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Spindrift 11N build in Scotland


Aphers

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Your boat is looking great.

 

I believe it is the isocyanates present in aliphatic polyurethanes that make it particularly hazardous to apply. I did not see isocyanates listed in the data sheet for your sml 2 pack paint. I am not an expert in paint chemistry, perhaps someone with more knowledge of these paints will weigh in. 

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Well I couldn't put it off any longer and last night cut the slot for the daggerboard. Just as daunting as when I sawed it in half- it feels so wrong to take a good solid structure and take a power tool to it!

I used an oscillating multi-tool which was perfect for the job, no breakout and a nice neat cut.

My building platform yet again proved itself useful. I can sit the boat up on its side; the slots for the keel in each cradle are also the right size for the gunwhale. The boat balances perfectly like this, but a couple of clamps help guard against an an accidental knock. Being able to easily work on both the inside and outside was very handy when making the cut for the slot, and put everything at a convenient height without having to climb into the boat.

 

You'll see in the close up photo of the slot that I have strips of plastic between the hull halves. I have filled up to these with micro-fibres, to help create a sharper edge on top of the taped seam, which of necessity is rounded off. This should give a seamless joint between the hull halves.

 

s11n on side.jpg

s11n cbd slot.jpg

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I have had some success removing (minimizing) runs and curtains by using a cabinet scrapper. Best done when the epoxy is hard enough but not to hard. Sandpaper is  inclined to get the surface smooth but not necessarily flat. Best is not to leave the runs in the first place. Force yourself to apply the epoxy as thin as possible, but epoxy can be a little diabolical, waiting patiently until you are tired and have turned in for the evening to creep into a line or lump. Do as well as you can but, remember it is a boat and at some point it will not be in your living room. 

 

Speaking of which is your workshop connected to your living area. I looked again and did find isocyanates in your 2 pack paint. and the solvents like xylene are quite strong. I don't think you need to be concerned about odors being absorbed into the walls, but the boat will have a strong odor for at least a day or so. Do the paint mixing in an area of maximum ventilation, get brushes, rags, unused paint outside as soon as possible. Keep the little one away and good luck.

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On 3/13/2021 at 8:54 AM, Joe Anderson said:

 I looked again and did find isocyanates in your 2 pack paint. and the solvents like xylene are quite strong. 

Isocyanates are the biggest issue with 2 part solvent based LPUs.  It is a carcinogen and is not removed by organic cartridge ventilators. Rolling and tipping puts far less into the air than spraying, which atomizes the paint. Professional painters wears suits and breath supplied air.  This is the only known way to prevent breathing isocyanates. Is painting a boat or two without supplied air and only some ventilation safe? I don't think any of us are qualified to answer that. I will not use solvent based LPUs as I don't have the equipment necessary to assure safety. Xlene is a carcinogen as well, but is removed by organic vapor cartridge resperators. Xylene is a great solvent, but I find no real need for it and therefore do not use it.

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So... I wanted to tape the edges of the centreboard slot. For whatever reason, I just couldn't get the tape to lie flat, and ended up removing it before it cured. That was the last of my second 50m roll; I'm looking at about a week delay to get any more.

 

I think the problem was probably that I didn't put enough of a radius on the edge of the slot. It's a very fiddly little job, and I don't think the instructions specifically said it was necessary- did anybody else try taping here, and is it ok to just move on without doing it?

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Aphers I had planned to fill and fair the inside of the trunk. I don't think taping inside there would be needed for strength. Also if it comes out rough it could bugger up the dagger board. If Graham and Alan say do it I guess I will have to rethink my idea.

 

 

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When building Spindrift hull #1 I wasn't happy with my job of taping the outside of the trunk and pulled it out and decided to see how long it would last and I have not taped the outside of a small daggerboard trunk since. I have been fighting my desire for perfection and productivity all of my life. So far I have never had or heard of a failure. I long ago sold hull #1 but I do have a S12 which is about 20 years old and I have  Amanda hull #1 which must be about 10 years old. Also on our racing Spindrifts we shaped the bottom slot to fit the foil to reduce turbulence which would made it very difficult to glass around the overhanging lip fore and aft.

 

Chick and Don are absolutely right that taping the outside of the trunk is superior. To help the joint I use a larger fillet and double glass the inside, this is still not as strong as taping both sides. It just shows how amazing epoxy joints are.

 

If your perfectionist side wins out and you want to glass the outside of the trunk make sure that there is at least a 1/4" round over that is smooth and go down a couple of weights in glass to 6 oz. which lays around corners better and will not reduce the width of the slot very much.

 

I do glass the slot on larger boats where there is more room.

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I did not glass over the corner into the trunk on my Spindrift. It is 16 years old and no sign of any issues.  I did do it on my Lapwing.  I rounded the corner as described above and had no issues.  I had some tedious sanding to do on my Lapwing to get the board to fit. I think I will make a rebate as Don describes if I do it again. I hate sanding, especially if it can be avoided by some other technique.

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Well before reading Graham's reply I had already prepped the area, sanding back and putting a bit of a radius on it. So I decided to bash ahead and have a second go at taping it.

Given how badly my first attempt went, I didn't want to take any chances. I made up a set of formers to hold the tape in position- two plastic wrapped pieces of ply for inside the slot, held in place with wedges, and two battens to hold down the other edges against the bottom of the hull. Securing these took a lot of messing about with clamps and straps.

With everything set, I applied the wetted out tape... and it just stayed nicely where I wanted it, no signs of it trying to lift or for any bubbles to form.

So I didn't bother with all the battens, clamps, etc etc, as that would just have disturbed it.

Ah well, no doubt if I hadn't gone to the effort, it wouldn't have wanted to stay in place!

16160918513958624764144946038602.jpg

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I used flat battens covered in wax paper wedged in as you describe, to put a sharper corner back on after taping.  The batten worked like one side of a mold to keep the goo out of the slot. It ended up giving that side of the fill a finish that only needed sanding. And then dull the sharp corner with a small radius by sanding.

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I feel like I'm very close to opening the paint tin now. Still some final sanding to do, and a couple of places that would benefit from a bit more epoxy. The underside of the gunwhales being the worst culprit.

 

Maybe I should make the cut-outs for the self bailers now, so that I can epoxy seal the edges? Rather than doing it after painting?

Anything else I am best off doing prior to painting?

 

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I cut the holes and pre-drilled the screw holes for the bailer and epoxied the edges before I painted the hull. I also rounded off the edges a little to make the water drain a little easier. it looks really good.

 

The one issue I had cutting the holes was all the interference from the centerboard trunk, the keel strip, etc etc etc. I had to do the cut from the outside of the hull to have enough room for the skillsaw.

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Aphers, I'm also in Scotland and hoping to build a Spindrift 10N. I see you got your plywood and timber from Robbins. I wonder where you got your epoxy and fibreglass tape. The materials list calls for 3” X 10 oz silene treated fibreglass tape (75mm X 350gsm). I can't find tape of that weight on any website in the UK. The only source seems to be B and B Yachts in the USA. Can you tell me where you got your tape please - and indeed your epoxy?

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