stripping paint

[robdalej]

Looking at the roof of our boat yesterday and thinking that it could probably do with a repaint. The boat is 22 years old so probably has a hell of a lot of layers of paint on it. Has anyone any advice how to remove all these old layers and get it back to original or would it be better to just put another layer on top? should add it is a sanded roof

[dor]

If you want to do it properly, then get it grit-blasted. You canb get it done at Aqueduct Marina not far from you.

Alternatively, if you want to do it the hard way, hire a scabbler and do it manually.

[RobinJ]

Looking at the roof of our boat yesterday and thinking that it could probably do with a repaint. The boat is 22 years old so probably has a hell of a lot of layers of paint on it. Has anyone any advice how to remove all these old layers and get it back to original or would it be better to just put another layer on top? should add it is a sanded roof

It depends pn the paint and ots condition!

If its the sort that is split and peeling or scratched and flaky, then a paint stripper product might help?

The more smooth and hard type finishes probably need blasting, sanding or grinding?

[Chalky]

If you've got sand in the paint to increase the grip it's going to be fun getting it off.

 

I found that a "wall paper scraper" - the type that has a large stanley knife type blade in it was very effective at removing lots of paint, however on sanded areas it was next to useless. In the sanded areas I used scrapers etc and eventually resorted to using 40 grit disks in an angle grinder. Wouldn't put sand in the paint again.

[Nose Miner]

I've stripped a fair few boats back to bare steel - abrasive disks on an angle grinder are the way to go. Get the coarsest disk you can get and expect to get through a disk every square meter or so. It will be a very messy business though, best done off the water.

[Ex- Member]

Looking at the roof of our boat yesterday and thinking that it could probably do with a repaint. The boat is 22 years old so probably has a hell of a lot of layers of paint on it. Has anyone any advice how to remove all these old layers and get it back to original or would it be better to just put another layer on top? should add it is a sanded roof

 

A heat gun would do ok, it'll soften the paint and the grit will lift with it but not get too gooey and make a mess. If your paintwork is not badly flaking cracking pealing or rust bubbling then I would just repaint, as it is clearly protecting the steelwork ok. It's a lot of work stripping of years of paint.

[bargemast]

If you want to do it properly, then get it grit-blasted. You canb get it done at Aqueduct Marina not far from you.

Alternatively, if you want to do it the hard way, hire a scabbler and do it manually.

 

 

Grit (and/or Sand) blasting makes a terrible mess and get everywhere, but it will get rid of all the unwanted paint layers.

 

I wrote a while ago on another post about what I saw on a yard not far from where I am based, which is much to far for the O.P. I know, but the same procedure may exist in the UK too.

 

It works with very high water pressure, much higher then a Karcher, at about 2500 Bar, which is 35.000 Lbs, this strips off all the paint without making dust, it's a very clean way of doing a serious job.

 

Here's one photograph to show what the boat looked like after this treatment.

 

 

Peter.

 

I've stripped a fair few boats back to bare steel - abrasive disks on an angle grinder are the way to go. Get the coarsest disk you can get and expect to get through a disk every square meter or so. It will be a very messy business though, best done off the water.

 

 

I've seen boats that were done with an angle grinder, but if the sun was shining you could see through the new coats of paint the round marks (circles) that the angle grinder had made.

 

Only if you are very good with filler you can maybe create a smooth enough surface to repaint without those marks showing up.

 

Peter.

[Nose Miner]

 

I've seen boats that were done with an angle grinder, but if the sun was shining you could see through the new coats of paint the round marks (circles) that the angle grinder had made.

 

Only if you are very good with filler you can maybe create a smooth enough surface to repaint without those marks showing up.

 

Peter.

 

Of course I maybe didn't make clear the use of plastic abrasive disks, not grinding disks. Using these disks it is very difficult to get through the millscale (assuming it's still on) because it's too hard. Even if the millscale has gone, a little care should ensure no sanding marks are left in the steel. Most paint shops I've seen use these.

 

High pressure water stripping is great, but I think costs about the same as grit blasting and not many people are geared up to do it. It does leave a surface that needs further treatment, because of oxidation film, before painting. If you are taking window frames out to do a proper job, it's hard to see how you'd keep the water out of the boat!

[bargemast]

Of course I maybe didn't make clear the use of plastic abrasive disks, not grinding disks. Using these disks it is very difficult to get through the millscale (assuming it's still on) because it's too hard. Even if the millscale has gone, a little care should ensure no sanding marks are left in the steel. Most paint shops I've seen use these.

