinking Granat might be an option, but I am curious if anyone has sanded Plexiglas before and what grits worked.  I did a test piece and was able to get it from frosted back to clear and shiny going through all the grits up to Platin 4000, but the Rubin paper I used for some grits loaded up quickly and just did not cut as well.  Brilliant was OK as was some of the Titan paper I have, but it is a 5x6 foot area (roughly) that I need to sand. 

Thanks in advance,

Scot

 

[Alan m]

hi there.
as far as getting it clear it should be easy with the right paper.  i would try the granat . that stuf is great.
i have heard of people using brasso to do this but havnt tried it. maybe a polishing mop etc would work for you

as far a getting it back to normal goes.  sanding will only create little dipps where you sanded areas and not others. this will cause the light to go through it differently and make it distort the light. it will look ripppled . kind of like old glass. maybe if you did that to the whole piece it might look intentional.
is it posible to take out the piece and put it through a thickness sander.

 

[ScotF]

Thanks, Alan.  Unfortunately I cannot take it out and it would be too big to go through a sander so I am limited to the powered hand sanding approach.  It is just going to take more elbow grease than I thought and I think I need to try some different papers that cut better. 

Scot

 

[atomicmike]

I second Alan's suggestion to try Granat. The abrasives guide in the catalog lists it as "for sanding and finishing clear coats, plastics, solid surface materials, acrylics and composites." Sounds like it would be exactly what you need.

 

[LBIsackson]

You can try liquid abrasives and use a buffer... They use it on glass to get scratches out... All sorts of automotive polishes with various degrees of grit...

 

[clinto]

HI

I just recently did acrylic on some motorcycle headlights.  I had bought a motorcylce that has been crashed and was repairing it as a project.  The headlights had broken tabs and was scratched all over the front lens.

I repaired the lens with my RO 90 and EQ150used some 240 grit to remove the scratches and then stepped up to 4000. 

I took it up to 1500 dry with extraction.  Then used the Platin 2000, 3000 and 4000 wet.  After that I used the RO 90 and with 5000, 8000 and 11000 polishes on a couple of different pads.  It came up as good as new, with no visible scratches or sanding marks.

however, it was a much smaller surface area to yours I guess.  Probably all up it took me an hour.  then another hour or so with my plastic welder to repair the tabs etc.  which was much better than $350 for a new one.

Clint

 

[fshanno]

I just did the headlight lenses on my 2002 Impala with my ETS150/3.  They were terrible.  It was getting dangerous.  Started with 220 and then used 400.  Finest grit I had was 400 so I finished with an $8 Turtle kit.  Came out pretty well.

 

[extiger]

I did plenty of the same work on automotive restoration. The key is to shift that gear in your head to accept the notion that polishing/sanding/grinding are the same process. Dilineated only by grit size. Nothing more.

With abrasive papers, work down as close as you can get to the equivalent of 400 or even 1200 wet/dry automotive sandpaper. Then when the surface is relatively bump-free and flat, get some McGuire's Mirror Finish liquid polish at the auto parts store and buff to a luster.

My close friend is manager at the Ferrari of Beverly Hills service shop. That's what they use.

 

[Michael Kellough]

I did plenty of the same work on automotive restoration. The key is to shift that gear in your head to accept the notion that polishing/sanding/grinding are the same process. Dilineated only by grit size. Nothing more.

With abrasive papers, work down as close as you can get to the equivalent of 400 or even 1200 wet/dry automotive sandpaper. Then when the surface is relatively bump-free and flat, get some McGuire's Mirror Finish liquid polish at the auto parts store and buff to a luster.

My close friend is manager at the Ferrari of Beverly Hills service shop. That's what they use.

Good point! The "active ingredient" in liquid polish is the fine abrasive suspended in the solution. The wiki entry for abrasives is short and clear.

 

[mouppe]

When I used to make model cars, the last stage of the painting and polishing process was to buff with toothpaste which of course is also a mild abrasive!

 

[extiger]

At my airline, out in the hangar, we had a paint shop. One of their messiest jobs was the polishing of the windshields removed from jet cockpits. The glass laminate was about 15mm (more than an inch). And they would remove the effects of debris and bugs hitting it at speeds close to 500 mph. Those windshields cost thousands of dollars.

