gisywaterboy 3 Posted April 24, 2017 Share Posted April 24, 2017 Hi, Does any one know if Toplac is happy to be painted over interprotect? I have some bare patches of timber on my deck, I have sealed them up with thinned epoxy and am thinking of using interprotect as an undercoat to give a little more protection prior to painting with Toplac. Is there any point to this or will Precote provide all the protection needed? Also, does anyone have any idea what the yellow undercoat pictured is? Its pretty hard so am guessing that it's a two pot system. Boat was built early 90s. Thanks! Quote Link to post Share on other sites
ScottiE 174 Posted April 24, 2017 Share Posted April 24, 2017 talk to the International people directly - they know their stuff and will tell you exactly what to do Quote Link to post Share on other sites
wheels 543 Posted April 24, 2017 Share Posted April 24, 2017 Yes you can paint Toplac over Interprotect. But do not allow the Interprotect to harden too long. It's best to get the top coat on as soon'ish as the minimum recoat time is reached, like the very next day if possible. Any longer than 3 days and it is likely not to adhere well. If you are going to use a two pot undercoat, why not use a two pot top. It will last 15 to 20 yrs. A single will last ruffly 10yrs. The use of Interprotect will likely mean you will only have to remove the top coat when it needs to be done in yrs to come and then you can recoat with a coat of Interprotect and topcoat again.Pre-Kote is fine as an undercoat for a single pot topcoat. But it will likely fail along with the top coat in time and will need removal before a recoat. Quote Link to post Share on other sites
Battleship 100 Posted April 25, 2017 Share Posted April 25, 2017 Are you sure about that Wheels? Would have thought it best to let the interprotect cure so no thinners are left and then sand prior to topcoat. I know some people don't like Toplac but I have always found it really nice to use as a brush on product, I always use precoat under it however. If I was spraying I would go with 2 pack but it is a lot more expensive. Oh yes and definitely give the international paints guys a call very helpful. Quote Link to post Share on other sites
erice 732 Posted April 25, 2017 Share Posted April 25, 2017 cross linking the polymer? chains by overcoating before fully cured seems to be the recommendation for 2-pot over 2-pot but once a full cure has happened the light sand to remove amine? blush is recommended at least that's what i understand for overcoating epoxy Quote Link to post Share on other sites
Battleship 100 Posted April 25, 2017 Share Posted April 25, 2017 Yes but in this instance you are overcoating 2pot with single pot. Quote Link to post Share on other sites
gisywaterboy 3 Posted April 25, 2017 Author Share Posted April 25, 2017 Thanks guys, I might do something in between and leave it two days, sand, clean and overcoat with Toplac. Its only part of my cockpit so not too critical, I would be alot fussier it it were the hull. Also I already have some Durapox primer and am thinking of using that instead of interprotect. Toplac specs does say it is suitable over any substrate... Quote Link to post Share on other sites
wheels 543 Posted April 25, 2017 Share Posted April 25, 2017 Epoxy is different to all other coatings. First of all, it usually has very little in the way of Solvent. They tend to be the least of all coatings re Solvent amount. Epoxy Resin for example, usually has no Solvent at all. Any Solvents in epoxy paints evaporate within hrs. It has too, because the Solvent is what stops the mix from reacting and going off in the Tin like Resin will. In fact, the biggest mistake many do is to apply a Coating too thick, which results in a slower drying time, not faster like Resin does.When Epoxies cure, they become a form of inert plastic. Nothing else reacts with it. It cannot be turned back into into liquid. This is due to the two molecules of each component reacting and and creating a whole new molecular chain and in doing so, turns from two components that are liquid into a whole new thing which is solid.The Reaction is exothermic, which means it produces heat. So solvents will not soften a fully cured surface and allow any other coating to bond. Hence why after the coat has fully cured, you need to sand the surface.There are two ways all coatings work in relation to additional coats boding. Mechanical Bonding and Chemical bonding. Mechanical is when you create a "key" by scratching the surface with Sand paper. The next coat locks into the scratch marks. Chemical bonding is when the actual coatings themselves "meld" into one another and bond.Even though Epoxy may cure to a dry hard finish overnight, it really has not fully cured. The curing process continues for ruffly 3 days. After that and the coating is pretty much inert and any additional coats of anything is relying on the roughness of the surface to adhere. Important points to remember.....Any Coating is only as good as what is underneath it.NEVER coat a two pot over a single.BUT, yes you can coat a single pot over a two pot.Most Paints, including some single pots, can have a Max and a Min recoat time. Make sure you read the instructions on what those times are.There are some two pots that are called "Recoatable" and have no time limit and do not need sanding, providing the surface is clean, before coating. Even years later. Quote Link to post Share on other sites
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