Basic Painting Questions

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Re: Basic Painting Questions

Postby marcusg » Wed Sep 16, 2020 10:27 pm

So the fairing went well I think. I ended up mostly using a 12" tape knife as that was wider than the repair and helped "stuff" the QuickFair into the depression still left from my fiberglass repair. Still need to try out my sandy board and do the neat epoxy.

Faired (Small).JPG
Faired (Small).JPG (78.75 KiB) Viewed 404821 times


Next up is the transom:

https://drive.google.com/file/d/1WROJTx ... sp=sharing

Basically it has a bunch of different wood/fiberglass/gelcoat repairs, and I'm not sure which ones can be done the same way as my big hole in the hull, and which need a different technique.

1. Transom top edge
https://drive.google.com/file/d/1OynmKx ... sp=sharing
It kind of looks like they replaced the transom at some point and faired(?) in the new transom. When I was sanding the paint off, there was an uneven patch of grey material that didn't sand as well as the gelcoat (paint kind of "swirled" in it) and seems to connect the back of the deck with the top of the transom. Along this edge there is a significant crack that I can almost kind of pull on with my finger nail. My guess is that I should use my dremel to sand that more open, and then fill it with some sort of adhesive (just epoxy, epoxy and mat?, "thickened" epoxy [whatever that is?].)

2. Places where old boat lettering peeled off clearcoat
https://drive.google.com/file/d/1_p1ig_ ... sp=sharing
So this isn't really a big deal, other than that it will obvious have divots when painted. So I'm guessing just fair these?

3. $&%#ed up screw holes
https://drive.google.com/file/d/1_U0-xx ... sp=sharing
https://drive.google.com/file/d/1LUXNJI ... sp=sharing
These are where the tiller mounting hardware goes, and a few places have been worn down all the way to the wood transom. Again, not sure what to fill such narrow gaps with, as I've only done a repair with fiberglass that was much wider and made sense to have layers, but maybe I'm thinking too big?!

4. Another spot of chipped gelcoat but on the bottom.
https://drive.google.com/file/d/14zlItV ... sp=sharing
In this one I can clearly see the (undamaged, I believe) fiberglass below the gelcoat. Can I just fair this, since the fiberglass is intact?

5. Motor "well" or whatever you call it
https://drive.google.com/file/d/1bRZM57 ... sp=sharing
https://drive.google.com/file/d/1Yz5DdY ... sp=sharing
https://drive.google.com/file/d/19SqCeH ... sp=sharing
So this spot is a bit of a mess. Inside the cubby/well where the motor sits, I went past the gelcoat (if there was any left?) in my sanding to expose laminate. So I'm guessing I should put something new down to cover that? Maybe I could use the airdry gelcoat you recommended Greenlake? And then there's the ridge that the motor mounts on, which is in worse condition. In some spots there's bare wood showing (apply Rotfix?) and that also needs some kind of fiberglass treatment? Would I just like fold over a series of sheets of fiberglass onto that, or?
marcusg
 
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Re: Basic Painting Questions

Postby GreenLake » Wed Sep 16, 2020 10:56 pm

Transom: you either paint this, or you "paint" gelcoat on it. No need to restore gelcoat under paint. I've used the gelcoat in the bilge, but my results look a bit "rough" - not nice enough yet for a hull or deck surface, but the whole bilge area was never a smooth surface so what I did "worked" and just by virtue of having it all in a single color, the bilge looks great. But, I assume that your plan is to paint the hull so then gelcoat isn't part of that plan.

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).

Exposed wood - if dry(!) should get a sealing coat w/ neat epoxy before you do anything else. That makes sure no rot starts from there.

At the transom top: if the gap closes flush with pressure (and the wood, probed with a long thin screwdriver is dry and firm) then you could just pull away the skin, pour some epoxy in, and clamp it flat. You could use "thickened epoxy" or simply use one formulated as a glue: GelMagic from System Three in the self-mixing cartridge would be my choice. Easy to squeeze it into the crack with the cartridge. A thin tongue depressor or similar (may need to be longer) to really distribute it on the wood / hull interface. Then clamp to force the hull to lay against the wood and be flat.

I would be aggressive in pulling away the hull, even inserting a strip of some wood, perhaps a shaved down paint stirrer to make sure you capture as much of the failed bond as possible. (And, yes, verify that the wood is still firm & dry. No good to try to glue the hull back to rotted wood).

