Lately I have added many new species of SPS to my coral collection so I have decided to build a new grow out tank. I picked up a 240 gallon acrylic aquarium off of craigslist for cheap but it was pretty scratched up. Since I would like to be able to take macro shots through the acrylic I did some research on buffing acrylic to improve the clarity. This article is the results and steps I ended up with by copying the instructions found on this video: https://www.youtube.com/watch?v=QnIwVp2a7F8. Overall with a few tweaks it worked out great, full credit and thanks to this video on buffing acrylic!
To start out you can see here a very scratched up aquarium. This is usually what happens when people try to clean acrylic aquariums using glass scrapers or getting sand trapped in magnet cleaners. Below are a few pictures of what the tank looked like after pickup. You can see the many scratches and why I had to do research on buffing acrylic in the first place.
From the videos suggestions I picked up the 3M 2000 grit and 1000 grit sandpaper. These are used with an electric handheld sander.
A polishing tool which is used in an electric drill.
Polish for buffing Acrylic. This has made me a little nervous to use on a future reef tank, but with extra rinsing and cleaning on the acrylic before adding saltwater and corals I’m sure it will be fine.
Before you start with the sandpaper I would recommend starting with the polishing tool and seeing if you can buff out your scratches before anything else. This didn’t work for me personally since the scratches were so deep but if there is no reason to tear into your tank with a sander then all the better.
I decided to start with just a small section and work through all the steps of the video in case something went bad I wouldn’t have destroyed the whole tank. As mentioned above I tried only buffing out the scratches first with no luck. I then moved to the 1000 grit, which I unfortunately still no luck.
In the end I had to buy 600 grain sandpaper as well since you can see the scratches were still to deep for the 1000 grit sandpaper.
Once i figured out I was going to have to go through all steps outlined in the video above here is how I did it.
Step one of polishing your acrylic is getting a spray bottle (pictured above) and coating down the acrylic where you are going to begin sanding with a mixture of water and a very small amount of soap. This keeps your electric palm sander from snagging in one spot and allows you to wet sand.
Next you will want to put your lowest grit sandpaper onto your electric sander. The lower the grit the rougher the sandpaper. This will allow you to get the deeper scratches in your acrylic but it will also make the tank more cloudy to see through. This is why you will have to sand your tank multiple times from lower grit to higher grit. In my case I went from 600 grit to 1000 grit to 2000 grit and finally polish, with each new sanding round the tank became clearer to see through.
Begin sanding your tank. I found what worked best for me was long top to bottom strokes of the sander over one area working from one side of the aquarium to the next. After my first round of 600 grit sandpaper I noticed that the left side of my tank (where I started) looked much better than the right side of the tank. I attributed this to me starting out very carefully on the left side of the tank but rushing by the end of the first round. I went back and made sure that i have each section of my tank at least 15 strokes of up to down sanding. This helped me sand the same amount on the whole front pane.
Once my 600 grit round was completed i went and wiped away all the soapy water and acrylic with a microfiber towel as instructed in the video. I assume this is so that any acrylic filaments you created do not cause scratches on the next round of sanding.
After wiping down the front pane I began another round of sanding with the 1000 grit using the same up and down method I used before.
Once that was completed i wiped everything down with the microfiber towel.
One last time for sanding with the 2000 grit and finally the sanding stages were done. I would like to say this was a quick process but I spent many hours sanding out scratches on the acrylic.
After giving the acrylic a very thorough wipe down with the microfiber towels one last time I was ready to begin polishing the acrylic. Using the polishing tool I put a small squirt of the Meguiars Plastx on the Powerball Mini and began polishing the acrylic. Spending as much time in one area as I did with sanding, I would move the Powerball Mini in a circular pattern over one area until all of the polish had begun to clear onto the acrylic. I buffed the inside of the front pane and the outside of the front pane both.
After I was finished polishing I wiped down the pane with a clean microfiber towel. I then filled the tank up and drained it a few times wiping more on the acrylic while dry and also filled with water making sure to get any left over residue from the Meguire Plastx. The images below is what I ended up with, I am pretty happy with the results. There are a few scratches that I have found but since 600 grit wouldn’t get them out I am just going to live with them for now.
I am in no way an expert on the subject of acrylic work but by following the instructions in the video I think this tank was restored pretty well!
After looking at the acrylic more and more I had decided that while it did look nice it was not clear enough to take pictures through. I spoke with a local acrylic tank builder and they suggested sand the tank by hand.
So I did the whole tank again, still using the methods found above except for the power sander.
Started with 600 grit and sanded in an up and down pattern.
Next was 1000 grit paper and per the acrylic this one was sanded side to side.
Next was 2000 grit paper up and down again
then finally 3000 grit side to side.