What is Gelcoat?

DavidB · 10-04-07, 06:41

Not being a Marine expert, I had to do some research to answer this question. Here's the answer from wikipedia:

"A gelcoat is a material used to provide a high quality finish on the visible surface of a fibre-reinforced composite material. The most common gelcoats are based on epoxy or unsaturated polyester resin chemistry. Gelcoats are modified resins which are applied to moulds in the liquid state."

So, other than the method of application, a Gelcoat finish is not that much different than automotive paint.

Facts about Gelcoat:

1. It needs to be waxed/protected to prevent oxidation.

2. It is damaged by the sun's UV light.

3. It is easily scratched.

4. You can wet sand, cut and buff Gelcoat in the same manner as automotive paint finishes.

When Gelcoat finished parts are removed from their mold, they are rarely perfect (at best, the part can be 99% as good as the mold itself). Most boat manufacturers finish their boats using a muti-step sand, cut and buff process to achieve the final finish.

The good news for boat owners is that Gelcoat is pretty thick (much thicker than automotive paint), so you have a good amount of material for scratch repair.

db

Danase · 10-04-07, 06:47

I'll have to dissagree on the easily scratched part. I used to work for a cutstom boat trailer builder and I have been around a lot of boats. Gelcoat is much stronger than most automotive paint from what I have seen and been involved with.

DavidB · 10-04-07, 07:00

Quote:

Originally Posted by Danase

I'll have to dissagree on the easily scratched part. I used to work for a cutstom boat trailer builder and I have been around a lot of boats. Gelcoat is much stronger than most automotive paint from what I have seen and been involved with.

Thank you for your input, Bob. I'm simply going by what I have seen watching gelcoat being sanded and buffed.

db

DavidB · 10-04-07, 08:00

Found this informative page:

AUTOS & BOATS : Maintenance & Repair : Gelcoat Repair: Getting Started : DIY Network

GregCavi · 10-04-07, 09:08

I detail boats during the summer and like Bob, I disagree with the scratch part. This is why you wash boats with brushes. To keep a boat looking tip top, you will need to compound/polish/wax a couple times a year.

Greg

DavidB · 10-04-07, 09:10

Quote:

Originally Posted by GregCavi

I detail boats during the summer and like Bob, I disagree with the scratch part. This is why you wash boats with brushes. To keep a boat looking tip top, you will need to compound/polish/wax a couple times a year.

Greg

Thanks for the great feedback, Greg. Look forward to any tips you might have.

mirrorfinishman · 10-08-07, 05:45

The outer skin of a fiberglass boat is called the gelcoat. In most cases it is a relatively thin layer of high quality resin pigment that gives the boat its color. The gelcoat helps to protect the layers of fiberglass beneath the surface. From the standpoint of appearance, it is the most important part of the entire laminate.

If not properly maintained from the beginning, almost all gelcoats will begin to fade and lose color and gloss over time. Discoloration from oxidation of the gelcoat does not structurally harm a boat, however, proper maintenance does help protect the fiberglass and improve overall resale value.

The best method of maintaining the gelcoat is to wash the boat often and apply a good coat of quality wax. This should be done at least three or four times a year. The wax on the surface of the boat provides a protective layer, lubricates the gelcoat and keeps the surface smooth. A top coat of premium marine sealant will provide additional protection from harsh environmental conditions.

For older boats that may already have a white chalky oxidation problem, it is usually necessary to use a marine cleaner polish first. If a cleaner polish does not remove the oxidation, then a slightly more abrasive product, such as a heavy duty compound may be needed. Removing oxidation from the gelcoat of a boat is not a simple job, especially if the oxidation has been allowed to build up over several years.

In summary, the easiest and best method for keeping a gelcoat looking new is to establish a regular maintenance routine from the beginning.

SShine · 10-16-07, 07:54

I also disagree with the part about gelcoat scratching easy. I will say this, once the gelcoat gets chalky, its ALOT of work to get it in the proper condition to wax. If its not polished enough, the wax will soak into the gelcoat and stain it. thats never fun.

if a boat has severe oxidation, expect to be compounding that hull for 1-3 days depending on the size of the boat. I had to compound a dark blue (the darker the color the more work involved) 32' boat a couple months ago and it took me 2 days just to compound the hull.

paul34 · 10-16-07, 04:17

So, why are gelcoats used on boats and "automotive" paint used on cars?

Why isn't car paint used on boats, or by the same token, gelcoat used on cars?

Joshua312 · 10-16-07, 05:02

I'll also have to disagree with Gel Coat being easily scratched...and since when is Wikipedia research? haha All my college courses clearly discredit it as a credible source for any information/papers.

SShine · 10-16-07, 05:10

Quote:

Originally Posted by paul34

So, why are gelcoats used on boats and "automotive" paint used on cars?

Why isn't car paint used on boats, or by the same token, gelcoat used on cars?

because gelcoat is alot of durable than paint.

It isnt used on cars because it is alot of work to maintain, and collision repair is difficult to match I would imagine. I'm sure there are other reasons too.

some Gelcoat work ;-)

Daragh · 10-16-07, 05:10

Some yachts have painted top-coats - See awlgrip.com (Good resource)