A huge monster moth, at least 3/8th inch long, decided it needed to meet its end in the middle of my new coat of varnish, leaving a trail of destruction behind it in its death throws. Damn!
When I'm faced with this kind of frustration, I often recall the wisdom of an old Navy engineer friend of mine. When you have to deal with a stubbornly intractable problem like this, "You just have to be more stubborn than it is." So, I'll keep re-doing it until it I'm satisfied. (Although I may give serious thought to lowering my standards.)
Still at home in the shop Saturday, I put aside the table fiasco, and worked on one of the two teak hatches from the main cabin, which had been leaking and needed refinishing. I filled the cracks and holes with epoxy putty, sanded off the excess and the old finish, sanded again with 220 grade paper, masked off the plex, and applied two coats of Cetol. No dead moths.
Sunday I headed out to the boat and worked on the bases for these hatches. Using knives, chisels, screwdrivers, pliers, grinder, sandpaper, sledgehammer and other assorted implements of destruction, I spent most of the morning removing the old sealant and prepping the surface for resealing with 3M 5200. 
Although I generally avoid using 5200 because it adheres so tenaciously that it is almost impossible to remove anything you bed with it, in this case I wanted strong adhesion to insure an effective and lasting seal despite potential movement from dimensional instability. Furthermore, because all the sealant is on the surface rather than bedded beneath a fitting, it can be chiseled and ground away (again) should that ever become necessary.
After prepping and masking, I applied a new line of sealant around both hatches. I have found that my index finger makes the ideal filleting tool to smooth the joint and press the sealant firmly against the surfaces and into the gaps. It's just the right size and allows me to feel how much pressure I'm applying. Of course I put on two layers of disposable vinyl gloves first. When the top glove gets gobbed up, I simply remove it and expose a new clean one. 
I took a lunch break while the sealant cured, and afterward removed the tape when the sealant had cured enough not to leave a stringy mess when the tape was pulled, yet was not so firm that tape could not be removed. 
I cleaned up the mess, put things away, and installed temporary covers on the hatches. It had become very hot and humid, the air was stagnant, and I had sweated enough. So I called it 'good' and headed home later that afternoon.
Enjoyed your hatch-it work this week. Not sure about the 5200 - is it gonna penetrate and be flexible enough to provide a seal and under UV? Usually use this for a bond, not a seal.
ReplyDeleteMoth - hmmm...as I am unsure of the brand of varnish, I'm assuming some high end glossy stuff, and well, after using a 50/50, and 75/25 mix to build up and seal lower coats, another couple of layers may be needed anyway, so no worries. Thank you mr moth for the extra coat. Although for interiors, I prefer poly, what you have here clearly shows off your fine efforts. One more week, so use only yellow lights if you can!
ps: I have gone up to 8 coats of varnish for some external bright work, so flex your muscles and hop to it Capt G =)
ReplyDeleteIn this application I felt that the bonding strength of 5200 trumps the less than optimal UV resistance. I wanted a maximum strength bond to the teak and the fiberglass to ensure a leak-free joint where there is no other mechanical bond and there is likely to be some movement between the two due to differntial expansion and contraction of the teak hatch frame. Rather than penetrating a small joint or crack, the 5200 is almost forming a bridge between these two slightly moving parts, so it's important that the ends of this bridge are firmly anchored and the bridge itself is strong. To mitigate the UV issue I may simply coat the 5200 joint with Cetol when I apply it to the teak hatch base. Cetol remains somewhat soft and flexible, so it might be able to handle the flexing base. Whether or not it will adhere over the long term is another question.... As you can tell from previous posts, I prefer butyl for sealing mechanically mounted hardware and trim where I can get it between the two parts before the part is secured mechanically. When I install the new ports, I plan on using butyl and 3M 101.
ReplyDeleteRegarding the varnish...only up to 8 coats? Whimp!!! I've gone to 12 or more, but usually stop counting around 10. I actually did use polyurethane on the table top. The harder surface stands up to sliding dishes and beer bottles better than softer traditional varnish, and since it's inside the cabin, it doesn't need to stand up to weather. I ended up using two brands over the course of lo these many coats that turned out to be surprisingly different. MinWax dried quickly and hard, but went on in relatively thin coats and shrank down into even 320 grit sanding marks. I had to go to 600 to be sure no sanding marks would show, which is ridiculous...might as well do a hand-rubbed finish with pumice and rottenstone. (To be fair, it was an old can I had lying around that I figured would be OK for build coats, cheapskate that I am.) I tried the Cabot brand next. It goes on thicker and doesn't shrink into the sanding marks. It dries slowly (despite claims to the contrary), however, and attracts moths :). I put on another coat last night after taking all the precautions I could think of. Checking it this morning, it looks as good as I will be able to achieve without an industrial clean room. No moths, no sanding marks, and a mirror finish marred only by some small dust specks. Good thing, cause it's at least coat #10! Now I need to do the two fold-out extensions. Call me the varnishing American!
You are insane. No question about it, and this record shows it. =)
ReplyDeleteThese are good details to record for posterity and for future reference...and as always a good lesson.
Me prefer matt finish poly inside to thwart seasickness, so I'm not too worried about glossy mirror moths too much.
Maybe you can construct a mini clean room with screens and such? The screens might also keep out dust?
I'm only insane because I'm too poor to be eccentric. I actually used my second "guest" bathroom as my clean room. It was the closest I had. "Clean" being a relative term, given my abominably low standard of general housekeeping. I've usually had pretty poor luck with matt or satin varnish. Whatever it is they add as a dulling agent seems to be some sort of fine solid poweder, and I can never get it to disperse evenly, resulting in uneven dullness/shininess. I can get a nice handrubbed finish from the gloss varnish if I really want it (but it's a lot of work). So what's the secret matt varnish seasickness preventative?
ReplyDeletePsychological testing from what I've read - apparently glossy wet surfaces somehow trigger the barf reflex. Reminder of waves and motion? Glossy surfaces do also sort of look like barf don't they? At least, I'm getting sick just thinking about that.
ReplyDeleteI've done ok with satin and matt. Cannot remember what brand I used since it's been a while, but it was particular. I'll see if I can find it. I'd feel guilty recommending using it on a very fine expensive piece of wood though.
Hmmm....Interesting. My guess is it might have something to do with the reflections off the gloss that move around as the boat moves, but move in different directions. Of course for most people, simply going below into the "vomitorium" is enough to make them sick.
ReplyDeleteWhy wouldn't you use matt varnish on nice wood? If you can get it to come out the way you want, it's just a matter of personal preference.
Came to me from my memory last night...life boats and why they painted blue on the inside instead of orange. Calming FX. Same with satin finish, my guess.
ReplyDeleteHmmm...matt varnish on a nice piece of cocobolo...NOT!!!