Core Sound 20 Mark 3 Build - Chesapeake, VA

[Steve W]

Dave, that was a good read. Where is it stated that " risks are minimal (not sure this is reassuring) if rolled or brushed and an organic vapors respirator is considered adequate". I'd like to use this paint, but consider my lungs more important.

[Hirilonde]

Steve:  I've lost track of the MSDS sheets I have read over the years.  Some have said the vapors of isocyanates are minimal unless atomised into the air like when spraying.  I am sure this is true in a relative sense.  But at what point or amount the vapors can be considered safe is something I choose to simply avoid.  You should be able to get the MSDS for just about anything on line in PDF form.  I would start there.

[PAR]

Once you get into spray painting, it becomes obvious you need respiratory protection and this usually means a lot more than a particulate mask. Even in the old days, spraying lacquer and alkyds, you knew you needed more than a cartridge mask. After an hour in the "booth" you had a buzz and this is a pretty clear indication, you're sucking in stuff you'd probably not want in you.

 

Portable respirators have changed dramatically in recent years. If you do more than a little painting, you'll need at least a half mask and personal breathing unit (grade D). I like the full mask setups, but it's a personal choice. These systems aren't exactly cheap, but good used ones can be found on Ebay at a fraction of the price of new. Possibly with some "consumable parts" replacements an essentially new system can be had, pretty cheaply. This is how I started. As your painting quality control and requirements go up, you'll have to make additional changes to your equipment (guns, filters, driers, compressors, etc.). Eventually you'll have a small professional setup and can spray automotive style finishes without runs, sags and perfect cured results.

 

For a one time paint job, there's not a lot of worry about isocyanates, if rolled and tipped, but if you do this regularly, you will need the same protections as spraying. You'd think waterborne paints could solve this problem, but they're actually worse. They do use water, but also have some seriously bad for you water soluble chemicals in it, that still need to be kept out of you. In fact, most waterborne 2 and 3 pack systems only the base coat is waterborne, with the primer and clear still being solvent based.

 

It's a complex subject and you do need to have a pretty substantial conversation with yourself, about the upgrade to spraying.

[AmosSwogger]

Boat flip.

 

 

I lashed an oak beam to both of the stern eyes and screwed in an eye in the middle of the beam.  This worked out well; the boat rotated easily on its center line.

 

 

 

 

Everyone was amazed at the lightness of the boat.

 

[Drew]

The oak beam is a nice solution. Now comes the fun part - sanding, glassing, sanding, sanding again, and painting.  

[AmosSwogger]

18 hours ago, Drew said:

The oak beam is a nice solution. Now comes the fun part - sanding, glassing, sanding, sanding again, and painting.  

 

Thanks Drew; I'm actually looking forward to sanding surfaces that don't have fillets.

[AmosSwogger]

My local fiberglass shop had 60" wide 10oz fiberglass listed as available on their website.  Of course, when I called them today I was informed they do not sell 60" wide any more.  The widest they carry is 50".

 

50" won't cover the joint between the coaming and main hull (the sheer line joint?, not sure of the right term here).

 

I could order 60" wide online but it is expensive.  I guess the other option is to apply fiberglass down horizontally which would make vertical seams.  What have other builders done; what width did you use?

[Paul356]

I ended up with vertical seams. As far as I remember I used 50 inch on the CS 17.  Some of the seams show a bit, some don't, although nothing shows from "8 feet". Making them not show can be done but it takes the usual to make them disappear:  extra care, extra epoxy/fillers, extra sanding.  I'm guessing you'll hear from PAR and others on this.  

[PAR]

One method I don't often use to hide seams is to overlap as usual, but wait until it goes "green" then take a fresh razor blade and a straight edge then cut through both layers of fabric. This creates a common line they can butt up against, after you remove the overlapping piece. It's easy to peel a little of the edge up when doing this, but a quick brushing of some neat goo under the offending edge will stick it back down, just fine.

[AmosSwogger]

8 minutes ago, PAR said:

One method I don't often use to hide seams is to overlap as usual, but wait until it goes "green" then take a fresh razor blade and a straight edge then cut through both layers of fabric. This creates a common line they can butt up against, after you remove the overlapping piece. It's easy to peel a little of the edge up when doing this, but a quick brushing of some neat goo under the offending edge will stick it back down, just fine.

