anyone made a fiberglass hull mold?

[steelhead]

Has anyone made thier own fiberglas hull mold for pulling glass hulls from?
Im trying to figure out how to make the symmetrical hull without a cnc machine

Dean

[The Enemy]

Steelhead,

All I know is that you start out by making all the formers and backbone such as you would a regular boat (for one hull). Plank it, sand it, (all as you would a regular boat)..... But then you use that as your beginning for a mold. From there I am unclear on what exactly you make the mold itself out of. (fiberglass?) But it should be enough to get you started. Maybe someone with more knowledge on the subject could take over from here.

Enemy

[Far4nugn]

I've been entertaining the notion of trying it for the FIRST TIME... I will probably go about it this way... Not sure its the best/fastest/cheapest way to do it, but you gotta learn somehow...

I would:
-Build a positive (plug) hull using frames and sheet or plank it
-Fair it well
-Coat in epoxy or varnish maybe (?) Or cover with Monokote
-Coat with wax numerous times
-Build a box a tad larger than the LOA and Beam of the hull, and just taller than the inverted plug
-Lay up cloth and resin over the plug using fine cloth (3/4Oz?) or silkspan
-Put the plug into the box inverted and top off with plaster before the layup cures. Making sure its sitting on a level surface
-Let cure and remove the plug


This should provide a smooth, solid mold to use for future layups, as the plaster reinforcement will prevent any warping or dents by weighting the cloth layup during cure and make it easy to handle later while using the mold.

Anyone see problems with this method other than its gonna take a fair amount of plaster to backfill the box? May have to use very slow resin and a couple pours of plater

[The Enemy]

I thought this was the most straight forward idea as well. But was unsure how you would prevent cracking in the plaster itself. Maybe if you re-bar it like in concrete applications, it might do the trick.

Enemy

[Far4nugn]

I helped my ex-girlfriend with an art project for school where they had to cast a half-shoebox-sized block so she could sculpt an object out of it. They made one pour of plaster and it didnt crack. I dont know what kind of plaster it was, but I could probably find out with, ahem, enough persuasion ; ) I remember that I, too was suprised it didnt crack.

I'm now trying to settle on a design to copy or emulate. Anyone have any suggestions for a hull? I'd like to keep it short (30-36") at first to test out the process.

I plan to vacuum-bag the layup in the mold, and I'll probably end up using Sig Silkspan as the outer most layer, and two layers of 3/4Oz glass on a bias with some light carbon matting in between and carbon 'hair' around the gunwales and keel line. This is just an estimated layup that I figure will be a good compromise of strength to weight, but if someone knows better, let me know.

[The Enemy]

Far4nugn,

Just keep in mind that if carbon fiber is used in the construction, it cannot be used in 'real' competition. (or so I've been told) I built mine using CF and don't plan on racing it anyway. ;)

Enemy

[Far4nugn]

Thanks for the warning. I dont think it'll ever be used in competition.. I've only seen one R/C sailboat in operation in my 27yrs, but I know they class race EC12's on the weekends at a nearby lake.. I ought to find out if they do OM's too... if thats the case, I may adjust the layup so I can compete in the future.

So what does one make a keel out of? I was thinking 6061-T6 aluminum would be great if I can find a piece with the right dimensions... how do you attach the lead bulb to the end of it and to the hull? I would think a keel that extends clear to the underside of the deck would be ideal for strength, but may get in the way of the radio gear?

How about decking... does 1/16 birch ply sound good? How do the kits do the hull-to-deck joint?

[joeygoose]

Just a suggestion.....

http://www.fibreglast.com/products.php?session=6b5ba0fd663faee6093a523f6275a 803&area=1&PHPSESSID=6b5ba0fd663faee6093a523f6275a803

Have Fun!!
Goose

[The Enemy]

Far4nugn,
Sorry its a bit late but.....

My keel is made of a ply core, with blasa epoxied to it, and the surface is epoxied (with cloth) and then sanded.

The Keel is 2 halves, bolted to the plywood core, and the seams filled using sandable filler. (bolts sunken and holes filled with filler)

The ply sticks through a hole cut into the hull, and is braced with more ply against the hull. Again seams filled with filler. (Also epoxied in hull with extra cloth to reinforce with little weight gain.)

Then the base for the electronics is epoxied to the top of the reinforcements above the keel in the hull. There is no need to go all the way up to the deck. (it should be plenty strong)

I'll try to remember to post pics.

Again, sorry it took so long. I've been busy with other projects lately.

Corey (The Enemy)

[steelhead]

Well? What about those pics?

