How to fix a scratched slab
ifthevamzarockin
Posts: 8,902 ✭✭✭✭✭
The things you need are: Ultra Fine polishing compound , Medium polishing compound & some ultra fine wet sandpaper 2000 & 3000 grit. (one sheet of each will be enough to do many slabs) These items can be purchased at your nearest auto paint supply store & some auto parts places. Meguiar's has a good selection for polishing compounds. You will be able to restore 100's of slabs & polish scratches off your car for very little money.
Note: You want the very finest ultra fine polish for your final step. Different brands may have a different idea of ultra fine. A good final step might be to look at a plastic polish designed for plexiglass and RV & boat windshields. It comes down to what products are available in your area. Heavy/Coarse cut compound should not be used, it will put deeper scratches than the sandpaper and will take extra steps to repair.
First off, do not use sandpaper or compound on the hologram labels!
If you feel you can't be quite careful enough around the label use some tape to protect it.
A little WD-40 works well to remove any tape/glue/adhesive that may be on the holder, use a small amount on a clean cotton cloth. Many slabs will look much better with just the ultra fine compound and about 5 minutes work, this is where you want to start. If that didn't remove everything you can try the medium compound next and then follow up with the ultra fine. You want to use a clean cotton cloth and a circular motion when polishing. Directional polishing or sanding can give the plastic a grain effect. Do not scrub on just the scratch or imperfection to remove it, you will create a visible dish or defect in the plastic. Even sanding and polishing across the entire slab surface is the secret to good results. For one like this you need to start with 3000 grit sandpaper. Cut a small 1 inch x 1 inch square of sandpaper and put a drop or 2 of water on the slab. Use an even circular sanding motion and sand until imperfections are gone. If needed use 2000 grit then go over it with the 3000 grit. Next use the medium compound to polish sanding scratches out then follow up with ultra fine to remove the medium compound scratches. Use ultra fine until crystal clear. All the time staying away from the hologram label as mentioned.
All operations are to be done by hand, do not use power sanders or polishers.
This works well with PCGS & NGC slabs. The ANACS and GSA holders are not as easy and take more time and a softer touch.
Found a slab to do a quick demo. This is the before photo.
Next I scratched up this slab with the edge of a new quarter, then used the edge of a razor to scrape rather than cut.
Lots of scratches and pretty messed up.
I started with 2000 grit wet sandpaper and sanded out the scratches.
I was not able to do the 3000 grit step for this demo because I am out and need to get another sheet.
Next I polished with medium cut compound then followed up with ultra fine. I could still see quite a few deeper scratches that were not removed so I re-sanded it. After another round of medium and ultra fine polish it is looking pretty good. There are still some fine scratches that need more polishing but this gives you a good idea of what can be done in a fairly short amount of time. I spent an hour taking photos, scratching the slab & repairing. The time repairing the slab was about 30 minutes but it still needs a little work. Most slabs will not be scratched by sharp reeds on a new quarter and a razor blade, I may have gotten a little carried away. You can practice this method on your old crack out slabs or buy a cheap modern off ebay for $7 to practice on.
Please do not use this method on your favorite 500K coin without practice and then PM me about how I ruined your coin.
Use at your own risk, I assume no liability for yours or my stupidity. 
Comments
I
buying scratched slabs at discounted prices from people that don't want to reholder. 
WOW ....... thank you for showing the result @ifthevamzarockin
I marked your thread for future reference!
Mahalo
Great post. In some cases there are old vintage slabs which add value to the coin that are scratched and conservation of these slabs makes more sense that sending them back for re-slabbing especially considering the cost of re-slabbing and the cost of registered shipping both ways.
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Very interesting. Thanks for the information.
A link to an informative post. Thanks @ifthevamzarockin!
Tag: Slab, Scratch, Polish, Fix
Thanks for the process description and the pictures.... great results. Cheers, RickO
Many thanks I'll give it a try on a "marginal" example. One question: any difference in results with PCGS plastic?
Works the same, in fact they are a little easier because the raised circular viewing area is all you really need to polish. I may do an update with a PCGS slab but I didn't have a bad one to demo.
Thank you.
It works great as I have done this many times.
Another great "trick" is to use clear oil on the scratches on the slab which disappear temporarily while photographing.
@ifthevamzarockin
Thanks for the post! Care to post another image? I want to see the finished slab when it is *tipped at an angle** as you did in the second image above.
@Insider2 No problem, but it will have to wait till I get home later and I still need to touch it up a bit. I will try to post it tonight but if not I should be able to get it by tomorrow.
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My US Mint Commemorative Medal Set
@Insider2 Here ya go, I think this is what you are wanting to see. Yes, there are still fine polishing hairline scratches and I need to work on it some more. I will do some more polishing when I can and post updated photos. The remaining fine scratches appear much worse in the photo than it does in hand. Keep in mind this was kind of a quick demo that I did not plan ahead for, time wise & materials wise. I also got a little carried away scratching it so it needs a little more work than most slabs would. I don't want anyone to have unreasonable expectations of the steps it takes and the final outcome. I put a coin in the holder to show what it looks like to photo through the plastic as is now. I should have been taking photos with a coin in it and without a coin in it and also straight on slab shots & angled. Might have to do another demo with this slab and maybe a PCGS slab.
Edited to add coin out of holder for comparison.
Edited to add:
A little more polishing seems to have helped quite a bit, it will take a bit more but I don't have time tonight.
I spent a few more minutes on it and it looks much better. Don't want to spend a bunch more time on it because I may end up scratching it all up again for another demo. May try scratching it so much that you can't see the coin and do photos with & without the coin in the holder.
I was hoping for a "miracle."
@Insider2 I was hoping for a "miracle."
Well if this doesn't work for ya you can shoot the lock off your wallet and send it in for a re-holder.
I did a similar post on this a couple years ago for PCGS slabs and also a thread on the NGC forum for their slabs. PCGS slabs are definitely easier to fix. I found sandpaper to be useful for deeper gouges and a motorized buffing wheel to be easier for fine scratches like you're showing.
Here's the link.
Sorry, it looks like the stupid Photobucket watermarks are appearing over all the photos now.
@BryceM
Nice demo you did there! Maybe I should have just bumped your thread rather than spending time I will never get back.
Thanks for the link!
It's always good to have other people try it. I'm absolutely certain there are better ways than the one I showed. The NGC slab wasn't easy to fix, I remember that much.
Thank you for your effort. As you know, reholdering is more than money, especially if the slab is stickered. Lots of hassle for a collector, one who doesn't routinely send a bunch of stuff to the TPG's and CAC.
Been searching here for the past two days. Just looking for a thread with good examples of before and after "pictures" of scratches removed from stabs.
This forum has a lot of threads out there about removing scratches from slabs. Most just talked about.
Finally found this one. Thanks!
One thing I can add. Hobby shops that sell plastic car models that you can build have sandpaper for polishing the paint on the models. It comes in packages about 4 by 6 inches and various grits going to 12000. You could really get that plastic to shine using these. I will have to find mine and try it out on a scratched up slab or two.
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I gotta say that Slab Renew has worked very easily and well for me. It’s gotten a lot of scratches out with only minor effort.
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I was putting together my ‘60 Corvette hardtop and found a way to put a nasty scratch in it with a screwdriver. You can buy from the Hardtop Shop a kit. It includes various degrees of micromesh sand paper and polishing compound.
http://www.thehardtopshop.com/acrylic-window-repair-kit.html
I haven’t tried this yet on a slab, but it sure worked on my hardtop rear glass!