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Repairing Scratches in Acrylic - Mini Tutorial


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Hi All, figured I would post up a quick quasi "How To" on Acrylic Scratch Repair. Two recent situations with customers having scratches on their tanks prompted this. Both of them very different however. On one a rock slide cause a deep scratch. On the other, the customer (later scolded for being silly) impulse purchased a used SeaClear tank off Craigslist only to find after cleaning off all the dust from the tank that it was scratched to all holy H-E-double hockey sticks.

 

In the first example we are dealing with a scratch on the inside of an established tank which requires a different approach than the latter which is predominantly scratched on the outside.

 

In the first example the first thing you have to do is find the appropriate grade of wet sandpaper that will make the surrounding material flush with the scratch depth. I generally recommend starting at a higher grit as you don't want to create more work for yourself than necessary and if you start down at 300 grit for something that would have sufficed with 800 grit then you just created several unneeded steps in the process. If the scratch is very shallow then seeing how it responds to 800 grit would be perfectly fine. If its deeper then start with 600 grit. If the selected grit doesn't make much headway move down to the next lower step in grit and so on until you find the "sweet spot". Then the process begins.

 

1. Sand back and forth across the scratched area exceeding the sides of the scratch by a small margin to blend the surface. Once the surrounding surface area is level with the scratch move up ONE step in grit.

2. With the next step up in grit you want to change directions. If you were sanding horizontally previously now we want to go vertically. Extend your strokes by a small margin again outside the previously sanded area.

3. Move up a step in grit. Repeat this process up in grit and changing directions until you get to the top of regularly available wet sandpaper which is generally 2000 or 2500. At this point you will likely see fine micro scratches or haziness in the treated area. To get rid of this we need to graduate further up the grit scale.

4. Move up further through use of products such as "Micro Mesh" which will allow you to continue all the way through upwards of 12000 grit. By that point you should have a completely imperceptible surface area and be good as new...or DANG close to it.

 

Please note that this whole process and how long it takes largely depends on how large the scratch is and how deep the scratch is. In almost all cases though be prepared for some muscle soreness and set aside a few hours to get the process done. Doing it manually is no fun, but is really the only viable option short of emptying your tank for the repair. Also note, this process is completely reef safe.

 

Now for the second example. After the mentioned customer emailed me telling me about her impulse buy, and horror upon discovery of the abundant tank wide scratches, she asked if I could repair it. I told her that I could but that the amount of time it takes to do it would likely be cost prohibitive considering the cheap price she acquired the tank for and that I didn't think paying me to do it would be in her best interest. I however said I would walk her through the process since she didn't mind giving it a go herself (would have turned it into a sump instead if the process didn't have favorable results).

 

For the most part the process is the same with one key difference...power tools =). Here she was able to acquire the use of an orbital palm sander which I told her would work great. She was instructed to pick up a pack of wet sand pads for the sander which she did....it contained grits 1000, 1500, 2000, and 2500. She didn't want to wait for Micro Mesh to come in the mail so I recommended she get a plastic polish to which she selected Plastx. All of these components are obtainable at your local AutoZone or Advanced AutoParts store.

 

In this case the scratches were abundant throughout the entire tank you just need to do the whole thing which she did...beginning with 1000 grit one direction then 1500 the opposing direction and so on until done with the 2500 grit. When applying the plastic polish I recommend using a microfiber bonnet on an orbital buffer. She didn't have one of these so I asked if she had a drill. She did so I told her to get one of the drill mounted buffing wheels instead and use that for applying the plastic polish.

 

One of the biggest keys when doing this on an empty tank, or the exterior of one that is filled with water (like this one), is LOTS OF WATER. The previous example makes it a given that lots of water will be involved, but don't forget the water in this one as it will make your efforts much easier and the results much better. Keep the acrylic and the sandpaper wet at all times. Another note, rinse really well between graduations of grit in the sandpaper to remove any grit and material from the surface before you move up in grade.

 

The possible results speak for themselves with the attached pictures (link to Flickr picture set) which show before and after shots of this latter example which my customer was gracious enough to send to me. She states that the whole process for the outer portion of the tank took her about 3 hours. Without having done this the tank would have been virtually useless to her, but it now has a new lease on life for our wet friends =). Also note, there are certainly still some fine swirl marks/scratches in the panels, but they are largely not visible when filled with water. To get past this point to having nothing left would have required going through the finer micro mesh stages as previously mentioned...albeit though this would have been done also with power tools in this example.

 

Anywho, I know this isn't the most organized fully detailed Tutorial, but hopefully it lends some guidance to those needing a bit of help in this area. If there are any questions of course feel free to ask below =).

http://www.flickr.co...57630018804553/

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Can we pin this?!? I hope I won't need it but if I do, it would be better off not buried under. Thanks for posting this!

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  • 1 year later...

Wow, this is right on time. I needed to freshen up the outside and repair a couple of inside scratches on my tank. Thanks for the tutorial

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Thanks for the bump because I totally missed it the first time.

 

Same here.

 

Also, great photos, thanks for sharing this with everyone!

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  • 2 months later...

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