Issues with finish using Resin Research Epoxy

I have been shaping and glassing boards for about a year now. I have built 8 surfboards and 6 stand up paddleboards at this point. Many of the first boards have imperfections, which I expected, seing as I was just learning. I have been teaching myself via internet research because I am in northern Vermont and dont know of any other shapers/ glassers in the area to learn from. The more boards I build, the pickier I get with the final resusts. So, here I am, hoping to learn from the masters. 

My typical shortboard glass schedule is 3x 4oz deck and 2x 4oz bottom. I am using Resin Research Fast Epoxy. The first boards I glassed, got a fill coat, sand, then gloss coat (to cover the dozens of burn throughs). I have gotten better at sanding and now able to just sand the fill coat to 600 grit for a nice sanded finish. I am lucky enough to have 2 rooms for working on boards. One for shaping and sanding, the other dedicated to glassing, meaning everything stays clean and dust free. I am doing a lot of prep and precautionary steps before the fill coats are brushed on and adding the propper amount of additive f to the resin. 

I have started adding some color to my boards, which is highlighting the problem I am having. After sanding to 600grit, blowing off with a compressor, and rinsing the boards with the hose, there are lots of places on the boards that are specked with white. It seems as if there are countless tiny air bubbles in my fill coat that are traping sanding dust and are so small that it wont blow or rinse out. (see photo)

Any ideas? 

 

 

 

 

One more photo:

Looks like weave to me, maybe its just the photos.  I see this with epoxy over painted colors, especially the darker colors.  I’m not seeing any air bubbles.  Can you describe your process?  Are you glassing clear over the color?

…hello Huck, is like he s saying; he is referring to those tiny white dots (looks like a constellation) not the fiberglass whiteness.
So Peakboards, I only see these with pigments but not with paint; I deduced that is the pigment itself; and may be in your case, a mix with dust etc as you says

I am using resin pigment. It does not seem to be consistent with only where the pigment is, as I look closer, because I can notice the same thing over my logo which is printed on rice paper and under one layer of glass.  It is just highlighted by having the darker background. 

Looks like dust filled pinholes in the sanding coat. 

Tape off fin boxes and leash plug.  Place a final coat of resin on each side and sand again. Try to blow out sanding dust prior to final coat of epoxy, but usually not necessary because fresh resin coat will disolve dust and disappear.

Lamination coat, then filler coat, then sand and expose boxes and plugs if applicable.  Last coat of resin to taped off rail,boxes and plugs on each side. sand to polish or sanded finish

In my experience to get to a sanded finsih with the only the lamination coat and filler coat would mean a PERFECT initial tight lamination and a non sloppy filler coat on the thick side using a brush. Then a perfect sanding.

At your experience level there is no shame in a final coat after sanding.  Lam, filler, final coat is the rule for me when hand glassing. Vac bagging glass jobs the lamination and filler coat happens simultaneously with the initial pull when using peel ply.

I’ve seen the same thing in my lam, and I think if you’re using resin pigments it could be a saturation issue, although slight. That sounds like the case over the logo also. The tint highlights the problem. Epoxy’s tough sometimes.

Thanks for all the feedback, everyone. 

bb30, what you are saying would explain why I don’t see this in my earlier boards. I will continue doing a final coat.  

Out of desire to understand more about what is happening, I cant help but wonder why am I getting all those tiny pin-holes. Is there anything more I could be doing to get rid of those? 

Here is exactly what I did to my most recent board (2lb superfused eps):

  1. laminate bottom with 2 layers of 4oz with pigment stripe. cut lap. sand lap. 

  2. laminate deck with 3 layers 4oz with matching pigment stripe. cut lap. 

  3. sand lap and other bumps and such in lamination. (part of why I am glassing heavy is so I can afford to sand some away)

  4. blow off dust with compressor, wipe down board with denatured alcohol, run sticky side of masking tape over board to pick up any fibers or stray dust. tape off rail for fill coat.  brush on fill coat. 

  5. repeat step 4 for deck. 

  6. install vented leash plug, which I have been having issues with pin-holes in the resin used to install leash plugs too. 

  7. sand to 600 grit.

So, am I missing something? Is this all because of the blank off-gassing? I have also heard about people heating up the resin. What is the purpose of that? 

I understand that I should just do another coat, but the better I can do each step, the easier it makes the next. Thanks for all the help!

When lamination just past sticky cure(30-40 minutes) I do a filler coat. Sand lap and do deck. Also I  preglass every thing like boxes, vents, handles, leash plugs, fiberglass patch prior to glassing.  Full disclosure: I have never been trained by anyone.

Have a friend, who I would consider a pro, who would flip board after initial lam in less than an hour, laminate the other side and eliminate lap sandning of the first lam. Put a filler coat on after laminating both sides. Using fast hardener and epoxy resin. this would be laminated and filler coat within an 8 hour day. Ready for sanding and final coat the next day. 

Never used denatured alcohol or masking tape to get dust off. I do Wash with soap and water the whole board before final coat sometimes. Dry sith clean rag and check with a clean bare hand to get for board boogers. Prior to final coat my board would be water tight, ready to surf but with a dull finish. Don’t do  stright up foam boards so I really have never seen off gassing situations. Warm resin to get a quicker set up and possibly cure time.  massive holes I would put drops of epoxy into while filler coat is curing .  Sanding is a whole topic on its own.

