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First time builder - Core Sound 17 Mark 3


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After much anticipation, I got my  Core Sound 17 Mark 3 kit in early January.  We  decided to epoxy all of the pieces --except for the finger joint ones-- before actually starting the build.  Our thinking is that it is much easier to flo-coat epoxy on flat surfaces now rather than trying to do all that epoxying later.  I have never built a boat before, but my husband has, and he is my instructor in this endeavor.  I know we will have to sand before actually starting construction, but I am worried that the secondary bonding of dried epoxy  won't be as strong as chemical bonding.  I'd appreciate any comments!

Samantha

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Hi Samantha

Congratulations on the new project.

I'll add my 2c worth.

There is absolutely no doubt epoxy coating flat sheets of ply on a table is much faster and easier and I have done this many times.

There are some problems.

If you do 3 coats and leave the panels for some time they become inflexible and can crack when trying to fit to the boat.

You do have to wash/sand/correctly prepare the pieces for taping/gluing when you need them.

You only get a mechanical bond rather than a chemical one which is not quite as strong- I prepare any edges for taping carefully.

I have chosen a middle path of precoating- usually 2 coats- and trying to do it not long before fitting if possible and hot coat if possible.

I've never had a well prepared epoxy/glass joint fail but I do remember one 25 years ago when I didn't prepare the surfaces well on a modification and when doing a further modification some years later was surprised by how easily the tape lifted off.

In summary- careful preparation of the precoated panels will be fine- mechanical bonds are how epoxy primarily sticks to the wood after all.

Cheers

Peter HK

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Peter gave you very good advise. You cannot build a boat without secondary bonds somewhere.  I am usually not not disciplined enough to coat my panels first. Do not coat the outside of the hull panels as it makes them stiffer to bend. I would only put on two thin coats, leaving a third to put on after the boat is together.

 

Make sure that you put on even coats, I have seen good intentions go bad by slopping the epoxy on. My preferred technique is to load up the roller with epoxy, start rolling it on the panel fore and aft, about 18" long until the roller is empty, before reloading I turn my roller 90 degrees and firmly roll out my epoxy, then turn my roller 90 again and with the lightest touch, roll it out. I reload again and repeat until the panel is done. Before moving on I check that the edges are good and scan the panel to make sure that it is perfect. If there is any hint of orange peel I will tip it off lightly with a brush.  I like to hot coat for the second round avoiding the need to sand and giving you a primary bond.

 

How soon can you second coat? As soon as it is firm enough to work on. 

 

Good luck with the build.

 

 

 

 

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My slant on the good advice from above. Some surfaces cry out to be precoated others not so much. I am not sure what you mean by flo coat but I think you want to apply the epoxy in as thin a coat as you can force yourself. It is possible but difficult to apply epoxy too thinly ,very easy to apply it too thickly.   I prefit many pieces  mark where they will be bonded and then precoat only selected areas of the panel, thus avoiding cold joints.

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I don't like to pre-coat, but as Joe has pointed out, there are a couple situations in a boat that cry out for it.  Under the seat tops is one IMO.

 

I am a huge fan of hot coating.  So much so that I will set an alarm for the middle of the night if I must to work a good hot coat schedule. Reducing sanding this significantly, is worth that much to me.

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I  agree Hirilonde.  Hot coating rules.

 

  In colder temps I would put a coat on before I went to bed, set an alarm for 4:30 in the morning, and put another coat on before leaving for work. In a weird way it was kind of fun. 

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Thank you all for your comments.  We are flo coating pretty much the way it is described in The Gougeon Brothers on Boat Construction.  We put down a thin film of Silvertip Fast Epoxy, wait about an hour, then use the notched squeegee to put on a coat that self-levels quite well.  The flo coat is meant to take the place of three thinner coats. All the pieces we have done thus far are for the interior of the boat, and it sounds like we should be particularly careful about preparing any edges that need to be bonded/filleted.  It also sounds like we should do the hull in the more traditional three coat way.  

