Deck Resurfacing

[JetStream]

This question is primarily addressed to Nathan and Tim as they resurfaced Nathan's deck by encapsulating it in 10 ounce cloth and epoxy. Like many boats of that era, mine has the same very tight gelcoat crazing that either must be ground back to the glass, or encapsulated as you have done. My question is whether or not you guys considered "Dynel" cloth instead of "E-Glass" when you did the job. It is my understanding that Dynel has some desireable qualities when used as an encapsulant rather than a structural application. Anyway, here are a few close ups of the kind of nasty crazing that I face:




I will probably end up peeling the topsides with a GelPlane, but really would have a lot of difficulty with inside radii and such if I were to do that on the deck and cockpit. Looking for your comments.

[dasein668]

MMmmmmmm. That's tasty looking.

I didn't really consider Dynel. I've never worked with the stuff, so I don't even really know much about it, and can't really comment.

I will say that so far things are holding up very nicely. I haven't seen any print through of the crazing at all. I do have a bit of print through of the weave of the cloth though. Still, it's not bad and way less noticeable and annoying than crazing would be.

Overall, I'm very pleased with the results from the encapsulation project.

Tim may have more to say regarding Dynel in this application.

[Hirilondë]

Dynel is the fabric of choice for wooden boats looking to replace canvas decks with a more permanent surface. It is very abrasion resistant and needs little sanding or fairing to end up looking like a canvas deck. It soaks up a ton of epoxy. The dust from sanding is no where near as irritating as glass. I can't really comment on whether it would be the best choice or not for your situation. But I can't imagine it is a poor choice.

edit: It is however somewhat difficult to work with as it is quite thick. If you are going around curves or working in tight details it will be very difficult to get it to lay well as it swells as the epoxy saturates.

[MikeD]

Mike (Figment) used dynel on his decks or cabin top, didn't he?

[Figment]

Yes, but not to cover crazed gelcoat. It was just for looks, and it's not a look that appeals to everyone.

Perhaps it comes in different weights, but the dynel I got from jamestown wasn't at all thick or hard to lay. Very soft. "Cottony", one might say.

One thing that canvas-texture dynel has going for it in this particular application is flexibility. By the time you're done diluting the epoxy to get it to leave an appropriate texture, it has very little structural value, it's really just wallpaper glue, so the dynel can "work" and move with the boat without fracturing.

[Tim]

Dynel has many good properties, and is a great choice for an updated version of the painted canvas decks on wooden boats. I have used it in the past and found it easy to work with, though with clearly different properties than light fiberglass. I didn't have any trouble getting the material to easily conform to the corners and curves on this boat. One does have to be careful about "floating" the material too much in the epoxy, but that goes for any sheathing operation. I didn't dilute the epoxy and am not quite sure why one would.

In this case, the Dynel was actually replacing an old painted canvas deck surface, and the texture (as well as protection) was what was desired. Here, I simply draped the dry material over the prepared surface and wet it out from the top. Later, I trimmed the excess during the "green" stage of cure.









For fully encapsulating a deck, I am not sure if it's the right choice or not, but not because of anything bad about the Dynel. Still, I assume you wouldn't want the Dynel texture on all parts of the deck. Also, if you want to fair over the material and sand things smooth before proceeding to different steps, be aware that Dynel will fuzz up when ground, unlike fiberglass that becomes a hard and easily-sandable medium.

That said, you can still fair and sand it, but if you're not going for the wooden boat-like texture that Dynel provides, I don't necessarily see it as being a better choice than E-glass. That doesn't mean it's a worse choice either.

I honestly have no idea which material is better suited to this sort of encapsulation, assuming that the texture of the Dynel isn't a desirable part of the equation. My inclination is to lean towards E-glass as being stronger, but I have no science to back this up.

So far, the results of "sealing" Dasein's badly crazed gelcoat with the epoxy and 10 oz. cloth seems to have been a good success. The cloth print-through problem could probably be avoided by filling the weave of the cloth with additional coats of raw epoxy before fairing, but as it is it is only noticeable under certain lighting conditions. It seems to me to be a decent manner of addressing this difficult problem. That doesn't mean it was easy or quick. But there are rarely easy or quick solutions to these old boat problems.

I am not sure that even grinding away all the gelcoat, when the problem is as bad as that on Dasein or Jetstream, would be sufficient on its own, as most of the time these sorts of cracks actually extend into the skin coat beneath as well; these cracks are diabolical and challenging to completely eliminate. This is what led to the decision to try the encapsulation on Dasein. I would have no qualms using, or recommending, this process on another boat.

If your gelcoat, Bruce, is unsound and loose, grinding it away before proceeding with the encapsulation is probably necessary if you want to take all steps to ensure that the crazing doesn't print through and to ensure good adhesion of the sheathing.

