Gel coat repair question.

[jamesk]

So my sx210 is black and dark grey.
I have many small scratches in random areas all over, obviously some are around the bow roller area.
I also have several larger ones that I know will need a gel coat repair kit and need to be filled in the hull.
Even the light scratches appear white underneath.
How deep is the colored portion of the gel coat on these yamaha boats?
It almost appears to me like the majority of the gel coats thickness is white but maybe not.
I am trying to figure out how much of this I want to try and fix....there is no way I would bother trying to fill all these areas with gel coat and at the same time it looks like if I tried to sand or buff out the scratches that there is not enough thickness to the black and dark grey portion and I would end up wet sanding the darker gel coat away all together.
Would have preferred a white boat, the colored gel coat looks nice but seems to show every little issue but it is was it is at this point.
Looking for some general advice about it. Thanks! Jim

 

[tdonoughue]

Jim,

Sorry for the delayed reply! The short answer: pretty thin. As a general rule of thumb, if you can still see color at the bottom of the scratch, you can sand/buff that out. But on the Yamahas the gel is pretty darn thin--you may be using 1/2 of your thickness on even a seemingly small scratch. Do that a few times and you are down to the glass or to the base white color (and up for a bigger job). So there really is some judgment there.

For a deeper scratch, you should consider getting the kit and filling that. The upside is that the Spectrum kits are color-matched and work well. At the end you will not even be able to tell you fixed anything. Down side is that in order to get gelcoat to adhere, you need to widen those scratches. Take a Dremel tool with a parabolic tip and draw over the scratches so they are like 2-3mm wide. That will give the gel enough bottom and side surface area to which to adhere. Then put in the new gelcoat. Then you need to sand. It can be very unnerving if you have not done this before, as it will look like you just ruined your boat. But be sure you use a sanding block (not just your hands) and work wet sanding from rougher down to fine grit (like 1000). Polish it all up at the end with a buffer and it will be good as new.

I have a thread around here somewhere of my first scratch repair, with pics. Do a search and you should be able to find it pretty easily.

Hope that helps!

 

[jamesk]

Jim,

Sorry for the delayed reply! The short answer: pretty thin. As a general rule of thumb, if you can still see color at the bottom of the scratch, you can sand/buff that out. But on the Yamahas the gel is pretty darn thin--you may be using 1/2 of your thickness on even a seemingly small scratch. Do that a few times and you are down to the glass or to the base white color (and up for a bigger job). So there really is some judgment there.

For a deeper scratch, you should consider getting the kit and filling that. The upside is that the Spectrum kits are color-matched and work well. At the end you will not even be able to tell you fixed anything. Down side is that in order to get gelcoat to adhere, you need to widen those scratches. Take a Dremel tool with a parabolic tip and draw over the scratches so they are like 2-3mm wide. That will give the gel enough bottom and side surface area to which to adhere. Then put in the new gelcoat. Then you need to sand. It can be very unnerving if you have not done this before, as it will look like you just ruined your boat. But be sure you use a sanding block (not just your hands) and work wet sanding from rougher down to fine grit (like 1000). Polish it all up at the end with a buffer and it will be good as new.

I have a thread around here somewhere of my first scratch repair, with pics. Do a search and you should be able to find it pretty easily.

Hope that helps!

Thanks for the reply. I can't seem to get any photos of my boat there is just too much reflection and they do not show correctly so I copied a pic from another thread. My boat is black / dark grey but the scratches are the same idea. There are several in this photo that for sure look like the need to be filled but like my boat many are not that deep but they look white.....looks like is you try to wet sand there is not much color gel coat? trying to figure out what need buffing, what needs wet sand and what need gel coat repair kit. I also which I could figure out the right tools and supplies that I need to buy....wish there was a kit that had like 4 grades of sand paper, compound, polish, wax, buffer and pads all in one so I am not having to order 15 different items from Amazon and try to figure out the best combo of products?

 

[YamaHog]

@jamesk , I performed a similar gelcoat repair last year and @tdonoughue and @mrcleanr6 were of great help. I would suggest reading through my thread linked below as I had many of the same questions I believe you have or will have. Very good information, especially in posts #11 & #16 of that thread.

https://jetboaters.net/threads/gelcoat-repair-kit-supplies.30048/

If you don't have an orbital buffer and don't want to spend a ton of money on one, I've had great luck with this Bauer model from Harbor Freight:

12 Amp, 7 in. Variable Speed Rotary Polisher/Sander

Amazing deals on this 7 In. 12Amp Hd Variable Speed Polisher at Harbor Freight. Quality tools & low prices.

www.harborfreight.com

You will want to get a 100% Wool Twisted pad and some Meguiars M100 Polish.

