Gelcoat repair -- A to Z

[Porkchunker]

Rather than screws, I'd recommend you replace with bolts and "nylock" nuts. The nylock nuts look like little acorns...they are rounded on top. Install the hardware, then cut any excess bolt off with a dremel tool and a "cutoff"wheel.

Smooth as a baby's butt, and will never snag anything...especially your skin.

 

[Bruce]

Why didn't I think of that? Thanks.

I have a Dremel; just got it this year. It might be the most useful tool I own.

 

[woodytoo]

couple questions from a gelcoat newbie ...

what does the temperature need to be (ideally) to perform a gelcoat repair?

i couldnt tell, but it appeared fairly thick? are there issues with it running when you apply it on a verticle surface?

i am rearranging electronics on my console, and will need to either cover it starboard, or do a patch and gelcoat repair. the console is such a noticeable area, and i really want it to come out well. going with my current thoughts i would have to fill and apply gel coat to a pair of 1.5 inch diameter holes and a half dozen screw holes.

thanks in advance for any thoughts ...

Bo

 

[DaleH]

what does the temperature need to be (ideally) to perform a gelcoat repair?

Ideally 60 to 70 degrees with the temperature FALLING so that the material cools as it cures. If it heats while it cures, like you started at noontime, gas bubbles from the core can be created as the temperature rises ... say when it gets hotter at 2-3pm.

I always, always, always ... do glass or critical painting AFTER the heat of the day. You can adjust your hardener amount to the ambient temps, more if <60> 70 degrees F.

i couldnt tell, but it appeared fairly thick? are there issues with it running when you apply it on a verticle surface?

You will need to thicken it using a filler like cabosil. If too much filler, it can lighten the gelcoat color.

You will need to fill the hole with a core of wood and then Forumla 27 from the front and around the sides of the core, but use an epoxy with glass patch on the back side, for strength and security (of the core patch).

You could do it and do it well ... the PATIENCE during sanding and religious wetting/rinsing of the wet/dry paper is critical, it should be ALWAYS used with a stiff backer block (I use plastic or hardwood so I can did it too into the bucket of water to rinse). You only want to do 3-4 back & forth strokes, then rinse. Then repeat and rinse. You will be rinsing more than you sand ... but that is how you will get a factory like match.

 

[TheOtherLine]

At what point would you want to add some additional fiberglass to the repair.

IMHO if you can see fiber substrate in the area of the repair, I'd add some "kitty hair" or other chopped FRP filler to the gelcoat.

Just a precaution when using fillers ... like cabosil is "snow white" in color, therefore it can lighten the stock Parker gelcoat color somewhat, so as minimal as needed is best, or fill with the filer base and then top-coat with straight gelcoat for a perfect color match .

And if so, do the epoxy sticks work as a temporary fix?

I think so, and I like the one from Boater's World that is an epoxy stick where you cut off what you need, kneed it together to mix it, and then apply it ... and it will even cure underwater, which is why I keep a stick on board.

If you can see subtate/fibers, you want to protect that ASAP against future/further water intrusion.

Do you think you can add color to these epoxy stick solutions? If so, where do you get the color to match the Parker ?

 

[rangerdog]

I understand the method and now I just have a few questions:

1. Where do I get Parker colored gelcoat?

2. Do you apply it with a stick or brush or what?

3. What ambient temp is required?

4. Can you use a random orbit sander or is hand sanding mostly recommended?

Thanks in advance. :wink:

 

[Bryan 2530]

1. I got a quart from my local Parker dealer, others have been able to buy smaller quantities.

2. Yes, anything that you can get it up there with. It just needs to be sealed from the air if it is raw gelcoat.

3. 50 degrees is optimum but you can use a heat lamp for a localized heat source. Don't get it too hot or the product will flash (harden) to fast.

4. Personally I think you have more control by hand but for larger areas a sander can be used. I like to mask off any of the original stuff just like was posted earlier.

Hope that helps.

 

[2320 pilothouse]

great read,now i know how to do it,thank you everyone

dave

 

[evinrudejim]

Most fiberglass/gelcoat professionals spray PVA over catalyzed gelcoat. I have never seen the box tape approach used. I suppose anything that keeps the air out would work to a degree, but PVA is the standard industry method.
Also repairs of this type can be easily accomplished by spraying on thinned catalyzed gelcoat with a PreVal (semi-disposable) spray gun. Eliminates most of the sanding and you end up with a nicer job.
Lastly, adding any type of "filler" to gel coat is a no-no. Gelcoat is designed to be, more or less, NONPOROUS. Any filler, PARTICULARLY fiberglass, will wick moisture into the repaired area and eventually spoil it.

