Some finishing questions and the obligatory epoxy ones too!

Hi Everyone!  I am working on a Shearwater 17 that has been in progress for going on 3 years.  This is what happens when you have 2 children and purchase a house right after getting a kit.  Well, we finally built a shop onto our house and the project is really back on track.  I have a hull and deck together, all is looking well at this point and I am just sanding in preparation for glassing the outside.

On to my questions.  First, I am concerned I am going to run out of the original epoxy which is now 3 years old.  I have an extra half gallon of resin, and I am getting new slow hardener (MAS by the way).  I am worried that if I run out of the original stuff after doing lets say just the hull, or even worse halfway through a hull or deck, what is the best way to assure an even color?  Should I mix the containers of resin that is left, and use only the new hardener? What carries the amber color? Looks to me like it is the hardener just from observation as my resin is still clear, but the hardener is yellowish.  Or... Just use the new stuff entierly?  I kinda like the amber hue actually.

Second, how ridiculous do I have to be about sanding before the glassing.  Specifically, when epoxy has stained the wood, but carries no wood flour or silica, will it just blend in when the whole boat is glassed? I am guessing you will never really get the wood back to its raw color anyway. So just remove any   drips, scratches and decreeable bumps and make it all smooth?

Finally, it seems the instructions don't tell you to glass the cockpit combing ply spacers on the outside of the boat, only wrap it to the inside.  Do you just make sure it is all coated in epoxy to protect the spacer from water? What about the edge of the rim itself on the outside? Cut it even? Same on the hatch openings, just glass up to the edge of the opening? Or do you have to fold the glass inside the hatch down to cover the spacers?

Sorry for the long post but I am just at that point of no return on a few steps and I just want to be sure! Can't wait to see this baby on the water!

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RE: Some finishing questions and the obligatory epoxy ones too!

Quick change to my question, and a simplification as I think I have 2&3 figured out from talking to folks. But can you mix old and new hardener to make sure to have a consistent color?  My hardener I have now is quite amber and I think my plan is to mix a pint of new in with the old to see if that gets all my glassing done without changing colors halfway through the deck.  Thanks!

RE: Some finishing questions and the obligatory epoxy ones too!

I'd suggest contacting MAS about the epoxy question - they can give you a definitive answer about mixing old and new or not, and if the old stuff is still OK. Their web site FAQs say that resing has an infinte shelf life and hardeners at least 1 year, but check with them directly (

RE: Some finishing questions and the obligatory epoxy ones too!

Oh, I know the old stuff is good.  I have gotten the boat to this stage with it.  Fillets, interior epoxy etc.  I am just not wanting to risk a two tone deck hence the desire to mix the two to create  a consistent color.  Contacting MAS is a good idea.

RE: Some finishing questions and the obligatory epoxy ones too!

Ok, have used gallons of MAS, old amber and new problem with color; it all comes out clear. Make sure you wash off the last cured layer of epoxy before you sand it. If the epoxy balls up on your sand paper, it has not cured enough! It should sand off in a fine white dust consistency. Progressive sanding of the veneer 120, 180 then 220 will give you a great looking natural finish. Without sanding, every scratch or rough spot will show...the glass will completely disappear in the epoxy. Just be careful on the joint edges so that you don't sand through the veneer edges. The hatches are cut out after you glass your hull, not before. That way they will not warp and will have the same shape as your deck. Just seal the inside edges of the hatch openings with two or three coats of clear epoxy. The coaming is glassed on the show surface only, right out to the edge; drape one big piece of glass over the entire cockpit & tape the edges to the deck, then cut out the center, or use about 6" wide strips taped to the deck . Be sure to put plastic tarp in your cockpit to catch any drips & clear wrapping tape on your deck to keep it clean of drips. Draper the glass over the edge, put on the epoxy, let it cure to a very tacky state, then knife off the edges on the rim & under the deck edge. Then press the edges down firmly with a gloved finger or a putty knife & let it harden. Add several more coats of epoxy. Let it cure very hard before you start to sand. On the underside of the rim edge, a small fillet into the spacer/rim angle will sufficiently reinforce the rim edge. Dirk

RE: Some finishing questions and the obligatory epoxy ones too!

