Out-of-date 2-pack paint

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Avocet

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Well it looks like the "summer" (if we can really call it that!) is coming to an end and yet again, I haven't got Avocet painted! I've applied my second coat of epoxy primer, and have been pleased with the results (other than a fair bit of "orange peel", which I'm in the process of flatting-out).

Unfortunately, I bought the 2-pack polyurethane paint to go over it in September 2010, and I'm just wondering whether this stuff is likely to still be useable by next summer? It's been stored unopened in the house, so has been protected from extremes of temperature and humidity.

Does anyone have any experience of using out-of-date 2-pack?
 
Avocet said:
Unfortunately, I bought the 2-pack polyurethane paint to go over it in September 2010, and I'm just wondering whether this stuff is likely to still be useable by next summer?
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2-pack polyurethane typically has a quoted "shelf life" of 2 years, and I guess that's a conservative estimate, so I'd imagine your paint will be OK. Is there a date on the can?
 
I've just mixed up (a week ago) a small quantity of International Perfection to touch up some areas. It came from an an already open tin that was last used just over 2 years ago but probably bought at least 6-8 months before that.

It has worked absolutely fine and had been stored in a cupboard at home. It did need a lot of stirring though to mix the colour part as the solids had settled into a thick lump at the bottom!
 
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When you are ready to use the old stock pop into your local paint supply outlet and them to put the tins on their paint mixing machine for a double run time, the type that shake the can.

Just tell them that you will be buying some bits while they get a good mix

Also try to warm the contents just before you open the cans by standing them in warm water, this will help thin the mix and improve the mixing process.

Standing the cans in sun will help but that's not geven in your part of the world is it.

Good luck and fair winds. :)

PS. Move the spray gun a bit faster next time. LOL
 
2 Pack Urethane paint shelf life

I have been using some white 2 pack paint that must be at least 4 years since I bought it and started. using it for touch up. The hardener expired by going hard so I bought more hardener. (crazy high price) but the paint itself looks like it will be still OK for next winter's touch up. I think if the hardener has not been opened and is still runny it will be OK but try some first. good luck olewill
 
out of date

i have used two pack,i think its 709 and it was at least ten years old ,painted the boat this spring and its now been in the water for six months and been washed down twice.all is well,Kieron
 
Regardless of whether the paint works, I think you should buy new as punishment for putting it off for 2 years :D
 
Oh kick a man while he's down, why don't you?! Yeah, it'a sore point. 5 years this 'ere tub's been in the garden now - and is starting to "become one" with it! I'm hoping the surrounding trees haven't grown enough to make it imposible to crane out! I am SO close, but the weather has been truly awful this summer (and it's not like West Cumbria sets the bar particularly high in that department to start with)! I literally can't remember any 72 hour continuous dry spell with peak daytime temperatures about 20 degrees this year. Last year I finished the high-build epoxy primer and faired it all. This year, I've put on the 2 coats of paint primer, and I'm SOoooooo close to slapping on the topcoat, yet so far!

Anyway, thanks all, that's encouraging. The hardener is stil lliquid if I shake the tins, so hopefully it's not scrap.

Last question: I hear that 2-pack PU paint does awful things if the temperature / humidity goes outside the permitted limits whilst it dries. The tin says "dust dry" (or maybe "touch dry") in 2 hours at 18 degrees, recoatable in 24 hours. Does that mean I only need to keep the atmospheric conditions right until it's touch-dry, or for the whole 24 hours?
 
Last question: I hear that 2-pack PU paint does awful things if the temperature / humidity goes outside the permitted limits whilst it dries. The tin says "dust dry" (or maybe "touch dry") in 2 hours at 18 degrees, recoatable in 24 hours. Does that mean I only need to keep the atmospheric conditions right until it's touch-dry, or for the whole 24 hours?
(End quote)

The effect of humidity can happen several hours after the surface is dry to the touch and a sudden change in temperature within 3 to 4 hours can cause a blush.

The good news is that both the above can be reduced by applying the coat in 3 stages.

Two pack almost flash dries in fair conditions and you can use this to your advantage. The trick is have full access around the boat before you start painting so the application can be made in continuous sweep.
Mix a brew and let it digest/react as per manufacturers notes and add all but the maximum amount of thinners again according to manufacturers notes; Now apply a mist coat over the full area/s to be treated, on your vessel this should only take 10 to 15 minutes, by the time you reach the start point again the mist coat will have hardened enough to not sag when the next coat is applied, a simple touch with a finger and side movement will give you a good feel of how solid the mist coat has dried.

Using the mix of paint and thinners apply a mid coat, the amount between full and mist coat, this will tale a little longer to apply but will dry rapidly so mix more than you need.

The next coat will be the final, so have a good look at what you have and make good any dodgy areas and respray if required. Then a the last at fill coat rates, this will be a full cover to full gloss and you should have trouble seeing the areas you have covered, if not you are still too thin.

Do not be tempted to fix any little bits or remove any masking, scaffolding, hoses or other equipment as the risk of marking the wet finish is high, have a rest and drink and wait till the finish is just beyond tacky before removing essential masking tape.

You should end up with layers of paint that are all part cured rather than a single thick layer wet to the hull, so improving the chances of any effects dur to changes in humidity or temperature.

Good luck and fair winds. :)

PS. Practice your speed and distance for each coat on some scrap material.
 
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