White gelcoat yellowing problem ?

[pescaloco]

Hey Guys,

I do primarily marine detailing and some gelcoat/fiberglass work.
I am pretty familiar with gelcoat chemistry and application.

Here is my problem I have a particular brand of boats that we maintain and they all have issues in the same locations.

Typical of this Mfgr.
transom corners outside
scupper drains in transom wall
any tight outside radius, like a toe tail or steps
large flat sections like the eye brow (striation area)

The yellowing is uniform in some locations and in others it is deeper in the gelcoat with striations or a marbled effect.

The one I take care of full time is very well taken care of it is washed 1 time a week and waxed every 2-3 months others i see have the same condition with less aggresive maintence programs.

The Mfgr. tells me it is a problem with the maintenance of the boat and that all white gelcoat turns yellow anyway

I think that at least some of the problem is traped styrene that is reacting with the sun light (deeper yellow striations) the rest not really sure, but it does seem strange that a very well maintained boat has all the same problems that a much lesser maintained one has in all the same areas.

Ok experts what do you think ???

[ondarvr]

You're correct in thinking its the styrene reacting from UV rays.

This is very common on a radius because these areas can be more difficult to spray and the gel coat will tend to be thicker. Thick gel coat can have a higher level of styrene and/or resin near the mold surface which will yellow sooner than thinner areas. Sometimes sanding the surface will remove the yellowed layer and it won't come back, but other times the layer is deep enough that it yellows again.

The areas with striations are typically from spraying the gel coat at an angle and it being blown across the surface, this can allow the pigments and fillers to separate slightly from the resin and styrene. Plus if there are several pigments used to make the color, the difference in weight between them will make them separate.

While the quality of the gel coat will help prevent these problems, it comes down to how well it was applied.

On some molds the design can make it almost impossible to spray it correctly, so it doesn’t always mean it was the gel coaters fault.

[pescaloco]

Ondarvr,

Thanks so much for the detailed explanation I know it's not a maintanence related problem.

It's very enlightening to know the physics of the problem.

[cleanaboat]

Hi to all, I have been reading your problem with gel coat yellowing.
I have been working with this for many years.
it is not one cause it can be a few.
it seems to be a larger problem in very hot climates, also some boat brands can be affected more or less.
You can only treat the yellowing when it is vissible at the surface,
there is no permanent fix, how ever there is a system that is easily used to keep it away. and maintaine a white boat.

[pescaloco]

Hi to all, I have been reading your problem with gel coat yellowing.
I have been working with this for many years.
it is not one cause it can be a few.
it seems to be a larger problem in very hot climates, also some boat brands can be affected more or less.
You can only treat the yellowing when it is vissible at the surface,
there is no permanent fix, how ever there is a system that is easily used to keep it away. and maintaine a white boat.



Let me guess Topgear

If so I inquired and the cost was quite expensive and only sold as a complete kit with buff pads and all the stuff a detailer allready has.

Since this is your first post and this is an old thread I was wondering are you from that company ?

[cleanaboat]

No I am not from that company.
I am from Cleanaboat.com we manufacture boat detailing products.
Cleanaboat has developed a simple system that will assist in removing the yellowing its called Cleanashine Gel Coat Restoration Treatment.
3 products only to carry out the 1st part of the treatment, then you use your own buffing and polishing products to complete the treatment.
step 1, apply Cleanashine X-1.
step 2, use X-Pad to clean exfoliate the surface.
step 3, apply Cleanashine X-2.
Rinse wash off with fresh water then chamois dry
Machine buff and polish gel coat using your own polishing products.
Repeat above proceedures untill surface has been restored yellowing has been removed.
If some slight yellowing does reapear retreat the areas as described above.
Its easy to maintain your gel coat and keep it looking white.
Cleanashine X-1 & X-2 are water based they are not toxic corrosive.