Another acrylic scratch removal thread

TonyD1988

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Good morning R2R, I've read plenty of threads on here in regards to removing scratches in acrylic but I want to know if anyone has a "guaranteed best results" method that's going to work. The idea I currently have in my head is to wet sand using 600 grit sandpaper, and work up to 2,000-3,000 grit, alternating horizontal and vertical patterns between grits, and finishing off with novus 1,2,3. I am all for putting in the hours even if its by hand or with an electric buffer.
 
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TonyD1988

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Use novus polish only
Why do you say that? There aren't many scratches but there are a few semi deep ones. The previous owner says his kids got some sand stuck under the magnetic algae scraper.
 

lapin

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You can do it your way or the polish only way. What you want to do is remove the deep scratch then polish it smooth. Trying not to cause more damage that needs to be polished out.
Novus 3 will cause scratches. It has a lot of grit in it.
If the tank is small and not much damage you can do it by hand.
If its a big tank with lots of scratches a orbital buffer might be the way to go.
 

Justanano

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Sandpaper distorts more than it helps from everything ihave seen
 

lapin

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Sandpaper distorts more than it helps from everything ihave seen
I think because the OP is going to sand a wide area around the scratch by going in 1 direction then cross ways the distortion will be spread out enough to not really be noticed.
 
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TonyD1988

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You can do it your way or the polish only way. What you want to do is remove the deep scratch then polish it smooth. Trying not to cause more damage that needs to be polished out.
Novus 3 will cause scratches. It has a lot of grit in it.
If the tank is small and not much damage you can do it by hand.
If its a big tank with lots of scratches a orbital buffer might be the way to go.
yeah its an 8 foot wide 300 gallon. I will try just the novus 2 and 1 first and see how it goes. Would you recommend by hand or using a drill attachment?
 

ZoWhat

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+1 on using polish.

NON ACRYLIC related story:

My 08 Maxima headlights were yellow and horrendous looking. I pulled each headlight and started with 120grit sandpaper on an orbital sander, then moved to 220 sandpaper..... then bought a buffing pad that fit my electric drill. I bought Maguire's 105 cut polish, use it. Then used Maguire's 205 polishing cut as my final buff. The lens looked 98% crystal clear. I then put 3 light coats of Spraymax 2k clear coat 36800061 on the headlights and they look brandnew. Stunningly brandnew. Showroom brandnew.

Reason I say all this is the fact that buffing out acrylic should follow using a cut-polish that goes from a heavy cut to a polishing cream. I'm sure the tank builders probably use some kind of 3 step, 5 step buffing out process.
 

pdxmonkeyboy

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Random orbital sander... no need to change sanding directions. Dont do anything until you go to harbor freight and buy a multi speed polisher. I think it's safe to say that you will never polish that big of a tank by hand.

You need a ROS, 400,800,1200, 1500, 2000, and 5000 grit sandpaper, a spray bottle with water and a drop of dish soap, your polisher, and novus 2 (the light scratch remover).

Find the big scratches on the inside and mark them with tape on the outside. Start with 400 grit and use even pressure. Back and forth back and forth until the scratch is completely gone. Move on to the next scratch, do the same.

Now you need to remove the scratches from the sander. Spray all the areas you sanded and wipe with s cloth!!! (The grit from the paper falls off and you dont want to sand with 800 with bits of 400 on the panel). Sand with the 800 and slightly enlarge the area to feather it into the areas you didnt sand. Spray clean, then 1200, enlarging the area. Each successive grit will take longer because you have less cutting power and you have to sand through the precious grits scratches. When you get to the 2000 grit keep the panel wet while sanding. You can likely polish all the remaining scratches out after 5k but honestly I find it easier to wet sand with 10k then polish.

Amazon has the really high grits. Make life easy on yourself and flip and turn the tank so you are always sanding down... not trying to sand on a vertical plane.

Polishing is straight forward, use a low to medium speed. Reapply polish when you can no longer see it swirling around.

Then just polish the outside.

It will likely take 8 hours to sand and polish. If you go up to 10k before you polish I PROMISE that the tank will look even better than new.

Trying to take deep scratches out with polishing only has a higher chance of creating distortions because people tend to turn the polisher on its edge and go to town on the scratches.

While it may seem frustrating and you will curse acrylic, this is actually the beauty of acrylic.. you can fix scratches!!!
 
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TonyD1988

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Random orbital sander... no need to change sanding directions. Dont do anything until you go to harbor freight and buy a multi speed polisher. I think it's safe to say that you will never polish that big of a tank by hand.

You need a ROS, 400,800,1200, 1500, 2000, and 5000 grit sandpaper, a spray bottle with water and a drop of dish soap, your polisher, and novus 2 (the light scratch remover).

Find the big scratches on the inside and mark them with tape on the outside. Start with 400 grit and use even pressure. Back and forth back and forth until the scratch is completely gone. Move on to the next scratch, do the same.

Now you need to remove the scratches from the sander. Spray all the areas you sanded and wipe with s cloth!!! (The grit from the paper falls off and you dont want to sand with 800 with bits of 400 on the panel). Sand with the 800 and slightly enlarge the area to feather it into the areas you didnt sand. Spray clean, then 1200, enlarging the area. Each successive grit will take longer because you have less cutting power and you have to sand through the precious grits scratches. When you get to the 2000 grit keep the panel wet while sanding. You can likely polish all the remaining scratches out after 5k but honestly I find it easier to wet sand with 10k then polish.

Amazon has the really high grits. Make life easy on yourself and flip and turn the tank so you are always sanding down... not trying to sand on a vertical plane.

Polishing is straight forward, use a low to medium speed. Reapply polish when you can no longer see it swirling around.

Then just polish the outside.

It will likely take 8 hours to sand and polish. If you go up to 10k before you polish I PROMISE that the tank will look even better than new.

Trying to take deep scratches out with polishing only has a higher chance of creating distortions because people tend to turn the polisher on its edge and go to town on the scratches.

While it may seem frustrating and you will curse acrylic, this is actually the beauty of acrylic.. you can fix scratches!!!
Thank you! This is what I was looking for.
 

pdxmonkeyboy

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glad to help.

You want a polisher like this: https://www.harborfreight.com/7-in-...mbpwzhN5rXAB2E82PWwfBiYgqk9GJlYoaAsiZEALw_wcB


not this: https://www.harborfreight.com/10-in...kARAPA80g20Gg3GOv1b1zMOdFeqiHbF0aApd7EALw_wcB

Also if, you have the ability, and the desire, I would look at getting a sheet sander in addition to a random orbital sander. They are cheap and get closer to the edges. The finer grit sandpaper sold in sheets is also much cheaper and readily available. That is the one I use for final sanding. Don't use it for the coarse grades because it is not random.

 

Daquan44

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I made a video of how I sanded a couple acrylic aquariums using magnets and sand paper while the tank was still running. The results were amazing. It should give you a good method of removing scratches from your system without distortion.
 

GreenreefSC

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The first time I sanded and used novus there was an obvious fish-eye in that spot afterwards. I found that if i started sanding the small circle directly on the scratch with the 600 paper and then sanded slightly bigger circles every time I moved up to a higher grit paper it would make the warp effect much less noticeable.
 
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