At the top edge you could rebuild with fiberglass mixed with short strands of fibers and some thickening agent, or you could use 3M High Strength Marine filler. That stuff is Vinylester, not epoxy, but pretty strong due to fibers mixed in and best in my book, already has the correct consistency. You use a knife or plastic spreader to form it into a nice looking corner, then sand down and finish off the fine details with QuickFair,

RotFix is something to apply if you have wood where you think you need the epoxy to soak in a bit. Can be used in early stages of dry rot (more details in their literature). It's simply a thin penetrating epoxy and one that's not solvent based, so good for enclosed spaces. You could use that as the first batch of epoxy down the transom gap. It's too thin to do the gluing, but may run deeper into the crack, so you just follow it up with the GelMagic.

Anyway, that's my off-the-top-of-my-head response. You've done one repair already, so you have experience of your own, and if anything I write doesn't sound right, just do something better.

The motor well: big cracks need to be ground. Neat epoxy to start and if still rough a touch of quick fair. Afterwards paint like the rest.
~ green ~ lake ~ ~
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Re: Basic Painting Questions

Postby marcusg » Thu Sep 17, 2020 3:36 pm

Thanks again Greenlake for helping me keep this old boat alive.

Went to our egg building/boat building workshop, and was excited to do some quick fairing of the "easy spots" on transom. Had them all sanded out, then thought, *maybe I'll check out that crack at the top of the transom real quick.* Oh boy....

So the biggest problem section IS like I said before, just the fiberglass separating from the transom wood. Doesn't even separate that far down, maybe a few inches. But...

Here's a video of what I found:
https://drive.google.com/file/d/1RiwNZp ... sp=sharing

The left hand corner appears to have rotted quite badly. There's even a 1"x1" or so section in that corner where there's just nothing underneath the fiberglass (https://drive.google.com/file/d/1Vjubrz ... sp=sharing), neither behind the transom or under the deck. Extending from that corner is a 2-3' stretch where the fiberglass is not only separating from the transom plywood, but the outer layer of the transom plywood is separating from the rest of the wood. I ended up snapping off a section of the loose glass/wood in that corner to see how far it went.

That said, the rest of the transom wood seems okay. That corner has some rot/separation, and of course the exposed wood at two bolt holes for the tiller have rot also, but other than that the wood is sound. I'm wondering (hoping!) that I don't need to tear out and replace the whole thing.

I assume for that corner I'll need to cut out the rotted wood and somehow seam it into the existing good wood. I wonder if ALL of the "separated" plywood needs to be ripped out, because where it separates it seems like only the outer layer has rotted and the inner layers are okay. There's some other weird stuff going on though, like in these two pics:

https://drive.google.com/file/d/1gM3tJP ... sp=sharing
Where my finger points, I sanded right through the concrete-looking "grey stuff" to a totally open cavity that goes into my boat. Seems like somehow they covered the gap between the transom and the back deck with that stuff...really not sure what the heck the plan was or what that should look like.

https://drive.google.com/file/d/1P1M95b ... sp=sharing
Again at my finger you can see the *inside* of the transom separating from the deck/motor well. This is pretty much the only spot it's happening in, but it's just more "egh" for this transom.

Then again...maybe I'm overthinking again. I could also just shoot some kind of resiny goop into these cavities and call it good...? Even the rotted wood isn't *that* soft.
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Re: Basic Painting Questions

Postby GreenLake » Thu Sep 17, 2020 4:09 pm

Small spots of rotted wood can be scooped out. Do drill a hole from the inside near the bottom to see what the condition is there. If the bottom is totally soggy rotten, you are better off with a radical cure (see @Wylie's post). If the bottom of the transom wood is OK, or damage really localized then apply these thoughts:

You do need to replace wood by wood, if the failed area is large. You can't make up too much volume with just resin. Moderate volume you could use the filler I suggested or also, you could use SystemThree SculpWood. It's a bit like modeling clay in the way you work it, that should suggest where you can use it. Or you can combine this with a bit of wood for bulk and filler or SculpWood for the gaps. (Saves money, as wood is cheaper in bulk).

