Basic Painting Questions

[marcusg]

Finished sanding the fairing on the transom today, just need to touch up a few spots:

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Was again sanding my wooden footboards today, and found more rot in one of them. It's salvagable with sculptwood, but I have a really hard time justifying throwing at least $100 worth of preservatives into wood that's already well into deteriorating. It's just 1/4" plywood anyways, easy to replace, but...

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If I need to buy wood anyways - and having seen the above picture of another Sailstar 17 with wooden furniture - I wonder why the heck not just replace the coamings too while I'm at it? I did some Microsoft Windows shopping at Home Depot and this was the best I could come up with:

https://www.homedepot.com/p/Columbia-Fo ... /204636957

Sure, it's plywood, but it's got a mahogany veneer (way better than the pine my coamings seem to be made of,) and the plywood aspect might actually make it easier to bend to form. Plus, I don't need a solid super strong piece of hardwood if I'm going to clearcoat + WPU the whole thing anyways. And there's enough wood in one 3/4" x 2' x 8' sheet to get both side coamings and the rear coaming out of it. And so that I wouldn't be sitting on a 3/4" edge of plywood, I would probably cut the tops of the coamings flush with the deck. On my boat, the coamings don't seem to be really reinforcing the side decks, as underneath them, and behind the coamings, there are a bunch of perpendicular triangles glassed in to support the deck.

Thoughts on this budget idea?

[GreenLake]

If you want to use plywood (veneer or not) make sure that it is fully sealed in epoxy and the that top edges have a strip of glass cloth over them because it's a heavy-use area. That's the only way you'll have that plywood last. Otherwise, it will get water in it and delaminate eventually.

You also need to meticulously seal any and all holes, but if you do, it should last many, many years.

Note that a glass strip, if fully embedded in epoxy will become transparent and invisible. So it won't detract from the wood. Just need to make sure you add enough epoxy until there's no 'print through' of the weave. Even if that means touching up by adding a bit of epoxy after the first layer has begun to cure.

The coamings need to be strong enough that you can't knock a piece out of them by sitting on, climbing over, etc. so, something closer to 1/2" would be better than 1/4" for plywood (and a bit of glass to protect the surface). The other load they carry is to hold up the side decks. That part is easy because that dimension is a few inches and even 1/4" would be strong enough.

PS: I would concur that trying to use SculpWood for repairing large areas of any piece of wood that can easily be removed/replaced is probably not ideal. It's intended for cases where you have a focused issue in a piece that's hard to remove, or otherwise difficult to replace (for example, if it's a piece milled/cut in a complicated state).

[marcusg]

"Fairing compound etc. then paint once everything looks smooth. Cracks need to be ground open (or all gelcoat around them ground away, as otherwise they "print through" the paint)."

Hrm...I know when I look at videos, people have a *few* cracks on their gelcoat that they can grind open and then fair. My deck is almost literally all cracks...Phone is broken ATM so a couple days until I can send a picture but...should I just fair everywhere where there's cracks? I really don't want to grind away pretty much all the gelcoat on the deck, but also wonder if I just paint it (even with primer and two layers?) will the cracks show through the paint?

[GreenLake]

Cracks will definitely print through paint.

If you get something that has a wide, sharp, triangular tip you may be able to efficiently rip open many of these cracks so that you can put filler into them. For the rest, an epoxy coat will give you a chance of perhaps filling/bridging the really small cracks. (Grinding off the gelcoat would be better, but I can understand why you might choose not to do that).

So, you are aiming at something that's not "perfect" but, with some luck, might be "good enough".

[marcusg]

Got access to the heated shop for a few days so experimented with the Clearcoat on another project - a small wooden stand my wife made for our water crock (we carry water from a spring to our cabin) which needed to be waterproofed. It was a rush job, as I did not have time to coat one side and finish it before coating another side, so there was quite a bit of runs, and on the edges/bottom the epoxy actually bonded to the wax paper and "pulled off" the was layer from the paper in some places. But it was good to get a sense of the Clearcoat and how it works.

What I learned:
1. Don't clearcoat on wax paper! Next time I'll raise the wood on blocks above some newspaper or something so it can't bond to what it's sitting on, and it's butted up right against it.

2. Leave enough time for the initial gel of the clearcoat before adding next layer. Bottle lists that as at least 7 hours, and in some cases I was recoating as early as 3 hours.

3. Lay whatever it is I'm coating flat, obviously, lol.

4. Sand with finer sandpaper. I only went up to 80 grit and I think that made the wood (softwood) suck up quite a bit of clearcoat. I used maybe 5 ounces on a project that was only around 1.5 square foot (albeit two-sided.)

