Bottom painted...mostly and rivet question

[Jackie]

I had a long day working on the boat today. Due to a family emergency down south I've had to move my ferry reservations up to this Monday....and I had a ton of things I wanted to do to the boat before I left it in the hands of my family. I had already put the boat in the water, but planned to pull it and do a good bottom paint as soon as I had time and good weather... I'm a bit short on time now and today was predicted to be the only good day for awhile, so I did the best I could. And by that I mean that I didn't have a way at the moment to raise it off the trailer. I have jack stands and, as a 'better than nothing' method, was going to raise the tongue as high as possible, jack the bow up and then lower the trailer to the ground. That would have let me get at least some of the area covered by the bunk, but in the end expedience won out. I'll do a really good job and get the bare spots next spring (probably).

Since it had been in the water I had a nice little line to show where the water came. I drew just under it with marker then pressure washed and scrubbed off all the tiny, baby barnacles that were already growing. Next I taped just above my line and then cleaned the mold release and wax off with solvent and many, many rags, sanded the bottom and cleaned the sanding residue with solvent again. After that I got smart and called a daughter over to help paint!

While waiting for her I removed the helm seat and got the sliding bracket ready to put on....only to discover that the holes in the bracket are just a tiny bit off from the hole pattern that was drilled for the seat. I'll adjust them and get that installed tomorrow. We painted the primer coat and while it dried I drilled the oversized holes for the downriggers. Even though I have sides covering the cockpit, the space behind the transom is open and I could reach far enough forward to make me happy with my placement. If you drew a line extending the front of the transom it would bisect the bases. That isn't far enough forward to get right behind them, but not so far back that I have to reach. And they are swivel mounts.

Anyway, she painted the first coat of bottom paint while I dremmeled out a nice under cut, then I painted the very bottom. While that dried we mixed the epoxy, wetted the holes and then thickened. I have never done this before and didn't know how fast the stuff would thicken up. I think it took me so long to get to peanut butter stage that the stuff was starting to cure in the cup. I managed to fill one set of holes, but it really was getting hard so I pushed and pushed and really hope there aren't any voids under there. It had gone from peanut butter to fudge by the time I was done. I threw the rest away and mixed up another batch to the consistency of honey for the other side. I dribbled it in bit by bit in each hole and it worked much better, but after I removed my tape I noticed a bubble had risen in one hole. The epoxy was still soft so I was able to poke around with a skewer and fill a few spots in that side. I'll let them cure till tomorrow then redrill and through bolt. I have starboard cut for backers, big fender washers, and some 4200. I hope there aren't holes in my epoxy plugs, but I learned a lot and think I did a good enough job.

We finished the second coat and I had my son-in-law pull the prop for me so I can mount my Permatrim tomorrow. Then I will be done! It will have been a good weekend and I'll feel better about leaving. Even if I didn't get to fish yet :?

Oh yeah, the question: while I was under the transom taping up the bottom of the holes I noticed that all the rub rail rivets are exposed. There are no little mounds of gel coat or anything over them. And some are actually broken and poking out at odd angles. Is this ok? I took pictures and posted them in my album. They aren't the clearest shots, but I hope you can see enough to give me some advice.

Thanks,
Jackie

 

[Sunbeam]

Busy days!

A couple of comments:

1) You mention that it "took you so long to get to the peanut butter stage" that the epoxy was starting to cure. Perhaps you just mean that you thickened it little by little, mixing in between, and so by the time you got it to the texture you wanted enough time had elapsed that it was starting to go off. I think we can all relate to that (who hasn't had to throw an "epoxy bomb" off the boat at least once ). But on the other hand, since you said it was the first time you'd used it, I wasn't completely sure that you weren't just expecting time to thicken it vs. added thickeners. Time will make it go off (cure) due to chemical reaction, but that kind of "thickening" is not the kind you want (once it starts to go off, best to stop using it). So I just thought I'd bring this up in case it was the latter (thinking time is what you use to "thicken it" vs. the former, correct way (adding thickener).

