!! Sanding Acrylic tank - need help !!

[Floyd R Turbo]

I'm working on sanding the inside surface of this tank:

http://www.aquariumadvice.com/forums/f45/tank-journal-225-sw-fowlr-possible-future-reef-127906.html

and am banging my head against the wall. If anyone out there has done a major resurfacing job (or minor, for that matter) PLEASE PM me and I will send you my phone number. I have some questions about how to get through the final stages.

This tank had some big, deep scratches. I had to do the whole inside and wrap around the rounded corners too. I started with 400. Got through 600, 800, 1200, 1500, and 2000, removing each previous pattern each time.

Today I got through the 2400 pattern in about an hour. I thought I was on a roll, and had it down. I started on the 3200 pattern and in about 45 minutes I got about 2 square feet done. This is a 220g tank, 6 feet long and 2.5 feet tall, not counting the wrap around, so it's a huge job.

I took a break and sanded out a small scuff on the front. I started with 3200, then 4k, 6k, 8k and after that, there is still a scratchy haze on the surface. I took this an a sign of what's to come.

I need to know if there is any method (shortcut, etc) to cutting the length of the job time down. I have a couple ideas:

1) use a power buffer, like what you use to buff out car scratches, or a similar pad on a hand sander.

2) use a propane torch with a flat torch on a low setting and sweep it quickly across the surface. My dad makes all kinds of acrylic display cases and this is what he does for his last step to get rid of small scuffs and scratches. When he does this (on thinner pieces, like 1/16-1/8") the acrylic warps slightly then goes back to shape. I do not see this being as much of an issue with this tank since the acrylic is thick, somewhere around 1/2" I believe. However I do not want to risk weakening the tank either, so this would be a last resort, probably after trying 12000 grit or even higher, and after #1 above.

Please PM me ASAP and I will send you my phone # - unless I head back to tackle it again, and in that case I'll be back by 5pm CT.

 

[Floyd R Turbo]

Ok scratch the torch idea. I tried it on a piece of 1/8" and it took way too much heat and warp the heck out of it. So still need advice on the #1 option.

 

[redneckgearhead]

I would use a buffer and a fine rubbing compound.

 

[yetee]

I would use a buffer and a fine rubbing compound.

+1 to that. although I would make sure you get it all out before anything goes back into the tank. I have been able to go to 800 grit then use a heavy scratch compound then a fine scratch compound with good results.

I know the torch method can work but I also know it can cause big problems, such as crazing if you do it wrong (the acrylic actually cracks)

 

[Floyd R Turbo]

Ok, that's what I needed to hear!! Exactly what scratch compound did you use, one made specifically for acrylic tanks, or did you use something purchased at a hardware store or automotive store? I've found several scratch-removal compounds that are for auto finishing, they don't list anything saying to not use specifically on acrylic, but sometimes say don't use on rubber or vinyl.

The woodworking store where I got the 800/1200/1500/2000 grit paper did say something about carrying a liquid compound, but I wasn't looking for that at the time, I was focused on going through to the 8000 grit paper.

Also, I found a buffer pad for the dual-action orbital sander that I have, but should I be looking at buying an actual buffer tool like you would use to polish a car?

 

[thincat]

Here you go Floyd:Amazon.com: Novus Polish Kit, Plastic Polish & Scratch Remover, 8 oz: Automotive

 

[Floyd R Turbo]

Thanks! I've seen that one several times before when researching, but I'm worried that 8 oz is just not enough for this job. Yetee, is this the one you used?

I guess what I'm wondering about is if there are other product that are easy to find (locally) that will do the job also, but maybe aren't explicitly made for aquariums, but work just fine. Kind of like how I got pool filter sand at Menards, it was exactly the same as the stuff you get at Leslie's Pool Supply, but just hadn't gone through the extra certification to get the 'pool safe' label.

 

[Floyd R Turbo]

Just found this online

Final polishing will give acrylic a high luster. Power-driven buffing tools are recommended without exception. Buffing wheels are available as attachments for electric drills. A good buffing wheel for acrylic consists of layers of 3/16" carbonized felt, or layers of unbleached muslin laid together to form a wheel. Solidly stitched wheels should be avoided.

The wheel should reach a surface speed of at least 1200 feet per minute. Speeds of up to 4000 feet per minute are useful for acrylic.

Acrylic should be polished using a commercial buffing compound of the type used for silver or brass, or you can use a non- silicone car polish that has no cleaning solvents in it.

First, however, tallow should be applied to the wheel as a base for the buffing compound. Just touch the tallow stick to the spinning wheel, and then quickly apply the buffing compound.

To polish, move the piece back and forth across the buffing wheel. Be careful not to apply too much pressure. Keep the work constantly moving to prevent heat buildup.
Never begin polishing at the edge of the sheet. The wheel could easily catch the top edge and throw the piece across the room or at you.

 

[yetee]

sorry I was gone. that is what I have used before. granted I wasnt doing as big of a surface as you. but it should work. I just used a soft towel and rubbed it in. a buffing wheel should work as long as its new and hasnt been used for anything else. just test it first.

 

[thincat]

You can get it at most automotive stores. 1 not enough...get 2....

 

[Floyd R Turbo]

I did not know that! I was thinking hobby stores, but none of mine carry it. Thanks!

 

[cabezon]

yup headlight polish.

 

[Floyd R Turbo]

Problem sovled - linking back to the main thread...

http://www.aquariumadvice.com/forums/f20/sanding-acrylic-tank-need-help-128217.html#post1094515