Newby question regarding Epoxy and fiberglass redecking and plywood choices

I was just at the system three epoxy web site and they discussed how, due to the lower quality of marine plywood the past few years that they see no reason to use it over exterior grade plywood when it's going to be sealed with epoxy. This was in their adobe epoxy guide.

I was curious about your opinions regarding this since I'm planning on redecking my boat in the spring as I now have a soft spot when my oversized overweight friend decided to JUMP into the boat. Since I have to rip up the rear section and entire floor covering I've decided to redeck it and replace the fuel tanks as well.

Second question is, I was going to cut out all of the pieces for the new floor using the old pieces as templates and then epoxy the underside of it with two coats.I plan on glassing the deck and wanted to know if when doing this it's best to glass after the first penetrating coat of epoxy or to have the fiberglass down already and epoxy over it for the first top side coat. I was curious as what fillers work best. Should I use a wood flour filler, milled glass fiber, or is there something else that's better.

Third Question, what weight fiber cloth should I use and should I use biaxial or just regular cloth? I read to stay away from the chopped matt. Also do I need more than one layer of fiber cloth? I'm really not up to date with fiber cloth and even after reading the brief description am not completely sure of how the differences effect the outcome. I figured that the higher the ounces the stronger it would be but am not sure of which to use for the the deck. Why do some list it with matt and other without matt finish. My guess is it has to do with sheer strength when bracing stringers, etc. What would give the best outcome for a deck and not be out of line regarding cost?

I didn't want to use any screws to attach the floor to the bracing and was going to use the exoxy or something like liquid nails or 3M to attach it. Because of that I wanted to know if it's worth it to use epoxy to then attach to center console down as well or use something similiar to what I read at system three on how to attach screws by drilling them out oversized and then attach them using epoxy. Does this work for seating as well as bolting them in?

Lastly what would be the easiest way to finish the floor. I was considering using an enamel with a non stick additive. Do I have to sand the epoxy for painting or can it be applied right over with no sanding required, except for blemishes.

Am I correct that you only have to sand epoxy between coats if you let it dry completely but if you don't you can add the coats as needed.

Basically are all epoxies that operate in the same temperature zone the same. What I mean is ones that dry over the same time frame. Since they seem to just use different hardners for different drying times.

Are there any systems to stay away from?

Sorry for such a long post for my first one, but I just spend a few hours online the past few days looking over info on replacing decking and got a ton of misinformation and conflicting info listed at other sites.

Thanks in advance

 

Conventional opinion is that when coated with epoxy, high quality exterior plywood is as good as marine plywood concerning the rot and water resistance. However marine ply will be stronger generally.

You should first coat the ply from both sides and the edges with liquid epoxy for good penetration. Then you can do what you have to do. I believe 1 layer of fiberglass for the deck is OK. Note that when applying the fiberglass you must to push strongly with the putty knife in order to remove the excess of epoxy and eventual bubbles. The color of the obtained layer is very specific. When curried sanded taking care to not sand the fiberglass. Sand between operations, don’t try to go faster then the music.
Good luck
CapKos

 

I agree with System Three in that the quality of Douglas fur marine grade panels have been pretty bad in the last ten years. The trees are fast growth, farm raised junk that is a poor substitute for the stuff we've loved for many generations.

That said, many major marine grade plywood suppliers have stopped carrying Douglas fur ply, for that and several other reasons.

Most exterior grade lumber has a good core and exterior veneers, all have water proof glue, but the construction of the panel is by far inferior to marine grade panels. This means the sheet will have many voids and other defects that can make the panel unreliable in a boat.

In a floor application like yours Baranex4, the ply will rest reasonably flat, so exterior grades will work. Used flat, with very little or no bend forced into it, the exterior grades work just fine. If much crown or twisting is involved in the layup, then I recommend marine stuff.

Yes, coat all the plywood with epoxy, preferably penetrating epoxy (different then laminating epoxy). Coat every face, edge (especially the edges) every cutout, hole and notch. Coat them until the wood will suck up no more, then put the 'glass on.

You deck surface requires 'glass for abrasion resistance and if the panel is made of Douglas fur, also to hold back the checking. The amount of 'glass you want is determined by how much protection you need. A work boat with men in cleated boots running around will need a lot of protection. If most of the worries you have are a dropped beer or fishing lure, then a single skin of 8 oz. 'cloth is more then enough.

Fasteners are a necessary evil, though many can be eliminated with epoxy. Liquid nails will not cut it. Ditto for 3M 5200. Tabbing and epoxy are the way to go, if you don't want to have to do this again in the next 20 years.

Bonding the fasteners (the over size hole thingie) is the only way I recommend fasteners be used in areas where is very likely to be quite wet from time to time. It's easy to do and is cheap insurance, plus the pull out strength of the fastener is greatly increased. Bolts and screws can benefit from this treatment. Bolts are better if the part is to be removed regularly.

The floor finish can be whatever you want, but textured paint is the typical choice. Don't use sand, because it's a real ***** to get up if damaged or other wise needs recoating or repairs. Try crushed walnut shells or other softer texture, which can be scraped off the surface, reasonably easily. Paints are available with the texture in it now. The cheap way is to use porch and deck enamel and add some texture material. Keep it stirred up, because it sinks to the bottom of the can leaving uneven texture patterns. Personally I add the texture to the wet paint after it's applied, but that's me and I'm a little touched (according to the other half).

All epoxies are similar, but have different good and bad things about them. It's sort of like cars. Some hate Fords (like me and especially the blue ones) and others love them. There isn't a true rational for this other then personal experience. Most of the epoxy manufactures make a good product. The trick with epoxy is the procedures, which must be followed exactly. If you don't it's a mess and a real problem to fix. The temperature zones of cure, the hardness, amount of blush and other properties of a particular brand of epoxy require you have an understanding of where, when and the conditions in which it will be used.

Most epoxies come in different speeds (pot life time) In warm weather you'll need a slow epoxy (I use an extra slow epoxy here in Florida) in cooler places you'll need a slow epoxy. Information for the epoxy manufacture you decide to go with will be a general guide, but experience will show you the best speed hardener to use for that day's epoxy work. As a rule, most epoxies are designed to kick (start the reaction process) at room temperature (low 70's) and will cure slower if the temperature is below this, or faster if the temperature is above. In the summer here it's in the 90's and a regular batch of epoxy will start to harden before I've got it fully mixed in the container, so I have to use a slower hardener. Being up by NY, you will need a fast hardener because the temperatures are lower then a comfortable room. This will provide you with the working time necessary to get the job done and more importantly, the epoxy will cure. If I used my supper slow stuff up there, it wouldn't cure at all. This epoxy requires temperatures above 78, just to start the reaction. In the summer in PA you may be able to move up to a regular speed, on hotter days (80's and up) you'll want a slower hardener.

Now get to it and keep you fat friend out of the boat until he knows how to act properly.

 

Thanks so much for a great question and an even better reply - how did you know just what I needed to know? I have hauled out my (husband says I should say 'our') Van de Stadt Dogger to re-do the antifoul and some other work and found that it is going to be better (I hope) to redeck than to try to fix the soft spots. Big mental trauma until I read your thread. Do you have any photos of the work in progress and the finished results yet?
I will ask again in hope - does anyone have a set of plans for the Dogger that they would be willing to copy/loan/donate????????

Rose.