Building Shesha, a Hunter Valley GIS, Australia

[woodeneye]

I'm glad I'm not the only one wearing a headlamp!

Drum sander. Great idea. 5 months too late.

My "over 50" eyes sometimes have difficulty distinguishing pencil lines and woodgrain, so need all the help I can get, including the glasses

[woodeneye]

I’ve built the centreboard and rudder casings and given the insides 3 coats of epoxy before final assembly. I’ve made the casings 3mm wider than the foils, so I spent a good amount of time getting all the internal framing spacers planed to exactly the right width. This is where a table saw or thickness planer would have come in handy. I want to add some strips of lexan or similar to snug the boards up and which will also take the wear away from the epoxy coating inside the casings.
Attachment 130400This shot shows the structure of the centre board case. The spacers are Paulownia.

I also tried something that I first tried with success when I made the foils. Immediately after laying down the final epoxy coat, I covered it with non stick oven paper and used a squeegee to remove all the air bubbles and even out the coating. Because it is silicon impregnated, the oven paper just peels off when the epoxy cures, leaving a nice smooth surface that doesn’t need sanding or further treatment. I knew it worked on curved surface but it’s good to know that is also works just as well on flat ones. The important thing I think is to make sure you lay the oven paper down straight away while the epoxy is still able to flow and spread, otherwise you may end up with a smooth but lumpy surface.
Attachment 130401 Removing air bubbles with the squeegee.
Attachment 130402 Air bubbles removed, now just waiting for the epoxy to cure before the oven paper is removed.
Attachment 130403 With the paper removed, the finish is smooth But matt. Another good outcome from this method is that flying insects and dust can't affect the surface.
Attachment 130404 Make sure you are using a non-stick type of oven paper. This paper is silconised and is not the "greaseproof" sort.

I had to stuff around with the tiller as the arms would not bend around the rudder case without pulling the back end of the case open due to the angle. This was a downfall of making the tiller before the case, which I had done while waiting for my ply to arrive from France via Tasmania. There was just too much stress on the back end of the rudder casing so I’ve cut out one of the Paulownia spacers on the tiller and now it fits just fine. Before I can assemble the rudder case, I have to buy some SS bolts to fix in during assembly as the bolt heads need to be inside the case.

I received a phone call from the chandlers to say some Ronstan rudder fittings I had ordered months ago had arrived. I had cancelled the order, but through some stuff up they did not cancel the order with Ronstan. As I’d paid a $40 deposit I decided to go over anyway and pick them up, and then make a decision about which ones to go with, the Ronstan or the Riley I had also bought from another supplier. The Ronstan ones are alloy and fitted the width of the rudder casing just perfectly and without any modification which I would have to do with the other Riley SS ones. The 8mm Riley SS pin also fits the 7.9mm Ronstan holes just perfectly too, without ANY play at all, so I’ve decided to go with the lighter Ronstan ones and sell the others on Evilbay or to anyone here who wants a set of these excellent and robust ss Riley rudder and transom gudgeon fittings.
Attachment 130405 Here is a pic of the Riley gudgeons I'll be selling soon.

[john goodman]

. The Ronstan ones are alloy and fitted the width of the rudder casing just perfectly and without any modification which I would have to do with the other Riley SS ones.

What were the Ronstan part numbers you purchased?
Did you buy the 2 hole of 3 hole fittings for the rudderhead?

JDG

[woodeneye]

What were the Ronstan part numbers you purchased?
Did you buy the 2 hole of 3 hole fittings for the rudderhead?

JDG

Hi John, these are they:
Attachment 130413
Attachment 130414

Not sure of the part numbers. The rudder gudgeon is 40mm wide.

I have 1/4 inch ss bolts for attachment.

[MiddleAgesMan]

I believe our parchment paper is the same stuff as what is called oven paper in Oz. I had no idea it contained silicone--might not have used it if I'd known.

