What do you use to polish up your white gel coat?

[JollyRodgers]

I did the antifoul the other week, so the bottom of the boat is looking very fresh now. However, this has highlighted some browny/yellow stains above the waterline and I was wondering what you guys find works best to get these back to a nice bright white colour and removing the stains.

I used (as recomended on an old thread here) a bit of Cilit Bang Grime and Lime with a kitchen sink sponge and that worked really well in removing any green/mouldy bits and stuck on things, however I still have the stains there. One stain in particular was coming out of one of the rear holes and had left a really big rusty/orange/brown leak down the side of the boat. I managed to clear this up a hell of a lot by using just some fairy liquid and washing it off with water, aswell as a little bit of light polishing with 2000 grit paper. I tried using T-Cut but found that it didnt really make any/much difference at all. Perhaps I wasn't using enough elbow grease?

Would an Orbital polisher on a drill work best for removing these?

There seem to be a LOT of products that do these and I was just wondering if anyone has had any success using them. I dont really want to spend out £100 on something if it turns out to be ****.

I think the main cause for this is that the previous owners didnt wash down the boat after each sail and leaving it on a swinging mooring. It doesn't look like its been polished up in a while.

 

[peter2407]

I used this stuff to great effect: http://www.wessexchemicalfactors.co.uk/product-detail.php?id=92

 

[jwilson]

Before you sand/polish away the gelcoat try some oxalic acid, either bought as powder from Ebay and mixed with water, or bought in a special (ie much more expensive) "boaty" product like Y10. Used on a warm day it will remove the browny-yellow stains very easily and quickly. See http://www.ybw.com/forums/showthread.php?296466-Isider-tips-oxalic-acid-cheapest-cleaner

 

[vyv_cox]

Oxalic acid in one form or another, from a DIY version costing £1 to one costing best part of £20 from your local chandlery, will remove most stains from hulls. Be very wary of using any abrasive methods - over the years these mount up and the gelcoat gets thinner and thinner until the glass fibres begin to show through. Enthusiastic previous owners of my boat have polished it to within an inch of its life.

 

[JollyRodgers]

I used this stuff to great effect: http://www.wessexchemicalfactors.co.uk/product-detail.php?id=92

Ooh that sounds good and VERY cheap!

How quick is it at removing stains? Is it wipe on/wipe off? Or do you have to leave it to soak in for 30 mins and scrub off?

I heard very good things about Starbrite Instant Hull Cleaner, which is £20 for 1Litre (again, I figured this was cheap too).

Before you sand/polish away the gelcoat try some oxalic acid, either bought as powder from Ebay and mixed with water, or bought in a special (ie much more expensive) "boaty" product like Y10. Used on a warm day it will remove the browny-yellow stains very easily and quickly. See http://www.ybw.com/forums/showthread.php?296466-Isider-tips-oxalic-acid-cheapest-cleaner

Yeah, I am really hesistant about using anything too abrasive because of gelcoat thinning issues. That's why I opted for the 2000 grade paper. I read about the acid before, but didn't read too much into it because I figured acid would be really bad against the gel coat - but I guess not?

Surely acid is an abrasive method though, as I imagine what it is essentially doing is burning the stain off?

Oxalic acid in one form or another, from a DIY version costing £1 to one costing best part of £20 from your local chandlery, will remove most stains from hulls. Be very wary of using any abrasive methods - over the years these mount up and the gelcoat gets thinner and thinner until the glass fibres begin to show through. Enthusiastic previous owners of my boat have polished it to within an inch of its life.

Acid seems like the way to go, and at £8.99 for 1kg of powder you cant really go wrong. Do you think 1kg would be enough for a 32' with reasonable brown marks?

Going to go down to the boat on Friday (before it gets lifted in) and try to clean up the last bits of it. I may get what peter suggested, but also some oxalic acid as back up or if there are any stubborn stains not coming out.

I guess after the stains have been removed I will need a wax or a polish to increase the shine and help prevent future stains, like you would on a car or motorbike?

 

[peter2407]

Its fairly much a wipe on wipe off job. I diluted some into a hand sprayer. You may need to do this a few times and/or go stronger.

 

[BruceK]

I'm not sure how good this is for your gelcoat with repeat use, but I used Starbright rust stain remover from the chandley to do some touch up work on the hull fittings once and with no elbow grease whatsoever the runs from where it was applied cleared up all the waterline staines completely. So marked was the difference I had no option but to use it all along the water line. A new white finish looked superb and nothing ever used before or since gave anywhere near the same results.

http://yachtchandlers.co.uk/acatalog/Rust-Stain-Remover-22-oz-MT089222GF.html

I however use Silky Cream Cleaner as standard for most GRP cleaning jobs.