My question still remains, if I'm clearcoating all 6 sides of my coamings, for example, how do I do the edges/corners, without it running and dripping? And for that fact, say I have the coaming propped up on blocks so that the wide side you sit against is totally level. Even so, once clearcoat gets close to the edges of that flat, it will run and drip over the edges and build up, no?

Also, I think I may have under-ordered clearcoat if this project was any sign of how much I'll need. I didn't use a roller, maybe rolling would be more efficient (used one of the 1" brushes I use for wetting out epoxy,) but I used quite a chunk of my quart of Clearcoat for square footage that is a fraction of what I'll need to coat for coamings/footboard/cuddy door.

[GreenLake]

Lots of good points. Good idea with a small trial project! Always the way to go.

You can use plastic sheeting like that for covering the floor for painting, just make sure it's smooth w/o any textured surface.

I don't think sanding better than 80 grit does much for ClearCoat. It's intended to leave a thicker layer than paint, I think. In fact, a slightly rougher surface makes a better bond. The manuals for it should be able to tell you what they think is ideal.

I used a sort of 'nail bed' to do mine. Just two 2x4s with some nails partially driven into them and the heads snipped off. And some longer nails to go through one of the screw holes to fix the piece while working on. I set up the pair of these so that they could support all my pieces next to each other. You get a point defect where they rest on the nails, but if you coat the backside first, you can flip while wet, and do the front w/o the supports interfering. The small defects on the back will either be hidden, or you can just sand them smooth and varnish or paint over them.

I've had reasonable luck with work pieces suspended from wire (if the piece has a suitable hole). I seem to have gotten the hang of how not to get too many runs. You can always sand those flat once cured, by the way. That would be trickier with paint.

If you are worried about the ClearCoat soaking into the wood you could start with a thin coat of RotFix.

[marcusg]

First snow yesterday and now it looks like I'll be getting my heated shop access in a week or two, so time to order paint etc.

Ordering Pettit Ezpoxy, Ezdecks, EZprimer, aaaand their performance additive from Jamestown distributors. But then I see there's even more products I supposedly need when I read their surface prep literature:

(from: http://www.pettitpaint.com/media/4776/p ... lletin.pdf)

SURFACE – BARE FIBERGLASS:
1. Thoroughly wash the entire surface that is to be painted with Pettit’s 92 Bio Blue or
95 Fiberglass Dewaxer to remove all traces of mold release agents and wax. *This
must be done regardless of age
2. Sand the gelcoat with 120 grit sandpaper yielding a dull, frosty appearance.
3. Solvent clean to remove sanding residue.
4. If the surface is in excellent condition, proceed with the first finish coat of EZ-Poxy

So quarts of this Bio blue stuff go for the same price as their paint...Do I really need that? What do you do to prep for painting on already sanded/stripped fiberglass? What do you clean the stripper off with? What do they mean by "solvent clean?" Like acetone?

As far as my own cleaning thus far, I've only used a stripper afterwash, which has just sort of swirled around all the dust and gunk from stripping and sanding. But I would prefer to stay away from spending another $100 alone on cleaning products from Pettit. The only stuff I'm really interested in cleaning more is the embossed non-skid pattern on parts of my deck, and Pettit has good instructions about using bronze wool or scotch brite pads on that.

They also recommend to sand and solvent clean between layers. Do you do that? Again with acetone or?

Finally, an unrelated question: you'd mentioned I want to put a layer of neat epoxy over the fairing on that hole in my hull as the final step. Why? And do I always need to put neat epoxy over something that I've faired? Doesn't that take forever to cure?

[tomodda]

Say what?!?!? Petit, I love your paint, but let's get real here.... OK, I could be wrong, but here's my thinking from when I painted my hull during the 2018-2019 winter, and my supplies prices from the "Big Box Store" (actually I bought some stuff from AutoZone as well, often has better prices for painting supplies):

-The "Mold release agent" in the 1960's was simply wax, not PVA's or anything fancy. Whatever time and my sanding efforts didn't get off will come off with a good scrubbing with TSP. Box of TSP - $5, 3 pack of scrubby sponges - $3. TSP is my all-purpose boat cleaner anyway, I'm 1/2 way thru that $5 box 2 years later.