[JetStream]

Thanks guys. I really appreciate the input. It sounds from all of the above that E-Glass is the way to go. Even though the gelcoat looks really terrible, it is quite amazing how well it is attached. It does not seem to be at all loose like you'd expect. Since it is extremely hard (probably one of the things that contributed to the severe crazing), I'm guessing that it will need to be roughed up pretty well with some 36 grit or so and then cleaned very well before adding the skin. I will probably use really slow hardener in hopes that some of the epoxy will penetrate the cracks. I guess if I was really fanatical, I'd try to vacuum bag it. Anyway, the whole thing is a ways off as I address other life priorities right now. From your comments Tim, it might not even be a bad thing to consider doing the topsides as well.

I'm wondering if it might make some sense to sort out how to do this whole job in a linear piecemeal fashion. I've been a little bothered by the butt joints required and how to keep going with such a large area. Perhaps if a piece were layed down with or without a vacuum bag, so that you leave a raw edge across the workpiece to cure overnight, it could be edge scraped with a carbide scraper the following morning (while it is still fairly green). That would taper the edge so that by doing an overlap, you could in effect, get a scarf joint at the seams and not be burdened with finishing it all in one go. I think you'd still get a good edge bond if you never let the previous piece get beyond "green". That way, you do the new piece each day (or maybe two per day) and then fill the weave of the preceeding piece while at it. All comments appreciated.

[Tim]

For encapsulating like this, I don't see any problems with butt joints on the material. The structure is already there; you're just sealing up the cracked gelcoat.

[dasein668]

Even though the gelcoat looks really terrible, it is quite amazing how well it is attached. It does not seem to be at all loose like you'd expect. Since it is extremely hard (probably one of the things that contributed to the severe crazing), I'm guessing that it will need to be roughed up pretty well with some 36 grit or so and then cleaned very well before adding the skin. I will probably use really slow hardener in hopes that some of the epoxy will penetrate the cracks.

I found the same thing over most of my deck. Some areas were loose, specifically the side decks where I had quite a bit of chipping while I was sanding. I ended up going over the whole deck with 40 grit first, then filling the areas where the gelcoat chipped out to have a reasonably smooth surface for the glass.

I've been a little bothered by the butt joints required and how to keep going with such a large area.

I just used butt joints without any issues. This is a cosmetic issue, after all. The butt joints also prevented me from having any "hump" at the overlaps. Though your idea of scraping might help eliminate that issue. I don't think it's really necessary though in this case.

[Arcadia]

Hello there,
I've been checking this site for a couple of years now, but this is my first post.
I have similar crazing problems as described here and in other threads, and I was wondering if anyone had considered using CPES as a possible solution to securing/filling crazing and even larger delamination of gelcoat problems described by Nathan of Dasein. My thought is CPES might be able penetrate and fill the crazing/cracks through capillary action creating a more stable surface for priming,etc. I spoke to someone at Smith &Co who stressed that CPES is not so much an adhesive as a hardener, but he did think it would work into fine crazing.
I'm in the process of preparing to repaint our cabin and deck this spring and am faced with the same decisions

[Figment]

Welcome, Arcadia.

Interesting notion.
I don't think CPES will reliably re-adhere delaminated areas. As the Smith rep said, it's not an adhesive, and certainly doesn't have any gap-filling properties.
For crazing, I think it could aid the adhesion of whatever filler or primer would follow. I don't know that adhesion is really a problem for any of these products, but the belt never hurt the suspenders.

[Arcadia]

Figment,
Thanks for the reply.
I was considering CPES as a way to perhaps forestall the reappearance of the crazing under the primer. Not sure it would have any other effect.
I haven't ever used the stuff, but it seems to me if the crazing could be filled at least the primer would not be bridging the gap, so to speak. I had thought of simply squeeging epoxy into the surface to try and fill the cracks, but think that would probably be a waste of time unless it penetrated deep enough to have some grip. Thats where the thought about CPES came from. I don't know if that would stop the progression of cracks or crazing.
I'm not entirely sure what causes the gelcoat to start crazing in the first place. Our boat is an old Luders 33, hull #4 1966. There are areas on deck which are badly crazed, similar to the problem Nathen of Dasein described on his site and which he decided to encapsulate. Similar to his description of sanding and loose pieces chipping out, our deck and cabin top also has areas that appear perfectly sound, no chipping or crazing.
We refinished the deck and cabin about 14 years ago when we first bought the boat. She also has Treadmaster on the deck. There was also some areas of the cabin top covered as well until I removed them prior to our first refinishing. Interestingly, the only areas that seem to be crazing are the areas where the deck was covered.