Thread: Question on the use of Penetrol in Marine Paint

There are two basic types of epoxy paints and if yours is a single part epoxy (not really an epoxy), it's really just a modified alkyd. You can use a wetting agent like Penetrol, but you probably don't need to. This is because most of these paints already have flow control agents in them. Simply put, Penetrol was useful with traditional alkyds, but not some much any more.

The best advise would be to use the paint straight out of the can, on a test sample and also some mixtures with different percentages of Penetrol added. This is a product that works well, up to about a 15% cut, but then affects the gloss of the paint. In fact, I've used Penetrol to knock high gloss paints down to a soft satin.

The new paints on the market now, have excellent flow control and generally lay down and smooth out nicely, without additional modifiers. If you're spraying, you'll want a solvent cut, but just enough to eliminate stipple. Penetrol can help in this regard, but only a 50/50 mix of solvent/Penetrol, for this cut, preferably less Penetrol.

Simply put, regardless of the application method (roll and tip, spray, etc.) you'd be best advised, to exsperment with different Penetrol cuts and see what happens. You can easily use too much and knock down the gloss, but it'll flow nice. In most cases, these new paints flow great all by themselves. Of course results will also depend on environmental conditions when you do the paint job and naturally, will reflect the prep work prior to the finish paint.

G'day PAR,

Thanks for the advice. I'll do a few test samples before applying the paint to the boat. I'll have to wait for cooler weather though because it's 40C degress here at present. To hot for painting, too bloody hot for doing anything!

Cheers,
redx

100+ heat isn't a good painting environment. What where the conditions for the current paint job?

Originally Posted by PAR

100+ heat isn't a good painting environment. What where the conditions for the current paint job?

Boat was painted by previous owner long before I bought it a couple of years ago. I stripped off all the old paint and have been slowly preparing it for a new paint job. I also built a new floor, new cabin, new rudder and new battery boxes for it and derusted, repaired and repainted the Yanmar diesel engine, but work on the hull has been slow because I'm not as fit as I used to be. Then there are the many delays caused by the the weather conditions and also the condition of ones finances.

It doesn't snow here but it can get awfully cold in my backyard during the winter because of the wind chill factor and then our summers are boiling hot, as it is now. It was 41C yesterday (105.8 degrees Fahrenheit) a real scorcher but not as bad as Black Saturday in 2009 when the temp reached just over 46C (115 F).

I still need to do something with the keel before I paint (I haven't forgotten the advice you gave me a few months ago on fitting a keelshoe). Once that's done and painting is finished I'll reinstall my engine, prop gear and deck fittings and do a complete electrical rewiring job. It will also need a new bowrail and gunnel rubber but after that it should be pretty well finished. At the rate of progress I've shown so far it should only take me about another few years

redx