Basic Painting Questions

For issues common to different models of DaySailer.
Except Rigging and Sails.

Moderator: GreenLake

Re: Basic Painting Questions

Postby GreenLake » Tue Jul 20, 2021 2:35 pm

You might want to read the guide on preserving outdoor wood that is put out by SystemThree.

Standard laminating epoxy is fine, unless you have a large project and can afford to buy something specific to the purpose, in which case you might get something that's formulated for the purpose (like ClearCoat). My sense, talking to the folks over there, was that there's a big overlap in what you can use their epoxies for. Like you can absolutely use their glue (GelMagic) to wet out laminate, if you have that mixed and would like to use it.

Not sure where the use case is for the solvent based stuff.

I would have picked the laminating epoxy in a case like yours.
~ green ~ lake ~ ~
GreenLake
 
Posts: 7136
Joined: Mon Jun 18, 2007 3:54 am

Re: Basic Painting Questions

Postby marcusg » Mon Jul 26, 2021 8:37 pm

Thanks, will epoxy transom tomorrow with laminating epoxy. Today I just finished up priming all the wooden furniture and cuddy door, getting ready to paint them. I laid all the boards out over some 2x4's and only painted one side at a time, and of course some of the paint/primer dripped around the edges and collected there or on the underside of the boards.

I also practiced getting familiar with roll and tip as I've never done that before, and have minimal painting experience in general.

Questions:
-Is there a way to prevent drips? I imagine that once I start doing my topside, the drips running down over the bottom will make quite the mess. Obviously I'll mask a line between top and bottom, but am I just putting the paint on too thick if there's drips?

-When I did my between-coat sanding my sanding discs were getting clogged up with paint super fast. Is this normal? I know I'm supposed to just do a glaze sanding, so I wasn't sanding a ton, and was using 220 grit as that's what the product I was using instructed.

-For solvents I used acetone for cleaning up pre-painting and between layers, and mineral spirits to clean out brushes and roller trays. Is that right? Is acetone okay to use on paint that's just dried?
marcusg
 
Posts: 133
Joined: Thu Aug 16, 2018 10:39 pm

Re: Basic Painting Questions

Postby GreenLake » Mon Jul 26, 2021 11:01 pm

Edges of horizontal pieces are tricky, it's hard to not apply a little too much.

With your transom sealed, you need to make sure *all* holes that penetrate it are sealed and remain so. For throughbolts that means overdrilling, then filling with epoxy, then drilling again normal size.

If paint hasn't cured, it'll clog faster.
~ green ~ lake ~ ~
GreenLake
 
Posts: 7136
Joined: Mon Jun 18, 2007 3:54 am

Re: Basic Painting Questions

Postby marcusg » Wed Jul 28, 2021 12:41 pm

Good reminder about sealing the holes in the transom. Man, this project just keeps growing and growing...one hole at a time.

So, I take it that there's two kinds of holes I'm working with re: sealing:

-"Throughholes" as you said, where actual bolts with nuts on the other end of them go through the hull. For these I would bore out a larger diameter hole, use laminating epoxy to seal them shut and sanded flush with the rest, and then drill a smaller hole through the epoxied hole.

-Screwholes that will have screws with threads. Would I just overdrill like in the other example? Or are these the ones that you put the screws into epoxy while the epoxy is still wet (and wax the screws?)

Also, I'm picturing holding the epoxy in the screw/bolt holes with something like masking tape (since liquid epoxy will run quite readily) and then sanding the masking tape off once it all cures? Or how do you fill an open vertical hole without using thickened epoxy?
marcusg
 
Posts: 133
Joined: Thu Aug 16, 2018 10:39 pm

Re: Basic Painting Questions

Postby GreenLake » Wed Jul 28, 2021 3:03 pm

If you can spring for it, I would get one cartridge of "GelMagic" from SystemThree (or the equivalent from WestSystem). Plus a few mixing tips.

GelMagic and similar glues are non-sagging, but otherwise not that different from laminating epoxies. Great for applications like this.

