Ok guys and girls, I’m about to start building sum hull plugs/molds. Anyone with any info that can save me sum hardship that would be great. So if you have any info/picks that could help me I would appreciate it very much
Start here
http://www.usaca.info/index.php?option=com_content&view=article&id=476:new-a-cat-design-racer-x-is-back&catid=67:icon&Itemid=122
Tony's A Cat
awesome that's a good start!!!! thx
You might as well asked for a manual on world peace! It's a tricky, artful process to make molds on this scale on a normal person budget. I've made a few on a considerably smaller scale and you can see some of it here (you have to read from the bottom up since the posts are chronological).
http:/
If I were doing it and intending to build only one boat, I would consider using a strip foam planking method like Ian did on his LR series of a-cats. The process would be the same for you - only the number of layers of fiber would need to increase and you probably need a little more structure in the hulls (including a sub-deck to help with spinnaker and forestay loads). I can't help with the exact lamination schedule but perhaps the Man Shed can shed some light relative to the trimaran he's building.
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Plugs and molds....are you starting production as opposed to a one off?
we are thinking production but are not even close yet.
Hobie, Micky, and Phil started with two surfboard blanks. Hobie Alter shaped the original Hobie 14 by eye and simple tools.
CAD programs suffice for now <img src="<>/smile.gif" alt="smile" title="smile" height="15" width="15" />
haha I hear u <img src="<>/smile.gif" alt="smile" title="smile" height="15" width="15" />
ok who did the design? Do you have renderings?
What you making?
2 cats a f16 and also a open20
So you want a couple of prototypes before tooling up for a production
Thermoform foam [Corecell/airex] in female formers, skin the inside, fit bulkheads, pull from formers, join the halves and then laminate the outside. Fill, fair and paint
Sail it, then if you are happy with it - you have a plug for production molds.
yea that's about what i was planing on. Guess im heading in the right direction.
Why not an F-18 too?
dead class......
Just kidding, wanted to jerk Dave's chain. <img src="<>/laugh.gif" alt="laugh" title="laugh" height="15" width="15" />
He's probably worried that he wont be able to make the boat heavy enough.
🙂
Worked with a guy we called
spoon
, for good reason.
who has a good lead to foam core strips?
Buy sheets, rip the strips on the table saw, and use a router table to machine a radiused bull-nose on one edge and matching relief in the other side. This way they will pivot inside each other to reduce the amount of fairing you need to do and will increase the glued surface area.
anyone building a Farrier trimaran - start at f-boat.com
How squishy is the foam? I'm just thinking about ways to do it, and if you set it up in a shaper you could have a powerfeed and keep things consistent for width and finish of the cut.
it's fairly rigid. If you were to hold a 1.5
x 1.5
x 8 foot from one end, it probably wouldn't flex 2 inches on the extreme end. It machines like butter.
Check this thread lot of good stuff.
http:/
A tip for one off customs. Have paper templates of what you want the core to look like between the female forms so you can make sure what you just built, matches what you designed(you may need templates for the form too, depending on what technique you use). Having the ability to make additional templates at 2AM, when things start looking odd and you need to check places you don't have templates for, helps. Some CAD programs can put alignment marks on 8.5x11 paper so you can tape them together to make big drawings.
The issue is, core strips don't usually bend the way the CAD curve-fit
bends
. Sometimes the strips don't lay up perfectly on a form. Curve-fits have assumptions that physically translates into compression or tension on the strips between female forms. If you create a curve-fit that assumes no tension or compression on the strip at the forms, friction on the real strip produces compression and tension. You can minimize this by using a curve-fit that approximates your strips and by making a CAD drawing of a strip built core but there are a lot of variables in assembly. If you make a CAD drawing of the strips, the CAD can give you measurements from one end of the core strip, to where the female forms touch that strip. You can measure and mark the strip so you can check to see the strip lays in the female forms they way it should. ALL of this is a pain in the butt but it beats discovering your hulls are different and having to build a third one, to match one of the first 2.
For boats built from good plans, this all been sorted out.
I don't want to start a discussion on merits of materials but you can use cedar instead of foam. Depending on where you are, there can be a huge price difference between foam and cedar and you will need less material in the laminate. Cut the strips out of 1-3
thick planks.
Wood battens, were used for
curve fits" once a upon a time. I read a article last year about simulating wood batten curves with CAD curve-fits. This went a long way toward explaining why I had such a bi**h of a time getting the real world to match what I created on a computer.
I like it im getting lots of great info and I appreciate all of it, you guys rock
Assume 64 sq. ft. area for an A-Class cat hull.
5.3#/cu.ft.foam (3/8
thick) equals 10.6 lb. and cost for material and labor cutting strips is $370.
21.2#/cu.ft. white cedar (1/4
thick) equals 28.26 lb. and cost is $512.
What would an an appropriate amount if Nomex cost?
Nomex needs to go into a mold
thick) equals 28.26 lb. and cost is $512.
1/4
(8mm)white ceder with 2 oz glass on each side and some reinforcement on the inside would make a very strong hull.
8mm of white ceder is roughly/sorta/depending the equivalent of 2mm bidirectional carbon
I would probably use 3mm or 2mm as a core
I think im going with Core-cell, for the prototype boat. will make changes in production boats if need be.