Key Largo cold mold question

Designs for inboard or outboard power

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Mickffly
Posts: 17
Joined: Thu Jul 30, 2015 9:02 am

Key Largo cold mold question

Postby Mickffly » Mon Jan 23, 2017 1:44 pm

I have the first layer of 1/8 okume on the bottom of my Key Largo build. I'm using the Raptor stapler with nylon staples...and using more than I thought I would need (~4 staples across a 5" plank and ~5 across an 8"). Seems like I have a solid bond between planking and longitudinals...so my question is really about the second layer. I just saw pictures of a build where the builder used vacuum bagging for the second layer! I have little interest in going that route, but wondered about stapling the second layer...since the laminations need to be sound. Can I still just shoot staples into keel, battens and chines? I hate to staple out in between the longitudinals because the staples will show on the inside and require extra work to sand off. Advice appreciated.
Mickffly
Charleston, SC
Key Largo Build
started 8/30/2015

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Jimbob
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Joined: Thu Jul 25, 2013 1:07 pm
Location: Sacramento, CA

Re: Key Largo cold mold question

Postby Jimbob » Mon Jan 23, 2017 4:30 pm

I used the raptor staples also. If any poke through, they break off easily.
I marked out where the battens were for the second layer, and any layer where the combined thickness was less than the staple I was using and stapled there. I did have "punch through" in places where I used scraps to hold seams together. I got to the point that I was more concerned having a good bond than if a staple punched through. I tried to avoid "punch throughs" but now I think I was overly concerned because the interior is later sealed and then coated with bilge paint, and not seen anyway. As shown in the picture, I sealed the inside of the bottom pieces before attaching so I would have complete coverage where the drains are located at the frames. Made it easier after the boat was flipped.

Jim
Attachments
20140817_180913.jpg
scraps to hold seams even
20140824_203359.jpg
I always marked where battens and frames were for the next layer.
Jim Neeley
Building a Barrelback in Sacramento, CA

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sscobra
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Joined: Wed Oct 24, 2012 2:11 pm
Location: Dripping Springs, TX

Re: Key Largo cold mold question

Postby sscobra » Mon Jan 23, 2017 11:13 pm

Are you really using 1/8 Okume? All the okume I bought was in millimeters. I used 4mm thick for the bottom which is about .025" thicker than 1/8. If you are using 4mm, you won't have much of a problem with the staples punching through. If you are using 3mm, then you could have some penetration, but it should be small. I used 1/2" staples where the structural pieces were and 1/4" in the field between battens. I used a lot of 1/4" staples! You definitely want to staple in the field to avoid any voids between layers of ply. I also lowered the pressure on my compressor a little so the head of the 1/4" staples wouldn't penetrate very much if at all into the top layer of plywood. After the epoxy dried, I removed the heads of all the staples. A chisel works very well and they are easy to sand off. A bit more work, but that insured a good bond between layers. Skip
Built the Glen-L Monaco, 2016.

Mickffly
Posts: 17
Joined: Thu Jul 30, 2015 9:02 am

Re: Key Largo cold mold question

Postby Mickffly » Tue Jan 24, 2017 10:36 am

Excellent replies...thanks. Yes, I have 4 mm Okume... so my 3/8 staples won't break through on the third layer! It's good to know that I shouldn't worry about putting staples in the "field" and will do so to enhance the lamination. I have 3/8 staples, but maybe I should buy some 1/4 to avoid punch through? I am finding the 3/8 staples only worked marginally well as I moved through the bow section where the bends were more acute--and holding power more important! Maybe I should buy some 1/2 inch for batten holding power. One more question...I assume that the battens can take multiple staples without splitting or cracking as the layers build up and the number of staples increases?
Mickffly
Charleston, SC
Key Largo Build
started 8/30/2015

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sscobra
Posts: 483
Joined: Wed Oct 24, 2012 2:11 pm
Location: Dripping Springs, TX

Re: Key Largo cold mold question

Postby sscobra » Tue Jan 24, 2017 11:01 pm

Yes, I would use the 1/4" staples in the field for the second layer. I also used them for the third layer in the field, but you could use your 3/8" there if you want. I pressed hard on the layers with the nose of the stapler to push the second layer down to the first layer before I fired the stapler. I also used narrower and narrower strips of ply the farther forward toward the bow and farther back toward the transom to fit the curves easier. I did not have any problem with the battens cracking or splitting with more staples. Skip
Built the Glen-L Monaco, 2016.

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Roberta
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Location: East Troy, Wisconsin

Re: Key Largo cold mold question

Postby Roberta » Wed Jan 25, 2017 6:16 am

Ditto what Skip said!!

Roberta :D
Roberta "Queen of the Boat Builders"
Built Zip "Oliver IV", Super Spartan "Jimmy 70", and Torpedo "The Glen L".


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