The cartridge dispenses both resin and hardener at the correct ratio. Either into a small cup for you to mix, or use a mixing tip. Mixing tips are great in that what exits the tip will be mixed, and you mix the epoxy "just in time", as you need it. As long as you don't exceed the pot time, you can keep moving from hole to hole and dispense more. But each time you use a tip, there's a certain amount of waste, because you'll loose the partially mixed amount in the tip.

(If you do a few holes at the same time, the waste will be on par with what you might have lost by mixing a batch and not using up all of it, but if you know you'll need just a tiny amount, I'd squirt some out onto a surface or into a cup and mix manually).

Cartridges keep for a long time, but you may need to warm them in hot water if you didn't keep them warm enough 70F in storage (epoxy can crystallize, but will be good as new, once heated).

Also, you got it in one, as far as the two types of holes are concerned: screws you embed. I'd make sure that the hole is not too generous, so that the screw has at least some purchase holding it in while the glue sets, but not so tight as to not allow a good coating of epoxy. So, just a bit looser than if you drilled it for a "dry" screw.
~ green ~ lake ~ ~
GreenLake
 
Posts: 7136
Joined: Mon Jun 18, 2007 3:54 am

Re: Basic Painting Questions

Postby marcusg » Wed Jul 28, 2021 4:14 pm

Cool that I can use gelmagic, I’m familiar with its cartridges and tips. Did you not mention thixxo because it’s Make-up is different than gelmagic? I thought they were basically the same?
marcusg
 
Posts: 133
Joined: Thu Aug 16, 2018 10:39 pm

Re: Basic Painting Questions

Postby GreenLake » Wed Jul 28, 2021 6:00 pm

You may have noticed that I recommend SystemThree products. All my favorite stores stock them and there is something about sticking with what you know. I've made universally good experiences with their epoxy products and am happy to share those. I tend to not recommend anything I've not used myself. I'll leave that to those that have tried and liked a product. (I may occasionally recommend a type of product based on reading extensive discussion or test results, but that's typically not a brand issue).
~ green ~ lake ~ ~
GreenLake
 
Posts: 7136
Joined: Mon Jun 18, 2007 3:54 am

Re: Basic Painting Questions

Postby marcusg » Fri Jul 30, 2021 4:12 pm

Overdrilled the holes in my transom where my rudder mounts, and filled those with Thixo. Masking tape on the inside. Easy peezy, as the thixo is nice and thick and doesn't run or sag, similar to gelmagic. Went overkill with the overdrilling at first, drilling holes that were like 5x the size, then eased it up to maybe 2x the size for the rest of the holes.

My one question is for the 3 larger holes at the bottom of this image. They are not overdrilled yet; that's their actual size. The top two are the bilge drain holes, and the bottom one is also a drain plug that connects to a cavity underneath the floor of the cabin. All get plugged by those rubber stopper doodads. I know that in theory I can overdrill those with a hole saw and then thixo them same as the smaller holes, but I'm really nervous because of their location.

If I overdrilled the top two holes, I'd likely drill into the cabin floor as well, and then would need to be sure to reconstruct it properly. And the bottom hole isn't accesible from the other side, so I'm nervous about the thixo getting in the way of the channel, although because it doesn't sag I probably won't have that problem. Any thoughts about how to go about this so as not to create another sub-sub-sub project? :)

thixo (Small).jpg
thixo (Small).jpg (60.2 KiB) Viewed 342701 times
marcusg
 
Posts: 133
Joined: Thu Aug 16, 2018 10:39 pm

Re: Basic Painting Questions

Postby GreenLake » Fri Jul 30, 2021 9:05 pm

for through hulls/ drain holes etc. it's fine to seal the edges of the holes.
~ green ~ lake ~ ~
GreenLake
 
Posts: 7136
Joined: Mon Jun 18, 2007 3:54 am

Re: Basic Painting Questions

Postby marcusg » Wed Aug 11, 2021 6:22 pm

Still working with that transom, which it looks like was at some point replaced, as the existing transom appears to have been "glued in" with whatever substance the PO(s) used to do such things. They used some kind of filler to fill what was probably erosion damage at the junction of transom and cabin floor, and in the cabin floor itself. And as I'm working, big chunks of this stuff are getting loose and I can just pull them off by hand or sometimes a screw driver. I'm thinking to replace it with 3m High strength marine filler, as I can't think of anything else that's designed to hold up in such a crucial area (transom bottom inside edge) and also where it gets foot traffic. Is that about right? Would be nice if there was something cheaper than the 3m marine filler, as I'll probably need quite a bit to replace what's falling off.

