Building is starting. Several questions in here. Answer any you like! :)

Steve, there is one big reason not to plan out the locations of the major hardware. I haven't decided on the running rigging or cockpit location yet.

I need a core that makes it convenient to install deck hardware because I have no idea what deck hardware I'll have, where the cockpit will be, or where, exactly, I'd like to place various control lines.

So what would you use for a core in this case?

 

I will re-review everything you sent me regarding the internal laminate. I remember a scheme for reaching everything, but it's a bit hazy... need to refresh on that.

I think your reasoning for not going balsa is probably the best one. I hadn't considered balsa sitting out in 80-90% humidity while I'm waiting to join the hull halves and glass the outside. For that matter, is there a problem with Core Cell sitting out for a month or two in 80-90% humidity?

I am doing the bulkheads and beams in balsa without question since they are protected from the elements and indoors. Also, I will be epoxy sealing the edges of the pre-installed bulkheads and beams so they can't get bilge water in them.

I have to go back and review the lamination information now...

 

Cat builder, sounds like you've got it covered on the core close out, BIG backing plates are the go- the more fibre you catch with them the better. so far as reaching the middle, a bridge style gantry or even a bashed up unregistered old pickup with a platform cantelevered over the job with a roll holder would do it, plenty of boats esp steelys built with rough cranes & scaffold hanging off the owners car, I used to build in steel in a paddock many years ago with scaffold planks tied onto the roof racks to access the topsides as a mobile scaf. All the best from Jeff.

 

You could even sit one of these on the platform http://www.boatdesign.net/gallery/showphoto.php/photo/11451/ppuser/12438 . Jeff.

 

It looks like Andrew has come up with the best way to do the glassing of the hull inside the female mold and had already told me how to do it. I'm embarrassed to have forgotten his earlier advice. It's a bit of information overload for me over here.

Anyway, the way suggested was to leave off the bilge and deck foam. Next, glass all the way up close to the sheer line. It's reachable because the bilge isn't in your way. After this, install the foam for the bilge. Glass that. Now, you are left with installing the sheer curve and deck foam. Glass that last. Looks like it works perfectly, but I have a couple questions on this process:

1) If I glass a long strip from stern to bow as in Andrew's method, all I have to sand is the overlap area, correct?

2) This is for Andrew directly... Andrew, when you glassed the bilge, did you do it by getting inside the mold and standing on your already-glassed topsides, or did you glass the bilge from outside the mold? Same question for the sheer/deck.

Wow, with this forum, things are moving right along! Thanks to everyone for your help on my first build.

 

One more: Is there a way to protect my balsa deck from the humidity?

I have a half hull that is glassed on the inside first in the female mold. It is then set aside while another half hull is made up. It will just be sitting there in the shop, which is a tent in FL (fairly high humidity). Andrew mentioned that the balsa sitting out might be ruined. Good point. Is there a way to protect the balsa?

 

Good choice. Balsa (and Divinycell) is stiff and has high shear strength so you could use a thinner core. Not good for hul bottom. Corecell and Airex has lesser shear strength but is elastic and good on slamming forces. You might want to play around with the core sizing formula I posted to prove the theory.

Of course, balsa may not be enough to withstand the bolt tightening forces (compression) with the hardware you will install on the deck. You need local reinforcement and all the precautions needed (higher density core, fender washers, caul plates, sealant, ect) so that water ingress is prevented.

 

Give it a light coat of resin A.S.A.P. before you leave it exposed. Wood core need 15% or less moisture content when encapsulated.

 

That should do it, I think. Makes sense. Thanks.

I will only have to coat the edges if it is AL600 balsa, correct? The tie coat that comes on the AL600 is already air and water tight, right?

 

Not sure about that. I don't have the data sheet. if it is not a barrier, coat all exposed edges.

 

I remember when we were working in an LR approved facility, we have to stop working when the humidity goes up to 70 or 75%. And it only happens when it is very very hot and suddenly rains.

What is the humidity you have there? You might be worrying about something that will not really affect your build?

There is also a cheap instrument the farmers use called a moisture grain meter. Measures the moisture in the grain. You might want to use it to check if your balsa (or a scrap sample) is becoming moisture logged. If it is not, maybe a simple plastic cover on the exposed core will suffice during the evening.

 

The relative humidity earlier this morning in my shop was 94%. Right now (clouds have come in and it is raining) it is 89% relative humidity. Water pools are forming in my shop, as they do when it rains. They drain out quickly after the rain is done.

Mostly, this fall/winter, it doesn't rain since this is the "dry season." During this time, normal humidity is about 70%.

During the hot summers (almost as hot as yours, but humidity likely much greater), the humidity is near 100% in the morning (98% or so), then by afternoon it falls off to around 60-70% before the afternoon thunderstorms develop, which brings it back up again some.

The boat builders I talk to down here say, "don't worry about humidity, we've been building boats here for 20 years." Then others on forums say my project is doomed. The truth, I suspect, is somewhere in between.

I have a moisture meter because I was going to build in wood to begin with. My wood stayed below or at about 12% moisture content. Why?

Because it's so DAMN HOT here in the summer. Humidity is relative to temperature, so as the temperature climbs, the damp is forced out of things and into the air. My wood moisture content goes down as the day heats up as well each day.

The relative humidity also drops by afternoon because it's so hot by then. Temperatures are 80-85F (26.6-29.4C) in the night here in the summer and 98-103F (36.6C-40C) in the daytime (my boat shed goes to 110F or 43.3C regularly). It sucks and you can't get any work done unless you start an epoxy batch at 3AM and work until 9AM. Good for kicking off the epoxy though!

The winter here is far preferable because humidity is generally lower and temperature allows you to work a good 10-12 hour day. Fall seems good as well, but I haven't yet been here in spring.

 

Question: I have reinforcement layers of triaxial around the main connective/bulkheads in addition to the standard triaxial that is all over the hull.

There are strips of added triaxial that go all around the inside of the hull surrounding the main strength/connective bulkheads.

When do I apply these layers? Do I do this during my female mold layup?

Also, I have biaxial reinforcement layers around the dagger board trunks and cassettes for the kick up rudders. When are these applied? In the female mold, or later when I cut a hole in the hull to install these items?

 

I will start my build soon and my two main sorces for foam sandwich construction are on the bateau website and Ed Horstmans book (Foam Fiberglass Sandwich Construction for boat building) it can be bought on his web site. I would think you would apply the tape around your bulkheads and dagger board case when you install them just as you would in a hand layup. I will be building in the Mobile area and have the same problem with humidity, if I had any balsa in my build I woud rent a dehue to dry it out and try for a 12% moisture content before the glass went on. I am following your posts as you ask a lot of the same questions I have, I went in a diffarent direction in core chorce , I could,nt get the price down and was concerned haveing to build an oven to bend it. The H80 may bend too much but I think I have that solved in how I form my male mold.good luck rick

 

Looking good catbuilder! And thanks for asking so many questions. I am learning a lot from your posts.