 

That's pretty slick, I just might try this.

[AmosSwogger]

Measured three times; the first cut into the centerboard well was centered in the opening.  By moving the fence on the router in or out I was able to get the base plate of the router level and use a bearing guided bit to rout the opening.

 

 

 

The temporary spacer board left in the centerboard well when initially inserting the module into the boat ends up getting glued in place due to epoxy squeeze out.  This kept the opening consistent, but you have to cut it away when routing the opening.

 

 

 

I glassed the opening per Chicks recommendation.

 

 

One nice feature of the overturned boat is the ease of epoxying and painting the cabin roof.

 

It might be hard to see, but there is a small gap I needed to fillet between the cabin roof and the side of the boat.  I didn't extend the cleat that gets glued to the shear strake up far enough past the lip of the panel.  The cleat gets planned down to match the angle of the cabin roof; if it doesn't extend up far enough to give you enough meat to plane down there will be a small gap  on the inside.

 

 

 

 

 

 

 

[Steve W]

Great pics. Reminds me of my kids when I was building the Suzy J. Now my wife and I run around three nights a week watching them in sports, plays and stuff. Cuts my productivity, but I wouldn't trade it. 

 

When I cut the slot in my 11N, I first poked a hole with a long drill and extension. It takes the nervousness away. I forgot on the 20.3, but I poked a hole through the penant housing and later patched it.

 

She's looking good. Gluing my seat tops down today.

[AmosSwogger]

Getting ready to plane down a flat for the skeg.  At what point on the keel should I stop the flat?  Is this something that is just determined by eye?  The skeg tapers down to meet the hull at some point; where is that point?

[Chick Ludwig]

The "point" that I started the keel was where the curve of the bow started. It was tapered down to a feather edge at this point. Don't worry too much about flattening for the keel. Poxy pucky fills any void. I like to glass the hull with overlap at the centerline before adding the keel. Then leave the keel uncovered. Just poxy coat and paint. Doing it this way will keep keel damage from letting water into the bottom ply. Also makes repairs to the keel much easier. I have a stainless strip full length on the bottom of the keel.

 

Way-to-go glassing over the c/b case joint. This is a prime area to allow water in to rot the bottom.

[AmosSwogger]

3 hours ago, Chick Ludwig said:

The "point" that I started the keel was where the curve of the bow started. It was tapered down to a feather edge at this point. Don't worry too much about flattening for the keel. Poxy pucky fills any void. I like to glass the hull with overlap at the centerline before adding the keel. Then leave the keel uncovered. Just poxy coat and paint. Doing it this way will keep keel damage from letting water into the bottom ply. Also makes repairs to the keel much easier. I have a stainless strip full length on the bottom of the keel.

 

Way-to-go glassing over the c/b case joint. This is a prime area to allow water in to rot the bottom.

 

Thanks Chick, that is real helpful.

[Drew]

I did the same as Chick regarding the double over at the keel and then attach the false keel over that. I routed a groove in the inside of the false keel and filled it with epoxy and flox then put the false keel in place and drove home the wooden dowels that I had pre-drilled. The rest was held in place by a lot of lead and many bricks until it cured. I'm calling it a false keel because it isn't really a structural member, just additional protection for the real keel.

Regarding the gap in your cabin. I had a couple of small ones where I hadn't planed down the timber correctly, so I just used a piping bag of goo (white filler to make it easy to hide) and filled the gap. That should be plenty strong enough.

[PAR]

I took a belt sander to the boat's centerline and made a flat, though not quite wide enough to place the "skeg" where it need to live. I plumbed up the skeg over a bead of thickened goo and let this setup for a few hours, before going back and backfilling the gaps with a cosmetic filler. The key is getting it straight and plumb, not so much the flat on the centerline.

[Don Silsbe]

It's good to have mini-workers.  They can get i to some pretty tight spaces.  And they'll remember this, for sure.

[PAR]

Yeah they do, which is why one of mine will never build a boat . . .

[AmosSwogger]

Fiberglassed the hull with 10oz glass.  It us about 3.5 hours to cut the glass and wet it out.