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Roof repaint..non slip


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Might be a well worn thread this..but here goes..

I've a non slip roof on the boat that needs stripping off so I can get some new paint on there. But I'm having trouble removing the non slip stuff.

I'm using Makita random orbital sander powered through a genny.. and 40 grit sanding discs but im not making much progress!

Considering using a grinder with wire brush cup..but don't want to go down to bare metal. Any advice?

G

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The wire wheels/angle grinder will take it back to bare metal. 

 

Why do you need to remove all the non slip paint? Is it that bad? Why can't you just go back to metal on the bits that need it, patch prime and possibly fill those areas, and just give any sound non slip paint a key and cover the lot with a good undercoat and topcoats of whatever you want.

 

If the existing paint is really that bad it all needs to come off then you may as well take it all back to bare metal.

Edited by blackrose
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Thanks for the replies. I'm trying to get the non slip off as the previous attempts to paint (sanding, undercoating and topcoating) the roof end with the new paint lifting off after 6 months or so.

The roof is relatively sound doesn't need much patching and there seems to be at least two layers of paint underneath the non slip which is OK and I'm happy to use this for a base to prime.

I can achieve this by using discs but it's a slow process and there appears to be a local shortage of sanding discs...all the DIY superstores are completely out of all of them, whichever size,  grade or type...bare shelves. I've been getting some from Screwfix but they're 50 grit..hence the question about going for a grinder/metal cup.

So questions are.

1. Can I get better quality discs?... Screwfix ones don't seem great. I can get stuff delivered home but it's 100 miles from the boat so can't get stuff to hand overnight. I'm working all next week so intend to get tooled up ready to attack it the week after.

2. Is there something between a sander and a cup grinder which will help me get back to the basecoat but not the metal. thinking of a plastic/nylon type wheel?

I've allowed most of the summer for this job along with painting the sides..so no rush and I know it takes elbow grease!

Thanks

G

 

 

 

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Go get a Scabbler head and discs for your orbital sander.

It will make light work of the anti slip grit and give you a really good surface to prime and paint.

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I used Bosch Flap Discs with an angle grinder for my boat roof. I got them from screwfix.

40 grit (26022) or 60 grit (24707) @ £5.49

 

Then finish off with a sander before painting.

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On 08/05/2021 at 08:24, Sprint955 said:

Thanks for the replies. I'm trying to get the non slip off as the previous attempts to paint (sanding, undercoating and topcoating) the roof end with the new paint lifting off after 6 months or so.

 

 

That doesn't make much sense to me. If the existing paint was sound and you keyed and cleaned it properly then I don't understand why it would lift unless you painted in poor environmental conditions (temperature, humidity) or the new paint you used wasn't compatible with the existing paint.

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  • 4 weeks later...
On 08/05/2021 at 08:31, MarkH2159 said:

Go get a Scabbler head and discs for your orbital sander.

Isn't a scabbler a seprate and specific tool? Is there such a thing as a scabbler "attachment" for a sander? I can't find anything by Googling...

 

  

On 07/05/2021 at 23:26, blackrose said:

Why do you need to remove all the non slip paint? Is it that bad? Why can't you just go back to metal on the bits that need it, patch prime and possibly fill those areas, and just give any sound non slip paint a key and cover the lot with a good undercoat and topcoats of whatever you want.

On 09/05/2021 at 15:40, blackrose said:

If the existing paint was sound and you keyed and cleaned it properly then I don't understand why it would lift

 

Just curious, how could you properly clean and key paint that had non-slip grit in it? You can't sand it, so isn't the only way is to take it back to bare steel?

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10 minutes ago, jetzi said:

Isn't a scabbler a seprate and specific tool? Is there such a thing as a scabbler "attachment" for a sander? I can't find anything by Googling...

 

    

That's what I thought

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4" blade scraper will be quicker and a bonus of less dust, followed by a small knotted cup brush - bigger is not better with these as the larger ones vibrate badly. You are unlikely to be able to retain much of the underlying paint using anything capable of removing the top layers.

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12 hours ago, jetzi said:

Just curious, how could you properly clean and key paint that had non-slip grit in it? You can't sand it, so isn't the only way is to take it back to bare steel?

You beat me to it! I have also wondered how to key a non-slip area. Can any painters here advise?

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1 minute ago, MrsM said:

You beat me to it! I have also wondered how to key a non-slip area. Can any painters here advise?

I thought this also, but using a normal sander i removed the non-slip fine.... roof now like a babies bottom!

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13 minutes ago, MrsM said:

You beat me to it! I have also wondered how to key a non-slip area. Can any painters here advise?

 

By no means a painter but on The Protectacote on the gunwales all I did was to scrub them off really well with a brass or copper wire brush and sugar soap, rinse and when dry make sure I could see scratches in the paint between the rubber granules and the paint with a silky type exterior black paint. It seemed to work fine apart from where weld blobs prevented getting below the blob.

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OK so the answer is that you don't key the non slip, you remove the non slip but try not to go too deep through the underlying layers.

 

@blackrosea was suggesting that it wasn't necessary to get all the nonslip off and @Sprint955 was saying they were having trouble getting the nonslip off anyway (as I have no doubt most would...seems to me like it would equivalent to sanding sandpaper).

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What non-slip paint did you use? I have had the oppisite problem (on brick, not metal) with non-slip paint on the brick steps leading up to our front door. For more than 30 years  I used to use Rustins matt step & tile paint, but that's no longer available. I then used Glidden paint from the Dulux decorator  centre that incorporated fine aggregate for grip,  also ok, but Glidden has been replaced by Armstrong non slip paint that also  incorporates aggrefate. I applied it using the recommended priming paint (non-aggregate floor paint diluted with white spirit) but it just peels off. Dulux found nothing wrong with the samples I sent them, but did refund the cost in a credit note. However  I would like to find something that works rather than stripping back to bare brick again like I did prior to applying the Armstrong stuff, and leaving it bare. 

 

 

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  • 4 weeks later...

I had a go at trying to sand the non-slip. Well, it does work, but it is going to take a long time and chew through a lot of sanding discs. I tried a flap disc, which is faster but still extremely slow and difficult to get it even.

 

I think it is definitely not possible to only key the previous non-slip by sanding. The raised bumps very much get in the way. I would love to just clean it and paint over it because the underlying paint is sound, but clearly some past owner painted over it and that paint is peeling.

 

I think the real answer is to hire a scabbler & genny and remove it properly, but that's a pretty intimidating prospect especially for a towpath job.

 

@Ronaldo47 I'm not sure who you're asking, I haven't used any non-slip yet, but I opted for buying the epifanes granules at a ridiculous price to go with the epifanes paint I'm using.

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1 minute ago, jetzi said:

I had a go at trying to sand the non-slip. Well, it does work, but it is going to take a long time and chew through a lot of sanding discs. I tried a flap disc, which is faster but still extremely slow and difficult to get it even.

 

I think it is definitely not possible to only key the previous non-slip by sanding. The raised bumps very much get in the way. I would love to just clean it and paint over it because the underlying paint is sound, but clearly some past owner painted over it and that paint is peeling.

 

I think the real answer is to hire a scabbler & genny and remove it properly, but that's a pretty intimidating prospect especially for a towpath job.

 

@Ronaldo47 I'm not sure who you're asking, I haven't used any non-slip yet, but I opted for buying the epifanes granules at a ridiculous price to go with the epifanes paint I'm using.

Have you tried a pressure washer to clean whats there

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On 03/06/2021 at 21:40, jetzi said:

 

Just curious, how could you properly clean and key paint that had non-slip grit in it? You can't sand it, so isn't the only way is to take it back to bare steel?

 

Sorry for the late reply.

 

It depends on the paint and the aggregate within it. The International Interdeck paint I use has a fine aggregate and sanding/keying/cleaning any old paint (or paint more than about a week old) before applying additional coats is a prerequisite. I've spoken to International's Technical Paint Dept and they advised me to give the paint a good key and clean it before applying new coats. That's despite the old paint having an "abrasive" finish.

 

https://www.boatpaint.co.uk/acatalog/datasheets/International/Product Data Sheets/Interdeck_GB.pdf

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Thanks, but I can't really wrap my head around this.

 

I don't know what kind of paint is on there (the non slip came with the original Black Prince paint job).

 

But sanding it won't key it unless I sand all the way through the raised bumps. Which I can do, but it takes a long time and basically ends up taking all the previous topcoat off. Not to mention will chew through sanding discs pretty fast.

But maybe I should just perservere with it.

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If your aggregate is coarse can't you key it with a wire brush or some sort of wire brush attachment on a power tool? If the paint is sound and non-flaking there's no need to take it back to metal.

 

You could try green scouring pads fun screwfix or Toolstation or even light abrasion with something like this? Or just a coarse sanding paper on a sander used very lightly.

 

If the paint is sound you're only looking to give it a key so the new paint has something to grip on.

image.png.42134a6d8c3f277affd266821fd22746.png

Edited by blackrose
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I feel your pain. The previous owner put artificial grass on the roof which destroyed the paintwork but mostly in patches. Some back to red oxide, some fine, but all remaining good areas were sand non slip

 I was hoping to work on it last year but the good weather was in lockdown, then it rained for months, then we went to lockdown again forever (up north). I'm doing it now, its not pretty but I just want, for now, a couple of layers of paint on there. It's not easy working with the non-slip. I'll just have to see how it holds up. 

 

A boat with artificial grass on the roof went past while I was on the roof painting. They said get some grass then you won't need to paint. I told them the only reason I was painting was because of the bloody grass but they weren't listening. Ah well, they will be on their roof painting before too long, if they ever bother to inspect it. 

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7 minutes ago, blackrose said:

If your aggregate is coarse can't you key it with a wire brush or some sort of wire brush attachment on a power tool? If the paint is sound and non-flaking there's no need to take it back to metal.

 

You could try green scouring pads fun screwfix or Toolstation or even light abrasion with something like this? Or just a coarse sanding paper on a sander used very lightly.

 

If the paint is sound you're only looking to give it a key so the new paint has something to grip on.

 

The wire brush is a good idea actually. I have a cup brush for my angle grinder that I can try tomorrow. Will give it a go.

 

The sound original non-slip paint was overcoated with paint that is now flaking, and that's the main reason I'm tackling it. I reckon that the previous owner painted over the non slip without keying (perhaps even without cleaning it properly). So I'm looking to avoid a repeat of that - either by taking it right back, or by getting the flaking paint off then giving it a good key and clean before repainting with primer first, then undercoat, then topcoat - my hope is that with a key and primer that the new paint will stick.

 

I wouldn't say that the non slip is particularly coarse, but I'd say it is at least an 80 grit ?

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After keying it brush it clean and then I use a cloth and white spirit to clean and degrease the surface. That's assuming white spirit is the solvent in the paint that you're putting on (often stated as thinners No.1 on the paint can). If it isn't used as the paint solvent don't use white spirit for cleaning because it might act as a contaminant.

 

It's best not to use water to clean if you've gone though the paint and exposed any metal in places. Keep it dry. Some people use tack wipes to clean the surface and get the last bit of dust off, but I found the ones I bought were greasy and put a layer of waxy oil on the surface so I don't use them.

 

Also I'd recommend doing the roof in manageable sections rather than trying to do the whole thing in one go.

Edited by blackrose
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We are half way through this job . The roof has been overpainted many times in the last tirty years using Dacrylate non-slip which incorporated iron oxide. A scabbler will not remove this it melts the paint and clogs almost immediately. The only method that works has been by using industrial strength paint stripper, Langlow is good or the slightly less expensive Strip-Away Pro from Maxolen.Buy plenty, if you need to hire a scabbler and genny it's  going to be cheaper anyway. Stanley 4" replaceable blade scrapers are also good allowing the multiple layers to be peeled away.

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