 

[Porkchunker]

Glad we could be of help.

I understand that there is a was one can mix in the gelcoat that comes to the surface and blocks the air. I couldn't find enough information about it, how to obtain it, and how to mix it, so I used the box tape approach. Had heard about the box tape from somewhere else...probably TheHullTruth.com or BoaterEd.com. Anyway, the box tape worked and the gelcoat hardened.

Dave

aka

 

[Croixboy]

I'm getting ready to do some gel coat work and found this post from last year ... just wanted to bring it to the top again. Great Tips!

 

[jeffnick]

I did a test - if you don't cover Parker gelcoat while curing, it will stay sticky to the touch.

 

[DaleH]

... if you don't cover Parker gelcoat while curing, it will stay sticky to the touch.

This isn't just specific to Parker gelcoats. Most are typically made so that it needs an anaerobic (without air) environment in whcih to cure. With most gelcoat, you block it off by covering with clear plastic shipping tape or plastic wrap.

But, you can make up gelcoat that has a surface-curing wax additive in it that will cure afer mixing and spreading. This is how they get spray-on glecoat to cure.

 

[Ranger Tim]

I heartily second the Pre-Val sprayer method of application. Purchase at any good auto parts store. Thin with acetone and spray. Buildup is easily accomplished as long as you don't thin excessively. Last year I used Parker gel coat on a Scout for some fairly extensive repair and did not cover with a barrier. It cured but it took a while (about four days).

I just did some gel coat repair on my hull (trailer vs. boat = trailer wins) and left some small spots open to cure without cover. I will report the differences.

 

[DaleH]

Thin with acetone and spray. Buildup is easily accomplished as long as you don't thin excessively.]/quote]
There is a better product for thinning gelcoat than acetone, believe it is a styrene derivitive.

... used Parker gel coat on a Scout for some fairly extensive repair and did not cover with a barrier. It cured but it took a while (about four days)

I use the spray on purple mold release. Fast, simple, water clean up !

Let us know how you make out.

 

[Ranger Tim]

After 24 hours there is no difference (so far) between covered and uncovered gel coat - Still pretty tacky and soft. I removed a few coverings to compare. I really liked the results of stretching glad wrap over the keel/stem repair. It yielded an extremely smooth and slick surface that conformed closely to the original shape. Gouges in the gel coat on high profile rounded locations such as this can be a bear to get back to normal. Keep in mind the pics below are before any sanding.

Perhaps thinning with acetone is what is keeping the gel coat from setting more rapidly. If there is another brand name product for this purpose it would be worth checking out. Straight gel coat is too thick to spray out of the PreVal sprayer.

My work on the Scout was extensive but turned out great - Except that the color is Parker-white! The Scout gel coat is a bit more yellow, however the boat owner is thrilled. He didn't have to pay for it! I posted some of my pics from that job somewhere. Big holes in the deck 2 inches in diameter and no wood to screw to! I came up with a method of using string to suspend the fiberglass patch with enough tension against the under side of the deck. I sure love those metered pumps for the epoxy/hardener.

 

[DaleH]

After 24 hours there is no difference (so far) between covered and uncovered gel coat ...

Wow :shock: ! I've had it cure and have been sanding within hours ...

Styrene monomer is what many use instead of acetone, you can get from hobby places. Some gelcoat brands ever go as far as cautioning against the use of acetone for best results. But many have luck with it, so who knows?

Others use Duratec additives as a hardener and thinner, ref: www.duratec1.com

 

[Fishaddict]

Hi I am not trying to resurrect an old thread, but I am trying to repair a 3/4'' round hole on the roof of 2120 from old GPS sensor. Any suggestions on imitating speckled texture of the roof? Also I am planning to glass the hole almost to the top and than use gel coat. Any downside to this method?
Mike

 

[Sara F]

There was a post a few years back not sure if it was Porkchuncker, but the post talk about using a Preval sprayer with unthinned gelcoat to match the non-skid pattern. If memory serves me correctly it was part of a post dealing with moving a windlass further back over the anchor locker. Good luck if you find the thread can you post a link. Thanks!

 

[TimC2520]

Hi I am not trying to resurrect an old thread, but I am trying to repair a 3/4'' round hole on the roof of 2120 from old GPS sensor. Any suggestions on imitating speckled texture of the roof? Also I am planning to glass the hole almost to the top and than use gel coat. Any downside to this method?
Mike

A few years ago, I replaced an old depth finder on my dash with a new one and had to fill four old holes that did not line up with the new MFD. Once I got the hole filled and topped with gel coat, I used a pipe cleaner (while the gel coat was still wet) and just kept dabbing the gel coat until I got the speckled texture I thought looked best. It turned out great.