 

High pressure water stripping is great, but I think costs about the same as grit blasting and not many people are geared up to do it. It does leave a surface that needs further treatment, because of oxidation film, before painting. If you are taking window frames out to do a proper job, it's hard to see how you'd keep the water out of the boat!

 

 

Using a heavy-duty professional orbital sander wiil give you the best chance not ending up with marks.

 

Sorry to say that I know nothing about the cost of this extreme high pressure water-blasting, but the result I saw was very good, after that they use a kind of acid, before the paint.

 

They used to grit-blast there before, but that left a terrible mess, and all the boats nearby had to be covered, which is not needed with the water-blasting.

 

This boat was fairly new 5 years, and the didn't have to remove the windows, they cleaned the paint around the windows with a little sander to about 5cm (2") around the windows.

 

If they had to be removed, I suppose that they could have fixed pieces of plexiglass with silicon-kit to seal them to prevent water damage, something that should be done too if they sand/grit blast.

 

Peter.

[Lampyrichard]

I've just finished stripping and repainting Zulu, which had the same problem of loose / flaky paint plus sand on the roof & gunwales.

 

Given that we don't have anywhere here on the Forth & Clyde that can grit blast, the most efficient solution I found was 75mm or 100mm wire cup brushes on a decent angle grinder (it helped that I had a 9" Bosch grinder already).

 

I found that 40-80 grit pads on the orbital sander were great for chewing off the non sanded paint areas but useless on the sanded bits. Likewise the zircon grinder discs seemed to wear out ridiculously fast on the sanded areas, plus they were leaving marks on the steel when they did bite through. I didn't have any marking problems with the wire brushes.

 

FWIW, I used a combination of Bosch 75mm & Titan 100mm brushes from Screwfix - probably not the cheapest supplier, but convenient. The 100mm ones were quicker at moving material but did create a lot more vibration & seemed to get unbalanced really quickly. The Bosch 75mm ones didn't seem to suffer from this as much (unsurprisingly).

 

You will need decent PPE though - it's amazing what paint & sand flecks can do when thrown off a 2500rpm grinder!

 

Hope this helps.

 

Richard

[howardang]

Using a heavy-duty professional orbital sander wiil give you the best chance not ending up with marks.

 

Sorry to say that I know nothing about the cost of this extreme high pressure water-blasting, but the result I saw was very good, after that they use a kind of acid, before the paint.

 

They used to grit-blast there before, but that left a terrible mess, and all the boats nearby had to be covered, which is not needed with the water-blasting.

 

This boat was fairly new 5 years, and the didn't have to remove the windows, they cleaned the paint around the windows with a little sander to about 5cm (2") around the windows.

 

If they had to be removed, I suppose that they could have fixed pieces of plexiglass with silicon-kit to seal them to prevent water damage, something that should be done too if they sand/grit blast.

 

Peter.

I have used high pressure water jetting (3000 bar) on a few ocasions to strip paint back to bare metal on sea going tug hulls with good results. It can be dangerous in the wrong hands, however - I saw a breeze block cut in two as a demo - so watch your feet (steel toe caps a must) and maybe best to use a contractor rather than DIY. I have seen water based primer used after blasting which worked reasonably well.

 

Howard

[bargemast]

I have used high pressure water jetting (3000 bar) on a few ocasions to strip paint back to bare metal on sea going tug hulls with good results. It can be dangerous in the wrong hands, however - I saw a breeze block cut in two as a demo - so watch your feet (steel toe caps a must) and maybe best to use a contractor rather than DIY. I have seen water based primer used after blasting which worked reasonably well.

 

Howard

 

 

The extreme high pressure waterblasting that's done at the yard I showed the photo of, is always done by a contractor who knows what he's doing, and who knows how dangerous his equipment could be in the hands of amateurs, that's why it's just him doing it.

 

Peter.

[leolady too]

We redid our roof a couple of years ago. It had grit in the paint that made the use of abbrasives very hard work. It is, after all, like trying to sand sand with sand paper. We used Nitromorse which was about £15 per gallon and used 3 gallons or so (62ft boat). The trick with that is to put a layer on (not too thin) and let is soak. Then remove and repeat. You'll probably need 2-3 goes. After that a wash down and dry and then it can be sanded smoot with a belt sander or random orbit sander. The stuff is nasty to skin and the vapour isn't good for you but with gloves and the job done outside it was OK and it worked very well.