Mark Pearse
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Lovely work; & it's interesting to see again just how elegant the hull shape is. -
Hi Frank, is there something to stop the mainsail halyard from getting in the way of the boom jaws (when the sail is up)? It looks like when the boom rotates, the jaws will push on the halyard -
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Hi Keith what was the tool you used for sanding the moulds? Also, a comment: what an amazing hull, & it's one of the pleasures of a model to be able to see the whole - especially when you probably can't really see the whole on such a large yacht. Also interesting how far aft the keel is, when you include how the bowsprit will make the sailplan even further forwards.
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Hi Keith, it is the same stuff, in medium weight. In his youtube videos, Tom Lauria who's using it as single thickness for a 1:48 model of a small cat boat, about 20 foot. The technique he shows really transforms the tissueyness of it, but I needed to beef it up even more. I decided to double the silkspan to then use that as a base material; I laid out one layer of silkspan on a flat surface &, using a 100mm sponge roller, rolled on acrylic house paint (matt finish) with about 20% standard PVA mixed in. I did this in strips across the sheet, about 150mm wide, & then quickly laid (& burnished) a second sheet of silkspan onto the wet part of the surface. Then painted another strip, etc. After the whole thing was beyond sticky I then painted one side with a good coat of the same paint/PVA mix, & when that was handleable I did the other side & then suspended it to dry for a day or two - (not worrying about it not being dead flat, photo somewhere above). This was the base material for me. The sail tack was one thickness of the above, with 3 reinforcing pieces each side (each cut from the same stuff), layered on top of each other, plus the edge tape (same stuff), overlapped at the corner. So it's the same technique as Tom's, but once I started fiddling it was clear that what would suit a 1:48 model of a small yacht wouldn't suit a 1:12 scale model of a medium sized yacht. I emailed Tom & he very generously gave some advice that helped a lot - as described above (the reinforcing pieces building up so much was my addition). So, the good news is that as a product & technique, it's quite adaptable. Unfortunately it doesn't suit my original idea of formed sails (at the scale & model size I'm doing, & with the amount of curvature I wanted in the sails). The ironing it really works well & fast, & I found that using the iron - without steam - at a 'wool/silk' setting, & the water/PVA was about 40/60 ratio. This part probably won't make sense if you haven't seen the videos. Hopefully this gives a good visual picture. At the risk of being repetitious, I'm amazed but how much it feels & bends like heavy dacron, even the sound. But if you were going to show the sails flaked, or rolled, or furled etc...my sails would possibly not work, probably a bit thick. Testing required.
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thanks all the jib is now pretty much done. The main cringles at the tack, clew & head were drilled by pre-drilling a piece of 1.5mm styrene to the final size (3mm), then using that as a guide, & the holes through the sails stayed sharp. I experimented with replicating eyelets, by adding some black oxide to PVA glue & using a toothpick to line it on a drilled hole...but it didn't work. The tinted glue is excellent but the technique is difficult to get even, so I will just leave them plain. Better to not draw unnecessary attention to them. There's possibly an error in my setout below, but I'm not sure & will accept it as is: you can't see the point at which the setout seams meet - I set out the seams to the edge of the sails, not to the edge tape seam, which is 3mm inside the sail edge. It would look better, & possibly be correct, to have allowed for the edge tape thickness in the setout. You can see here how thick the corners are, which is fairly scale-correct.Each piece of Silkspan was doubled, & there's 11 thicknesses of that. I think that the material is quite strong & won't be at risk of tearing unless there's a major accident. The whole thing had 2 coats each side of turps based matt clear polyurethane finish, hopefully t won't yellow significantly over time. I considered treating the edges with the same, or paint, or something else - but with a clean cut edge, & the mass off silkspan/acrylic paint/PVA glue is quite well bonded into a mass, it doesn't seem to need anything.
