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GRP or not GRP


Cliffy

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In danger of sounding thick.

 

I keep reading that polishing GRP requires different polish than polishing steel/aluminium

 

How do I know which panels are GRP, if any. I assume the curved panels GRP but what about the flat side panels.

 

I have a 2004 Autotrail Tracker.

 

 

 

.

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Guest pelmetman
I use "Mer" on all of it ;-)...........If the GRP has gone flat then you might need a different polish to revive it, which is available from any yacht chandlers :D
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Cliffy - 2013-03-12 9:27 PM

 

 

In danger of sounding thick.

 

I keep reading that polishing GRP requires different polish than polishing steel/aluminium

 

How do I know which panels are GRP, if any. I assume the curved panels GRP but what about the flat side panels.

 

I have a 2004 Autotrail Tracker.

 

Just use a good quality automotive (or marine) polish for everything that needs polishing.

 

See this earlier thread:

 

http://www.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Pledge-Polish-Motorhome/22058/

 

 

 

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Cliffy - 2013-03-12 9:27 PM

 

 

In danger of sounding thick.

 

I keep reading that polishing GRP requires different polish than polishing steel/aluminium

 

How do I know which panels are GRP, if any. I assume the curved panels GRP but what about the flat side panels.

 

I have a 2004 Autotrail Tracker.

 

 

 

.

Curved panels aren't always GRP they could also be Aluminium or ABS plastic.
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I think you will find that your Tracker has GRP bodywork, I wash with a wash and wax from Aldi it contains Carnuba wax. Silicone polishes can cause crazing on GRP, Mer certainly contains silicone, I have just used some to polish the end of a piece of Acrylic rod, it with the use of some 600 grade abrasive cloth and then polish off with a soft cloth came up with a brilliant finnish.
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Guest pelmetman
PJay - 2013-03-13 11:27 AM

 

We used MER on our GRP boat, and found that it went very yellowy, in the sun , so stopped using it. Probably Ok on any colour but white body.

PJay

 

Never had any problems with it on my boat or camper :-S...............

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Guest peter

Silicone does not craze GRP. Stresses most certainly do, around screw holes and fixings etc.

It just makes it difficult to repair, as you have to remove any silicone or the new glass will not adhere, just as you do with cars etc.

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peter - 2013-03-13 1:35 PM

 

Silicone does not craze GRP....

 

I echo Peter's statement.

 

Autoglym is a major producer of automotive polishes and all of these contain silicone. The information on Autoglym polishes says that they are "ideal for glass fibre surfaces" and within the Autoglym website's FAQ section is this:

 

"Q. How effective is Autoglym on GRP boat hulls?

 

A. Autoglym Super Resin Polish is very effective on GRP boat hulls, especially if you follow up the polish with an application of Extra Gloss Protection, a wax sealant that will protect your polished GRP and ensure it stays better for longer."

 

This issue has been mauled over on the forum in the past (as should be evident from the forum link I gave earlier).

 

If there is credible evidence that polishes with a silicone component can damage GRP I've yet to encounter it. Conversely, expert opinion seems to be that it does not.

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The hand book for Rapido motorhomes with GRP panels tells you in BIG CAPITAL LETTERS NOT TO USE ANY POLISH CONTAINING SILICON AS IT WILL DEGRADE THE GEL COAT.

 

Why take the risk when using the correct polish for the job will cost no more than some of the alternatives. We used Starbright Marine Polish on our Rapido which we had for six years from new. The finish was as white and possibly even more glossy than when new. We were often asked what we used on site.

 

The date of your Tracker is round about the time that AutoTrail changed prom painted alloy to GRP. If it is GRP the side will be one continuous sheet. If alloy it will have a seam in it where AutoTrail joined two sheets. Note this does not apply to all manufacturers as some use single sheets of painted alloy to make the sides.

 

If you use a good quality silicon free marine polish it will not matter as it will be safe to use on all surfaces.

 

As regard the comment that silicon will not cause crazing that may well be true but that is not thje problem. What happens is that it degrades the gel coat which can lead to a dull appearance and or yellowing.

