Scratches in acrylic

[calihawker]

I have some really bad scratches on the front of my tank. I have everything I need and understand how to do it but I was wondering if I can use a vibrator sander to help.

Any advice?

Steve-O

[moon_knight1971]

I'm interested in an answer to this too. I see tanks on craigslist all the time at good prices "with minor scratches" and would love to know how to fix them if possible.

[jcardona1]

Most of the time you can buff out scratches in acrylic by hand. If the scratch catches your nail, then it's pretty deep and you'll want to sand the area down first. Otherwise you'll be buffing forever with no results. You'll want to wetsand the area down with some 1500 grit sandpaper, and be sure to use a sanding block. I wouldn't use an electric sander for this. Once you've sanded the the scratch down to where you can't feel it with your nail, you can start buffing it.

I like the Novus 1-2-3 compounds for this. You can find them online anywhere and sell for about $20 for the kit. Start with 3, then work your way up to 2. 1 is a spray cleaner/polish only.
http://www.snowdomes.com/mm5/graphics/00000001/novus_S.jpg

To actually do the buffing/polishing, you'll need a heavy duty direct drive buffer. These are quite pricey, so see if you can rent one locally. Avoid the crappy random orbit polishers they sell for waxing/buffing cars. These are useless for getting scratches out as they lack the direct drive high speed and torque of a heavy duty buffer.

This is what you want:
http://apolloautodetailing.com/images/milwaukee_polisher.gif

And NOT one of these:
http://www.hardwarestore.com/media/product/134155_front200.jpg

That's all there is to it. It's real easy, but it takes a lot of elbow grease. Plan to spend several hours if the tank is really scratched up. I've buffed out several tanks and they all come out good as new. I even buffed out my old 400g. That was quite a project! It's really hard to ruin the acrylic. I've sat with the buffer at high speed in one section with no ill effects on the material. In fact, you need to heat up the acrylic to a certain point to allow the scratches to disappear. Well not disappear per say, but remove the surrounding material so it's leveled out with the scratch, making it seem like the scratch is gone :)

[moon_knight1971]

That does sound like alot of work but not too bad if you have the right equiptment. I'm going to try wet sanding it with 1500 grit by hand and go from there. Thanks Jose!

[calihawker]

Cool, thanks, that was the answer I was looking for. Definitely 1500 for the rough work, its really bad, then I was gonna work down to at least 3000 grit before buffing if you think there's a benefit.

Steve-O

[alron2]

The plastic lense cover over my car headlights are frosted on the outside. Can this be fixed the same way?
Thanks
Ron

[jcardona1]

Cool, thanks, that was the answer I was looking for. Definitely 1500 for the rough work, its really bad, then I was gonna work down to at least 3000 grit before buffing if you think there's a benefit.

Steve-O

If it's really bad, I'd start with something rougher, like 600 or 800. Then work you're way up to 1500. I wouldn't bother with 3000. If using a good buffer with the right compound, that will get rid of all the finer scratches from sanding.


The plastic lense cover over my car headlights are frosted on the outside. Can this be fixed the same way?
Thanks
Ron

Definitely! I do this regularly on our Infiniti G35 as a big portion of the headlights face the sky. This is why I hate these modern headlights that are facing directly up; the sun will beat them up in no time. On our Infiniti, I buff out the headlights about twice a year. I don't sand them though, haven't had the need to. Just using the Novus 3 and 2 by hand makes them look brand new.

I did sand the headlights on an older Civic though, since they were almost solid yellow from the sun. Those took a lot of work. But be warned, once you sand them, they'll turn yellow much quicker in the sun. You'll have to repeat the process 3-4 times a year to keep them looking good. If you can, avoid sanding them and just polish by hand or with a buffer.

[calihawker]

Yeah, I just put some 1500 to it and the scratches just laughed at it. Gonna start with 600 and go from there.

Steve-O

[laborelch]

I use the Novus products and they work fine with elbow grease. Also tried to use a Dremel with the polishing pad/novus 3 once - not a good idea. Left some marks on the acrylic that took me a long (!) time to get out - again with novus polish 3 & 2 and more elbow grease. Lots of the latter, actually :-)

[Skip]

do i really need an electric machine to buff?! :)

[adam_withrow]

i have a friend who goes all the way down to 6000 grit paper, and he doesn't need anything for buffing after that.

[jeff@zina.com]

do i really need an electric machine to buff?! :)
No. But it's easier. :)

Jeff