You may already know this but there are slow, fast, and sometimes medium hardeners that you can use to "adjust" the working time. You can also keep epoxy cool (physically) if it's a hot day. On the other hand, I can relate to the (sometimes precious) amount of time it can take to get a batch just how you like with thickener - especially if you are new to it and not sure how much to add so you add bit by bit (as the clock ticks).

2) The bubbles coming up make me think you were filling a "blind" hole (in other words, only one opening). A blind hole is prone to trapped air in the bottom. There are various ways to work around it. One is to try to put the epoxy in from the bottom up (poke a syringe in), or sometimes you can create a second small air hole, or poke it as you did, or etc. Somewhat less thick epoxy does flow in better - but you do want to have some thickener as "neat" epoxy is rather brittle.

3) The rivets do look questionable. If they are in normally unseen areas, then the fact that there are not cosmetic blobs over them (as there are in the 22 at least, where they can be seen in the cabin) isn't a big deal. But I can't really see the squashed part of the rivet or a washer that provides the "back support." Maybe it's just not visible, but maybe it's compromised or missing. At least on the 22's (which I'm more familiar with) the rub rail rivets are bit prone to problems. It seems they may have used aluminum rivets with steel mandrels, plus in some places (salt) water can sit against them (like at the low point amidships inside the hollow of the rail), so corrosion ensues. It's not unusual to have to replace some of them when they fail. I can't tell for sure what's going on with yours in the photos though. Has the rubrail pulled away from the boat at all? Mine did where the rivets failed amidships (pulled away to leave a 3/8" or so gap between the rail and the boat).

 

[Jackie]

Busy days!

A couple of comments:

1) You mention that it "took you so long to get to the peanut butter stage" that the epoxy was starting to cure. Perhaps you just mean that you thickened it little by little, mixing in between, and so by the time you got it to the texture you wanted enough time had elapsed that it was starting to go off. I think we can all relate to that (who hasn't had to throw an "epoxy bomb" off the boat at least once ). But on the other hand, since you said it was the first time you'd used it, I wasn't completely sure that you weren't just expecting time to thicken it vs. added thickeners. Time will make it go off (cure) due to chemical reaction, but that kind of "thickening" is not the kind you want (once it starts to go off, best to stop using it). So I just thought I'd bring this up in case it was the latter (thinking time is what you use to "thicken it" vs. the former, correct way (adding thickener).

Thanks. You described it exactly, I just didn't have the terminology. I wasn't sure how long the neat epoxy should sit after wetting so I waited a few minutes. Then I started adding the filler about a half teaspoon at a time followed by stirring as I wasn't sure what combination of quantity and time made it thicken. I soon started putting in larger amounts, but by the time it got to the consistency I thought I wanted the cup was quite hot in my hand. I worked faster on the second batch.

2) The bubbles coming up make me think you were filling a "blind" hole (in other words, only one opening). A blind hole is prone to trapped air in the bottom. There are various ways to work around it. One is to try to put the epoxy in from the bottom up (poke a syringe in), or sometimes you can create a second small air hole, or poke it as you did, or etc. Somewhat less thick epoxy does flow in better - but you do want to have some thickener as "neat" epoxy is rather brittle.

I'd read that I should cover the bottom so it didn't just flow out, so I taped them and was filling a blind hole. The thick stuff in my first set probably would have worked better without being blocked. I'm afraid there might be voids in the bottom. I haven't taken that tape off yet but can inspect then. If it looks like I didn't get it mooshed all the way in, what should I do? I figure there are three options: 1) nothing, just drill and proceed 2) shoot something else in the holes when putting on the hardware, like some 4200 (it's what I have ) or 3) mixing up more epoxy and shooting it in from the bottom. I imagine it depends on the size of the void. And if the initial epoxy is fully cured, will the second batch bond well?

