Next topic about painting the bottom :)

[panadol]

Hi
I am renovating the bottom of an older 16ft GRP boat. After minor repairs, I want to use 2 part epoxy for Osmosis protection.
As the boat will be on the trailer most of the time and will not be on the water for more than a week, I don't want to do anti-fouling.
I think what to do next - above the waterline and want to use 2 part polyurethane paint (for example international perfection)
Below I think whether:
- paint the same paint 2 k polyurethane or
- leave only 2k epoxy (or add 2 coats of more of this paint)

I have questions about this:
- What would you choose?
- I am a bit for the second option because I think if in 2 or 3 years I may want to apply antifouling, I will have to remove the whole two-part polyurethane paint again?
- I know that standard epoxy paints do not have UV protection. In addition to the possible color change, can there be other problems with the durability of the paint?
- I found that International has a special epoxy paint version for this: "International VC Performance Epoxy" but it is not available in Europe. Do you think it has some extra UV protection or it is possible to apply another two part epoxy paint without further painting? Maybe there are any additives to mix?

 

[panadol]

PS To make work easier I invited friends and we turned the boat

 

[salar]

Beware of overthinking this. If you don't keep a boat in the water, I doubt you will ever have an osmosis problem because it is caused by water pressure. You will be able to overcoat with antifoul in the future, and even if there is an incompatability with existing paint (usually antifoul) you can apply a barrier coat rather than strip the existing paint. I would just paint the whole hull with the same paint. They are designed for marine use in much more demanding conditions than a 16 foot boat kept on a trailer.

 

[panadol]

I do not know if this is true but I read somewhere that nothing sticks to 2k polyurethane. So I think whether or not to leave the epoxy alone under waterline.
I am now cleaning many layers of old paint from the bottom and this is a job that I would definitely not want to do in two or three years again when when i decide to do antifouling

Can topside paints be applied to below water surfaces?
VC Performance Epoxy | Interlux

Can I use "normal" 2k epoxy as replecment for "vc-performance-epoxy" ? for example "International Gelshield 200" or "Epifanes Epoxy HB Coat 0,75L" ?

 

[Neeves]

I do not know if this is true but I read somewhere that nothing sticks to 2k polyurethane. So I think whether or not to leave the epoxy alone under waterline.
I am now cleaning many layers of old paint from the bottom and this is a job that I would definitely not want to do in two or three years again when when i decide to do antifouling

Can topside paints be applied to below water surfaces?
VC Performance Epoxy | Interlux

Can I use "normal" 2k epoxy as replecment for "vc-performance-epoxy" ? for example "International Gelshield 200" or "Epifanes Epoxy HB Coat 0,75L" ?

Ask the technical depart of the surface coatings company of your choice. Your purchase supports the employment of the technicians and their kit - use them.

Jonathan

 

[slawosz]

Osmosis needs time to happen and some boats are prone to them more - quality of GRP is huge factor. It’s not that common as people think - there is lot of good threads here. Or it you are very curious you can read Amazon.co.uk

If you really want boat to shine I would use some epoxy primer then proper primer for your paint. The shape of the hull will make roll and tip harder - unless you spray? The small radius of the faux clinker will prevent roller from reaching there.

I would cover bottom with some cheaper paint or use it to test your tip n roll skills and techniques before painting sides.

 

[slawosz]

Osmosis needs time to happen and some boats are prone to them more - quality of GRP is huge factor. It’s not that common as people think - there is lot of good threads here. Or it you are very curious you can read Amazon.co.uk

If you really want boat to shine I would use some epoxy primer then proper primer for your paint. The shape of the hull will make roll and tip harder - unless you spray? The small radius of the faux clinker will prevent roller from reaching there.

I would cover bottom with some cheaper paint or use it to test your tip n roll skills and techniques before painting sides.

 

[panadol]

If you really want boat to shine I would use some epoxy primer then proper primer for your paint. The shape of the hull will make roll and tip harder - unless you spray? The small radius of the faux clinker will prevent roller from reaching there.

I would cover bottom with some cheaper paint or use it to test your tip n roll skills and techniques before painting sides.

Thanks. I will use airspray or airless spray (I can borrow a professional airless wagner machine from a friend)
What kind of cheap paint do you suggest to use for the bottom?
My basic question is whether there can only be epoxy 2 component primer below the waterline.

 

[slawosz]

If I am not mistaken I have seen your post somewhere else (I am an international internet troll ). The problem with epoxy is that it’s not UV resistant - not sure if someone tried it and you will get an answer. So the default answer is - to cover it with some paint. I would use a cheaper 2 pack on the bottom (polish one) or if you spraying just spray everything. Obviously, to get good results with a 2-pack you have to have a perfectly prepared surface. Happy sanding! For better timing, I would use standard car body filler - I have some on my boat, and after several years, no problem. You can sand after 20 minutes, not 3 hours like with epoxy filler.

Oh, and instead of using International Perfection, you could use some car paint - as far as I understand, those are pretty much the same and it will be easier to find out about the correct procedure if you want a perfect finish. Or experiment first. My boat is sprayed using some car 2 pack paint and I have to say, that it's strong. Sadly in places, it got damaged (dinghy rubbing on mooring or mooring buoy) so I will repaint it using Toplac as have no possibility to do spray painting.

 

[panadol]

If I am not mistaken I have seen your post somewhere else (I am an international internet troll ). The problem with epoxy is that it’s not UV resistant - not sure if someone tried it and you will get an answer.

You're right. I'm an internet troll too
In the US they use 2 part epoxy paint for the bottom and have good reviews
VC Performance Epoxy | Interlux
I think this paint have no UV protection too...

 

[slawosz]

Oh, ok, in this case it will work I pressume.

 

[panadol]

Oh, ok, in this case it will work I pressume.

Yes but i can't buy this paint so question is will another 2k epoxy paint be ok too
If not, what paint will be ok over 2k epoxy paint on which I will be able to apply antifouling someday in future.
I would put 2k polyurethane but I am looking and I do not see any primer that sticks to 2k polyurethane (or mayby i am wrong).

 

[panadol]

I have confirmation that I not apply any antifouling on top of the Poly-urethane.Also with a primer coat, this would not be possible. I will apply Poly-urerthane only above the waterline and Epoxy Primer below the waterline.