 

[alahol2]

Acid seems like the way to go, and at £8.99 for 1kg of powder you cant really go wrong. Do you think 1kg would be enough for a 32' with reasonable brown marks?

A kilo should keep you going for many years. Use (say) a litre of warm water and dissolve as much of the powder into it as you can (a saturated solution). Don't breath the fumes. Add a bit more water and a squirt of washing up liquid.
On a warmish day, paint around the waterline and go off for a coffee. When you return the brown stains will have been magicked away. Possibly may need another coat or more depending on density of stains. Give a quick wash with your choice of detergent then add polish to taste.
The acid will definitely not affect the gel coat.

 

[skyflyer]

Just did it all last weekend. The photo shows my boat which a few hours before looked like the one behind it as far as stains were concerned

I used 500g of Oxalic acid dissolved in half a bucket of warm water, and then added a sachet of wallpaper paste (mistake - wallpaper paste should only ever be added to COLD water to get the full gloopiness, but it still gelled up a bit).
This gave me enough to do all the hull sides and transom and go back over the waterline a second time and I still have over half the mix left.

That got rid of the yellow

Then we started with a variable speed polisher using a wool bonnet (Machine Mart) and 3m compound

This was most expensive item of the process at £33 but well worth it.

I used about 2/3rds of the bottle to do the hull and then two coats of wax on top

This shows the before and after of a section as we did it

Total cost (excluding use of my mates polisher, and our time) about £50

 

[Spi D]

Oxalic acid should be tested before use on other than white gelcoat. Tend to bleach more than dark hulls like.

 

[JollyRodgers]

Just did it all last weekend. The photo shows my boat which a few hours before looked like the one behind it as far as stains were concerned

I used 500g of Oxalic acid dissolved in half a bucket of warm water, and then added a sachet of wallpaper paste (mistake - wallpaper paste should only ever be added to COLD water to get the full gloopiness, but it still gelled up a bit).
This gave me enough to do all the hull sides and transom and go back over the waterline a second time and I still have over half the mix left.

That got rid of the yellow

Then we started with a variable speed polisher using a wool bonnet (Machine Mart) and 3m compound

This was most expensive item of the process at £33 but well worth it.

I used about 2/3rds of the bottle to do the hull and then two coats of wax on top

This shows the before and after of a section as we did it

Total cost (excluding use of my mates polisher, and our time) about £50

Looks great, shame you didnt take some before pictures.

What does the wallpaper paste do? And arent you made to use the acid in warm water, so you didnt have an alternative?

I may buy some of the Oxalic acid and use 200g and dilute it up and go over the boat with that, then get a wool bonnet like your one and attach that onto a battery drill. I dont really have access to power (I am ashore and even though I have a solar panel, I want to conserve my charge for turning over the engine), wouldnt want to use an electric/corded drill if it is in the marina incase I electric myself.

Did you find that the 3M compound really made a lot of difference? Did it just bring the 'shine' back to it after the stains were removed? How long did it take to go around it. Also, any issues if you get the acid onto the antifoul? Will it make it run or ruin the paintwork?

Boat is going back into the water friday afternoon, so will have to see if I can get next day shipping for the acid. If not, will pop to the chandlery and grab some of the Starbrite instant hull cleaner and then do the rest of the polishing up in a dinghy when the boat is in the marina.

 

[skyflyer]

the wallpaper paste makes the mixture thick and jelly like so it clings to hull and doesn't run off. Yes you need to dissolve it in warm water (t get set concentration) so the answer is then to let it cool and THEN add the paste. (apparently its a starch based product and hot water cooks it or converts it to something else - not sure!) The paste is not essential but I think it helps otherwise you find yourself having to go over it again and again where it has run off.

I have tried dozens of "GRP restorer" type products and even tried T-cut, and none have ever worked on the rather aged hull. This is a bit coarser I guess and cuts back enough to put a real shine on it; however it si important to realise that it the needs a protective coat of wax or polish on top. The shine is not polish, it is a smooth hull! Howevert the general advice is to use the mildest possible compound that works so maybe try something else first? I saw a professional doing another boat the day before and asked what he as using and basically went straight out and bought some!