 

We have limited space in the shop, so plan to do the piece-work described in the plans while we still have a big surface to work on, before starting the hull.  

 

Thus far, I have learned the following:

1.  Even if the shipper loses my boat kit for three weeks (which did in fact happen), I should not lose my cool.  They did eventually find it.  Alan helped encourage them to look! 

2.  There is an art to epoxying, and it is learnable.  

3.  Particularly in this time of Covid, it's really fun to have a big, interesting project.

Samantha

 

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Congratulations on getting the CS17 Mk3 kit (eventually) and taking on the project.  I skipped the building part and purchased one that popped up on the forum as being for sale.  I haven’t used it yet, since it went right into winter storage.  Maybe you’ll sail yours before I sail mine. ?
 

My two “retirement” boat-build projects (during COVID) have been great to have and provided LOTS of hands-on activity.   Even more fun for me was using my stimulus check to help “stimulate” some business for B&B Yachts.  My wife and my mom also tossed their stimulus checks into the B&B project and that mostly took care of the rest the kit’s expense.  It was a GREAT way to use stimulus checks. 
 

Be sure to let folks know and see your progress on the build.  Photos are always appreciated.  A couple times during my build I received some very helpful and timely advice just because the Designer noticed things in my photos.  Oh, and be sure to check out Alan and Taylor’s video series on making their Mark 3.  The most helpful information for me was gained from watching Alan’s 20-video series on building the CS15. 
 

I have enjoyed making “build-blogs” on this website almost as much as the actual building.  Most nights, after getting some things done on the project, I’d take some photos and do some writing. A primary reason was that it provided me a way to share stuff with my family and friends. 
 

I concur with your three “learnings” above, except that I drove my Toyota Sienna to B&B’s to get my kit. 

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13 hours ago, Samantha Ritchie said:

I enjoyed reading the blog about the pink boat built by Weezer

Yeah, she’s been really fun to mentor through the process.  And, I’m glad she finally decided to do her own painting instead of hiring it out.  (I think it will enhance the pride she takes in the project.)
 

I find this cute and endearing… and probably very important…

Throughout the process, I always let her know that she needs to be the one to decide if and when something is done to her level of satisfaction.  While her level might be different sometimes from what I’d hoped for in my own work, I didn’t want to project that onto her.  She always seemed delighted whenever she brought a step or process to whatever level of completion she decided.  And the results are really satisfying to her.  It also helps to start with such a high quality kit.
 

SUMMER’s Comin’ Kid!!  ?

It’ll be a gas to sail our boats together. 

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27 minutes ago, PadrePoint said:

Be sure to let folks know and see your progress on the build.  Photos are always appreciated.


Samantha, your thread already has about 100 views.  See!  People are interested. ?

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20 hours ago, Samantha Ritchie said:

We are flo coating pretty much the way it is described in The Gougeon Brothers on Boat Construction. 

Sure enough on page 156 Flocoat procedures. Thank you for mentioning the reference. Please post pictures if you like.  Ask lots of questions we all learn that way. Have fun with the build.

 

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Graham (“Designer”) said 

How soon can you second coat? As soon as it is firm enough to work on. 

I learned a nice trick to test for when it’s firm enough: a way that keeps you from getting goo on your fingertips.  It’s called the cotton ball test.  You simply dab a cotton ball  on the epoxied surface.  If fibers pull away, and stay stuck to the epoxy, it is not firm enough.  If no fibers are retained on the surface, you are ready for a second coat.

 

Last night:

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This morning:

C7692095-2731-470A-AC1A-7D249DAC8152.thumb.jpeg.26b2b97ab2a4d8b3be623b384f28362d.jpeg

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We are almost done putting together the bulkheads, and the next step is working on the bunk hatches.  I read a thread from 2019 about piano hinges vs other possibilities, including carbon fiber hinges.  Any updates on that? And any good sources for stainless steal piano hinges appropriate for the bunk hatches?  

 

I like the idea of the cotton ball test-- thanks for posting that!

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