For small areas and just to get a corner to be square it depends on whether adding a strip of wood or just filler/SculpWood is easier, but for those kinds of situations you don't have to worry about loss of strength.

Now, for the separation of the plywood and the separation of the skin from the plywood, you could try using RotFix. After first using a thin blade to force things apart as much as you can - on the idea that if you can separate things with a spatula, screwdriver, paint stirrer easily enough, they might come apart on their own, so you want to accelerate that a bit before making a repair.

RotFix does not fill wide gaps really well, but it penetrates. So my thinking would be that you pour it into all the widened cracks and spaces between the laminate, or between the layers of the plywood. Then you clamp that briefly to force the epoxy into all the capillary spaces, but don't let it "gel" or even cure. Open up the cracks and fill all the parts that need actual gluing together with GelMagic (from the caulk-guncartridge with the self-mixing tip; you may need two cartridges and a few extra tips).

After that, you clamp again and this time the goal would be to make sure that the laminate sits flat on the plywood and when the glue cures, the two are bonded well.

Where you've sanded through laminate, you can add a new layer of glass cloth and epoxy (or two layers or three) before fairing. While you can paint epoxy sealed wood, it's not preferred because it's not as tough a surface as laminate, so it might scratch more easily.

This may well help hold things together for another 10-15 years. But key is that there's no wet/rotted plywood at the bottom.

You need to take a bit of laminate off in that area, from the inside, perhaps with a hole saw, just to check on the state of affairs. If very localized damage, you might be able to scoop out bad stuff and dry the are (then treat w/ Rotfix, bits of new wood and filler etc.). If not so localized, you may find a point where it might be easier to open up the whole transom and to replace it with fresh wood. (Unlike @Wylie, I think in your case, it would boil down to taking the aft laminate off as a solid sheet, by cutting around the edges, scooping out the transom wood, and replacing it and then gluing the old skin back on. Not too horrible.

Deciding between these approaches can only be done with local knowledge.
~ green ~ lake ~ ~
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Re: Basic Painting Questions

Postby marcusg » Thu Sep 17, 2020 10:05 pm

So I took out a 1.5" core from the bottom of the transom and it looks great. I'll be ordering supplies tonight and am eager to get to it.

Question: I googled images of what it would look like to clamp the transom as you said, but all I found were examples where the back deck wasn't present. I'm assuming the best way would be to bolt a 2x4 horizontally to the deck and then use that as a base to clamp from (made easier because everything I need to clamp will be at the top of the transom.)??

Also - to put the 1.5" core back (and fill the above bolt holes,) is that the same as the repair I just did on the hull?
1. laminate a backing plate
2. glue backing plate on
3. put core back in/fill holes with filler
4. taper and put fiberglass on other side?
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Re: Basic Painting Questions

Postby marcusg » Thu Sep 17, 2020 10:16 pm

Ah so I think I just deduced that the grey filler stuff that the PO rebuild the transom edge out of - and filled all sorts of weird gaps - is Bondo?
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Re: Basic Painting Questions

Postby GreenLake » Thu Sep 17, 2020 10:56 pm

Bondo: bad juju - it's not formulated for water immersion. Otherwise it's a polyester filler, so technically a distant cousin of the 3M High Strength Marine Filler that (a) uses Vinylester instead (better) and (b) is filled with chopped fiber (stronger) for structural filling, so to speak. I don't know what the polyester in Bondo is mixed with, but polyester is only so-so when in contact with water and the filling agent may have worse properties - it sands well, but so does QuickFair (which is the functional equivalent of Bondo for marine application and epoxy based).

To put your core back in: grind the edge of the hole to a bit of a bevel, but no need to overdo that. Use GelMagic (or thickened epoxy). Cover the "plug" liberally with that and stick it in the hole. Squeeze GelMagic into any air pockets. Lay up 2-3 layers of cloth (small disks of varying diameter) directly in the GelMagic (for a small job like that, it can be used as to do a bit of laminating as well; there's no need t mess with mixing two different kinds of epoxy). [I have that info from talking to a rep, so it's "official"].

As it's on the inside (I assume?) and perhaps not in full view - apply as little or as much fairing as you like, and then paint over.

