17' 0" Freedom

[Patricks Dad]

I pulled the hull off the mold over the weekend...
https://www.facebook.com/randy.pfeifer. ... 22885/?t=0

[Jim Dodd]

You need another set of hands on the opposite end ! Ha ! Looks great !

So it was a wood plug, not glassed ?

Hull looks shiny on the outside. Are you going to sand later ?

Lastly Did the plastic leave any wrinkles in the epoxy on the inside of the hull ?

You are really giving me the Bug to build another !!!

Love the video !

Jim

[Patricks Dad]

The "plug" is a glassed Freedom 17 hull. After this boat is done, I'll finish that hull.

I'll sand the outside of this new hull later. Maybe while the epoxy for the core is curing (see below).

The inside of this hull is like glass. The heat shrink material is very smooth. Only a couple minor wrinkles down near the sheer line (I'm going to cut another 1.25" off the sheer line before I finish the hull - allowing for 50" wide interior material).

I'm experimenting with a new core for the football area on this build. It's a honeycomb material that weighs almost nothing (1.8 lb / ft^3). My plan is to cut the core and double-face tape it to the plug (with plastic coating still in place) and then apply epoxy (ever so slightly thickened) to the inside of the (yet to be sanded) carbon surface of the hull and put it back onto the plug . This will allow for 100% contact of the core with the new hull. I can put a few straps around the pair to make sure there is a tight connection. Once that epoxy sets, I can separate them again leaving the core attached to the new hull.

I'm also experimenting with a new (to me) material for the inside. I'm going to try a 3.8 oz Innegra cloth.

[Jim Dodd]

For the core, here is a Youtube video that might give you some insight on what to use. Far better explained than I could do !

https://www.youtube.com/watch?v=3Pc-Sd_J26E

I was very happy with my 1/8" WRC insert on my Black Pearl. I made it on the forms, and it matched the hull shape.

Looking forward to hearing about the Innegra !

Jim

[stripperguy]

Thanks Randy !

Another builder, I know from another site, used 1/8" Divynicel. He thought his insert was just over 1 #.
For now I'm content with my wood insert, but will definitely look into foam on my next composite build !

Glad the carbon sleeve worked !

Again Thanks !

Jim

I just joined here, due to Jim's link in another forum.
For the record, I'm the other builder from another site, and yes, it was 1/8'" H80 Divinycell. I highly recommend it.

I'm excited to see your build moving along, Mr. Dad. It looks great so far, anxious to see what the final weight is.

[Patricks Dad]

I recognize "stripperguy" from another forum Jim pointed me to... You have some nice work there.

I used 1/8" divicell in my previous build (actually 2 layers). I found it to be fairly thirsty on the epoxy and I ended up with a heavier core than I expected. the honeycomb I'm using now has it's own issues. It's pretty light (1.8 lb/ft^2) but I struggled to minimize the epoxy on it's install too... I just got it glued in to the hull last night.

What was your approach for installing your core?

I used 2.2 oz kevlar on the inside of my prior build but am experimenting with Innegra (3.8 oz) on this one so I'll probably give back some of the savings I have so far on this build with that inner layer.

I expect the final weight of this tandem to still be north of 40 pounds. With the core it is now at about 22. I'll build my gunwales with foam inside a carbon fiber sleeve. yoke will be cedar with carbon fiber top and bottom. Seats nylon webbing on cherry frames. No decks. Carbon / foam thwart & hand holds.

[Patricks Dad]

Here's a picture of the hull with the core being pressed in place:





and upright with the core in it...



close up of the core:

[stripperguy]

Wow, that's a large core!!
I used some Cabosil thickened epoxy, squeegeed into place to a penciled in outline. I then layed in the H80 foam, and piled everything I could find to hold the foam in place. Later, I feathered the sharp edge of the foam, and added a single layer (a collection of scraps, actually) of carbon on top of the foam. I can stand in the unsupported hull will no discernible deflections.

I'm surprised that your double layer soaked up so much resin, the H80 is a closed cell foam, not sure where your epoxy went...

Here's a look at my desperation weighting of the foam core.



The next composite hull I build will be two layer of 6 oz glass in and out, with a 1/8" H80 foam core. I'm pretty sure that would have adequate stiffness and keep the costs and weight down.