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HI Michael, Many thanks for the description. What is the forward-facing central light? (I can only think it's an occasional white light, for visibility assistance when approaching a mooring or jetty after dark)
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thanks everyone. Hi Carl, yes, it is 6H not 6B. It works well when nice & sharp, & the paint surface is slightly abrasive.
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The sails are looking good, not finished but the effect of this technique suits the 1:12 scale well. The technique is fascinating, & the hot ironing of the strips details (with diluted PVA painted on) works quickly & easily. See Tom Lauria's YouTube videos on silkspan sails. The seams are done with a 6H pencil, & I've given the jib two coats each side with a matt finish clear polyurethane coat. I think it will help with durability & cleaning, & I like the feel. All in all, they really do feel like scaled dacron. Here is the jib, it's now a non-overlapping jib, a #3. The mainsail, still going. Th stiffening effect of the reinforcing patches is also very lifelike, & although I wasn't going to put battens on the jib, I did put a few because I think it's worth it to ensure it doesn't curl at the leech. The battens are short, to suit the 1960s period. You can also see that the pencil lines are a little uneven, I like this effect also, & I like the slight scuffs & marks you get from moving the sail from one spot to another while you work - they have a realistic look to me. A sail is usually quite marked, creased & with bits of dirt & stains - so I'm not trying too hard to keep it perfect. Also, the seams are usually not perfectly even in visibility, & the slight varying weight of the pencil lines seems to match this. I used pencil lines on the edges of the reinforcing patches. There's a lot of thicknesses of silkspan at this corner, & it feels 'right'. The edges of the sail have a strip guide on each side all the way around. I'll trim them to size somewhere on the strip.
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Hi Michael, regarding the stability stiffness, do you know if the hull is ballasted?
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Hi Samson thank you for posting it, the model looks lovely & captures the beautiful aesthetic balance of the design. I have never seen a Junior Folkboat but have admired them since I became aware of the design. There's quite a few International FBs in Sydney, but I doubt there are any 'Juniors', we race against the Internationals quite often. Mark
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Keith that is a long hull, & what you can see of the lines are interesting. The rig is going to be dramatic indeed.
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Hi Druxey - yes, staggering the joints is what I was thinking of, just thinking with some degree of trepidation. handling wet silkspan makes me feel like a 3 year old trying to handle household plastic wrap - you just know disaster is lurking. The Silkspan obviously has some ability to do compound curves, but not as much as I thought. The work area - I prep sanded lumps etc off the ply. The overlaps were done on opposite ends & a spot of CA glue to help sheet alignment. Once two sheets of Silkspan are painted & against each other it's quite difficult to move one without making a mess of it. I mixed acrylic paint plus about 10-15% plain PVA, painted this on one side of the first sheet in strips & quickly laid the second sheet on it before it had started to dry (it's been warm here). Then painted the top of the second sheet, & after about 5 mins I could turn it over & do the same on the other side. Then hung it up to dry. The colour is whiter than the previous sample, a creamy white with just a tiny dot of black to stop it being yellow. Then the other one (jib). I'm happy with the effect: the colour, texture, weight & feel are all good. This is one of the joints, not bad. I even like the wrinkles - they look like the wrinkles in dacron. It's not what I was imagining 3 weeks ago, but I'm pleased. Next is string up the sail sea, adding reinforcing latches, cringles, sail numbers.
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thanks, that's better: it's interesting to see the rig changes in between the 1926 & 1933 designs - the headsail is very small initially
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the curved roach of the mainsail balances the curves of the hull beautifully; such a good looking boat would you be able to post a link to the website that has the original drawings?
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The curved form is great but I should have experimented with the Silkspan first. It really doesn't want to form a 2-way curved shape, or at least not one as curved as this is - but it does look & feel good. The process was: I painted some small sheets using flat acrylic paint in an off white colour, & after they had dried I laminated 3 layers using standard PVA diluted with about 20% water - with a small roller to apply the glue. It's quite difficult to laminate a second or third sheet when it's all on a curved surface, the wrinkles form because the curves are too great. The wrinkles aren't bad at all, a real dacron sail is quite wrinkled if it's had some work, but it remains flexible enough to not retain the curved shape. As an experiment I also gave both sides a couple of coats of a matt spray polyurethane based clear varnish, each time laying it back on the form to dry...no good. It yellowed a bit & didn't stiffen it up. One useful conclusion is that 3 layers of Silkspan is probably too thick, but 2 layers feels good, you can see a corner where I pulled the outer layer back. The videos I watched were for 1:48 models & this is 1:12, so really that's 16x the size. Good news is the 6H pencil lines are nice, & I think that if I tone some glue with grey paint I can do sail cringles by putting a blob on the sail & drilling or punching the centre out. So, I'll likely use a double thickness of Silkspan, laid flat. If it doesn't go well or if it's just too big to have up, then I can still furl the sails - the mainsail is a little taller than a 36" Silkspan sheet. The family might have something to say about it.....
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The dynel & fibreglass went well. At the time it appeared to be going very badly, the dynel needs a lot more edge support than the poly/cotton does. At the time it appeared that only the parts bounded by the timber sticks were going to work out, but I used pieces of string & lots of clothes pegs to pull the loose edge (the sail's leech in this case). The brown is beach sand, & it appears that the Dynel kept sagging a bit after I'd done it, the bagginess is just a little too much, so I'll adjust in the way the jib is shaped. Good news is that I reckon I can use this form for the jib as well. The photos don't fully show the shape, it's more even that it appears. I'm now doing a test of Silkspan as a sail - the Tom Lauria videos on youtube were extremely helpful. I emailed Tom via his website & he was kind enough to answer & give guidance. The videos show a 1:48 sail, using a single thickness of Silkspan. I am testing doing a triple thickness: the outside face of the outside sheets being painted, seams drawn in pencil, reinforcing patches & battens etc. Then lay them up on the form using diluted PVA as a bonding & stiffening agent. It will also tell me if the minor irregularities that are still visible on the form will matter or not. thanks
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Hi GL that's very nice. Are you planning to finish the hull? Mark
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Hi Keith, looks lovely already Do you know how they manoeuvred the top staysail & topsail when going about?
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Hi Roger initially I did do that, but it was still very flexible. If the cloth was to be the actual sail that might be fine, but the plan is to build up a Silkspan sail over a curved form. It looks that the Silkspan part won't be as difficult as making the form. I think the reason it wasn't stiffer is that polyester/cotton mix of the fabric has poor tensile rigidity - my guess is that resin & fibreglass is rigid because the components are fairly rigid in compression & tension. The Dynel is a quite an open weave, so a test will see how well it holds the thicker epoxy. As part of the test I'll probably do part of it with a piece of fibreglass cloth on top & see both how rigid that is & how well the two together hold the resin.
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thanks for the assistance & suggestions. Keith, you'll be horrified that I had to use the www to find out what splicing the mainbrace means. Not always helpful, but a timely glass can help with thinking sometimes. I saturated the fabric with Everdure epoxy & laid on top some fibreglass tape that I had, then added more epoxy. Initially I was disappointed with the results, but in separating what worked from what hasn't I think I can get it to work. These things didn't go to plan: Everdure is too thin for this job, a more standard thickness epoxy would work better; the fabric is rippled on the underside (the face side of the form), I think because the cotton blend fabric stretched & the glass fabric doesn't. The Everdure has soaked right through the fabrics & didn't get held in the fibreglass, so the layer of fibreglass didn't't really bond too the fabric below. What I'm thinking is to use Dynel fabric for the lower layer & a sheet of fibreglass on top, then some thicker runny epoxy, applied with a brush. Possibly I'll do a small test to see if I need to put a sheet of plastic film below the Dynel. The good side is: the sail shape is very nice, this view is as if looking up at the sail & the twist at about the throat height looks good to my eye. You can see how the fibreglass hasn't bonded. thanks
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