Cleaning a GRP Hull

andythefiddler

andythefiddler

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Hi all,

I was surprised not to see a thread on this!

My Hull needs a good clean and polish before it goes back in the water.

T-Cut has been suggested for cleaning before 2 coats of UV protection wax polish, rather than silicone based.

I thought I'd tackle the group mind on this.

It may be a machine polish or it may be by hand - Which I would not be looking forward to.

Andy
 
andythefiddler said:
Hi all,

I was surprised not to see a thread on this!

My Hull needs a good clean and polish before it goes back in the water.

T-Cut has been suggested for cleaning before 2 coats of UV protection wax polish, rather than silicone based.

I thought I'd tackle the group mind on this.

It may be a machine polish or it may be by hand - Which I would not be looking forward to.

Andy
Click to expand...

Hi Andy I used a diluted Oxalic acid solution to get most of the Stains and markings of the boat then 600 wet sanded then 800 wet sanded then 1000 wet sanded (all by Hand) then went down the coarse polish then fine cut polish I used Presta products , with a good buffing machine with the recommended buffing heads 1 white 1 yellow 3M products.
Then waxed with CARNAUBA Luxury paste wax (no silicone)
This was on a bad and dirty hull and took 4 days of prep and work , the hull is 40 years old and now you can see you face in it even had people come over and compliment the shine in the yard,
I recommend a good buffer with variable speeds I used a De Walt , expensive but worth the time and effort .
Some stages can be missed if the hull is not too bad .
I got all my products from these guys
https://www.slimsdetailing.co.uk/finishing/car-wax/page/3 (No affiliation , just the products I researched and they had all in stock)
Hope this helps
 
Whether it needs cutting depends on its condition. My hull is about 20 yrs old and has only ever been polished and waxed, and for the last ten years only waxed.

I usually start off by using a gel cleaner, usually International, followed by a wash down. Unless it is chalky, you could go straight on to a polish. My hull is white, with the HR blue band. The blue does need to be cut, which I do with a rotary pad. There are many machines for the purpose but I find them too heavy and prefer a lambswool pad on a drill. The polishing and waxing I prefer to do entirely by hand. Another product that you might find useful is Startbrite Colour Restorer polish. This is a bit more abrasive than ordinary polishes and can be very effective. Also, after waxing with solid wax I use a wax sealant, from International. this is a liquid and takes very little time.


There are all sorts of variations that people use, and they probably all work much the same. The chief thing is to work at a comfortable height and for most boats this will mean that using a platform instead of a ladder makes it much quicker and easier.
 
andythefiddler said:
I was surprised not to see a thread on this!
Click to expand...

You might have had more luck if you'd searched for "topsides", which I presume is what you wish to clean.

Posts #2 & #3 give good advice. But if might be helpful if you could clarify whether merely cleaning is required, or the removal of scratches/dullness/chalkiness. It makes a considerable difference to the job required.
 
Hello,

Yes, all good points.

There is 'a bit' of chalkines' though not I would say bad, but attention needed this year.

Yes topsides would be a good description too, above the waterline.

If I don't do it it will start to get out of hand I fear and having just had the electronics sorted and the mast stepped for other work seems a good idea to send her back into the water in good shape all round.

I have a few GRP repairs to manage too, but very few.

Bit of a test patch on port bow section.

IMG_1267.jpg
 
That is not an old boat, so if it were me I'd do some basic work, maybe using the mildest abrasive or just polish and see what it looks like next year. It might be that after a year or two it will have improved enough to avoid needing any harsh work.
 
johnalison said:
That is not an old boat, so if it were me I'd do some basic work, maybe using the mildest abrasive or just polish and see what it looks like next year. It might be that after a year or two it will have improved enough to avoid needing any harsh work.
Click to expand...

Agree! I'd wash it with sudsy water and cheap own-brand "cream cleaner" to remove grime. Then 2 coats of Meguiars #45 Polish, followed by 1 or 2 coats of Meguiars #56 Pure Wax. The Meguiars products are very easy to apply and buff off by hand, and leave an excellent finish. I'd avoid using any mechanical polisher on the hull until after you've tried doing it by hand.
 
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The gel coat on your hull will be quite thin, so be careful with any cutting compounds. The gel coat will have been sprayed on to the mould, not brushed. It will be only about 0.5mm thick compared to a brushed gel coat the can be 2 to 4mm depending if a single or double coat. The sprayed gel coat can be slightly more porous as some of it is slightly dried by the air before it coats the mould. This was all told to me by an expert fiberglass repair man who was doing a repair on a motorboat moored a couple of berths away from my boat.
 
Re: Cleaning a GRP Hullm

Oh good! Just the subject that is on my mind.

For fifty years I owned wooden boats and happily painted the topsides and was rather smug about all that polishing. Now I have had my come-uppance!

Am confronted with an acreage of seven year old Awlgrip, once bright red, now pink and chalky..



An experiment on a small patch shows that it can be brought back to bright red...
So far, I have bought a polisher... I think a small scaffold tower is in my future... what do I need by way of cutting and polishing stuff - the chandlery shelves are baffling!

