Yellowing gelcoat - solution?

[Scream And Fly]

My Carolina Skiff has a white gelcoat, but parts of it are yellowing. Not sure why, the boat is not left outside. From what I have read, the yellowing occurs from catalyzers in the gelcoat or solvents. I've read many solutions ranging from the use of oxalic acid to wet sanding.

I was wondering if anybody here has any solutions they have tried that have worked?

Thanks!
Greg

[XstreamVking]

Where is the yellow showing up at?

[Scream And Fly]

Where is the yellow showing up at?

I see some of it on the deck, and some on the sides. It's not consistent with waterline stains - mainly in corner areas.

[Ziemer]

Not sure it would work in your case, but I use the Power One on mine. The yellowing on mine though is staining from being in the water over long periods of time. I like it because it works the same as pure acid products, but is not as corrosive or abrasive. ;)

[Scream And Fly]

Thanks Jeff, I'll definitely look into that! I appreciate it!

[FUJIMO]

It may or may not be a surface yellowing that comes with age as the gelcoat cures over time. This is caused by poorly catylized and or mixed gelcoat, and/or the first layer of lamination resin applied on top of the gelcoat. Fairly common in mass production boat manufacturing. Sometimes happens in smaller shops & lower production number boats as well, but not as commom. Test a small area by wet sanding with 600. High speed buff with finish compound, while noting not to heat the surface while doing so. Under-catylized gels/resins can "post-cure" if subjected to heat from a high speed polisher & will ripple or wave the surface.

[FUJIMO]

Then again...it could just be some poor quality wax you've applied in the past, that has finally yellowed...:)

[XstreamVking]

Try some "on and off " hull cleaner. (acid) If that won't take it off, it is in the gell. Maybe all the way thru. Goo gone makes a good acid stain remover too.

[RobF]

decks are rolled gelcoat over chop, maybe its areas that were gelcoated after the boat had been made. Either at the dealer or the factory before you got it

[FUJIMO]

decks are rolled gelcoat over chop...
...or...maybe...chop over rolled gelcoat?;)

[FUJIMO]

Try some "on and off " hull cleaner. (acid) If that won't take it off, it is in the gell. Maybe all the way thru.
Yes, agreed, you could give "On and Off" a try. Good stuff. (Careful with it...It is acid.)

[RobF]

...or...maybe...chop over rolled gelcoat?;)


foam blocks, chopper gun, gelcoat

[FUJIMO]

decks are rolled gelcoat over chop, maybe its areas that were gelcoated after the boat had been made. Either at the dealer or the factory before you got it
Yes...This too is a possibility. You'd be surprised how many gelcoat repairs & area touch-up resprays are made "after" the boat leaves the mold at the factory. Fixes are needed due to "alligatoring", parts(boats) stuck to the mold, sharp corner chips broken due to excessive gel application in corners, laminators not using the appropriate size laminate roller(s) on the skin coat, sweat(water) dripping off the applicators forehead, causing multiple "fish-eye" contamination(s), hull slipping off the shop dollys onto the concrete floor, some dummy spraying aerosol spray silicone lubricant nearby during lamination, etc., etc., etc...lol...its endless.:rolleyes: Most of these quicky spray batches of gelcoat(for the repair), are a radically different recipe, and applied in an entirely different envirement, that the boats mold application was.

[albypine]

It's because your hydro stream is lonely and doing bad things to your skiff while you're asleep :D

[FUJIMO]

It's because your hydro stream is lonely and doing bad things to your skiff while you're asleep :D
Jeeees...Never thought of that. Don't know why...

[RobF]

for a guy with all that fancy camera stuff you think a picture would have been included :)

[bullet20vee]

Try wetsanding and buffing a test spot to see if that helps. I just did a white bass boat for a neighbor that had the same issues. I started with 800 and went to 1500 on the first spot and it looked new. I went with 1000 on the first cut on the other spot and it worked the same. I wound up doing the whole top cap because the spots that were wetsanded looked better that the rest. I also used the Protec sealant/polish and it turned out great.

[Markus]

foam blocks, chopper gun, gelcoat

That makes it topcoat, doesn't it?

[RobF]

That makes it topcoat, doesn't it?


not sure what the question is.

The exterior the boat is out of the mold, it is smooth and shiny. He has some yellow spots here and there- my guess would be from repairs that were made.
The interior of the boat is rolled gelcoat over raw chopper gun. they lay foam blocks in place- chopper gun over that, and then roll gelcoat. its a raw rolled finish not a smooth finish that can be sanded or polished.

[Markus]

not sure what the question is.

If it is on top, it is topcoat. If it is applied to the mold, it it gelcoat.

What you describe sounds like topcoat.

[RobF]

If it is on top, it is topcoat. If it is applied to the mold, it it gelcoat.

What you describe sounds like topcoat.


I guess when you put it that way- yes.
It is still gelcoat, but it is raw rolled, not able to be sanded and polished.
I always considered "topcoat" to be more of a paint or a finished surface, not a raw finish.
I would not consider gelcoat rolled in a bilge to be topcoat either, but I guess it is "on top" of a surface :D

[flabum1017]

Stop missing when you pee overboard...... :D :leaving: