Trouble Painting Roof.......

[NewCanalBoy]

I am attempting to re-paint my roof. The original paint has just faded by the UV effects.

 

I ordered a tin of cellulose paint. First attempt this morning I mixed a bit of white spirit with it to thin it. It was cool with a light breeze. After a couple of goes with the roller there was fine hairs coming up so I thought the roller was wrong. Quickly changed to a sponge type roller but no different. The stuff just seemed to dry out.

 

Phoned up the paint people and they said I shouldn't have used white spirit but other thinners. Fair enough my fault.

 

Said to try without any thinners so just had another go. Big umbrella up so in shade, cooled down, light breeze, same effect, just dry and a mess.

 

I don't know whether I've got the right paint - thought cellulose paint was good for automotive/steel work ?

 

Is it reacting to existing surface ?

 

Still too warm ?

 

Bloody boats........

 

 

[Tracy D'arth]

Very unlikely that your boat was painted with cellulose. New cellulose will react with almost every other paint.

Boat paints are oil based enamels or 2 pack curing paints.

Who told you to buy cellulose, there is not a lot of it around these days, cars use other paints now?

[Tony Brooks]

Not if its going over oil based pain and you don't thin cellulose paint with white spirit.

 

Cellulose paint will soften, crinkle and lift the existing oil based paint. Unless you know someone sprayed the boat with cellulose its almost certainly to be oil based paint but just might be two pack but I very much doubt it.

 

You may have to scrape your existing painting off and start again with oil based paint. And only a few hairy rollers are suitable for oil base and I suspect none for cellulose. They will disintegrate.

[NewCanalBoy]

Ok cheers - thought cellulose paint was what I needed. Bum.

 

Clean up operation needs to start.........

[Tony Brooks]

Don't be tempted to buy "gloss" paint from the DIY sheds because it will probably be water based. If you don't want so called marine paint use one of the trade paint outlets. I use Johnstons.

[NewCanalBoy]

So what is oil based paint known as now ?! I'm confused with all the different terms !!

[Tony Brooks]

Its known as "oil based paint" and you should be able to get it in gloss and semi-mat or even mat finish. So oil based gloss, oil based semi-mat, oil based mat paint.

 

Oil based paint normally thin with white spirit.

 

Seems you may not know much about paint. Paint manufacturers give fancy names to colours that may or may not accord with certain standards. If you ignore the name and choose based on one of the BS colour numbers or similar RAL then any trade supplier should be able to mix to that colour and although it wont be a perfect match it should be near enough for most people.

 

Oh, I very much doubt being under a sun umbrella would keep the surface cool enough at this time of year to give the paint time to flow and for you to keep a wet edge. When I was painting the boat I was up at 5 am to leather down and dry off as soon as the mist had cleared and completed the painting by 8.30 to 9.00 am  at the latest

[Tracy D'arth]

It will say clean brushes and thin with white spirit, will have a VOC rating, smelly volatile solvent.

International, Rylards, etc. Expensive and in 750ml tins

 

There is some good stuff on ebay https://www.ebay.co.uk/itm/Boat-Barge-Paint-Yacht-Marine-Enamel/272420451311?

 

Or if you want non slip  https://www.ebay.co.uk/itm/Premier-Anti-Slip-Deck-Paint-1-L-Beige-BS4800-08C31-boat-yacht-anti-slip-paint/273804937062?  but keep stirring it as you paint to distribute the grit.

Both in 1 litre cans, good value.

TD'

 

[BEngo]

Look for a sort of blue and brown globe symbol on the tin.  Next to this it will tell you about VOC content.  If it is not 'High' or "very high" don't bother with that paint.

N

[dmr]

6 minutes ago, NewCanalBoy said:

So what is oil based paint known as now ?! I'm confused with all the different terms !!

It is confusing and complicated. Most "proper" boat paints are loosely called "enamel" but this is not really correct. Their more technical name is "modified alkyd" though this term is not often used and a few manufacturers use a different chemistry (I think). These are all paints where you clean the brush with white spirit. Cellulose paints were what the automotive industry used before it moved to water based paints, and would be thinned with cellulose thinners, so they are based on a different solvent.  A few specialist paints like Hammerite use yet another type of solvent that is not always compatible with other paints.  

In general paints should be thinned with the correct thinners and even though white spirit is the brush cleaner its not the best thinner.

 

.................Dave

[LadyG]

27 minutes ago, Tony Brooks said:

Don't be tempted to buy "gloss" paint from the DIY sheds because it will probably be water based. If you don't want so called marine paint use one of the trade paint outlets. I use Johnstons.

Be aware Johnstons now have a water based outdoor paint,

imho you should avoid anything around £ 12/litre! Expect to pay over £20, but having cocked up, after doing your best to remedy, I would put on primer/undercoat and wait a month

 

 

 

Edited June 22, 2020 by LadyG

[NewCanalBoy]

@dmr - yes thank you - just reading up on alkyd as seen it advertised. Still wasn't described as 'oil based' in the blurb !!

[Tony Brooks]

Just now, LadyG said:

Be aware Johnstons now have a water based outdoor paint, you should avoid anything around £ 12/litre!

 

 

I agree,  think  paid over £20 a litre. That is why I said "oil based gloss paint". The idiots a the likes of B&Q will only hear gloss paint and sell you junk.

[dmr]

25 minutes ago, NewCanalBoy said:

@dmr - yes thank you - just reading up on alkyd as seen it advertised. Still wasn't described as 'oil based' in the blurb !!

"Oil based" or solvent based (smelly and brushes clean in white spirit, good stuff,  essential for boats) is a term used by a lot of people to distinguish it from "water based" (ok for indoor use) but its not an official term.

 

In general £20 to £30 per litre though it can be found cheaper from some "trade" type suppliers.

 

..............Dave

 

[WotEver]

And if you want to keep a wet edge and help it to flow, use Owatrol, not white spirit.  White spirit will just thin it down and lessen the opacity.