Oh, I forgot to mention...if the resin has been sitting for a long time, especially in your garage (cooler than the house) some tends to crystalize into a gooey paste in the bottom of the jug, and/or may look cloudy when you dispense it. The resin is still good, but just needs to be heated up to about 150 degrees to melt. Think ice. Put a small dowel in the jug & scrape the bottom, if it is thick the whole jug needs to be heated in a hot water pot. An alternative is to put small amounts, like two cups, in your microwave & heat for 10 - 20 seconds intervals until absolutely clear; let cool, then put it in a separate container. If you want an extra tough boat, once the the final epoxy has been used & you are ready to varnish, wrap a black tarp over your hull & place it in the sun for about an hour or two. This will allow the epoxy molecules to reach maximum bond strength. This is similar to tempering steel. Put a thermometer on the deck & let it get to about 130 degrees, so if you live in a pretty hot climate area, check it every 15 min or so. Good luck & you should have a great boat to paddle. Dirk

RE: Some finishing questions and the obligatory epoxy ones too!


I am at that stage with a shearwater. What are the answers to two and three?

RE: Some finishing questions and the obligatory epoxy ones too!

For sanding questions see the 14 part CLC vid where they built a Chesapeak 16.  They explain it very well there.


But the quick answer is the time to pay attention to a perfect finish is before the glass is laid on.  Sanding is fun, sanding is fun, sanding is fun...  <<<The Video<<<

RE: Some finishing questions and the obligatory epoxy ones too!

If you arn't to fanatic about how it looks and just want to get to the water, sanding to 120 will do fine.  I still have drips where the deck glass overlapped the hull and I was in a rush to get to the water.  I slapped several coats of varnish over it and went kayaking.

5 years later, scratches, dings etc.  Every time I launch people stop to tell me how great the boat looks.  Some day I may finally sand the drips out. I can not see that it effects the performance at all. 

Someone said that "perfection is the enemy of good."  

Just my opinion.  I truly admire boats with a fantastic finish.  It's just not for me.





RE: Some finishing questions and the obligatory epoxy ones too!

if you're going to paddle around Manhattan, like Ed, Joey and I just did, a coffee table finish is not in your best interest.

Do the best you can and have fun!

RE: Some finishing questions and the obligatory epoxy ones too!

Hey everyone!  Just thought I would give an update on my build and the questions that I had above.

1.  Epoxy age.  Didn't matter.  When I glassed  the boat the color matched perfectly.  I tested before I glassed by taking one of the deck forms that I had removed and glassed over it with half being done with the old and the other half new epoxy.  I couldn't tell where the line was where the two met at all and neither could anyone else.  

2. Sanding.  Again I was worried about spots where epoxy had stained the boat and if it would leave tell tale spots.  Nope.  Blended in perfectly.  Sanded her smooth and glassed away.

3. Cockpit outer rim.  I was just confused on this one.  Glass on the inside, good large filet on the outside.  Looks fine and dandy.  I did come up with one trick though.  I flipped the boat upside down to do the filet around the cockpit rim to avoid any sagging or running on the deck.  Also I taped off the whole area to avoid any more sanding than I had to do.  

I just finished my second coat of varnish and I am so happy to see her almost complete.  A few mistakes here and there that I will always notice, but for my first boat and learning a lot about wood, epoxy, glass etc I am very happy. 

Here is a shot after the end pour.  Dang they look huge when propped up against a house!

end pour

RE: Some finishing questions and the obligatory epoxy ones too!

Ooops.  Here it is.

RE: Some finishing questions and the obligatory epoxy ones too!

Beautiful boat! Get used to hearing that everywhere you go.  Now get it in the water!  Dave

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