If you did drill a clean hole all the way through, then you'd need to restore the skin on both inside and outside, of course. Same approach but a small nail or two, or tooth picks can be used to hold the wooden plug in position and then you simply patch both sides. If you tape over your repair with a stiffish sheet of plastic, you can safe yourself most of the effort of sanding and fairing it later. (Somebody mentioned here on the forum to use a replacement face shield - was that you? Can't remember, but that's a brilliant thing to do - I usually use the plastic from display case packaging).

Your idea with a clamping bar should work. Make sure to test before you have live epoxy - always less stress.
~ green ~ lake ~ ~
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Re: Basic Painting Questions

Postby marcusg » Thu Sep 17, 2020 11:08 pm

OOOOoooh. That's what you meant by drill a hole "inside" the transom. I went inside the boat and drilled a hole straight through. LOL!

Glad I made a valuable contribution with my face shield thing. I was looking at $80 saw blades for the nice thick plastic packaging and thinking "don't dooo it."

So whatever this grey stuff is, Bondo, polyester filler or whatever, the PO used it all over the boat, including at the base of the bench floorboards, as a protection from water flowing under them and into, I assume, the floatation foam behind them. I'm going to leave them bare wood (treated with something of course,) so I'll need to rebuild this sort of ledge/footer setup with some kind of material. Would the 3m marine filler be good for that (is it "too good"?) Would QuickFair work? (it's cheaper.) Seems the Marine filler is needed for something more structural that needs to hold it's own shape, and I don't know if these "footers" qualify as that.

PO also used grey stuff to build up a ledge/footer around an access port that goes down under the cockpit, leading to the drain channel for the lowest drain hole in the transom (see pics)

Bench without "footer":
https://drive.google.com/file/d/1Gf-Q2N ... sp=sharing

Bench with "footer":
https://drive.google.com/file/d/1E-wPPN ... sp=sharing

The footer itself, half on half broken off:
https://drive.google.com/file/d/19gW6UL ... sp=sharing

He also built up a similar Bondo footer around the access hole that goes down under the cockpit (and leads to what is, from what I can tell, a tunnel that drains water from the lowest drain hole in the back of the boat.)

Cockpit access hole, with its own footer also:
https://drive.google.com/file/d/1DgKwj_ ... sp=sharing
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Re: Basic Painting Questions

Postby GreenLake » Thu Sep 17, 2020 11:26 pm

QuickFair should only be used in thin layers that are to be sanded into a fair shape.

What you are describing are "fillets". If you want, you can use EZ-Fillet from SystemThree which is ready mixed. It would work well for applications like around the base of the seats and it's OK to shape it into something like a small wall or dike around something. It's not super strong because it's intended in wooden boot construction to then have a layer of glass tape run over it to tab together something like the hull and the bench. It serves to provide an easy curve for the corner, but it's more than simply fairing, so it's a bit structural as well and should be stronger than Bondo.

You could get glass tape and EZ-Fillet to apply around your benches. The glass tape will be transparent if coated in epoxy, which would work well if you wanted to leave your benches natural wood color. (The EZ Fillet is wood color and would provide a nice transition to a painted floor - you could paint it part-way.

If leaving the benches natural, I would coat them with ClearCoat to seal them and some varnish for UV protection. I've used the SystemThree WR-LPU on an epoxy base and and it works well. You may use a water based wood stain on the benches to even the color before applying epoxy.

1034

Currently, both thwarts and coamings are done this way and it's proven very durable (multi-season durable).
~ green ~ lake ~ ~
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Re: Basic Painting Questions

Postby marcusg » Fri Sep 25, 2020 7:17 pm

Okay, so I've got all my supplies. Here's my thoughts for how to start my transom repair, let me know what you think:

https://drive.google.com/file/d/1xIXkGm ... sp=sharing

And then I also want to get ready to do the gelcoat on the floor, but wonder about the order of gelcoat/fillet/clearcoat (on wood,) and also the couple access hatches and what they're for/whether they need to be left accessible:

https://drive.google.com/file/d/12nsJP9 ... sp=sharing

https://drive.google.com/file/d/1Y8cTcw ... sp=sharing (sorry for the sideways video)
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Re: Basic Painting Questions

Postby GreenLake » Fri Sep 25, 2020 7:53 pm

Wow. That's a lot to unpack here and not much I can reference (I'm not going to take time stamps from your videos :) ).

