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new hull planking method (possibly)....long
YSTay:
You are a day late and a dollar short - look at Derek Kelsal's web site for panel construction method - if he still lists it; he's into the third iteration at this time. Hello all, I've been working alot with fibreglass lately and this idea popped into my head: Say you want to plank a hull with ply sheets, traditionally, you would cut out the strakes and fit them onto stringers. Instead of using ply, I'm thinking that I could use pre-made fibreglass sheets instead of ply. Here's the kicker; Instead of just laying up large sheets of FRP, I suspect that one could get better results from the following method ; Spray gel coat onto large flat surface. Lay up one (or however many) layers of glass. Lay the resin on really wet such that its really juicy. Then place a layer of core mat (spongy core material used to add stiffness) onto juicy laminate. Gently press into laminate such that the core mat takes some of the resin. Let cure. You should now have a large laminate with hard gel coat on one side and raw, untouched core mat on the other. This will be very floppy, which is the general idea. Now cut the required shapes out of this laminate. This is easily done with a sabre saw or even double action shears. Install onto stringers with gel coat facing outwards. Then lay up lay up on the inside with FRP. You will end up with a very stiff hull because of the sandwich construction. I've done this on small flat sided boxes and had good success. Maybe some one would like to take this on? Pro's: Good where quality ply is not available or too expensive. Cheap! None of that "woody" type issues. Pre-faired hull surface. Extreme hull stiffness Con's: Scantling issues. Possibility of resin starved areas under the core mat. Bonding of hull strakes to wooden stringers prior to interior glassing (Poly resin and wood isn't that great, so I'm told although I have evidence that it can be done). And many others, I'm sure. BTW, complaining that FRP is horrible itchy stuff is not valid! Good dust control takes care of everything. I look forward to all comments. Cheers, Arnold |
new hull planking method (possibly)....long
Hello all,
I've been working alot with fibreglass lately and this idea popped into my head: Say you want to plank a hull with ply sheets, traditionally, you would cut out the strakes and fit them onto stringers. Instead of using ply, I'm thinking that I could use pre-made fibreglass sheets instead of ply. Here's the kicker; Instead of just laying up large sheets of FRP, I suspect that one could get better results from the following method ; Spray gel coat onto large flat surface. Lay up one (or however many) layers of glass. Lay the resin on really wet such that its really juicy. Then place a layer of core mat (spongy core material used to add stiffness) onto juicy laminate. Gently press into laminate such that the core mat takes some of the resin. Let cure. You should now have a large laminate with hard gel coat on one side and raw, untouched core mat on the other. This will be very floppy, which is the general idea. Now cut the required shapes out of this laminate. This is easily done with a sabre saw or even double action shears. Install onto stringers with gel coat facing outwards. Then lay up lay up on the inside with FRP. You will end up with a very stiff hull because of the sandwich construction. I've done this on small flat sided boxes and had good success. Maybe some one would like to take this on? Pro's: Good where quality ply is not available or too expensive. Cheap! None of that "woody" type issues. Pre-faired hull surface. Extreme hull stiffness Con's: Scantling issues. Possibility of resin starved areas under the core mat. Bonding of hull strakes to wooden stringers prior to interior glassing (Poly resin and wood isn't that great, so I'm told although I have evidence that it can be done). And many others, I'm sure. BTW, complaining that FRP is horrible itchy stuff is not valid! Good dust control takes care of everything. I look forward to all comments. Cheers, Arnold |
new hull planking method (possibly)....long
In "New Plywood Boats" TF Jones gives details of building a Dobbler 16 that way. He sells plans for the Dobbler 16 on his website at www.jonesboats.com. The boat is normally built of plywood. "YSTay" ) writes: Hello all, I've been working alot with fibreglass lately and this idea popped into my head: Say you want to plank a hull with ply sheets, traditionally, you would cut out the strakes and fit them onto stringers. Instead of using ply, I'm thinking that I could use pre-made fibreglass sheets instead of ply. Here's the kicker; Instead of just laying up large sheets of FRP, I suspect that one could get better results from the following method ; Spray gel coat onto large flat surface. Lay up one (or however many) layers of glass. Lay the resin on really wet such that its really juicy. Then place a layer of core mat (spongy core material used to add stiffness) onto juicy laminate. Gently press into laminate such that the core mat takes some of the resin. Let cure. You should now have a large laminate with hard gel coat on one side and raw, untouched core mat on the other. This will be very floppy, which is the general idea. Now cut the required shapes out of this laminate. This is easily done with a sabre saw or even double action shears. Install onto stringers with gel coat facing outwards. Then lay up lay up on the inside with FRP. You will end up with a very stiff hull because of the sandwich construction. I've done this on small flat sided boxes and had good success. Maybe some one would like to take this on? Pro's: Good where quality ply is not available or too expensive. Cheap! None of that "woody" type issues. Pre-faired hull surface. Extreme hull stiffness Con's: Scantling issues. Possibility of resin starved areas under the core mat. Bonding of hull strakes to wooden stringers prior to interior glassing (Poly resin and wood isn't that great, so I'm told although I have evidence that it can be done). And many others, I'm sure. BTW, complaining that FRP is horrible itchy stuff is not valid! Good dust control takes care of everything. I look forward to all comments. Cheers, Arnold -- ------------------------------------------------------------------------------ William R Watt National Capital FreeNet Ottawa's free community network homepage: www.ncf.ca/~ag384/top.htm warning: non-FreeNet email must have "notspam" in subject or it's returned |
new hull planking method (possibly)....long
I suggest some experimentation.