I just checked the box and it doesn't mention what it's treated with, just that it's "waterproof, greaseproof, and biodegradable." BTW--we also have our wax paper or waxed paper but that's a different animal entirely.

Wouldn't the silicone have an adverse effect on whatever comes next, be it more epoxy or a paint?

[Boatmik]

One would have to be careful about residues. Silicon is particularly bad as it is hard to wash off or dissolve with solvent.

MIK

[woodeneye]

One would have to be careful about residues. Silicon is particularly bad as it is hard to wash off or dissolve with solvent.

MIK

The silicon is cured into the paper, and works similarly to solid silicon cooking equipment like cake molds. If it came off it would be of much more concern than the residues on the epoxy.

Besides, I overcoated my rudder and centreboard without any adhesion problems, so it works fine and there are no residues. The thing to remember is that wax paper is not the same. Check the temperature rating of the paper to be sure.

[Boatmik]

look forward to more successful reports!

It is heartbreaking in the boat repair field to find the boat has been polished with silicon. Really hard to get rid of and contaminates all the surfaces being worked on.

MIK

[callsign222]

Mik,

What was the alternative to silicon that you suggest for sealing hatches and inspection ports? I know its written down somewhere, can't find it at the moment.

[MiddleAgesMan]

In order, starting with the least expensive and least adhesive:

Ordinary acrylic latex house caulk. If I don't need a lot of adhesion I use White Lightning 40 year adhesive caulk. About $3.50 a tube. Just make sure it says "paintable" on the label. What I like most about WL is that you clean up with water. (WL has some silicon in it per the label but it takes paint very well...must be a tiny amount.)

Sikaflex 221 or 291; very good adhesive qualities in both; from $6 to $10 a tube. Paintable and sandable.

3M 4000; bonds just about anything even metal to wood and the adhesion is not as strong or permanent as their more famous 5200; about $10 per tube. Paintable

3M 5200; very sticky and very permanent but not recommended for metal bonding; $10-12 per tube. Paintable

Sika makes some specialty sealants for glass and polycarbonate window installation. They cost about double any of the above and probably aren't what you want or need around your deck plates.

[callsign222]

Thanks MAM, fantastic recommendations.

If you used a very sticky one like the 5200, would you still screw in the deckplate?

Edit: I think I know the answer, and it's going to be "yes."

[Boatmik]

With Sika and hard cure silicon they cure hard (or rather solid) so act as an effective glue.

It works for deck plates (inspection ports) because the contact area is high and the loads are small. With the really big inspection ports that allow big items to be put inside for canoes etc (eg tents, sleeping bags) - these might not be easy to glue as the surface area is much smaller for the size of the hatch. We had a few come adrift on the kayaks we paddled on the Colorado. But with sailing boat sized ones haven't had a prob since I discontinued using screws.

I have never used 5200, but would suspect it would be OK at gluing.

But only suspect.

MIK

[callsign222]

What about thru-hull bolts, like for the rudder?

I drill a hole through the transom, screw in the bolt. I should apply some goop on the backside of the metal plate, should I squeeze some in the pre-drilled hole for the fastener, or cover the fastener, or what? What is the best/most effective way to keep water out from getting into the ply?

Thanks

[SimonLew]

My favorite method of sealing holes in balsa cored decks on fiberglass boats is to drill the hole oversize then fill it with thickened epoxy. (use packing tape as a dam) Once the epoxy is set drill the correct size hole in the center of the epoxy plug and the wood core is sealed for life. I would imagine the same technique will work on plywood. I am planning on doing this for all of the fasteners on my Goat. Maybe it's overkill but it's easy to do.

[woodeneye]

I'm thinking of not sealing my deck hatches at all. Just fit them well and fix them down with little stainless bolts and nuts? Surely not much water, if any, will get under the rim of the hatch into the hull if they're fitted well enough?

On my last boat, the deck hatches were sealed, and they used to really pop when they were unscrewed if the boat was in the sun for a while. All that pressure can't be a good thing for a wooden boat.