How to get white gelcoat back to white

[MohavValley]

I`m working on a project I picked up and I`m wondering if it`s possible to get the white gelcoat to either lighten up a few shades or more or get it back to ultra pure white.

There`s thousands of shades of "white" and this boat`s current white is more like a light mocha or Swiss Coffee and I`d like to get it back to or as close as possible to ultra pure white.

I have a rotary buffer with a Lake Country white wool pad, a LC yellow wool (for polishing), a LC Orange curved waffle (for light polishing). On product I have Presta Super Cut Compound, Regular Cut Compound, and Polish (plus a shit load of car products, DA, pads, and products if needed). Current plan is Presta compound, Presta polish, colonite 446 super double coat as a sealer.


So far I used the rotary with the white wool pad and the Presta regular cut down one side. It got most of the oxydization off but it didn`t really remove most of the marks in the gel coat or really clean it up and make it white-white. It`s shiney but not super white, still kind of yellowish. I haven`t polished it yet but I`m holding off until I see if there`s something I can do to make the white whiter or possibally the red more fire truck red vs maroonish-red?

The rear upper parts of the sides have been re-shot with more of a pure white gelcoat and I`d like to try and get closer to that white, if possible.

Here`s some pics

 

[MohavValley]

Heres how the side turned out.

In these you can see the difference between the original swiss coffee and
the fresh pure white and some of the original white that was covered up from the sun.

The hatch cover white edge VS. the swiss coffee gelcoat

Also have some burn marks from being covered in the sun

 

[MohavValley]

Is it possible to lighten the gel a few shades with wet sanding it, or using a different product, or possibally wiping it down with a solvent (mineral spirits, aceatone, etc prior to buffing???

I have not ran the Super Cut yet, I always start off with the least agressive product to get the job done, so not sure if that`ll whiten it up or handle the burn marks?




Thanks

 

[HubbaHubbaLife]

Vintage Warlock... sweet 27'.... will she see some offshore jumping perhaps? Definitely built for it.

 

[DarkHorseRacing]

You could have a yellowing clear over the white. I'd recommend like a pass with a 2000 grit wet sander, see if you can take just a skosh of the clear off and see if it lightens up. Note that you might need to hit that area with a cut & polish product to get the haze from the wet sanding out so you can get it shiny and see the difference better.

Just remember, less is more. Light pressure, lots of water. Go until the water run-off just gets milky. Might be hard do see against the white of the boat.

 

[Gelcoater]

You could have a yellowing clear over the white. I'd recommend like a pass with a 2000 grit wet sander, see if you can take just a skosh of the clear off and see if it lightens up. Note that you might need to hit that area with a cut & polish product to get the haze from the wet sanding out so you can get it shiny and see the difference better.

Just remember, less is more. Light pressure, lots of water. Go until the water run-off just gets milky. Might be hard do see against the white of the boat.

I really doubt there is clear on the white.
We only did that typically when we were floating pearl over it and the clear does cause a Browning but different than what I see going on here.

@MohavValley take caution before trying to “take off the clear”

The question is why was some of the white reshot at some point?

Like said there are many shades of white.

Some white gelcoat has a slight blue, some has a slight brown or yellow.
For yours I would try stripping all the wax first.
Typical carnuba can yellow white after time. I’d start there.
There is a chance there is just a difference between the OG white and the reshot sections that at the time were not noticable but old age has caught up with it.
Your thought process of least aggressive cut is spot on. Don’t take more than is needed, once it’s gone it’s gone.

 

[DarkHorseRacing]

I really doubt there is clear on the white.
We only did that typically when we were floating pearl over it and the clear does cause a Browning but different than what I see going on here.

@MohavValley take caution before trying to “take off the clear”

The question is why was some of the white reshot at some point?

Like said there are many shades of white.

Some white gelcoat has a slight blue, some has a slight brown or yellow.
For yours I would try stripping all the wax first.
Typical carnuba can yellow white after time. I’d start there.
There is a chance there is just a difference between the OG white and the reshot sections that at the time were not noticable but old age has caught up with it.
Your thought process of least aggressive cut is spot on. Don’t take more than is needed, once it’s gone it’s gone.

Fair enough. I just know we have clear because of that pearl and its yellowing like a mofo. I've thought about doing what I suggested to try and lighten it up. Not enough UV inhibitor in the clear?

 

[Gelcoater]

Fair enough. I just know we have clear because of that pearl and its yellowing like a mofo. I've thought about doing what I suggested to try and lighten it up. Not enough UV inhibitor in the clear?

Don’t do it.

Is something pretty well known in the industry.
In the mold clear turns white to off white.
Pearl or no.
The yellowing or Browning is (I believe) Titanium.
Theory is when the catalyst is introduced and mixed, the oxygen in the catalyst oxidizes the titanium.
In the can it has a pink tint to it.
After mixed it turns, I can see it as I pour it into the pot.

I’ve played with a couple cleats that are supposed to be “more clear) and they may have been?
Don’t know as I ripped it out of the mold and threw it in the trash.
It had curtained, fish eyed, sagged, every bad thing clear can do it did.

The rep told me I didn’t apply it right.
I told him he made it wrong.

He suggested a method that just won’t work in the real world. It may on a 2 foot panel in his climate controlled lab.
And again suggested I applied it incorrectly.

I told him I applied it the way I have been since he was in the 2nd grade
And, apparently applying it wrong all these years is why my work is on the covers of magazines

I don’t use that guys stuff anymore except his Dark green.

I’m no chemist but some stuff works and holds up, some less so.
Even from trusted vendors.
As rules and refs change so does the formula and along the way, issues arise.

Like yellow turning white and clear that isn’t exactly clear.

 

[MohavValley]

Hi Gelcoater,
I've detailed cars for 20+ years (not to earn a living), based on what I know and have researched, when the gel oxidizes, the pores open up and the boat has sat for a while collecting dust & dirt. I think the yellowing/Browning is dirt in the pores as it's sat for the last 8-10 years.

The resprayed white is what I've had done on purpose to spray over original graphics above the rail line.

I've also posted this up on other forums and have stumbled across oxalic acid and Marykates on & off hull & bottom cleaner ( which is a mix of Hydrocloric Acid/Muratic Acid, Phorphoric Acid, & Oxyalic Acid). This stuff is commonly used on sail boats to clean rust & calcium stains/ Browning on sail boat gel coat. From what I've found it looks like it'll clean up what's in the pores and then I can continue cutting it and Polish and seal it.

Have you heard of any I'll effects from these acids on the color graphics (they're gel also)?

Thanks

 

[Gelcoater]

Hi Gelcoater,
I've detailed cars for 20+ years (not to earn a living), based on what I know and have researched, when the gel oxidizes, the pores open up and the boat has sat for a while collecting dust & dirt. I think the yellowing/Browning is dirt in the pores as it's sat for the last 8-10 years.

The resprayed white is what I've had done on purpose to spray over original graphics above the rail line.

I've also posted this up on other forums and have stumbled across oxalic acid and Marykates on & off hull & bottom cleaner ( which is a mix of acids). This stuff is commonly used on sail boats to clean rust & calcium stains/ Browning on sail boat gel coat. From what I've found it looks like it'll clean up what's in the pores and then I can continue cutting it and Polish and seal it.

Have you heard of any I'll effects from these acids on the color graphics (they're gel also)?

Thanks

I have not heard anything good or bad about the acids so use caution!