Refinishing coamings--the fine points

[tc53]

Thanks, Greenlake. I plan to build the "nail bed" and, I hope, apply the first epoxy coat today. I appreciate your thoughts about the number of coats. I may have to order more of the Clear Coat (just got the one quart kit to start), but it makes sense to go with three coats. With a bit of thinning, I think the quart of WR-LPU will suffice for four coats. Providing it all comes out a nicely as I am hoping, I'll post photos once I'm done.

[GreenLake]

Should you happen to have SilverTip you can substitute that for the ClearCoat. I remember I used both in alternation as that allowed me to use up existing supplies.

[tc53]

Okay, I've done a light sanding of the epoxy (three coats), just to get any drip bumps or other rough spots smoothed out, and I am ready to begin with the WR-LPU. I am a bit confused, though, about the use of the crosslinker that came with the WR-LPU. I've never used a two-part urethane before. A question or two:

1. The directions on the can suggest the WR-LPU can be applied with our without adding the crosslinker, though they are clear that the final coat (I plan on three, four if I have enough). Is that the case, or is it better to go with the crosslinker for all coats? Does leaving out the crosslinker just slow the drying/curing time?

2. The directions specify 8 drops of the crosslinker per ounce of the urethane. If I am thinning the latter a bit with water (I'm planning on 10%), do I stick with that ratio or adjust it to the larger liquid volume (water plus urethane)?

I am planning to apply with high quality synthetic brushes on all surfaces (benches, thwarts, coamings).

The can says clean-up can be accomplished with water (presumably with a bit of soap) if done right away. I want to be able to use the new (and expensive) brushes for each of the coats on both sides. Any advice on cleaning the brushes for reuse?

Thanks for any advice.

[GreenLake]

You can take them by their word and save the cross linker for the final coat(s). I would not just leave it for the very last coat, because there's always a chance that you accidentally won't cover a spot (it's easy do to when painting clear on clear). The linker makes the paint harder, which is what you want for the surface.

The cross linker is a catalyst. As such, I highly doubt that the mixture is sensitive to within 10%. (And, if I recall, you can re-crosslink any paint that you didn't use up, within some limits).

More importantly, you need to mix the cross-linker with the liquid you use for thinning. Otherwise you'll not be able to mix those few drops evenly.

I've always been able to wash out my brushes. Having a spare, just in case, doesn't hurt.

In terms of brush quality. If you are brushing on the clear LPU, any decent high quality synthetic brush should be fine. Where I found the need to move to the very highest quality brushes was in roll-and-tip application of the white paint of the same family. The clear (I used the satin) didn't show any obvious brush marks when I did it with decent but not outstanding brushes (thwarts and coamings). However, when applying white paint to the hull with a roller, to flatten the little bubbles behind the roller simply required an excellent brush, otherwise the paint would show brush marks.

The more coast you can give it the better. So, as long as you have paint left, give it another coat.

[tc53]

Thanks, Greenlake. I appreciate the clarifications. Do you know if I need to wait longer before recoating a non-crosslinked coat? The directions on the can are ambiguous about this.

Also, while I have been planning to apply the WR-LPU to all coaming, thwart, and bench surfaces (back and front, underside and topside), if I find I am running low, do you suppose the less or un-exposed areas could do with fewer coats? When you did yours, did you apply the same number of coats to all sides/surfaces?

Thanks again. I plan to begin applying coats today. I want to be sailing (instead of working on) the boat by June!

[GreenLake]

Is there such a difference in time that it matters? The maximal recoating time is fairly long, so if in doubt, just wait a bit longer between coats and you would still be fine. The main reason for the minimum times is to make sure enough water evaporates that you don't "trap" it with the next coat. (My layman's understanding of this).

With epoxy sealed surfaces, you could use an automotive spray primer and paint to coat any "invisible" surfaces. Some generic brown color, for example. For the coamings, part of their "back side" is revealed, so this trick would be good for the lower half. A bit unusual, but if you have difficulties getting more WR-LPU where you are, perhaps a way to get the job done.

[tc53]

I'm closing in on it, guys! Benches, thwarts, and coamings are completely done, underside of cabin top will receive the final (3rd) coat today (ended up going with a flat, latex exterior house paint after returning an oil-based Rustoleum marine topside paint; we'll see how long the house paint stands up), and the centerboard is shimmed, repaired, and ready for reinstallation.

I will begin putting everything back together in the next couple of days. Greenlake, I reread your comments earlier in this string about putting a thin foam hatch tape between the coamings and the deck when I reinstall. The product you linked to these comments looks like it is about 1/8" thick. Is that right? Did you apply it to the deck so the top edge was flush with the top of the deck? The hatch tape looks similar to various products I've seen in my local hardware store's weather stripping section such as this:

http://www.amazon.com/3M-Foam-Insulation-Insulate-Camper/dp/B00TYZTFTE/ref=pd_sim_sbs_200_5?ie=UTF8&refRID=0GBEXTK7FQ69XF4ZJ2AE.

