Denny,

The recent Pre-Kote thread has some good info in it.

My experience is with System 3 Yacht Primer (which I wish CLC would stock), not Pre-Kote. Since both are high-build primers there's some similarity, but someone with Pre-Kote experience should jump in here to give you the real info.

The toughness, BTW, is a good thing. You want a tough layer to support your paint. One thing I can suggest is not to sand the first coat. Put on 2 or 3 thin coats before sanding. That way you'll get a good buildup and fill in some of the previous coats' tool marks. A thicker set of coats also lets you use a more aggressive sandpaper which makes the initial smoothing easier.

As far as thinning, that's a question for the Pre-Kote users.

Good luck,

Laszlo

I just got done using the prekote.  I really like it.  I thinned the first coat 10%.  I applied with a 6" white foam roller and no tipping.  The key is to apply rather thin.  It took about 26 hours to dry fully at about 50-60 degrees in my shop.  When fully cured it sands really easily in big clouds of dust. I sanded with 220 on a random orbit sander.

 The second primer coat I did not thin at all and it came out great and filled the little pinholes I had.  I hand sanded the second coat with 220 after 24 hours and have now applied 2 coats of brightsides.  I gave each coat 24 hours to cure then wet sand with 320 before applying another coat.  Again, thin coats are key and I do tip the brightsides with a brush.  The results are great.  I will apply the last coat today.  So far this has yielded excellent results.

If youre having trouble sanding the prekote, I have to think it hasnt fully cured.

Interlux Pre-Kote doesn't "flow."  It's meant to be a thick coating that gets sanded, filling the low spots in the surface while the high spots are sanded away.  I use primer as a fairing compound, essentially, not as a paint coating.  The high-build qualities of the primer don't lend themselves to flowing out smoothly, or really behaving much like paint at all. (The active ingredient is titanium dioxide: talcum powder.)

I never, ever use a brush with that primer.  Since brush strokes won't flow out, they become instead deep "valleys" in the finish that will themselves need filling.  Instead, I use a roller alone to apply primer.  This leaves a somewhat mottled surface, but the roller is great at getting the primer on in a coating that is a uniform thickness.

So. Do we thin the first coat 10% or not. And if so, with what? Any opinions?

Although I did thin the pre-kote I do not think it makes a noticable difference. 

It was however noticeable with the brightsides.  The lap marks and tip brush strokes seemed to dissapear better when thinned 10%

In general, I don't think you want to be thinning a high build primer.  Kinda defeats the purpose of the product.

FWIW, the only time I've ever seen a manufacturer recommend thinning a high-build primer was for spray application in a hot and dry environment. Even then, they recommended that a test coat be applied unthinned first to see if thinning was truly necessary. It was not an Interlux product.

Laszlo