using existing hull as mold?

[JEM]

Originally Posted by Rippin Lips

i was thinking about buying a design kit from bateau.com. their smaller designs are for beginners but all of them look really good and they have many different styles.

Carefull with this. If you're doing this just for your own boat and want to try a "one off" (the term for what you want to do) then you'd be just fine.

But if you want to sell these, then bateau will probably want a fee for each hull you sell.

Plywood building via Stitch and Glue is a nice technique to get a hull for your own personal use. But building a design meant to be a plywood hull and using it for a plug is a bad idea. I know because I did it by designing and building the prototype for www.tailboats.com. We originally set out for it just to be a plywood and fiberglass prototype hull for testing. Then we were going to build a second hull to be used as a plug.

Well to be honest, I grossly underestimated the time it would take. The design was complex and some modificatins were made after the initial testing too. Tailboats needed to get their hull to market so no time to build a second plug. We cleaned up the original prototype and took it a local fiberglass shop that will do the finishing work and pull the molds. It turned out very nice but a lot of hours and sweat went into it going that route.

Quite a hard learning experience but I'm well schooled if I do that sort of project again.

Anyway back to my original train of thought. I say build something stitch and glue to get the experience of building. That will give you a good indication if you want to try your luck at building a plug. You'll gain some good insight and the quality of your second project will be that much better. Then if you want to build a plug, get with a designer and tell them you want to build a plug.

If the designer is worth their salt, then they will provide a method and design that can be built to ensure the hull is fair and symetrical. You could strip build with a strongback or a Stitch and Glue with a strong back will provide the most accurate results.

Other option is to have a plug 5-axis CNC cut from foam. The cheapest I've found for a smaller hull is about $5k. And that's just for milling. You still have to sand and finish to be ready to pull molds.

Good luck!

[Rippin Lips]

excuse me if i didnt remeber you gfinish, i didnt recognize the name. the only one i have ever talked to about building a mold was a person by the name of blackhawk or something like that.....dont attack me! i'm new at this and i have never, ever built a boat before so i use this site as a discovery tool. i publicly question others because your reply to to my queries are very short and not descriptive. dont get me wrong, i appreciate the answers you did give me but because i ask a little more in the forums to get a straight answer is no reason bash me in your first post. once again, i know nothing thats why i seek advice. that's all i came to this forum for and i thought that this forum was all about helping the unknowing and for this other guy down here to say to just tell me to do it is not what ive come to expect out of a help forum. i'll keep in mind not to ask you 2 for any advice.....

SLAPPY.

[Rippin Lips]

i do appreciate your advice also. i've done some research on mold building since the last time i was here and have come to realize that it is definately NOT the route i want to go. ive recently ordered the plans and precuts for an 18' dory which is very similar to the boat i really would like to build (panga) from bateau.com. it looks very tailored to the new and i look forward to starting my project. upon completion i still do hope to find a panga mold ( and not build one) so i can learn to build that way too.....once again thanks alot.

[solrac]

May you guys use this homemade method:
1. polish & wax the original hull
2. Newspapers, old newspapers, a lot of them & a pot of vaseline (not for that you're thinking, you freaks). the idea is to make a thin foil of paper (3 to 4 papers thick). let it dry overnight
3, get some metal wire, the type used for fences,(chicken mesh) some construction reinforcement iron bars & stick them to form a kind of a skin.
4. Concrete or plaster about 2.5 to 5cm (1" to 2") to cover all the stuff
let it complete drying process (depending on weather/temp, a couple of days to a week)
5. Now it came the real work, let's turn the monster upside down. get help, a lot of help, (even a crane or a hydrolift the concrete mold weights about 12/15kg/m2, a 3.70 laser hull mold is about 100kg, not recomended for a 30" sailboat) Caution: keep children away & think twice while planning the manoeuver...
6. with a reasonable long wood stick & a piece of rope, tie to some hanger in the hull & softly try to unmold the original hull, (I grant, it's not so dificult, don't be scared, it pops out really easy, the newspaper & vaseline are gorgeous)
So, you ended with a mold very similar to the original hull, in case any break, can easily fix with some plaster & sanding....
For making a new hull on the mold, follow the same process inversely, sand & clean the mold, fix w/plaster any hole, apply newspaper& vaseline, and you're ready to glue the epoxi.
I've been using this method for 20 years...
good luck

[Rippin Lips]

wow Solrec, didnt know this thread was still read. thanks for the tip. I'll give it a try on a small skiff.

[MrBlack]

Rippin Lips IM very sorry to read this thread and to hear/read the anal idiots reply in the way they did.
If you take another boat and copy it fine do it and learn from it as the boat will probably be vry average.
If its very good and your lucky then great.
Im sure these anal people do not think twice when downloading mp3's.
gfinishline if someone wants to pm you then ask more questions else where so what?
That means they are seeking more infomation which is a good thing.
Oh and you tell no one nothing you inform.
Get over yourselves who the f do you think you are.

[MrBlack]

im SERIOUSLY cheesed off as i printed this trash out thinking I was going to get some quality insight.
What a waste of time.

[Rippin Lips]

im just a newbie trying to find out how this is done, i am NOT trying to copy a boat, i am not trying to build to sell. just wanna learn so i can eventually build one of my own. i just came back to look around for anything new, my brother and i are entered into a contest to build a boat in 4hrs during harbor days just for fun to see who can make it across the harbor and back. I feel that could be a start.

i DO wanna learn and still seek a step by step tutorial if at all possible, thanks for the replies.

[MrBlack]

Good luck to you matey I wish you well in your dream.

[solrac]

Hey.... nobody is talking about infringing copiright laws, this metod was applied by me a couple of times for repair purposes only....we used to think it's easier to make a new hull for an optimist or laser that was hardly broken by the kids at a regatta than trying to repair it. the hulls already made with this method were mostly used for kid sailing at a sail club here....
I also used this method once on a development of a homemade hull, because it's esayly modifiable...

[solrac]

Originally Posted by MrBlack

Rippin Lips IM very sorry to read this thread and to hear/read the anal idiots reply in the way they did.
If you take another boat and copy it fine do it and learn from it as the boat will probably be vry average.
If its very good and your lucky then great.
Im sure these anal people do not think twice when downloading mp3's.
gfinishline if someone wants to pm you then ask more questions else where so what?
That means they are seeking more infomation which is a good thing.
Oh and you tell no one nothing you inform.
Get over yourselves who the f do you think you are.

Oops, kid, have you argued with your boyfrend?
No need to be so rough, someone asked for a method & I answered that's all.
Of course, the results are average, as you stated but the hulls I've done in the past with this method were for training purpses only, they can't compete with vacuum molding, but the "average" hulls were not too bad....