The rivets are aluminum and there doesn't seem to be any backing plates that I can see. The stud just pokes thru and on some is split like it had been forced into something, but not like I think rivets set. I'll look closer and check to see if the rub rail is separating. That would be a far future job if there isn't separation.

Thanks for your help and sharing your knowledge. I appreciate it.

Jackie

 

[journey on]

Rub rails on some C-Dorys can be a problem. On Journey On, the heads on the rivets fell off under the rub rail plastic insert. You can only see that if you pull off the insert, which I did. Yup, replaced them all; a job and a half. Used stainless bolts and nylon washers, to avoid stainless/aluminum corrosion. Also drilled weep holes in the railing.

I don't know what they used on the 16, but I'd check the outside. If all the rivets on the outside look OK, don't worry about the inside. BYW, the factory doesn't do it that way anymore. I'm curious as to what they do. Anyone know?

Boris

 

[thataway]

If the rub rail is tight, no leakage when rain or wash, the rivets may be OK. I would much prefer to see machine screws and nuts as Boris described, or use longer pop rivets and have a washer over the rived inside before it is expanded, working as a backing plate. If I can get to the back of fiberglass, I always use the backing with pop rivets.

 

[Sunbeam]

Now that you said more about the epoxy mixing, a note: You never need any "time" when mixing epoxy. What I mean is, other than the time it takes to make sure you have physically blended the resin and hardener (stirring), it's "go time" right from the first moment. So just mix, thicken (if you are using thickened) and go. No waiting.

If you are going back to add/improve while in the green stage (the epoxy you just previously did hasn't hardened completely and you can dent it with a fingernail), then you get a chemical bond and can just add (the time varies due to temperature/etc. so that's why the fingernail test, but typically I'd say it's maybe 12 hours or so). After the green stage has passed you are going for a mechanical bond. Best to scrub off any possible blush with plain water and a 3M pad, then rinse and dry. Then sand, then proceed. (As you can tell, it's great to just get it in the green stage.)


I've had issues a time or two over the years when doing holes (and other glassing). Sinkage, voids, an incorrect mix, etc. If it's more than just a simple sunken spot or the like, what I'll sometimes do is just re-drill the hole (presuming this is appropriate for the situation). The drill bit removes the questionable stuff and roughs things up all in one. Then you just fill again. It can be easier than fiddling with something that's only half right -- or having any "I wonder if that..." type of thoughts later on.

Lots of folks here have good epoxying tips, but you'll likely also find that you build up your own "tips and tricks" as you go.

If you want to see a bit more about the rub rail rivets, I wrote up my repair which can be found by clicking the link. There are also some great descriptions and photos by other Brats, which I was grateful for when I was deciding how to proceed.

http://www.c-brats.com/viewtopic.php?p=267126#267126

 

[Jackie]

When I drilled out the holes for the downriggers, they all appeared solid all the way through. No evidence of voids or bubbles so bolted everything up. I also got the slider installed for the helm seat and am able to swivel all the way around without hitting the controls. It is really nice.

Lastly I got the permatrim installed so everything is as good to go as I can make it. The boat is looking good and I can't wait to really have a chance to enjoy it.

The rub rails are nice and tight and don't appear to be coming away at all. I had a good chance to really look at the rivets while I was tightening the downriggers from underneath and I can't see any kind of backer on them. They appear to be hollow aluminum tubes through the side and each one splits in three parts which are bent outward and supposed to hold them on? That's what I see anyway and I suppose that is how they are supposed to work, but many are broken. That isn't how I've ever seen a rivet done, but for the moment they aren't leaking and the rail is tight so I'm not going to worry about it.

Have fun boating!

Jackie

 

[Sunbeam]

That all sounds good, Jackie :thup

I can't speak to the 16, but on the 22, if a rivet were to start leaking, there would be no harm done to the hull itself (no coring, etc.). Sure, if you had something right below a rivet that could be damaged (charger, papers, etc.) but not to the boat itself. I don't know if the 16 has rivets behind built in flotation or something that might make the situation different. But otherwise I totally see your plan. Go fish!