 

Auto Gleam claim their polish is safe to use on GRP but I see no reason to risk it rather than use the correct polish for the job.

 

Incidently I notice that our dealer, Johns Cross who have just switched to selling AutoTrail now stock Starbright Marine Polish in their shop.

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Colin Leake - 2013-03-13 4:58 PM

 

The hand book for Rapido motorhomes with GRP panels tells you in BIG CAPITAL LETTERS NOT TO USE ANY POLISH CONTAINING SILICON AS IT WILL DEGRADE THE GEL COAT.

 

If you use a good quality silicon free marine polish it will not matter as it will be safe to use on all surfaces.

 

As regard the comment that silicon will not cause crazing that may well be true but that is not thje problem. What happens is that it degrades the gel coat which can lead to a dull appearance and or yellowing.

 

Auto Gleam claim their polish is safe to use on GRP but I see no reason to risk it rather than use the correct polish for the job.

 

Incidently I notice that our dealer, Johns Cross who have just switched to selling AutoTrail now stock Starbright Marine Polish in their shop.

As I've said in threads about this in the past, I've had my boat over 20 Yrs and used silicone polish all the time and it has not degraded the gelcoat. All the boaters I know do the same and their boats are not degraded. Do you really think that owners of boats that cost over 100k would intentionally use a product that would damage it? I will conede that a wax finish lasts longer than silicone, but it costs a lot more and you have to strip off the old wax before re-coating to get the best finish. Persoanlly I use vinyl floor liquid polish on my boat and it lasts at least a year and gives a brilliant permanent shine. I think brownhills sell a similar polish and market it as motorhome polish, it's a white liquid.
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I had an 1988 Autosleeper Talisman with a GRP monocoque Body, The Gelcoat was intact, but very 'Chalky' and never really shone when polished (with Bog standard car polish), no matter how hard or long you rubbed for, even using a power buffer never touched it. I phoned Autosleeper and they recommended 'Farecla Paste', I managed to get some cheaper off of E-Bay, and it worked, a lot of hard work though, It removed all the 'Chalky' haze off and actually 'Shone'. (get to the Point Man !)

I suspect that that old van had never seen a 'Yacht Polish' in it's whole life and had always been polished with Bog Standard car polish (containing silicone) It didn't damage the GRP, (mind you it was Thick on those early Autosleepers) BUT it did leave the Chalky 'Haze' that I couldn't Shift. So, I think a Yacht polish or any polish NOT containing silicone is probably the best way to treat GRP, I now have a New Autotrail with a nice shiny GRP Body, I will be using a Carnuba wax based polish called 'Showroom Shine' , (yes the one on the TV, but get it cheaper on flea-bay) by Greased Lightning. Mainly because it is a 'Doddle' to completely polish the van with very little effort. Ray

 

Perhaps Rapido give their advice because the Gelcoat now fitted is not particularly thick, that may be the same with Autotrail of course.

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Rapido warns against using polishes containing silicone for their motorhomes, but cliffy does not own a Rapido. As far as I’m concerned this “silicon polishes harm cured unpainted GRP surfaces” claim has no foundation but, if one owns a Rapido and Rapido says “Don’t”, why should one ignore that instruction?

 

The ‘chalking’ phenomenon mentioned by Rayjsj is not that rare and it can happen with paint finishes as well as GRP gel-coat. See:

 

http://www.ybw.com/forums/showthread.php?52062-what-does-chalking-mean

 

(I’m sure I remember George Collings reporting in MMM how he had polished the dulled GRP on his Auto-Sleepers Clubman using Farecla products as Ray describes.)

 

Cutting back the top surface of the paint/gel-coat with an abrasive compound may not offer a long-term solution. I owned a car where, a year after a respray, the paint on one panel dulled. Although I could restore the shine, the cure was temporary and the panel needed regularly re-polishing and waxing.

 

Other than the fact that using a polish with silicone in it may complicate future repairs (and that will be true for painted finishes as well as unpainted GRP), as I’ve said earlier I’ve yet to encounter anything that causes me to believe such polishes harm cured unpainted GRP.