 

[JollyRodgers]

the wallpaper paste makes the mixture thick and jelly like so it clings to hull and doesn't run off. Yes you need to dissolve it in warm water (t get set concentration) so the answer is then to let it cool and THEN add the paste. (apparently its a starch based product and hot water cooks it or converts it to something else - not sure!) The paste is not essential but I think it helps otherwise you find yourself having to go over it again and again where it has run off.

I have tried dozens of "GRP restorer" type products and even tried T-cut, and none have ever worked on the rather aged hull. This is a bit coarser I guess and cuts back enough to put a real shine on it; however it si important to realise that it the needs a protective coat of wax or polish on top. The shine is not polish, it is a smooth hull! Howevert the general advice is to use the mildest possible compound that works so maybe try something else first? I saw a professional doing another boat the day before and asked what he as using and basically went straight out and bought some!

Ah, that first bit makes sense then. Definitely worth doing. I imagine if it had a water like consistency it will run straight off and be a pain to do.

I think I have some Autoglym Super Resin polish, so will probably use that over it after the stains have been removed. I read on YBW in the past that it is very good. Will use the drill/wool mitten to apply it on.

I think what is making me feel worse about the stains, is the boat next to mine is perfectly bright white and I see my reflection in it every time I walk past haha.

For the Acid, did you use a sponge to apply it on and then wash off a couple minutes later with a fresh sponge with clean water. I've read some people leave the acid on for 30 mins and then wash it off with cold water and others leave it on for less than 30 seconds and scrub off. I guess it will all make sense once I am down there and doing it. I just like to have a rough idea of what to expect prior to going down.

 

[Corribee Boy]

At the risk of stating the bleeding obvious, do wear gloves!

 

[Thedreamoneday]

I've never tried this on a boat but has anyone used a 'Clay bar' I used one on my car. I washed the car (twice) then clay barred it, it had black bits all over it, then washed the car again then wax- the car looked wet for months! A lovely shine!

 

[Heckler]

Ooh that sounds good and VERY cheap!

How quick is it at removing stains? Is it wipe on/wipe off? Or do you have to leave it to soak in for 30 mins and scrub off?

I heard very good things about Starbrite Instant Hull Cleaner, which is £20 for 1Litre (again, I figured this was cheap too).


Yeah, I am really hesistant about using anything too abrasive because of gelcoat thinning issues. That's why I opted for the 2000 grade paper. I read about the acid before, but didn't read too much into it because I figured acid would be really bad against the gel coat - but I guess not?

Surely acid is an abrasive method though, as I imagine what it is essentially doing is burning the stain off?



Acid seems like the way to go, and at £8.99 for 1kg of powder you cant really go wrong. Do you think 1kg would be enough for a 32' with reasonable brown marks?

Going to go down to the boat on Friday (before it gets lifted in) and try to clean up the last bits of it. I may get what peter suggested, but also some oxalic acid as back up or if there are any stubborn stains not coming out.

I guess after the stains have been removed I will need a wax or a polish to increase the shine and help prevent future stains, like you would on a car or motorbike?

Oxalic acid, followed by swmbo with 3m cleaner and restorer a few years ago then Autoglym every year. Looks good eh?
View attachment 50309

 

[KREW2]

Forget the wallpaper paste, just douse it on.
I found that when the paste dries it takes a lot of rinsing and wiping to get it off.
The 3M imperial compound is very good if your hull is badly oxidised, if it is not use Farcela fine cut polish it's very good and much cheaper.
All this prep wont last though, and is no good unless you finally apply at least 2 coats of a good UV wax.

 

[Pavalijo]

Forget the wallpaper paste, just douse it on.
I found that when the paste dries it takes a lot of rinsing and wiping to get it off.

I read somewhere in an article or forum post that wallpaper paste can be extremely difficult to remove if left to dry. You need something gloopy to stop the solution running straight off - I used washing up liquid and applied with an emulsion roller. I also read that temperature makes a huge difference and that you want an air temperature of 15c and above, ideally.

 

[Jamesuk]

Autosmart

G101 EVO 6/3/1/Wax

http://www.autosmart.co.uk/Evo.html

 

[FulmarJeddo]

At the risk of stating the bleeding obvious, do wear gloves!

and eye protection, it hurts!!! Splashes will also bleach your clothes. As you can probably guess, both are from personal experience. Oxalic acid is still the best thing I have found for removing the stains without being too aggressive if you splash it anywhere else. It does also attack galvanising, as I found out when my previous boat was in a galvanised cradle.