LOL yes I realize these things can move up and down. I'd prefer to still be able to use my short boards. I'm mostly being a dick and trying to solve a problem that doesn't exist, but its a slow day in the office.

So I took apart the beams and seated them in epoxy. While doing this I have noticed gelcoat cracking at the center seam underneath the beams on all 4 corners. This worries me a bit. Has anyone else noticed this?

YOu seated the beams in expoxy? Aren't Infusion polyester resin. Yes I know that epoxy will stick to polyester.

What will happen when you want to remove the beams?

I haven't looked under the beams on my Infusion yet.

It has been my experience that the epoxy won't stick to the aluminum beam, as long as they are relatively clean and waxed prior to placing them on the epoxy.

You need to wax the aluminum prior to seating the beams. Almost any wax will do. Wax the inside of the beam bolt holes too because if any creeps inside there it can be a pain later on.

The hulls have gelcoat over the polyester resin, just sand the beam sockets lightly and smooth, clean with some acetone and the epoxy will stick fine.

I prefer to use epoxy, I've been told the class rules specify only gel coat may be used so if you're worried about that use gel coat.

On the infusion, make sure you don't end up with any epoxy in the gap between the the top front of the beam and the hull. It will make it impossible to get the beam out.

If you do all this it will require a very slight nudge to get the beams off but hardly any more effort than before you seated them.

I think some people use non-stick baking-paper to stop the beam from sticking to the epoxy.

Or that green PVA mold release spray
Or cooking spray (tradename PAM)
Or carnuba car wax

I think I may have used Rain-X in a bind once for a rudder repair.. If I'd only have used Jake's hotel key-card idea....

your options are pretty open as long as it doesn't bind to the epoxy...

I followed the instructions here: http://www.microwindracing.com/boat.html

I used partall paste #2 wax plus pva for a release agent. No issues with removing the beams. If someone protests me because I used epoxy instead of gelcoat I'm not sure how I would respond...technically gelcoat is an epoxy based product...I have lots of epoxy not a lot of gelcoat on hand.

interesting protest... the basis would be that the epoxy gave you an advantage for the weight saving? Or just that it was an arbitrarily unapproved substance?

The protest would be lodged since epoxy isn't a suitable material for use in the hull construction. However, carefully reading the 2013 F18 class rules (http://www.f18-international.org/index.php?option=com_phocadownload&view=file&id=51:updated-2013-class-rules&Itemid=50) I think I am fine:

"D.3 HULL SHELLS
D.3.1 MATERIALS
(a) The hull shells shall be built from polyester or vinylester resin, glass
fibres, polyester gel coat, the combination of wood-epoxy or injected
plastic with a core of PVC or balsa or felt. The hull shells shall not be
altered, other than locally for fittings and passage of equipment and normal
reinforcement. Epoxy glue is permitted for joining components. Every
material that is not expressly permitted is prohibited."

The "epoxy glue is permitted for joining components" statement may apply here. Furthermore I couldn't find anything that states the beams must be removable but there is probably another rulebook that says otherwise.

"Joining" can mean a whole mess of things. Bonding is a different story, and you are not.

Fair enough.

So class measurers, am I in violation of the rules with my removable but seated beams in epoxy splodge?

Would I be in violation of the class rules if I effected a repair to a localized area of the hull using epoxy resin instead of glass+polyester (no I don't have a hole nor intend to but things happen)?

Well no one seems ready to answer the million dollar question above...

Went sailing on the boat last weekend..it's fast and fun even in the light air but we're sailing slightly above minimum class weight and not carrying the corrector weights for our size (305 lb crew weight). It was double wire conditions on day 1 and really fun.

I knew I had some minor gelcoat issues that I patched before sailing but after flipping the boat over yesterday and re-evaluating it's worse. The original area of concern was created because there was a very minor void in the joggle seam next to the hull center line. This wasn't all the way through the hull but I filled with epoxy left over from the repair below.

I found a fairly long crack that was forming next to one of my dagger board wells in my port hull. It was damn close to the same area on Jakes boat (http://www.teamseacats.com/2011/08/13/its-stronger-than-air/), so I figured it was worth investigating further. I dremeled down and sure enough there was a void in the glass, and the core was wet. Luckily this void was all on the dagger board case side, no real voids in the seam area like Jake found. I mixed up a batch of epoxy splooge (95% collidol silica, 5% West 410 filler), filled my handy epoxy syringe and went to town. Added about 15g of epoxy to the area. Of course it rained overnight, I covered the boat in case it did and the epoxy cured rock solid. Tonight I'll fair in both spots. Work will pause as I'm waiting for gelcoat to arrive. Still haven't decided if I'll roll it on or spray it on, likely the latter.

I have seen this, and just read thru it again.

I'm figuring just about everything here would also work for the Mk1 infusion also, right?

Todd,

It worked well on my boat, which I am currently disgusted with (frankly if it was my factory these hulls would never have left the floor, owner #3 will be very happy since I'm fixing all of Nacra's QC issues).

-Sam

I prefer not to add any type of coating other than wax to the beams when seating them since any other type of coating will add space between the beam and the hull you are trying to eliminate. I've seated a ton of boat beams/hulls with only waxing the beam (partall wax) and using a thickened epoxy resin mixture (will use gelcoat in the future as it doesn't yellow and will match the hull). With this process, it only takes a gentle tap with a rubber mallet to get the beam to release once cured...PVA, wax paper, etc. is not needed. The aluminum doesn't like to stick to resins as it is - the wax gives it just a little extra incentive to not stick.

Guess we were lucky enough & didn't use anything on the N20 beams and they popped off just like you said, Jake.