 

There’s a discussion here regarding GRP boats

 

http://www.ybw.com/forums/archive/index.php/t-237550.html

 

As Colin suggests, if a motorhome owner’s vehicle has unpainted GRP parts, it’s possible to obtain silicone-free polishes if the owner is wary of ‘silicone damage’. However, care will be needed to ensure that a polish is genuinely silicone-free, as most aren’t. Colin mentions Starbright Marine Polish, but...

 

https://www.whitworths.com.au/main_itemdetail.asp?cat=174&item=65062&intAbsolutePage=29

 

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Well I'll be a Monkeys Uncle, Staybrite is a 'Silicone based product' !! so much for 'Yacht Polish' being the 'way to go' then.

Yes Cliffy, on here, ALL you can hope for are 'opinions' some experience based, some 'Book' knowledge based, Some (very few) Scientific based, plus a lot of 'Likes', 'Dislikes' and some downright bigoted , but All just opinions, A few Heads are better than just one though.(in my opinion !) Ray

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well if the manufacturers make the polish and say its for fibreglass whether it contains silicon or not they aren't gonna let you slather it all over and stand back and watch your MH melt (!) :-D

so its starbright for me link below

http://www.sussexmarinesupplies.com/product_info.php?cPath=73_75_80&products_id=5&osCsid=1e1196122b6686ea28f1bb0092448ad8

 

jonathan

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I have used autoglymn super resin polish for cars, boats and motorhomes for many years and consider it too be the very best product for GRP and car bodywork. Also reccomend "one dry wash" products in between seasonal polishes.
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Regarding Starbrite polishes, this 2008 USA boat-related thread may be of interest, as much as anything because a Starbrite representative was participating.

 

http://www.thehulltruth.com/boating-forum/198647-starbrite-teflon-wax.html

 

On Page 3 there's a 12-30-2008, 04:51 PM posting from "Leverage" in which he says:

 

"Starbrite Marine Polish with PTEF for example contains Petroleum Distillates, Kerosine, Silicone & Alcohol. These ingredients promote Oxidation and Fading. They're also flammable and contain health hazards. Don't get it in your eye."

 

PTEF is Starbrite's name for polytetrafluoroethylene which is more commonly known by the brand-name "Teflon". It's an inert material that, within a polish, shouldn't harm the material being treated whatever the material's type. Whether Starbrite Marine Polish also contains silicone is anybody's guess, but the Starbrite representative did not deny this and Starbrite (as far as I'm aware) does not claim that its Marine Polish with PTEF is silicone-free. I'm guessing that (in the States at least) use on unpainted GRP of polishes with silicone in them is not a big issue.

 

If a motorhome owner is silicone-phobic about polishes, there seem to be two options. Either buy a polish specifically advertised as silicone-free (GOOGLE on "silicone-free polish") or, if a particular polish is attractive and it's not advertised as being silicone-free, to seek confirmation of the ingredients from the product's manufacturer.

 

 

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I must admit that the Starbright polish we use is the Premium Marine Polish with PTFE which as far as I know is silicon free. I polish the motorhome in the Spring and late Autumn. It does give a superb finish and lasts very well. I must admit that it is expensive and not as easy to apply as they would have you believe. Its the polish that most serious racers use on their racing dingies because of its low resistance. I'd rather hoped for an improvement to say 45mpg fuel consumption but no such luck.
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Its PD's that primarily undermine gelcoat and envariably polishes that contain PD also have a degree of silicone - the two need one another as part of the composition in the majorty of polishes.

 

Gelcoat is not 100% impervious to moisture so a good wax - ie caranuba is always a better option.

GRP is very complex art and the integrity of gelcoats can be effected considerably by the resin and glass substrate it is applied to.

 

Polish alone will slowly erode gelcoat, my advice would be - minimise polishing, maximise waxing.

 

As for the chalky effect, this is normally attributed to pigment errosion. I knew a chap with a red GRP hull who would polish it every weekend only for it to turn pink overnight! - once pigment starts to leach badly it's normally too late to rectify.

 

Many polishes contain chalk, so ironically polishing [not waxing] can excerbate the problem.

 

WAX to the max gentlemen!

 

 

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