IMG_8550 (Small).JPG
IMG_8550 (Small).JPG (123.74 KiB) Viewed 342626 times


IMG_8551 (Small).JPG
IMG_8551 (Small).JPG (79.73 KiB) Viewed 342626 times
marcusg
 
Posts: 133
Joined: Thu Aug 16, 2018 10:39 pm

Re: Basic Painting Questions

Postby GreenLake » Wed Aug 11, 2021 7:25 pm

What you are showing looks like fiberglass and it looks like you have an actual channel gouged out of the inside of the hull???

I get you on the pricing for the filler. It may not be the right solution for this.

I would clean out the that gouge, by solvent (acetone) and sanding. And then rebuild with laminating epoxy and fiberglass. As always, if the channel is V shaped after sanding you put first the biggest patch and then smaller, nested patches of glass to fill. You can grind/sand off any excess at the end, but don't overdo it. If you could do a cross section you would see a set of small v's nested in larger Vs instead of an inverted pyramid of short - below longer --.

Where transom meets the floor, you might want to tab that in, also with fiberglass. You need to round the corner, so you get some wood flour and mix a bit of paste with some laminating epoxy. (You could use sawdust, if you have it, or get wood flour from a vendor like SystemThree). You use that paste like you would a caulk around your bathtub, making it form a gentle transition (curve). You then put a strip of 4" wide fiberglass to connect floor and transom.

You can use the filler (sparingly) to smooth out everything when done, or to fill smaller holes
~ green ~ lake ~ ~
GreenLake
 
Posts: 7136
Joined: Mon Jun 18, 2007 3:54 am

Re: Basic Painting Questions

Postby marcusg » Thu Aug 12, 2021 12:51 pm

Ok that's easy enough. Looks like the PO actually did tab in new transom as I can see fiberglass/epoxy rising up about 4" high on transom before it turns to just wood.

Sigh...in other news...the more I work on this old boat it seems like the further it gets from being done. I was exploring those "channels" that I pictured in my last post. One of them I was able to remove all the old glass/epoxy that was peeling off (why does it peel off and separate like that? is it because of whatever the grey stuff is that PO used? bondo? or I think you might've said it was a polyester resin?) and can just be re-filled like you said with laminate patches.

But the other one....there was a small hole through the floor laminate that went straight through to the thin cavity between floor and hull, and when I started poking around in that hole I found a lot of dry rot, similar to what I'd found in a spot on the transom last year. I haven't finished multitool'ing/grinding out all the rot, but it looks to be about a 1' x 1' piece once all is done.

IMG_8574 (Small).JPG
IMG_8574 (Small).JPG (108.27 KiB) Viewed 342618 times


Here's a video of me pulling around on it and so on...
https://drive.google.com/file/d/1H7wVdr ... sp=sharing

Anyways, so I'm guessing I need to laminate a new piece of plywood (1/4"?) and glue it in there, beveling the edges onto the existing good floor. As seen in the above pic, the PO has that grey bondo/polyester resin stuff where the floor meets the curve of the hull at the top of the picture...and while I feel less than confident about the longetivity of that stuff, I'm starting to run out of gas/funds to keep this project going. I'd really hoped to sail this summer, but a combination of different factors, including my 1 year old undergoing chemo and spending one our of every three weeks in the hospital has seriously slowed things down.

