fibre glass yellowing

[Brian Peters]

hello campers, i have a burstner t-star 710 (05) model. The problem i have is the fibre glass low profile section above the cab is going a yucky yellow colour mainly around the front marker light moldings, Is this just age related and if so can i restore the finish back to the gleaming white it once was, without reverting to trying to spray match the area with a white that might actually match.

[Basil]

Hi Brian,

 

Have you been using a silcone polish? Or are you in a high carbon pollution area i.e. under an airport flight path, near a dock, railway or motorway?

The reason I ask the second question is this has happened to our van when on holiday on the Rhine between the Rhine and the railway and is a known problem there.

In the first instance, use of silicone polish which can eventually discolour and soften the gel coat surface, you can use Feraclae G10 though there are other GRP cleaners available from boat chandlers this I have found best to polish off the discolourment, and then follow up with a proper GRP polish such as 'Starbrite' which I have found to be particularly effective. The use of this though is quite hard work, needs lots of 'elbow grease'.

In the second instance, heavy carbon deposit, I have found that Autoglym Engine and Machinery cleaner takes the yellow off easily, again follow up with a good polish with 'Starbrite' cleaner and polish or any similar GRP polish from a boat chandler.

There has been much talk about the effects of silicone polishes on GRP, though there is not much on the net, however I used to have GRP sailing cruisers and live near to where they are built and they have always stated that only silicone free polishes for GRP should be used on GRP as silicone has a detrimental effect, at the end of the day it is your choice.

 

Bas

[Brian Peters]

thanks for advice basil,i dont live in what i would describe as a high pollution area, and the cleaners i have used is "bobby dazzler" , turtle wax and autoglym.

I will look into GRP cleaner/restorers on line to see if i can find a product that will improve the looks of my van. many thanks again for your advic

:-D

[Brian Peters]

thanks for advice basil,i dont live in what i would describe as a high pollution area, and the cleaners i have used is "bobby dazzler" , turtle wax and autoglym.

I will look into GRP cleaner/restorers on line to see if i can find a product that will improve the looks of my van. many thanks again for your advic

:-D

[Guest peter]

Basil - 2008-01-28 10:10 AM

 

Hi Brian,

 

Have you been using a silcone polish? Or are you in a high carbon pollution area i.e. under an airport flight path, near a dock, railway or motorway?

The reason I ask the second question is this has happened to our van when on holiday on the Rhine between the Rhine and the railway and is a known problem there.

In the first instance, use of silicone polish which can eventually discolour and soften the gel coat surface, you can use Feraclae G10 though there are other GRP cleaners available from boat chandlers this I have found best to polish off the discolourment, and then follow up with a proper GRP polish such as 'Starbrite' which I have found to be particularly effective. The use of this though is quite hard work, needs lots of 'elbow grease'.

In the second instance, heavy carbon deposit, I have found that Autoglym Engine and Machinery cleaner takes the yellow off easily, again follow up with a good polish with 'Starbrite' cleaner and polish or any similar GRP polish from a boat chandler.

There has been much talk about the effects of silicone polishes on GRP, though there is not much on the net, however I used to have GRP sailing cruisers and live near to where they are built and they have always stated that only silicone free polishes for GRP should be used on GRP as silicone has a detrimental effect, at the end of the day it is your choice.

 

Bas

Please can people stop perpetuating the Myth that Silicone polish softens Gel Coat. It is simply not true. Otherwise half the boats and GRP cars would be a mushy mess. Anyone with proof of this myth please produce it.>:-)

[Basil]

Sorry don't agree its a myth. Hunter boats expressly state in their literature, when you buy a new boat from them, that you should not use silicone polish on GRP. Also why would special polish that is silicone free be made specifically for boats?

As always people must do what they want but having discussed this on more than one occasion with several boat builders, I am convinced by them it is not a myth, its your choice.

 

Peter why should anyone accept what you say that it is a myth any more than it isn't, what information do you have to base your comment on?