Looks to me like overworked/cold resin, it can become milky and have tiny bubbles or foam in it, often you don’t see them until you have a dark background. Seen it with fill coats (thicker ) final coat is usually thin and the bubbles work their way out. You also see it on dark laps where gravity is working against the bubbles getting out.

Often they are just tiny bubbles suspended in the fill coat, hard to see, then when you sand them you break them open, they fill with sanding dust and bam, little white dots.

I have found heat , both the room and the resin is key, heat makes the resin less viscous, reducing foaming and letting bubbles escape the surface tension,  Work the resin less, and use a bit more resin if you are having to pull it to far around the board.

One of the guys here, cant remember who, runs a hair drier over his fill coats/ final coats to get the bubbles out, never tried it but sounds workable.

Hope that helps

 

 

 

board from 3 days ago.

fin box patch just past tacky

double 6 oz bottom lam  with 35 minute cure just past tacky and then filler coat.

Green room resin blanco with west coast fast hardner. Just mix, no additives, no baby sitting.

next step would be sand lap do deck the sam exact way.

Then sand, fix any problems around fin boxes if needed, wash with soap and water, dry off, tape off rails and boxes and start final coat with same resin/hardener. Keep an eye on for 10-15 minutes adding drops epoxy from final coat mixture if any fish eyes pop up. remove taped off areas in 35-45 minutes.

Pics of bottom fin box patch and lam  with fill coat. Temp during lam and fill coat around 85 F


Your part A (resin) is probably too viscous, so your fill coat has lots of tiny bubbles in it either from mixing or spreading–when you sand, those tiny bubbles get opened and the dust ends up in them–it can be basically impossible to get it all out (compressed air and a toothbrush and way too much time).

A quick zap in the microwave (just resin, no hardener, start with 5-10 sec, check and stir. You want it to feel slightly warm, but not hot…you’ll get a smoking mess if you overdo it), will make it much thinner and mix with the hardener without generating lots of bubbles. Stir slow, stir for 2 minutes, reversing direction and scraping the sides of your container. When you do your fill coat, anywhere the resin is even vaguely thick will retain tiny bubbles if you got them either when stirring or when spreading with your brush (or roller)–big bubbles will usually make their way out, but the small ones don’t have enough lift to float to the top. 

Best technique is to minimize the amount of spreading required and don’t move big masses of resin long distances on the board…you’ll generate lots of bubbles that way. 

If you get bubbles, a hairdryer (ok) or heat gun (much better–the cheapo one from harbor freight works fine and you won’t care if you get resin on it) will help lift any remaining bubbles to the surface–but better to avoid getting them in the first place. Don’t keep the heat on any one place for long…just move it back and forth, you’ll see the bubbles popping.

 

I agree with Offshore. Make sure your room and your resin is warm. Regardless, dark colors always highlight any imperfections, which is why so many production epoxy boards are clears. If you do not want to add the extra weight of a 2nd fill coat, why don’t you try the Behr masonry sealer from Home Depot. Search this site for info on it. I do 2-3 coats. Basically weightless and may be able to fill those tiny bubble holes. Only need to sand your board to 320 before applying the sealer. Then you can buff out with maroon/grey scotchbrite to get your 600 equivalent finish.

Thanks for all the info and ideas everyone. I have brushed on finish coats on 2 different boards using different tips that some of you gave me. When I get around to sanding them, I will let you know how it worked out. 

In the meantime, I have a 9’2" longboard shaped and ready to glass. This one is a poly blank and I want to put 2 layers of 6oz on the bottom and 3 on the deck, using epoxy. I would like to give this a traditional looking tint. Same color on both sides. So, when trimming the glass, should I extend all the layers all the way to the tape line? Seems like if I dont, then the color would be uneven where different layers of glass are holding different amounts of resin, therefore tint. I am wondering what is typically done in this situation.  I have been having all the layers extend to the tape, but then end up sanding some away to blend the lap anyway.  

The color, resin and cloth have to extend past the tape line all the way around the board.  You can do the cutlap in the gel state.  Yes you are correct about the multiple layers of cloth holding more tint and resin therefore affecting the colour.  The darker rail effect you see on tinted boards is the result of multiple layers of cloth, resin and tint.  Check out the Fiberglass Hawaii videos.  You will see a good example of resin tinting and cutlaps.

You could wrap the bottom 2 layers, end the first 2 top layers inside the lap line, then wrap the 3rd top layer. That’s the way I would do it.

It might be pulling the lam too tight.  That gave me some pinholes in the past.  Basically if you pull the cloth too tight you are overworking the resin and adding tons of bubbles.  Could be that’s why your first boards had less pinholes. Are your laminations more aggressive now?  Also I’ve had luck using the yellow foam rollers for laminations.  Puts down just the right amount of resin with minimum of bubbles. Squeegees can push bubbles around their leading edge and froth up with bubbles.  Do you see frothy resin when dragging the resin to the rails?  the yellow foam rollers are made specifically for resin application. 

My steps are heat resin in microwave, mix up with hardener, spread whole lot onto paint tray (avoids heat buildup), roller it onto the cloth and board, get it as far as you can with the roller, tighten around rails and do any detail touchups with the squeegee. Come back with a heat gun and hit all the bubbles. That should give you a very clean lam.  I usually do shortboards with 6oz bottom and 6+4 oz deck.  All lams are done individually so I’m not dealling with the extra cloth and the roller.

Good luck!

Jamie… How does that Behr Masonry sealer stand up to abuse?

Is this the stuff???:

http://www.behr.com/consumer/products/floor-coatings-sealers-and-prep/behr-premium-wet-look-sealer-985