While ripping up the dry rot in the floor, I was really tempted to just keep pulling everything up, and some part of me knows there's tons of dry rot all over/and under the floor, but at this point I'm pretty sure I'll just get defeated if I have to forestall sailing for another year.
marcusg
 
Posts: 133
Joined: Thu Aug 16, 2018 10:39 pm

Re: Basic Painting Questions

Postby GreenLake » Thu Aug 12, 2021 6:26 pm

OK. So you have a cockpit floor that's separate from the hull. I hadn't realized this (or forgotten - it's been a while since you first discussed your boat). We'll have to figure out what this means for your repair. Mainly, the issue is how to fix the floor when the repair isn't supported. We'll find an approach.

Next, your boat seems to have been put together with Bondo (or similar filler). Those fillers don't have any strength, certainly not in form of a sheet. The high-strength filler might have held up a bit better, but I wouldn't use it for anything unsupported extending beyond 1/2" of a supported area (like, it's good to add / restore the edge of a rudder/centerboard because you can build it up with some strength unlike other filler, but it's not something you can use to replace places where you'd want to use laminate.

Then, we've learned that your PO either didn't scuff sand where he applied repairs or didn't solvent wash (read the literature on your epoxy for recommended solvents) to get any traces of wax off the existing substrate. That's the reason for the separation (and yes, it's happened to me recently - luckily nothing structural - and it came off when that area was damaged and needed fixing). Being meticulous in this would be good.

Now, first, you need to get a grinder in there and grind away at the edges of these "channels" to get nice bevels at a slope of 1:12 and also to grind any wood that isn't really solid.

The openings will be too wide to just lay laminate unsupported. You can either (1) use a sheet of something that you can pull tight against the cockpit floor from below and which gets abandoned after the repair (2) laminate a very thin layer of laminate that you attempt slide in and then glue from below - in both cases held up by some wires that you can cut when the repair is done. Or, (3) you can carefully wedge a piece of good styrofoam (the builders kind, that's at least a bit waterproof) so that the new laminate has something to rest on. Again, you'd have to abandon it in place.

With the support in place, you can just lay new laminate to fill the gap. If you have a 1:12 bevel, that should be wide enough to anchor it. As some of the bevel is wood, I suggest you first seal the wood with a coat of epoxy - I happen to have a penetrating epoxy (SystemThree S-1) in my shop, and would use that. But failing that, ordinary unthickened epoxy would do. Make sure it doesn't all get wicked in, before you apply the laminate by adding a bit extra as needed.

Theoretically you could instead lay up a flat piece of laminate on some plastic/wax paper on your work bench, then saw and grind that to be a "plug" with the opposite bevel, and finally glue that in place - but the precision of the fit would make that unlikely to succeed.

If your repair isn't totally smooth (but without really big voids) you can use filler to create a smooth surface, but follow instructions on preparation!

When mixing your epoxy be really precise in the ratio - use a 2:1 if you can, they are easier to mix - and make sure to scrape bottom and sides of the container so there are no pockets of unmixed epoxy. (For the same reason, best to have a bit of epoxy left when you are done, so you don't need to scrape the final bits which are often not as good a mix. And doing so leaves a plug in the container that you can later inspect as to how well it hardened, and if you pull it out, whether there are any places where it didn't get mixed near the container walls - think of it as quality insurance).

The good news is that the actual repair, filling the gap with laminate is really no big deal; as long as the laminate doesn't bridge an open gap because you've supported it from below. If executed well, it will not come apart and be as strong as what it repairs.

PS: I would ordinarily not necessarily bother to restore the wood layer separately from the laminate, but teat it all as a single gap to fill. However, if the depth gets to be over 1/2", that might make it attractive to save on laminate. If the beveling leaves you with nicely beveled wood, you could try to fit a piece of wood with matching bevel and glue that in place with thickened epoxy - it would then serve as support for the laminate. The fit wouldn't have to be perfect, the glue should help fill small gaps up to 1/8", and you'll seal the surface when you laminate over it. Only if you can fashion something to fit with reasonable effort.

