Enough Epoxy ?

Well, I rolled on the third coat of epoxy yesterday on the interior of my NE Dory. This morning I did a "test sanding" to get an idea of how to get from a bumpy gloss epoxy finish to a "flat cloudy grey" surface appropriate for varnish. I sanded (lightly) by hand starting with 120 grit and then switching to 220 to smooth out any sanding marks. To my dismay, it seems like I've sanded down to wood (!?). I've attached a picture of the test site (see link below) and would be grateful for your comments/suggestions.

Many thanks.

https://plus.google.com/photos/102830667398257653917/albums/6110909574746514113

 

 

 

 

 

 

 

 


12 replies:

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RE: Enough Epoxy ?

   I though the link would be active but you need to cut and paste the address into the google search window and the picture comes up.

RE: Enough Epoxy ?

Sawfish,

From the photograph, it appears that you are not sanding epoxy on glass but rather epoxy on wood.  It is hard to tell from the picture how much epoxy is left.  The primary objective of epoxy on wood is to seal the pores of the wood to prevent the wood from absorbing moisture.

If you can wipe the area with a damp cloth without wetting the underlying wood, it is probably sealed well enough.  If not, apply some more epoxy and be a little less aggressive with the sanding.  Remember that epoxy is easily damaged by UV light and will always require paint or varnish to protect it.

I did not leave any wood bright on my Peeler Skiff --- and I'm no expert in the kind of finish you are trying to get --- but 220 seems a little fine for the epoxy coat.  You might want to revisit the "Finishing" section of this site's "Tips for Boatbuilters".  There is a lot of good advice there.

Cheers,

Dick

RE: Enough Epoxy ?

120 is a bit aggressive for roughing up for varnish. 220 should be more than enough. you are only trying to scratch the surface enough to give the varnish something to hold on to. If in doubt roll on another thin coat, and lightly sand with 220. good luck. JRC 

RE: Enough Epoxy ?

JRC, did you look at the photo?  We're not talking about merely roughing the surface so the varnish will adhere.

RE: Enough Epoxy ?

Sawfish,

In future, when you roll epoxy on, you might want to tip it with a foam brush to flatten the roller marks.  Might help with the sagging as well.  I've come to believe that reading, asking questions, practice, and patience are the most important tools for the amateur boatbuilder.

Looks like she's going to come out great!

Regards,

Dick

RE: Enough Epoxy ?

SawFish, It appears that personally building ten boats is not enough experience for Mr Dowdell. So, I will not add anymore of my insight to your question. However, I stick to my previous recomendation, sand with 220, If you have other issues, reassess, and move on to varnishing. Or you can spend the next year chasing a "perfect finish". JRC

RE: Enough Epoxy ?

Sorry for the short reply earlier. Any progress? JRC   

RE: Enough Epoxy ?

FYI - The photo doesn't come up because Barney Google wants a log in. You need to provide an open photo host for the CLC forum software to be able to access images, as well as using the image dialog box to embed the URl into the post.

Laszlo

RE: Enough Epoxy ?

  I had an interesting conversation with the Interlux rep at the AC Boat Show last week. He absolutely recommended sanding to 320 between coats and 120 to give tooth on the initial coat. His biggest contension was to use epoxy primekote on painted surfaces. He absolutely discounted any use of regular prekote before Brightsides due to delamination of layers from contaminates (amine blush).  He acknowledged many builders having success but was just as quick to state that we never hear from the failures. In the tips section CLC actually mentions not using epoxy prekote in thier shop but does recognize the possibility of contamination. I haven't found anyone on here using anything but regular prekote so that is what I purchased before my talk with the rep. When the weather breaks and I approach the varnish and paint stage in my dory build I guess trial and error will again be the deciding factor. My intention is to roughen up with 120 on the entire boat, adding layers if I sand through.  Lay down the varnish and sand with 220 in between coats. I hope not to chase the ever elusive perfect finish, however if my OCD kicks in, I may try 320.  

Another point of emphasis was not to use scotchbright pads ANYWHERE. It just didn't provide enough adhesion surface. I 've noticed some builders describing the use of these. Are they really useful or should I listen to the rep and sand? Dan

RE: Enough Epoxy ?

Jacardin2,

We had excellent success using Interlux Brightsides over Pre-Kote on my Peeler Skiff.  The exterior looked like gelcoat after a final buffing with a very fine rubbing compound.  We mixed a Interlux Flattening Agent for One-Part Finishes, to keep down glare, into the Brightsides on the interior and added Interlux Intergrip Non-Skid Additive for the seats and the sole.

As to amine blush, we didn't notice it with the MAS epoxy in the CLC kit.  We sanded the entire boat with 120-grit and wiped it down with Interlux 202 before applying the Pre-Kote.  http://www.clcboats.com/shoptips/finishing-tips/painting_polyurethanes.html pretty much covers it all.

Cheers,

Dick

http://www.clcboats.com/images/photos/boats/peeler/2014/peeler-abouttime--dick-dowdell.jpg

 

RE: Enough Epoxy ?

Brief update from my shop -

I had really slathered the epoxy on the interior resulting in many runs and sags. I have been using 80 grit (very carefully and by hand) to knock-off the bumps and drips followed by 120 grit to get to a flat finish and finally the 220 grit for a satin smooth surface. This is working well.

No doubt that I have gone too far in a few small spots (some edges & corners) and got back down to the wood but will remedy this with more epoxy & sanding before I move on to the varnish.

Annoying me are the miniscule specs of unsanded epoxy that refuse to disappear and working those very tight spots where the thwarts join the hull. 

Thanks for all the advice. You're helping to keep a lone builder sane !

 

 

 

RE: Enough Epoxy ?

I guess I was pretty lucky, my two oldest friends in the world helped me with my build.  Make sure you keep reaching out to the builder community.  We are a pretty opinionated group, but we mean well.  The folks at CLC are great at answering questions as well.

As I close in on 70, I tend to focus more on utility than brightwork.  You might consider saving the varnish for the seats and the shear strake.  Interlux Brightsides is beautiful and durable stuff.  It has the advantage of being opaque which allows you to use filler (like Bondo) and high-build primers to cover imperfections and still have a goog looking finish that will handle hard use.

Chin up and good luck.  It'll come out great in the end.

Cheers,

Dick 

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