-We don't need any special magic pixie juice between coats. A light sanding and a solvent will do. Agreed with wanting to "cloud" the previous layer, but I prefer to do it with 220 grit, that's just me. And while paint thinner is a fine and very cheap solvent, I prefer not to huff it for hours on end. Mineral spirits are $15ish a quart, way less deadly (wear your respirator anyhow) and works just fine. Cost: Quart of Mineral Spirits: $15 (or maybe it was $12?), 3 Pack of blue shop towels: $6

-Shop towels are great, but you want to get off the last bit of dust before painting - hopefully you're painting indoors. This is where lint-free cloth (aka microfiber) comes in. I think it was $2 each, I used 1 and washed it as needed. Also, because I'm crazy,, I used tack-cloth - basically a sticky rag - to get off the very last of anything I can't see. $3 for a pack that will last you for your entire boat job. By the way, tack cloth is essential if you are doing any varnishing, so I have a few packs laying around as it is.

So that's it! Total investment, $34 with plenty of leftovers for the next job. All told, my routine is:

Hull prep: Wash down the hull with TSP, sand it/fill it/sand it summore, Wash with TSP again.
Paint prep: Clean with mineral spirits, wipe off with shop towel, second wipe with lint free cloth. (3rd wipe right before painting with tack cloth, below waterline only). Paint (roll and tip!), dry
Next coat: Cut previous coat with 220grit, repeat paint prep/painting.

That's it! I did 3 coats on my hull, an underlayer and two topcoats. That being said, I used Kirby Paints Marine enamel, it's pretty straightforward and has a nice high build. Also, Kirby has a "conditioner" at $25/quart which you use to thin the paint/make it more rollable. I called the company and went over it with them, basically I used the same paint for all three layers, but thinned out my first layer (undercoat) considerably, it was just there for the initial hull/paint adhesion. I think, maybe it was the other way around (first layer less thinned). If you use Kirby's call them.

Obviously, you are NOT using Kirby's, you're using Petit. I'm just spelling out what I did to illustrate that you should use common sense for how to clean your hull, but do call the manufacturer re: how to lay on the paint. Tell them exactly what you are doing (brushing? rolling? 50-year old hull?) and see what they say. And then do some research to separate the good advice (they know their paints!) from the upselling (Bio Blue ). Anyway, Easypoxy is pretty much polyutherane paint + magic silicon fairy dust. Mineral Spirits is what one uses to thin Polyurethane, so you'll be fine using it as a between-coats cleaner. Just my not-so-humble opinion!

Warning, I went bat-poop crazy on my topcoat layer, I think I wound up wet-sanding it down to 2000-grit (by hand!). Once you see all those pretty sandpapers at Autozone, it's easy to go way overboard. I definitely did, a few trailer launching and retrievals pretty much screwed my 2000-grit finish. Hours of work and $20 in sandpaper down the drain. GreenLake says that, according to some scientific study or other, anything over 600-grit is overkill, I just know that the only way to keep a "perfect finish" is to either keep it in the water (preferably in a separate pool of Alpine spring water, blessed by Uffa Fox himself) or to hoist the boat rather than trailer-launch it, then put it in a nice expensive whole-hull trailering bag. Too much aggravation if you are not racing at a top level. GL is right, 600-grit will do.

Best,

Tom

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[marcusg]

Thanks Tom, that's what I needed to hear.

[tomodda]

Read.... but you're welcome. Don't forget that George O'Day meant this to be a working man's "family boat." Basically Levittown with sails. Using expensive magic goop on your hull goes against everything that he believed in.

BTW, one of my post-pandemic bucket-list items is to trailer my boat up to Maine. Let's meet up. Fingers crossed for next summer.

[marcusg]

Oh I don't live in Maine. I'm *from* New Hampshire, but currently I live in southwestern Wisconsin. Where are you?

[tomodda]

I'm mixing up my forum members, sorry! I'm in North Carolina. Door County, WI is also on my trailer-sailing destination list, but a few years further down the road....

[GreenLake]

We've had so many people show up here with new boats, it's easy to get them mixed up. The overall numbers are still small, but it does feel like a pattern. There seemed to have been an increase in interest in small boats and 2020 seems to have accelerated that. Just my impression.

[marcusg]

Hey Greenlake - could you tell me why to put neat epoxy on that hole I patched and faired? And do I always cover fairing with neat epoxy? How long does that take to cure?

[GreenLake]

My recollection is that S3 suggests to coat their QuickFair. However, check their "EpoxyBook" or whatever they call the current edition of their manual. Could be that the fairing compound, when sanded, has a surface that's not sealed, because some of the outer filler grains would be exposed by sanding (not covered by a coat of epoxy). Just speculation, so to be sure, look it up.