PPS: don't hesitate: if you feel like adding another layer of glass over the repair because you're not quite sure it's strong enough, go for it, It's sufficiently far in a corner that one extra layer, nicely sanded and made smooth with a bit of filler, will not look too bad. Extend 2-3" over the edge, but make sure to sand/clean that area down to the old laminate.
~ green ~ lake ~ ~
GreenLake
 
Posts: 7136
Joined: Mon Jun 18, 2007 3:54 am

Re: Basic Painting Questions

Postby marcusg » Thu Aug 19, 2021 9:43 am

In the process of grinding away all the bondo at my repair site, I found a section that was all this amber-colored resin. I'm guessing this is what epoxy looks like after decades of break down?

gold.JPG
gold.JPG (129.81 KiB) Viewed 342528 times


repair.JPG
repair.JPG (112.75 KiB) Viewed 342528 times


Once again, I'm turning to my trusty face shield plastic for a repair. Like you said, GL, I put a bead of glue on it and slid it under the existing floor (bottom of picture) then pulled it up for a good clamping action using some thin wire I tied off to some screws in the bottom of the rear deck. Glue was TotalBoat's version of Gelmagic (thixo). On the right hand side where the blue is where I filled in a spot using 3m marine high strength filler, because that whole spot was all that amber colored resin and there was no space there to slide the plastic under the floor (I actually notched the plastic there so it would go all the way in.) Today I will start glassing it probably. I feel pretty confident, except about the left side because I wasn't able to get anywhere near a 1/12 bevel there. I tried to give it at least a 45 degree bevel by doing a sort of fillet with my thixo there. I might just focus on the main body of the repair and then tab the sides in later. Oh, and this time I used some of the little bottle of S3 Rotfix to epoxy the remaining beveled wood - and I really like the penetration of that thinned epoxy as opposed to thickened stuff, which I feel like just sits atop the wood.

Side note: the half a leftover face shield from my last repair has been serving me well as a sort of painter's pallette for mixing up my 3m filler/fairing filler. I mix it on the plastic and then carry it with me onto my boat. Afterwards I wipe it down with a solvent, which doesn't get it completely clean, but the fillers just harden into a thin film and it's ready for many many uses. Been doing this for months.

I also started making the fillets on those 1/4" boards that go underneath my benches. The first one I did with thixo (from a caulk gun) which was fairly easy to apply except for when the centerboard made it hard to angle the gun right. One thing I forgot about thixo is that it's a PITA to sand. Like even hard for me to machine sand, and I don't have any machine to do a small concave bevel (not reliably at least, I have one of those long, thin, band stick sanders, but it gouges really easily.) So I don't know if I'll have much luck smoothing out my fillet since it's already cured. After the fact, I saw a note about using a solvent-drenched rag while the thixo is curing to smooth it out, so I'll try that on my next fillet. I also have a little pint of S3's EZ fillet, and will do a comparison of that for ease of sanding when cured/ease of smoothing with solvent cloth when gelled.
marcusg
 
Posts: 133
Joined: Thu Aug 16, 2018 10:39 pm

Re: Basic Painting Questions

Postby GreenLake » Sat Aug 21, 2021 12:33 am

Yes, there's a technique to smoothing fillets. Is it alcohol? You may need to locate the info. Don't use anything that affects curing. (I saw it recently in a video of someone building a boat, but wasn't taking notes as I'm not planning on doing that any time soon ....)

Yep, plastic substrates for mixing, I reuse them all the time.

If you have a place where your bevel feels questionable, you can always lay up a "band-aid" strip along the joint later, it would be visible, but in some places it may not matter.

"electric file" type sanders take a feather touch, but I agree, they are not the thing to use for sanding a fillet. A dowel with a but of sandpaper wrapped around, and replacing the paper often. (And go a touch coarser than you'd think)
~ green ~ lake ~ ~
GreenLake
 
Posts: 7136
Joined: Mon Jun 18, 2007 3:54 am

PreviousNext

Return to Repair and Improvement

Who is online

Users browsing this forum: No registered users and 14 guests

cron