 

Bas

[Guest peter]

Basil - 2008-01-29 9:49 AM

 

Sorry don't agree its a myth. Hunter boats expressly state in their literature, when you buy a new boat from them, that you should not use silicone polish on GRP. Also why would special polish that is silicone free be made specifically for boats?

As always people must do what they want but having discussed this on more than one occasion with several boat builders, I am convinced by them it is not a myth, its your choice.

 

Peter why should anyone accept what you say that it is a myth any more than it isn't, what information do you have to base your comment on?

 

Bas

The fact that my 30 foot boat is 20 years old and shows absolutely no sign of Gel Coat degradation. Speak to boaters and the majority will tell you that they use either Mer or Autoglym. But as you say, it's peoples choice. As for the so called polish made specially for boats, because motorists won't pay the inflated prices. They think boaters have more money than sense. (some have) Like I said the argument for not using Silicone is the difficulty of removing it for hull repairs.

[Basil]

Hi Peter,

 

Having owned several Colvic's and laterly a Hunter 40, I can honestly say neither have any of mine shown any deterioration, but then I have never had silicone polish used on them, so far as I know. I will still follow the no silicone rule to be on the safe side as that is what I have been advised by the builders that I have dealt with. I have had friends that have had to have two pack spray coat to repair what was said to be deterioration due to unknown causes but suspected to be silicone damage, on boats that is.

Also, as I understand it, cars are different in that they are normally either spray painted from new or are laid up with a different material (Lotus I believe use polyester rather than the normal gel material) so are unaffected. most motorhomes that I have seen don't seem to use either of these processes so I will continue to err on the safe side. Thanks for your input though it would be interesting to get some definitive information on this subject.

 

Bas

[Guest peter]

Boats, Cars, Motorhomes all use either Polyester or maybe Epoxy Gel coat.

Some boats suffering from Osmosis do have to have a two pack Epoxy finish applied to the BOTTOM of them, after the Osmotic blisters have been removed. This is because Epoxy is totally waterproof, unlike a poorly appled Polyester. Epoxy Resin is very seldom used for building as it is very expensive.

[Derek Uzzell]

As the silicone polish 'danger' thing repeatedly crops up, out of idle curiosity I thought I'd attempt to obtain a definitive answer.

 

I know that Mel Eastburn has warned, in the past, that tests have shown that use of polishes containing silicone can damage the GRP used in glider construction. I'm aware that there are plenty of polishes being advertised as "silicone-free", hence suitable for use on GRP boats. I'm aware too that well-respected polishes (eg. Auto-Glym and Mer), that I understand contain silicone, claim that these products are suitable for use on GRP.

 

I'm also aware that polishes containing silicone should not be employed as a release agent on the moulds used in GRP-component construction and that (for obvious reasons) polishing 'through-coloured' GRP with a silicone-content polish is a unwise plan if there is the possibility that the GRP will need to be painted subsequently.

 

I did try, a good few years back, to pin the 'damage factor' down by contacting the Cheltenham firm that provided Auto-Sleepers with their monocoque GRP bodies and was told to use whatever A-S recommended - which, in fact, was a polish made by Farécla. I've also read what's been said in this thread.

 

(I'm just providing this background so that it's apparent I'm not starting from scratch!)

 

Anyway, I e-mailed CYB Glass Fibre (a company that should know what it's talking about) and asked whether a polish containing silicone might damage the gel-coat surface of cured unpainted GRP. I was told that it would NOT. This advice came from CYB's technical advisor who (so I was informed) has over 40 years experience in this field. I was also told that, should I wish to discuss the subject further, the advisor would be happy to oblige. I don't intend to progress this myself, but, for anyone wishing to do so, CYB's contact details are on their informative website.

 

http://www.cybglassfibre.co.uk/contact.html

 

Personally, over the years I've used a variety of polishes on unpainted GRP gel-coat surfaces and never seen any untoward reactions. Having said that, if I owned a motorhome, aircraft, boat, car, etc. whose manufacturer recommended a particular polish, that's what I'd use.