Two pot paint on top of one pot paint.

[gordontytler]

My deck needs repainting and I would like to do it properly but I have been told I can not put expoxy resin on top of ordinary paint. Rather than scraping it all off is there some primer I could use instead? I was also advised to test a small area first but it took 6 months for wrong paint on my house to start flaking off.

 

[MrCramp]

I would use International non slip deck paint. I would not want to use epoxy resin on it.

 

[Rigger Mortice]

I wouldn't put epoxy on a deck. It's not the best for UV resistance. Two pack poly would be better for durability but but you would have exactly the same problem putting it on top of ordinary paint.
I'm not aware of a primer which would help.

 

[oldsaltoz]

If you know what paint is on the deck now, just pop into your local paint supplier and get their advice.

There are barrier coats available but the preparation is not a doddle.

Good luck and fair winds.

 

[penfold]

If you know what paint is on the deck now, just pop into your local paint supplier and get their advice.

There are barrier coats available but the preparation is not a doddle.

Good luck and fair winds.

What he said; barrier coats are available, but the existing paint has to be very sound to make it worthwhile.

 

[gordontytler]

Thanks for the advice which I will follow up. The flaking is patchy. I think most of it is solid. I suspect it may be possible to purchase paint at a fraction of the price of the top brands but don't know how much I need or if it is worth the risk trying to save a small amount relative to my time. (I also need to work on engines and hull) I also don't know if the difference between a two pot paint and a good one pot is worth the hastle of a barrier. Epoxy is difficult to apply and yellows when exposed to air but there are many types of "poly". I need something hard, flexible and waterproof. The internal woodwork is already dripping in places...

 

[Amulet]

My deck needs repainting and I would like to do it properly but I have been told I can not put expoxy resin on top of ordinary paint. Rather than scraping it all off is there some primer I could use instead? I was also advised to test a small area first but it took 6 months for wrong paint on my house to start flaking off.

I'm afraid you have no option but to take the old paint off. There may be exceptions, but I've read the blurb from many manufacturers and basically you can't put two part on top of traditional paint. (You can do the other way round.) As has been pointed out, poxy is not the stuff really - two part polyurethane might be. If you do poxy it for some reason than you have to cover the poxy with some uv protecting coat.

Anyway - it will end in tears if you don't get the existing stuff off. Heat gun or Nitromors might make it easier.

 

[basil421]

Two pack polyurethane is a great solution for painting old GRP but unfortunately the solvent mix in it will act like a paint stripper on traditional air dry paints, usually alkyd based, so you would have to remove any old non-two-pack P/U from the substrait before application.

If it were me I would use 2-pk P/U on the smooth bits of the deck having removed the old paint with a heat gun and wet and dry. I wouldn't use Nitromors on gel coat.

For the textured areas I would overcoat the old paint (after removing the loose and flaking bits) with International non-slip deck paint.

This is roughly what I intend to do to mine next season.

 

[Tranona]

Thanks for the advice which I will follow up. The flaking is patchy. I think most of it is solid. I suspect it may be possible to purchase paint at a fraction of the price of the top brands but don't know how much I need or if it is worth the risk trying to save a small amount relative to my time. (I also need to work on engines and hull) I also don't know if the difference between a two pot paint and a good one pot is worth the hastle of a barrier. Epoxy is difficult to apply and yellows when exposed to air but there are many types of "poly". I need something hard, flexible and waterproof. The internal woodwork is already dripping in places...

What is your deck made of? Hard, flexible and waterproof apart from being a bit contradictory are not the key properties for painting GRP. Is it cosmetic or are you looking for non-slip properties? If it is wood then paint is not going to waterproof a leaking deck.

As a surface coating Toplac one pot is an excellent finish which keeps its gloss well, is easy to apply and goes on top of other paint, altthough you will want to prepare the surface by removing the flaky bits, rubbing it down well, filling the dents etc and using an undercoat. If you want non slip you can mask off areas after the undercoat and finish with Interdeck.

 

[ianj99]

My deck needs repainting and I would like to do it properly but I have been told I can not put expoxy resin on top of ordinary paint. Rather than scraping it all off is there some primer I could use instead? I was also advised to test a small area first but it took 6 months for wrong paint on my house to start flaking off.

I have used epoxy mastic paint from rust.co.uk with 100% success on my steel ketch.
It was applied over clean steel, overlapped on to the existing epoxy, and on existing paint all with out problems. It also adheres to teak very well (damn!)
It can be over painted or left bare.
I overpainted it with International yacht primer and then Toplac on the side decks around the strip between Trackmark and teak toe rails.
After 12months, no sign of problems and the strip outside of the toe rails has been left bare, for 2 years in some places. Hopefully we'll have better weather this year and I will get to finish it...

 

[Clyde_Wanderer]

Thanks for the advice which I will follow up. The flaking is patchy. I think most of it is solid. I suspect it may be possible to purchase paint at a fraction of the price of the top brands but don't know how much I need or if it is worth the risk trying to save a small amount relative to my time. (I also need to work on engines and hull) I also don't know if the difference between a two pot paint and a good one pot is worth the hastle of a barrier. Epoxy is difficult to apply and yellows when exposed to air but there are many types of "poly". I need something hard, flexible and waterproof. The internal woodwork is already dripping in places...

Sounds like a wooden deck in need of some serious sealing if the "internal woodwork is already dripping wet"
Think you would be better stripping back to bare wood and either sheating with epoxy and cloth then painting, or sealing the plank grooves providing the planks are in good condition, then painting.
Pointless wasting money on paint if the substrate is in bad condition.
Follow the BS5750 Rule.
C_W

 

[gordontytler]

The construction is GRP (it is a Birchwood 33) but has been remodelled. The large windows have been replaced with yacht windows and the gaps filled with plywood and plastic padding. Water may be comming in through small cracks but this needs to be investigated. I will insert pictures once I work out how.

 

[Pasarell]

As sgtated by several people above already you generally can't put a 2 pack paint over a 1 pack. In practice though, you will often get away with it if the 1 pack was something like a urethane alkyd, as most 1 pack deck paints are, anad it is well aged. Unfortunately there is no way of testing whether it will work other than trying it. BUT, and it's a big BUT! The adhesion to your deck will come from the underlying single pack paint that, as you say, is flaking in many places. There seems little point in applying an expensive 2 pack polyurethane onto a poorly adhered underlying paint. When the single pack product comes away it will take the expensive 2 pack with it.
Seems to me you need to sort out the windows and leaks first and come back to the deck when you are sure the rest is OK

 

[gordontytler]

I think the water may be seeping down these cracks. I will attack it with a chisel in various places and see what is going on underneath.

 

[Didi]

My deck needs repainting and I would like to do it properly but I have been told I can not put expoxy resin on top of ordinary paint. Rather than scraping it all off is there some primer I could use instead? I was also advised to test a small area first but it took 6 months for wrong paint on my house to start flaking off.

Shellac may work as a barrier - it is often used as such between incompatible finishes.

However, I would scrape the old paint off because IMO epoxy applied to bare wood sticks far more tenaciously than any paint. Coarse sanding is needed to provide a mechanical key. As mentioned you will need to overcoat the epoxy with a uv resistant finish.

 

[pyrojames]

Best solution may well be Coolean. Tough, flexible relatively easy to apply.