8.5 Inch 4 Ply 100 Percent Twisted Wool Compounding Pad

8.5 inch 4 Ply 100% Twisted Wool Compounding Pad

www.autogeek.net

Amazon.com: Meguiar’s M100 Mirror Glaze Pro Speed Compound, 32 oz: Automotive

Buy Meguiar’s M100 Mirror Glaze Pro Speed Compound, 32 oz: Polishing & Rubbing Compounds - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

For my repairs, I didn't even end up using the black foam pad and 3M Perfect it at the end. Everything ended up nice and glossy. I'll probably polish the whole boat at the end of this season though, just for maintenance.

For the sanding, I believe I started my wetsanding at 220 grit and worked my way up to 2000 grit (220, 320, 400, 600, 1000, 1500, 2000). If you aren't doing huge areas I had great luck using the 3M Automotive double-sided sanding sponges. Got them in the automotive section at Walmart. Each sponge will be double-sided with a different grit on each side (180, 220) (320, 400), etc. I used these for my wetsanding and everything stayed nice and level like using a sanding block.

The most important thing when ordering your gelcoat patch paste kit from Spectrum is ensuring you get the correct color. Have your model, year, and Hull ID (HIN/VIN) and give Spectrum a call to get the exact part # for the kit you need to order.

And finally, when wetsanding, take your time and make sure you have removed all the sanding scratches before moving up to the next grit. A flashlight is helpful as well as looking at the sanded area from different angles.

 

[tdonoughue]

I guess the main thing I would add is consider whether you have enough good scratches to go for the gelcoat repair. I waited until I had a good collection. It is a lot of work to set up to take care of 3 scratches. I would say if you are seeing white, you definitely need to do a red gelcoat repair. If you are just still seeing red--consider whether you need to do anything. Yes, you will still have a scratch there, but who will know? If you try to sand/buff it, you may go through to the white (and then you are back in gelcoat repair territory--only over a flat surface rather than a single scratch).

Found my original scratch repair writeup... https://jetboaters.net/threads/gelcoat-repair-question.9039/

 

[Inthrustwetrust]

I decided it was time to do some repair work. After a hurricane last year the slips at the launch we use are in rough shape. I use fenders but I’ve managed to get some scratches. I’ve never really done any wet sanding/buffing/waxing/polishing. I watched some YouTube videos and figured out the best way to attempt the repairs. I started wet sanding with 1000, then 1500, and 2000. I was pretty satisfied with the results. Used a rotary buffer with wool pad and 3m marine compound. Then used the harbor fright orbital buffer with foam pad and 3m polish. Couple spots turned out great, but I have other spots that don’t have that perfect reflective glassy smooth finish. They don’t look bad by any means, but when I look at them from certain angles I can see they are more dull than the factory finish. I’m nervous about over polishing and burning the gel coat, so I’m curious what anyone with more experience recommends to get that nice reflective finish. Thanks!

 

[RobbieO]

I decided it was time to do some repair work. After a hurricane last year the slips at the launch we use are in rough shape. I use fenders but I’ve managed to get some scratches. I’ve never really done any wet sanding/buffing/waxing/polishing. I watched some YouTube videos and figured out the best way to attempt the repairs. I started wet sanding with 1000, then 1500, and 2000. I was pretty satisfied with the results. Used a rotary buffer with wool pad and 3m marine compound. Then used the harbor fright orbital buffer with foam pad and 3m polish. Couple spots turned out great, but I have other spots that don’t have that perfect reflective glassy smooth finish. They don’t look bad by any means, but when I look at them from certain angles I can see they are more dull than the factory finish. I’m nervous about over polishing and burning the gel coat, so I’m curious what anyone with more experience recommends to get that nice reflective finish. Thanks!

1000,1200,1500 is the best way to go. Gelcoat is durable but very soft. The owner of a gelcoat/fiberglass repair shop said any minor scratches and blemishes can be fixed this way with good results. When they had my boat for repairs, one of the lifting strap shackles gouged my gelcoat pretty good. I was durprised how easy it cleaned up. The 1500 will get a nice gloss finish. I wet sanded and used quality paper.