Interlux Pre-kote gumming up

I applied the first coat of interlux pre-kote on the exterior of my NE dory build after sanding the epoxy and an acetone wipedown.  After drying for 48 hours, the primer is gumming up my sanding pad within 30 seconds of sanding.  The 'thick white cloud of dust' is absent from this sanding and it is not sanding easily.  I ran out of pads within thirty minutes. 

Is this normal?  Most of the boat passes the fingernail test, except for a couple small spots which got sanded off today.  

How should I proceed?  

 


7 replies:

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RE: Interlux Pre-kote gumming up

Does your sander have speed control? If so, the slower, the better. I use mine almost exclusively on settings 1 or 2 for paint, epoxy or varnish. Higher speed simply warms up the surface and you get clogging.  

RE: Interlux Pre-kote gumming up

I had the same thing happen with my Skerry that I'm wrapping up.  Yambo is right -- the sander is too fast and just melts the pre-kote.  I had MUCH better luck with a sanding block with light to medium pressure -- it may sound slower, but in the end was much more efficient.  I sanded the whole thing with 120, and then followed up with 220, again by hand with a block.  First coat of Brightside went on beautifully after that.

Good luck.

Matt

RE: Interlux Pre-kote gumming up

 

   Matt & Yambo, can't thank you enough for the advice, I was about to spend another $30 on sanding pads.  I'll give that a try today and let you know how it goes

 

 

RE: Interlux Pre-kote gumming up

Giggin,

PreKote is infamous for absorbing moisture as CLC warns in http://www.clcboats.com/shoptips/finishing-tips/painting_polyurethanes.html.  Are you sure that ambient humidity was low enough?  I hope Matt and Yambo are right and all goes well.

Good luck,

Dick

RE: Interlux Pre-kote gumming up

> I hope Matt and Yambo are right ...

Me, too!  I watched the forecast for two weeks before I had two consective days of sun and about 50% humidity, so I was able to get the pre-kote on the first evening, and it was sanded and painted the next afternoon.  

RE: Interlux Pre-kote gumming up

   All went well sanding by hand, I put on the first coat of brightside yesterday.  I plan on sanding and recoating this afternoon.  Any tips for this?  Should I wet sand with 320 first or start with 220? 

Thanks again 'guys!

RE: Interlux Pre-kote gumming up

Giggin,

Quoting from Painting with Marine Polyurethanes:

How Many Coats Of Paint? Applying the paint so thinly will probably require three coats for coverage, depending on the color and your patience. Wetsand with 400 grit between coats for maximum smoothness and to avoid removing too much of the thin coat.

When painting my Peeler Skiff we spent a lot of time filling and fairing before glassing and filling and sanding before applying Pre-Kote.  It seemed to pay off.  We only lightly dry sanded with 220 between coats, wet sanded with 400 after the final coat, and then used an automotive buffer with buffing compound.  Two years later it still looks like gelcoat.  I cannot over-emphasize using many thin coats and not oversanding between them.  The extra time pays off.

Enjoy,

Dick

 

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