Help!
 
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Re: Cleaning a GRP Hullm

I am taken the easy route this years here In Tunisia they will clean the top side then polish and finish off with a waxing .
Quite expensive €60 , it took me all about 5 second to agree to have it done .
 
Re: Cleaning a GRP Hullm

Minn said:
An experiment on a small patch shows that it can be brought back to bright red...
So far, I have bought a polisher... I think a small scaffold tower is in my future... what do I need by way of cutting and polishing stuff - the chandlery shelves are baffling!

Help!
Click to expand...
That's quite a height to be working at! My own 1.5m keel seems high enough to me. The £120 or so that I paid for a platform was money well spent as far as I am concerned. In your case safety is going to be important and a proper platform necessary. As for the products, I think that technique is probably more important than which you use. I tend to get whatever is available.
 
Re: Cleaning a GRP Hullm

Minn said:
Oh good! Just the subject that is on my mind.

For fifty years I owned wooden boats and happily painted the topsides and was rather smug about all that polishing. Now I have had my come-uppance!

Am confronted with an acreage of seven year old Awlgrip, once bright red, now pink and chalky..



An experiment on a small patch shows that it can be brought back to bright red...
So far, I have bought a polisher... I think a small scaffold tower is in my future... what do I need by way of cutting and polishing stuff - the chandlery shelves are baffling!

Help!
Click to expand...

Hi I used a cutting compound then moved onto a finer cutting , and used a good buffing machine , this will make your life easier, but be careful not to burn through , after than a good wax by hand with no silicone . see my post 2 for the company I used but there are other products
 
Re: Cleaning a GRP Hullm

Minn said:
Oh good! Just the subject that is on my mind.

For fifty years I owned wooden boats and happily painted the topsides and was rather smug about all that polishing. Now I have had my come-uppance!

Am confronted with an acreage of seven year old Awlgrip, once bright red, now pink and chalky..



An experiment on a small patch shows that it can be brought back to bright red...
So far, I have bought a polisher... I think a small scaffold tower is in my future... what do I need by way of cutting and polishing stuff - the chandlery shelves are baffling!

Help!
Click to expand...

This article will certainly help you, even though it is talking about gel coat rather than Awlgrip, as the principle is the same. I used the advise and this is the results. The gel coat was dull and creamy in colour and became white and shiny.





 
Re: Cleaning a GRP Hullm

Minn said:
Am confronted with an acreage of seven year old Awlgrip, once bright red, now pink and chalky..
Click to expand...

It would be useful if you could determine whether the boat has been painted with classic Awlgrip or with Awlcraft 2000. If you then get in touch with Awlgrip, you should find that they will be helpful in suggesting which products you can safely use on it.

Some years ago, I had the faded blue stripes on my old HR resprayed with Awlcraft 2000. There were some minor quality issues and the local Awlgrip technical rep actually came along and inspected the boat with me and suggested remedial action.
 
Re: Cleaning a GRP Hullm

alahol2 said:
Our resident expert, Marine Reflections, did an extensive test of waxes/finishing products (http://www.ybw.com/forums/showthread.php?443397-Protection-product-test&highlight=protection+product )and came to the conclusion that 3M Scotchguard Marine Liquid Wax was the most effective conventional finish.
I use Farecla G10 to get the shine back (machine or hand) then the 3M to protect.
Click to expand...

But the 3M wax actually came second in the tests; Gtechniq was the best product.
 
Re: Cleaning a GRP Hullm

If a white topsides ... start with a simple wipe of oxalic acid mix to the correct ratio and then make a decision if you need to do anything else.

Last time i did mine it was looking bad... A year around scotland and norway there were yellow waterline marks, a few rust stains and so on. I thought it would need a full cut and polish but after 20 mins of oxalic acid it was bright white do I left it at that. Obviously rinse the oxalic off though.
 
Re: Cleaning a GRP Hullm

northcave said:
If a white topsides ... start with a simple wipe of oxalic acid mix to the correct ratio and then make a decision if you need to do anything else.

Last time i did mine it was looking bad... A year around scotland and norway there were yellow waterline marks, a few rust stains and so on. I thought it would need a full cut and polish but after 20 mins of oxalic acid it was bright white do I left it at that. Obviously rinse the oxalic off though.
Click to expand...

Yes. I think that sometimes people attempt too much. This is us in our 17th season. The white has only been treated with an Oxalic product from Yachticon while the blue has been cut before waxing. This was after having our AF taken off, hence the bare patches.

006%20copy.jpg
 
Re: Cleaning a GRP Hullm

johnalison said:
Yes. I think that sometimes people attempt too much. This is us in our 17th season. The white has only been treated with an Oxalic product from Yachticon while the blue has been cut before waxing.
Click to expand...

Yeah we have a blue stripe also and that needs polishing. Not sure how much you boat specific oxalic cost but this is what I use and works fine. Not thickened though.

https://www.ebay.co.uk/itm/1kg-Oxal...h=item1e6cad1a49:g:IVgAAOSwBLlVACMc:rk:6:pf:0
 
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