Do you think this sort of adhesive backed foam tape would work as well? I assume whatever I use should be able to compress a fair amount as I refasten the coamings with screws.

Having spent many hours now sealing and finishing the wood, I want to be careful about maintaining the moisture seal as I reinstall everything. When I am doing all of this refastening (with new stainless all the way around), should I be putting some sort of sealant into each screw and bolt hole? Epoxy? 4200?

[K.C. Walker]

Keep us posted over time as to how the house paint worked, as I am curious.

I reseal the screw holes with epoxy. I often use a Q-tip to put the epoxy in the hole. Be sure and wax the screws thoroughly so that you can back them out later.

[GreenLake]

Greenlake, I reread your comments earlier in this string about putting a thin foam hatch tape between the coamings and the deck when I reinstall. The product you linked to these comments looks like it is about 1/8" thick. Is that right? Did you apply it to the deck so the top edge was flush with the top of the deck? The hatch tape looks similar to various products I've seen in my local hardware store's weather stripping section such as this:

http://www.amazon.com/3M-Foam-Insulation-Insulate-Camper/dp/B00TYZTFTE/ref=pd_sim_sbs_200_5?ie=UTF8&refRID=0GBEXTK7FQ69XF4ZJ2AE.

Do you think this sort of adhesive backed foam tape would work as well? I assume whatever I use should be able to compress a fair amount as I refasten the coamings with screws.

The foam tape you linked says: "closed-cell foam insulation" and "Designed for the rough life of camper-tops"; those two properties would mean that this would fit the bill. I applied the tape on the fiberglass flush with the top edge of the deck. About 1/8" uncompressed should work, you'll probably compress it down to around 1/16" as you tighten the screws for the coamings. The adhesive is used only to hold the tape in place while you mount everything, so, from that perspective, it doesn't matter all that much, but the one you are planning to use would probably hold in place even in door or hatch openings, where there's no pressure with the door or hatch open.

And +1 on what K.C. writes on epoxy sealing your screw holes.

[tc53]

Thanks, KC and Greenlake. KC, for waxing the screws, is the best way to dip them in melted paraffin? I could probably do this is "batches" of screws to be used in the various phases of the reinstallation.

The newly painted underside of the cabin top looks great with the three coats of house paint. Having already scraped it pretty much bare, I sanded thoroughly with a palm sander, cleaned with a mild TSP/water solution, and then rinsed and dried before applying the first coat using a combination of an 8" roller and brush. I will keep you posted on how it stands up once I (finally!) start sailing the boat again. I rejected and returned the oil-based marine paint I'd bought once I read the "fine print" on the label about needing to sand in between each of three coats. I just couldn't bear the thought of that extra work in those very cramped quarters.

[GreenLake]

My thought is I would go with something like the wax used for waxing the hull, or, failing that, floor was. No need for melting anything. K.C. may have other ides...

[K.C. Walker]

I just use Johnson's paste wax, because I have a can, but I think any wax would do fine.

[tc53]

Not quite finished (still need to re-install fittings), but here are some photos:

IMG_1588.jpg (91.09 KiB) Viewed 15410 times

This one offers a view of the solution I chose for supporting the bench seats, short sections of 2" PVC pipe bevel cut on the bottom (but not attached in any way to cockpit deck) with the tops inserted into flat-topped PVC caps that are screwed into short sections of 1 X 4 pine (also epoxy encapsulated) fastened to the underside of the mahogany bench running perpendicular to the bench length (sorry, I should have taken some detail photos before I re-installed). I added these to spread the load out a bit. Not as aesthetically pleasing as wood, but inexpensive, and I don't think they look too bad. In this shot you can also get a glimpse of the newly painted (with three coats of latex flat exterior house paint) underside of cabin top.

IMG_1590.jpg (93.26 KiB) Viewed 15410 times

IMG_1591.jpg (71.95 KiB) Viewed 15410 times

Interestingly, once I began adding coats of epoxy and then the urethane topcoat, I saw how different the thwarts looked compared with the benches. When they were all weathered and faded, they looked more or less identical.

Only a few blemishes/mistakes here and there. Finding, here and there, a sheared off end of one of the old brass wood screws in some of the gusset holes (front end of each bench is gusseted to thwart with a 9" square of marine ply--now also epoxy encapsulated--screwed into underside of each), I carefully tried to drill each out to allow for the new fasteners. on one of these the bit popped through to the topside of the bench. I filled that with epoxy mixed with a bit of sawdust and will put another few coats of the topcoat over this patch. Other than these, the only other blemishes are one or two very small spots on one bench and one coaming section where the epoxy seemed to turn a bit "cloudy." Not sure what caused this, but you have to look pretty hard to even notice them.

I still have to finish the installation of the centerboard and, as I said, re-attach the various fittings, but we hope to be sailing again within a couple of weeks.

Let me know if you would like me to post any more detailed photos.

Thanks again for all of your help!