Scarf joint epoxy filler and keel nose question

Welcome to PocketShip.net! This bulletin board is for builders of the Chesapeake Light Craft-John C. Harris "PocketShip" design, a 15-foot micro cruiser sailboat built from a kit or plans.

For more information on PocketShip, click here: http://www.clcboats.com/pocketship

This site gathers PocketShip builders in one place. Here you can share photos, tips, questions, and---eventually---your sailing adventures in PocketShip! CLC will also post design updates and tips here as they come up.

We'll try to knock down spam as quickly as possible.

Moderator: John C. Harris

Forum rules
Spam or commercial posts will be deleted.
This is a civil forum: no flames or drunken tirades.
Please stay on-topic.
PocketShip's Web Page: http://www.clcboats.com/pocketship
If you need CLC customer service: http://www.clcboats.com/forms/contact_us.html
We'll try to delete spam as soon as it appears.

Re: Scarf joint epoxy filler and keel nose question

Postby craig on Mon Apr 07, 2014 3:17 pm

Thank you all for your comments. Here's how it turned out:

My first attempt was an abject failure (see the first picture): it was very uneven, with many gaps in the plywood that I tried to fill with epoxy. I decided that "good enough" wasn't a good way to start this project and cut the wood right down the middle of the joint. I then made jig for my router. That thing is a beast - sawdust everywhere very difficult to get "right". You can see some rough edges in my second picture, but I finally got into the groove by picture #3. The scarf for the keelson turned out beautifully. I can write up a longer post about it if anybody wants, but this is definitely better than using a block plane (for me at least). Scarfing the plywood sheet only took 10 minutes or so.

20140322_205248858_iOS.jpg
First attempt - so bad I cut it in half and started over
20140322_205248858_iOS.jpg (44.65 KiB) Viewed 1405 times


20140323_212408621_iOS.jpg
A little rough in the middle
20140323_212408621_iOS.jpg (107.65 KiB) Viewed 1396 times


20140323_222906035_iOS.jpg
My cleanest attempt
20140323_222906035_iOS.jpg (118.43 KiB) Viewed 1371 times


My glue-up didn't work out as well. I think my problem was over-saturation with epoxy. Afraid of epoxy starving the joint, I liberally applied epoxy to both sides of the plywood and then added carbosil-thickened epoxy in the middle in a thin film. Lead weights then pressed the two sides together. In retrospect I should have used more thickened epoxy, but I had plenty of run-out so it wasn't TOO bad. Anyway, I think the epoxy actually oozed out completely in the lower side of my joint. The top part was glued tight, but the bottom had nothing in it at all. It's almost like I didn't put any glue there (but I did - I promise!). I could actually break the joint in scrap pieces with my hands after cutting out the hull sides - terrifying! I ended up injecting thickened epoxy with a syringe to hopefully get it into the deepest part of the joint.

My other problem was that the two sides didn't perfectly align. The top of one plywood sheet was maybe 1mm on top of the other piece of wood. Instead of sanding through the face veneer and weakening the wood, I just used wood-flour thickened epoxy to make the surface smooth. One side is still higher than the other, but there is a gradual gradient from one thickness to the other, so I hope it won't be noticeable from the cabin.

Finally, when fiberglassing the topsides and middle panels, I placed an extra strip of fiberglass at the joint for strength.
Titania, launched January 2015
craig
 
Posts: 284
Joined: Fri Feb 21, 2014 1:04 pm
Location: Chapel Hill, NC

Re: Scarf joint epoxy filler and keel nose question

Postby DanaDCole on Mon Apr 07, 2014 4:06 pm

Sorry for all your troubles. I hate to say it but this makes me glad I bought the kit. I think I would have ended up spending more on the plans-only version because of all the thrown-out material. I wish that finger-joint jig idea would have been real--web-site still not working.
DanaDCole
 
Posts: 497
Joined: Wed Sep 25, 2013 2:06 pm
Location: Stillwater, Oklahoma

Previous

Return to PocketShip Forum

Who is online

Users browsing this forum: No registered users and 80 guests