BTW, I built a 17 ft cedar stripper long back and it weighed 38 lbs. My hull design, a bit narrower than that Freedom 17. If only I had access back then to the H80 stuff...could have been closer to 30 lbs...maybe.

[Patricks Dad]

In my previous 2 composite builds, I used the station molds strapped into the hull to hold the foam core down at 1' intervals. It worked fairly well but it does tend to pucker a bit between stations so I added some ceramic tiles I had laying around to keep it in place. Using the original wood hull was really easy and with a few straps around the "sandwich" ensured 100% contact of the core with the hull.

[stripperguy]

Randy,
Was your previous core material scrim cut? In both directions? If so, had you thought of non-scrim cut foam, and heat forming?
I remember Jim used sand bags to weigh down his wood cores, that seemed quite effective.

I'm currently homeless, sort of, squatting at my daughter's house while MDB (My Darling Bride) and I build a new home and large shop.
So I'm mentally preparing for my next full composite build and trying to sort out all the details ahead of time.

I'm also particularly interested in your carbon sleeving wrapped foam gunnels. I have previously wrapped my foam gunnels after epoxying the foam in place on the sheer line. It's really tedious work and challenging to produce a clean result.

Do you have any photos and/or details about the gunnels?

[Patricks Dad]

All of the foam I have used so far was not scrim cut in either direction. the first canoe I built used a single layer of 3/8" thick foam. It was hard to shape and I did use a heat gun to get it to lay down but still needed to use the station molds to hold it in place as I described above. I beveled the edges and added foam ribs up to just short of the gunwales in maybe 10 places along the hull on each side. Those ribs were heat formed using my wife's toaster over and the hull itself as the form. The 1/8" thick version of the same foam was much easier to put in place on the 2nd hull I built (and I skipped the ribs entirely). I didn't think of using the original Freedom 17 wood hull to press the core in place until this build. That worked much better.

For gunwales, I considered wrapping the them with carbon fiber cloth after the foam was installed on the hull but a complete sleeve made more sense to me (I knew it wouldn't peel off). I just built up the gunwales from leftovers of the 3/8" foam I had from my first build and then cut a channel on the underside of it wide enough to allow the carbon fiber sleeve to be tucked up into it and still leave enough room for the edge of the hull to fit in.

I covered the edge of the hull with plastic and installed the foam and sleeve on the hull to match the curve and then wet it out on the hull. I let it cure there and then took it off, removed the plastic and then installed with epoxy. This way I could be sure the gunwale matched the shape of the sheerline without having to force it from a straight structure (had i just installed the sleeve over the foam and wet-out on the bench)...

I must have some pictures somewhere.. here's a couple:

[Jim Dodd]

Really enjoying this build Randy ! Great pics !

Funny how we come up with different methods to accomplish the same goal ! I like using the mold to force the insert core against the inside of the hull. I do wonder if the resin runs away from the joint between the hull and the core ?

I'm betting stripper guy is dreaming of another build !

Looking at the honey comb core, I wonder how you will cover it with cloth to seal it, and not fill the cavities of the core ?

Thanks Randy ! Inspiring !

Jim

[Patricks Dad]

The epoxy won't run away if it is sufficiently thickened (I use carbosil to thicken my epoxy - I also mixed in a bit of graphite to match the color of the carbon fiber hull. And of course there is no rule that says you couldn't flip the sandwiched pair of hulls over so they are both upright while the epoxy is setting on the core.


As for avoiding (not) filling the honey comb with epoxy, I've pondered that quite a bit lately. That was a primary concern with using it (that and its cost - it's outrageous). I'm going to cover the honey comb with a thin (0.2 oz) carbon veil before i put the real cloth over it...

It will be something new to me.... but it's made for this sort of thing...

[Jim Dodd]

Yes, thickening the epoxy for the bond between the hull and core ! Good move !

The gunnels look stout. With 4 layers of carbon they shouldn't move in or out easily !

Where they hard to install ?

Thanks !

Jim

[Patricks Dad]

dimensions on gunwales was 3/4 X 3/4". Once they were built and the carbon fiber saturated and cured, they were easy to install with some thickened epoxy. Note that I saturated the carbon with epoxy while the gunwales were on the hull (but the hull edge covered with plastic so they would have the same curve as the hull - making them easy to subsequently install)