View Full Version : M45 after M67 loses shine...

May 25th, 2016, 07:06 AM
I have a 1999 Four Winns that has been a bit neglected and stored in the water the last several years. The gel coat is oxidized but not as bad as some of the pictures I have seen around. However it does need correction on the hull and top parts of the exterior. The areas are white with almost no reflected image from a flashlight. I am using a HF DA polisher with an orange cutting pad and M67. It is working well in my opinion with a fair amount of shine returning. However the reflection is much less clear when I add m45 as the next step. I tried by hand and with a polishing pad. M45 on the black stripe just under the rub rail works great and looks good.

Should this loss in clarity of reflection be happening? Does this mean that I should make more passes with M67 or use a more aggressive product to remove more "oxidation"? The resulting shine with M67 alone is not a new gelcoat appearance but I am fairly happy with the result. My current plan to just use m67 with a final coat of wax or ****** sealant.

Any ideas/help is greatly appreciated. Thanks Meguiar's for a great product. I considered selling the boat after getting a good look at how bad the gelcoat had become...now I have the boat fever once again.


Michael Stoops
May 25th, 2016, 12:32 PM
Hi Bob, and welcome to MOL!

M45 is a pure polish and as such it's kind of an optional step. Just as with auto paint, light colors on gel coat don't tend to give that really deep and rich look like darker colors do, so using a pure polish on lighter colors often doesn't return as much of a gain as you might have expected. On white gel, especially as old as the gel on your Four Winns is, we'd probably just stick with M67 and then move on to Flagship Premium Marine Wax to finish it off.

Another thing to consider as you're working on this boat is the amount of oxidation you're actually trying to pull off. Gel coat is really porous and as such it can absorb a much greater amount of polish, or polishing oils from a compound, or even the various "carrier ingredients" in said compound. This can often fool you into thinking you're making more progress, and getting more correction, than you actually are. What happens is you think you've gotten a great result but you've actually done some correction and some concealing; once the solvents or oils evaporate out it gives the appearance that the finish has degraded very rapidly since the correction. We introduced a new product this year that has a lot of guys who work on oxidized gel coat really excited - our new Heavy Oxidation Scrub (http://www.meguiarsonline.com/forums/showthread.php?63830). This product is designed to be a pre-cleaner that removes all that oxidation - the white chalky build up that will come off on your hand if you simply wipe over the finish. Removing this first with the Heavy Oxidation Scrub means you aren't pulling all that chalky build up into your pad, and loading it with that crud right away. The process is super easy - simply squirt some onto the hull and brush it with a typical hull brush, then rinse of with water. I've personally spoken with a few guys who were at first a bit disappointed with it because, as they described it, the gel coat didn't look any better after they used it. But then they noticed that wiping their hand over the gel coat revealed.....nothing! No more chalky residue on their hands, meaning no more chalky residue to overload the pad and slow down the buffing process. They all said that the buffing process did indeed go faster, and they got a better result because of the initial cleaning with the scrub. It's now part of their regular routine because of the time savings and gain in quality of finish. Win-win.

Jun 1st, 2016, 06:09 AM
Thanks for the tip. I will have to get a bottle and check it out.