Make up test panels of the fiberglass layup you described and a panel of the plywood of your choice. Compare them for weight, stiffness and cost. I suspect that, for a given weight, the FRP will be much less stiff than the ply. Let us know the results. YSTay wrote: Hello all, I've been working alot with fibreglass lately and this idea popped into my head: Say you want to plank a hull with ply sheets, traditionally, you would cut out the strakes and fit them onto stringers. Instead of using ply, I'm thinking that I could use pre-made fibreglass sheets instead of ply. Here's the kicker; Instead of just laying up large sheets of FRP, I suspect that one could get better results from the following method ; Spray gel coat onto large flat surface. Lay up one (or however many) layers of glass. Lay the resin on really wet such that its really juicy. Then place a layer of core mat (spongy core material used to add stiffness) onto juicy laminate. Gently press into laminate such that the core mat takes some of the resin. Let cure. You should now have a large laminate with hard gel coat on one side and raw, untouched core mat on the other. This will be very floppy, which is the general idea. Now cut the required shapes out of this laminate. This is easily done with a sabre saw or even double action shears. Install onto stringers with gel coat facing outwards. Then lay up lay up on the inside with FRP. You will end up with a very stiff hull because of the sandwich construction. I've done this on small flat sided boxes and had good success. Maybe some one would like to take this on? Pro's: Good where quality ply is not available or too expensive. Cheap! None of that "woody" type issues. Pre-faired hull surface. Extreme hull stiffness Con's: Scantling issues. Possibility of resin starved areas under the core mat. Bonding of hull strakes to wooden stringers prior to interior glassing (Poly resin and wood isn't that great, so I'm told although I have evidence that it can be done). And many others, I'm sure. BTW, complaining that FRP is horrible itchy stuff is not valid! Good dust control takes care of everything. I look forward to all comments. Cheers, Arnold |
new hull planking method (possibly)....long
Interesting. I'd be concerned about the sandwich properties though.
Bare with me as I think "outloud". I'm certaintly not the expert so I'll try to keep my reasoning general. In sanwich construction, the skins are supposed to work together to offset tension and compression in the sandwich. By building the panels flat and then bending them, you're placing the outer skin in tension already. It seems like you'd lose some of the benefits. Someone help me. Am I comparing apples and oranges? -- Matt Langenfeld JEM Watercraft http://jemwatercraft.com YSTay wrote: Hello all, I've been working alot with fibreglass lately and this idea popped into my head: Say you want to plank a hull with ply sheets, traditionally, you would cut out the strakes and fit them onto stringers. Instead of using ply, I'm thinking that I could use pre-made fibreglass sheets instead of ply. Here's the kicker; Instead of just laying up large sheets of FRP, I suspect that one could get better results from the following method ; Spray gel coat onto large flat surface. Lay up one (or however many) layers of glass. Lay the resin on really wet such that its really juicy. Then place a layer of core mat (spongy core material used to add stiffness) onto juicy laminate. Gently press into laminate such that the core mat takes some of the resin. Let cure. You should now have a large laminate with hard gel coat on one side and raw, untouched core mat on the other. This will be very floppy, which is the general idea. Now cut the required shapes out of this laminate. This is easily done with a sabre saw or even double action shears. Install onto stringers with gel coat facing outwards. Then lay up lay up on the inside with FRP. You will end up with a very stiff hull because of the sandwich construction. I've done this on small flat sided boxes and had good success. Maybe some one would like to take this on? Pro's: Good where quality ply is not available or too expensive. Cheap! None of that "woody" type issues. Pre-faired hull surface. Extreme hull stiffness Con's: Scantling issues. Possibility of resin starved areas under the core mat. Bonding of hull strakes to wooden stringers prior to interior glassing (Poly resin and wood isn't that great, so I'm told although I have evidence that it can be done). And many others, I'm sure. BTW, complaining that FRP is horrible itchy stuff is not valid! Good dust control takes care of everything. I look forward to all comments. Cheers, Arnold |
new hull planking method (possibly)....long
On Fri, 30 Jul 2004 00:27:05 GMT, Matt Langenfeld
wrote: In sanwich construction, the skins are supposed to work together to offset tension and compression in the sandwich. By building the panels flat and then bending them, you're placing the outer skin in tension already. It seems like you'd lose some of the benefits. Someone help me. Am I comparing apples and oranges? ========================================== I think that the proposal was to build a "single skin" laminate, bend it into place, and then add the inner skin as a last step. Could be wrong, but that's how I interpreted it. |
new hull planking method (possibly)....long
YSTay wrote: Hello all, I've been working alot with fibreglass lately and this idea popped into my head: Say you want to plank a hull with ply sheets, traditionally, you would cut out the strakes and fit them onto stringers. Instead of using ply, I'm thinking that I could use pre-made fibreglass sheets instead of ply. Here's the kicker; Instead of just laying up large sheets of FRP, I suspect that one could get better results from the following method ; Sounds a bit like: http://www.glen-l.com/supplies/cflex.html Dale |
new hull planking method (possibly)....long
Hello all,
Sure seems that there's never anything new under the sun! No worries that this has been done before. I just thought I might put this out there and create some discourse. Who knows where it may lead. Anyway, cheers, Arnold |
new hull planking method (possibly)....long
On Thu, 29 Jul 2004 21:54:32 +0800, "YSTay"
vaguely proposed a theory .......and in reply I say!: remove ns from my header address to reply via email Speak for yourself. I would need _perfect_ dust control. BTW, complaining that FRP is horrible itchy stuff is not valid! Good dust control takes care of everything. I look forward to all comments. Cheers, Arnold ************************************************** *** It's not the milk and honey we hate. It's having it rammed down our throats. |
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