3M Perfect-It Gelcoat Heavy Cutting Compound

Should you use this 3M Heavy? Here's some parameters for fiberglass gel coat: This is the stuff for boats/RVs that are a few years old but don't leave a white dust on your shirt or hand if you brush it (after a good pressure wash, of course). If you're getting significant dust, you should probably dry-sand first, use this second, use a lighter compound third, then rinse or vacuum or blow off fourth and then wax. Compounding leaves significant abrasive dust behind on the boat that needs removed before waxing. The whole process takes several days to over a week for a 25-ft boat.. Sorry, but it does. I use this if wet-sanding is not quite necessary but somewhat close. It's a little more aggressive than Presta Gel Coat Compound, but not by much, making the Presto a very good second-rounder or for lighter work. (Presta also provides more shine at that stage but not as much efficiency at oxy-cutting.) 3M Heavy shines somewhat when done on glitter gel coat, but mostly provides a flat, polished consistency to the finished product when viewing askance to the light. It's unlike some with polish in them, which create a false impression that early in the process. 3M Heavy is indeed for cutting old oxy and must be used with a good rotary, not a DA. If you want oscillation, set your rotary's velcro pad off-center one or two millimeters. But muscle is required and consistent RPM rotary polishers provide this, along with the 3M Heavy. In hot weather, dot the surface being polished rather than applying it all to the rotary pad. Do a picking-up action as you rotate and as you keep moving. This keeps the compound from drying too fast upon use, because it's in a droplet and already placed, rather than smeared on thinly, as we're taught. This stuff is expensive, but when you're into working on something with a lot of value, it's best to spend the money and be sure you're making good progress safely. Never linger in one spot too long, as it can burn, but this is not likely if you keep moving and feel the surface frequently against your cheek.

We swear by the 3M Gelcoat Medium Cutting Compound for our fiberglass pool manufacturing, and it never fails to impress. This product excels in effortlessly polishing gelcoat surfaces, erasing fine scratches, and eliminating dullness with minimal elbow grease. Living up to its claims, this compound is a breeze to apply, spreads smoothly and evenly, and buffs out flawlessly to reveal a pristine, high-gloss sheen. It not only saves us time and effort but also ensures we achieve the top-notch finish our customers demand. Having tested various alternatives, we can confidently say that 3M's formula is the most dependable and consistent, earning its permanent spot in our workshop. Whether for final detailing or restoring shine post-surface prep, this product consistently delivers outstanding results. For those seeking professional-level polishing and long-lasting shine on gelcoat surfaces, I highly recommend giving this product a try.

This compound cuts very well, it did a great job removing the oxidation from my fiberglass boat. I buffed with a wool pad and had no complaints. This is not meant to be a final product though, you'll notice swirl marks etc after use. Recommend going from the 3M Heavy to 3M Medium and/or 3M light depending on how the finish is looking in between and finishing up with a wax. I buffed the rubbing compounds in with a wool pad but the wax I moved to a foam pad to finish. I really like the 3M products and with time and quite a bit of work it made my 20 year old boat look like new when I was questioning if I was going to be able to revive the gel coat.

I own a marine services company and the product does a great job and happy customers

Does a great job of removing oxidation and surface imperfections on my old boat.

Great product that's well worth the price. It removed years of chalking on my boats gel coat with ease. I'm going to do a second pass on the scratches

Best product i have ever used to remove heavy oxidation from my boat. Restored my 25 year old boat gel coat to like new.

Works great. It returned the shine to our boat.