Dean

[The Enemy]

My parents just got a digital camera. I'll get over there tonight and email them to myself here. Then I can post them. Thanks for reminding me. I've been sidetracked for a bit on a new plane. IPS powered flying wing. :D

Corey

[martin richards]

You can also make the female mold from fibreglass. Anyhow the real work is getting a perfect finish on the plug. Gradually work down to the finest sandpaper you can find and then a burnishing compound. The plug should be as solid as possible as any mold making method puts a lot of stress on it. Remember too that the mold has to be released and epoxy/polyester resin sticks to most things very well ;) Also care with the transom and hull sides - you won't get the mold out of any greater than 180º curves:eek: Finally treat the female mold in the sme way as the plug.

[The Enemy]

My parents took off for the weekend! I'm going to have to wait till Sunday night or monday morning to get the shots. Sorry.


Corey

[The Enemy]

Alright. I nabbed their digi cam today and had to burn them onto CD. I skipped the mold making stage, but haven't gotten very far from it. So here goes. Sorry to repeat anything you already know. I also may have done things differently than others have.

1. Lay the backbone of the boat.
2. Attach formers to backbone.
3. Plank boat. Tightly, we don't want gaps.
4. Rough sand.
5. Fill any small gaps with light weight filler. (They're inevitable.)
6. Trim fore and aft planks and fit bow/stern blocks.
7. Sand again. This time blend in the blocks to a beautiful ship shape.
8. Glass the hull.

This is where you decide to have a plug, for a mold.

For just one hull, sand the epoxy/fiberglass to a smooth finish. Remove formers. Add keel. (see later steps)

9. Cover the hull in the extremely hard, robust material of your choice. It needs to be REALLY strong.
10. Work your way down to a wet sand paper so that the finish on the plug (hull) is as shiny smooth as you can get it. Your hard work here will pay off soon...
11. Build a box to hold your mold. (Just bigger than your model.)
12. Suspend the plug atop the box. (Lightly coated with your favorite cooking spray?)
13. Pour plaster. (This is where I am unsure about it being in one foul swoop, or in layers, or possibly even reinforced.)
14. Remove plug after mold has set.
15. Hopefully you have a smooth surface, if not, get sanding... again.

And VOILA!!!

After this, you can make a hull from the mold.

To attach the keel, carefully cut along the centre line of the hull.
Then add ply reinforcement. Like these...

[The Enemy]

Oh cr@p. Pics aren't working. I'll have to get them tomorrow after work. Sorry.


Corey

[The Enemy]

Got em!

Here's a few to show where I'm at right now. Unfortunately we didn't think to take any pics before hand.


Corey

[The Enemy]

another...

[The Enemy]

front...

[The Enemy]

bulb...

[The Enemy]

and the other side of the bulb. We counter sunk the bolts in the lead and filled the holes. The ply you see at the trailing edge of the keel is laminated with carbon fiber along the center, and then balsa. It is then of course glassed and sanded. The ply itself goes through the bulb, and up into the hull.

[The Enemy]

As you can see in this shot...

[The Enemy]

here's a closer shot of how we used more ply to brace the keel against the hull. In this and the prevoius shot, you can still see where the centre of the boat was constructed on a flat surface. If you look even closer, where the formers went is also still visible.

[RyanPSU21]

Regarding comments made about Carbon. It is legal in almost every boat class except for a few One Designs like EC12. Go to www.amya.org for information on the different classes.

[rcsoar4fun]

Which design is this? Looks a lot like the RCM Magazine Soling. First sailboat I ever built, really nice sailing boat.

Kristopher

[The Enemy]

It is a Soling, thanks. I started it when I had no idea how to build anything. Winter is coming, and I hope to get more work done on her soon.

Corey

[steelhead]

UNDEAD THREAD

Dean

[steelhead]

The enemy- did you get that Soling done?

Dean

[hew565]

http://members.tripod.com/ghmyc_1m/germanrubber-305.html

Read up on this method of reproducing a hull. I know someone that made a very nice looking CF hull from a male plug in one step using the method there.

I have made one-offs by shaping a block of styrofoam, 2X 5 oz. glassing with epoxy resin, and then acetone'ing the foam away.

Or here: http://ghmyc_1m.tripod.com/germanrubber-305.html

Thanks to Greg Vasileff, Fran Gowash and Richard Ellis for getting the photos back up!

[steelhead]

Forgot about this thread. Great stuff!

Dean

[ROADTOAD]

http://www.google.com/search?q=building+a+mold+fiberglass&btnG=Search&hl=en

[Tugboat Andy]

Great timing! Thank you for these suggestions.

[dsquire]

Wake up time!


Don