Finishing under decks

[erikgreen]

So, I'm getting close to done with my underdeck structure, and I'm wondering how necessary it is to glass over the surface of everything. Right now, the stringers are held in place by epoxy putty and glassed roving, and are encapsulated completely with a coat of epoxy. Do I still need to put a layer of glass over that? If so, is that for abrasion resistance or something?

I'm looking at how solid and waterproof it already is, and trying to decide if I want to spend the glass, epoxy, and time to cover it all again, when I could just as well finish the floor supports and cleats and get the wiring done.

Has anyone skipped coating everything with glass and just painted epoxy on, and if so, how well is it working?

I'm going to coat my bilges with a spray of Interlux Brightsides, in white, by the way.

Erik

 

[sdunt]

Re: Finishing under decks

It sounds like you have already encapsulated the stringers.. The problem comes in and this is whether you glass over them again or not, when you put in the floor, and screw it down.. You just put X number of holes in that nice epoxy encapsulation.. You can work to prevent it by putting putty on top of the stringers as you lay the floor and when you glass over the floor.

From a structural point, is what you have done so far the same as when the boat was built? If the manufacturer had glassed all of the way over the stringers, then they were planning on that for support.

I take the angle of always over building. If there were 3 layers there before, then I am going 4 layers..

 

[BillP]

Re: Finishing under decks

If you coated it well the epoxy is certainly strong and tenacious enough to keep water out and will flex without cracking. When doing the deck, test fit and drill pilot holes for screws...do deep countersinks. Then put thickened putty on the tops of the stringers and lay the deck down. Pour epoxy res into the screw hole to seal everything before screwing. Fill the countersink with epoxy.

bp

 

[erikgreen]

Re: Finishing under decks

Hmmm.. I was actually not planning on screwing the deck down, but rather using epoxy putty to glue to cleats which themselves would be glued to the stringers and floor supports ("ribs"). Plenty of strength that way, and no holes in the floor to leak. After it was puttied to the stringers, I'd glass over the floor with epoxy and 8 oz. cloth before painting and probably nautolex.

The original floor design doesn't transfer well... I've worked out that Sea Ray actually assembled the floor upside down and out of the boat, then flipped it over, lowered it in onto large blobs of glue, then glassed it to the rest of the hull. So I'm a little bit on my own as far as structure goes. I'm sure the stringers are waterproof, so it sounds like I'm ok to proceed... maybe I'll just glass over a few critical points for extra strength before I put the floor on.. I need to do the wiring first anyway, and I'll probably use some epoxy and glass to hold the conduit in place.

I'll see if I can post some pictures of how things stand soon, that'll explain better.

Erik

 

[BillP]

Re: Finishing under decks

Nothing wrong doing it without screws. Most production boats are built by setting the liner down on "glue" without screws. Screws just make it easier to pull the deck down if it isn't a perfect fit. Also, even heavily thickened epoxy tends to sag and run off the tops of stringers as it kicks off. Screws assure contact and if done right are no problem later. I've pulled 30yr old galvanized screws that were encapsulated in glass and they looked new. Anyway, old car batteries are great for weights to keep pressure on plywood decks when gluing without screws.

bp

 

[erikgreen]

Re: Finishing under decks

Thanks... I may just use some stainless screws here and there if I need a clamp in a tight corner. I don't have any car batteries around, but I do have some aluminum billets I can use, plus the three batteries for this boat.

In case anyone's interested, I'm using some of the boat building techniques detailed at bateau.com, where you epoxy/clamp a pair of 1x1 cleats to the top edge of the stringers and floor supports, to provide a 2"plus flat surface for the epoxy putty to be spread onto as a contact surface for the deck panels. Here's a link to the bateau2.com site - the folks that own that company seem really nice about helping people out with boat repairs or building their designs.

http://bateau2.com/content/view/144/28/


Erik

 

[Zetman]

Re: Finishing under decks

5 gallon buckets filled with water or sand are a great way to use instead of batteries for weight...