However: your transom plan makes sense. I think that with some good clamps you can narrow the big gap a bit more than you can by hand. Screw type clamps may work better than pistol-grip ones for this. The more you can reduce the width of the gap the better off you'll be, is my idea. For the gap where you were thinking of using the filler - try embedding a small chunk of plywood to reduce the volume a bit. If you leave 1/4" of filler on the outside, the result will be strong enough. Yes to glassing over the edge after you've glued everything together. With all of this, start the next phase while the epoxy from the previous phase is still "green" and you get a better bond.

You'll find people will tell you that gelcoat may not hold well on epoxy. Apparently it can be problematic but isn't always 100% the case. Careful mixing (no excess of either component) and washing off any "blush" with soap and water would improve. If you fillet first, you could run the gelcoat up from the floor to where it meets the vertical surface. Tape the wood to keep gelcoat off. That would visually hide the fillet. Or you could opt for the reverse (where the fillet remains visible). In that case, I'd tape the area that will be the base of the fillet and have it just slightly overlap the gelcoat.

99% an aesthetic question, I think. If your plan had been to paint the seats with an opaque paint, then the line where gelcoat and paint meet can be chosen arbitrarily, e.g. you can cover the fillet 50/50. You get the idea.

For your box you'd want to run the gelcoat up to and under the lid. Unless the lid looks amazing after you sand off the paint, I would contemplate rebuilding it. In either case, it needs clearcoat plus paint. The former, to keep water out (cover every surface) and the latter to keep UV out and to give it an appearance that either blends in or contrasts - again, season to taste.

The lid should either have a bungee below that keeps it in pace or some other latching mechanism.

For the forward compartment. First, to check that the foam is dry and stable. If yes, you can simply glass over the opening. You might want to a small 1" drain at the lowest corner so you can check whether water gets in over time.

Good luck!
~ green ~ lake ~ ~
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Re: Basic Painting Questions

Postby marcusg » Sun Oct 04, 2020 5:46 pm

Any recommendation on a brand/type of clearcoat? Or varnish for that matter?
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Re: Basic Painting Questions

Postby GreenLake » Mon Oct 05, 2020 5:14 pm

I take it that's for exposed wood?

You have three choices:
  1. oiling (requires constant repeat application/touchup but limited prep)
  2. standard varnish (requires less frequent touchup, but may require more prep/occasional sanding to bare wood)
  3. sealing in epoxy, followed by a clear PU (very durable, but takes real effort to redo - but that can be multiple seasons later)

The problem with varnish is that it allows the wood to "cycle" w/ moisture and temperature. That usually leads to the varnish cracking. You don't have that problem with oil, so yo can just reapply when it fades. You also don't have that problem if you can get to all six sides of a piece of wood and seal it with epoxy (also sealing all holes!). That makes it very stable and you can apply a hard coating like a water reducible PU. Expect multiple seasons out of that (definitely in moderate climate when shaded from the sun).

Read about coating clear wood on the SystemThree website. (I've used their ClearCoat epoxy followed by their WR-LPU on coaming and thwarts (and tiller) and have made very good experience. The PU protects the epoxy from UV. If it rubs off or gets chipped off, I reapply it locally, as needed. I use a Satin, which is a bit more forgiving than high gloss.
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Re: Basic Painting Questions

Postby marcusg » Tue Oct 06, 2020 8:53 pm

Did some RotFixing, GelMagic'ing, and SculptWooding today on a small portion. So far so good but...I learned to leave plenty of time to go over everything before I start. I forgot to Rotfix under the worst rotted place before sculptwooding. And once I did get the Rotfix out I was rushing because it only had 5 minutes working time...ripped my nice squirting tube, blah blah. Live and learn.

I managed to get my coamings off and intact, so I could in theory coat all 6 sides of those with clearcoat and PU. With the "footboards," however, the screws were all stripping, and I'm a bit afraid of how big of a project I'm creating (and how many holes I'll put in the wood) once I drill all those out, so I'd prefer to leave them intact. But if clearcoat + PU'ing one side of those boards is bad because of moisture cycling, wouldn't painting only one side have the same problem?
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Re: Basic Painting Questions

Postby marcusg » Tue Oct 06, 2020 8:58 pm

And holy cow this stuff is expensive, especially since Systemthree is advising like 3 coats each of CC and PU.
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