Acrylic Tank Scratch Removal Help

I can tell you from experience how to do this. I sanded and polished the tank at Taki Steakhouse in Urbandale, which had "zorro" scratches all over it.

Start with the highest grade sandpaper you think is needed to get the scratch out. Usually start with 1200 I would say. If that doesn't take the scratch out, then go to 800. Then 600, and if it's really, really deep, 400. But remember that each 'level' of sanding must be taken out before going to the next level. So spend as little time as you need at the rough grit levels and feather out with finer and finer grades.

Some advice says alternate direction of sanding, but this is really so that you can "see" that you have removed the scratches from the previous pattern IMO. You don't need to do it this way, but if you don't, it you might end up sanding a whole lot more at 1200 to get out a 400 grit pattern than you would if you had removed it with the 800 grit in between.

It's hard to describe unless you see it in person, but when you sand an area that has a scratch in it, then rinse and wipe that area, sometimes you can see the "ghost" of the scratch. This is easily apparent when you first hit the tank with your first pass of sandpaper. If you stay sanding in one direction over a scratched area, then rinse the area with clean water (I use a sprayer bottle) and wipe it with a microfiber cloth, you will see the pattern you just made, and the scratch you are trying to remove. Keep sanding until you don't see the scratch at all. Then the scratch is removed and the next step is to remove the pattern you just made using the next grade of sandpaper up. Switching directions of sanding 90 degrees helps you to see if you removed the 800 grit pattern with the 1200 grit paper, and so on.

I use wet/dry from the Woodsmith Store in Clive, they carry 800-2000 in 8.5x11 sheets cheap. This -> http://www.rockler.com/product.cfm?page=16762&filter=preppin%20weapon%20sanding%20block&ne_ppc_id=776&mkwid=8779686&pcrid=5325298800&ne_key_id=saJb6XrfT&gclid=CPuo4OyLkLICFahFMgodBhcABA is the best sanding block I have found. If that link doesn't work, it's the Preppin' Weapon. Get one.

you can also get this -> http://www.sisweb.com/micromesh/acrylic_plastic_hand_kits.htm goes to 6000 grit

Although I think I have 2 of these -> http://www.sisweb.com/micromesh/craftsman_kits.htm goes to 18000 grit

But small sheets and will make your arms like Jello if you need to do a whole tank.

Rinse, rinse, rinse. Remove particles very often from the acrylic you are sanding and the sandpaper, as these will just re-scratch the area you just sanded. Water is your friend. Spray bottles are your friend.

Rest often. This can be tedious.

You will get to the point where it seems that your work is fruitless. For me, this was when I was trying to remove the 1200 grit pattern with 1500 grit paper. That's when I switched to an acrylic polish and a drill with an arbor bit and a 3-stitch wheel. Now that I know better, I go to a buffer and Meguiar's:

So after sanding out all the scratches with wet/dry down to 1200 grit or finer (1500 or 2000 if you have it)

Then use this to get those scratches out

http://www.meguiars.com/en/professional/products/m10532-ultra-cut-compound-32-oz/

then this after that

http://www.meguiars.com/en/professional/products/m8232-swirl-free-polish-32oz/

using this pad

http://www.meguiars.com/en/professional/products/w7000-softbuff-foam-cutting-pad-8in/

on this buffer (or one like it)

http://www.northerntool.com/shop/tools/product_200442254_200442254

I use 2 pads so I don't mix the polishes.

I get it the meg stuff at international refinish products in DSM

http://www.irpppg.com/index2.html

The last part I had handy as someone else PMd me with a similar question.

 

Oh yeah and you should never run the buffer at more than level 3 out of about 6 (mine has 6 level). The point is that you want to polish the acrylic but not heat it up. Heat is the enemy. The first polish takes out 1200 grit scratches. The swirl-free polish takes out the haze left behind from the ultra-cut compound. You can use more than just these 2, but this is what was recommended to me by Conde who was featured in an LA Fishguys video and whom I spoke with personally.

 

I've never polished a tank, but I do have a nice porter cable DA car buffer you could borrow if it will work for the job.