They used a compound produced by the 3M corporation. I had one of the painters there spray an old Volvo I restored for my son. I asked him questions while he worked away at a spray booth we rented. He said the polishing compound they used wasn't much different from products you can buy at your auto supply store. Serious auto collectors lean towards the McGuire line of compounds.

If you want take a fancy route and spend extravagantly go to the website for Griot's Garage. Many choices of abrasives, polishes and waxes. By the way, I used Glasserit (from Germany) clearcoat paint to finish my dining room table. It is laminated Maple. The spraying was done in 1999 over a single coat of sealer. The top is still beautiful and flawless after 12 years of hard use. I did not polish it. Glasserit, for those of you who don't know, is the brand used by Porche and BMW.

 

[Jonhilgen]

Question, can you use this on glass shower enclosures?  Same problem with hard water deposits in my shower.

Jon

Edited for spelling

 

[extiger]

Sure. Glass, plexiglass, lacquer paint. I believe the results would be less satisfying on any surface that is soft and squishy. For the same reason that sandpaper loads up heavily when working on house paint.

Your eyeglasses are probably made of CR-39, an acrylic similar to Kevlar. And you have to see clearly through them. They were ground using lap polishes. Polish just won't remove deep cavities or visible pitting.

 

[Michael Kellough]

Wiki on CR-39

 

[ScotF]

I have had limited success with this so far....I tried some polish and it actually looked great when I finished, but as soon as I got the enclosure wet again it started to wash the polish away and it went back to the hazy finish.  It was a lot more work than I anticipated and removing the scratches takes forever.  I tried going up in grit all the way to Platin 4000, but it is hard to get rid of all the fine scratches and I was burning through abrasives at 400 grit and higher.  What is weird is on my test piece I went all the way from 180 up to 4000 and it looked just like new (without polish) but for some reason on a larger area I cannot get the same results.  Maybe because it is vertical?  I will try it again in time and maybe give some other types of polishes a go to see if I have better luck.

Scot 

 

[peter halle]

Scot,

You might want to look at this link:  Hasslefactor's Shiney Boat Project and also send her a PM asking advice.  I know that in several of the threads about this project there was talk about different polishes etc. and durability.

Peter

 

[ScotF]

Thanks, Peter.  I will check it out and see if I can get some better results. 

Scot

 

[extiger]

The saying goes in car finishing, sand until it looks as smooth as a baby's butt. Starting from the coarsest grit of abrasive, get rid of the scratches. Stop for a bit, wipe with a wet rag and determine if you are ready to progress to a smaller grit. When it is wet, you just want SMOOTH at the first stage.

Change grits and your next plateau (viewed wet) should be BUFF). By now, there should be no high/low ridges delineating a scratch. Chant to the next finer grit and sand until you get DULL SHINY (viewed wet). Drop down a grit size and sand until you get SHINY.

Now you are ready for polishing compounds. This progression will be obvious to you. At each stage, wipe with a wet rag and review your progress. On race cars, and perhaps on your shower, your ultimate fine polish can be plain old powdered corn starch. Make a slurry. It has the equivalent grit rating of about 10,000 or 12,000 honing stone. Again, they use this method on Ferrari's displayed at shows.

And you thought only the rich can have fun.

 

[extiger]

One last thought. If you have progressed to the finest sandpaper and the finish is still dull, polishing compounds might be too mild. It sounds as if you still have scratches. Minute ones.

At an auto store, buy some DuPont Polishing Compound. This is a liquid that is between fine polish and sandpaper in abrasive quality. But go real easy. Seriously. Polishing compound used with a machine buffer will burn through 1/64" of paint in a heartbeat. Try rubbing it by hand using a rag and then progress to other polishes by hand or machine.

 

[mohrab]

This isn't sanding but related... I like to shave in the shower but my mirror attached to the shower head often gets a chemical build-up making it hard to see.  Someone suggested that I cover it with shaving cream, let it dry some and rub with a damp cloth - worked great, have been doing it ever since.  After reading your post I noticed my shower head wasn't it the best of shape either so I covered it with shaving cream and rubbed it down - it removed a lot of the deposits but wil probably need a few more applications.  You might try it and then sand if your have to.