Fiberglass Kayak

[neon14]

Anybody ever tried using a kayak as a mold to make a fiberglass kayak? Do the bottom and top separately and glass them together. It wouldnt have to look perfict or anything. Been thinking about this for awhile. Thanks

Will

[RealBigReel]

Anybody ever tried using a kayak as a mold to make a fiberglass kayak? Do the bottom and top separately and glass them together. It wouldn't have to look perfect or anything. Been thinking about this for awhile. Thanks

Will

It has been done. Some prototypes are built like that. Building an acceptable mold is not a simple process. Takes lots of work. Any defect will be transfered. And then there is the process of getting the mold to separate from the blank. Even with very low adhesion there is a large area, and it requires either considerable force of the application of technology.

To really do this right, would require the use of prepreg material and an autoclave.

[Pogo]

Sounds like RBR knows a thing or two about it.

I'll add a couple notes: when prototyping, a manufacturer essentially has to build the mold twice. First, he makes a plug, which is the exact shape he wants. Then the mold is formed on the plug. The plug is tossed and the mold used to make the final part.

I'll also emphasize what RBR says when he mentions the precision with which your mold must be made, and the difficulty in releasing the laid-up part from it. It's a LOT of work!

Having said that, there are a few individuals here in Texas who make boats this way, tend to be kevlar-graphite composite canoes and kayaks for racing - the ones I know, anyway. So that tells us it isn't impossible. I've alway meant to see how they go about it, but haven't gotten around to it yet since it's only a curiosity thing.

[Too Busy]

There are a couple of things you can do to make releasing the plug from the mold easier.

1. make your plug as smooth as you possibly can, then wax it, buff it, wax it again.

2. be ure to use a good mold release agent.

3. put one or two "blow ports" on the plug or the mold, whichever is easier. Basically you mold in a 1/8 inch pipe port that you can attach a air line quick disconnect. use low pressure air to pop the mold off the plug. If you use water soluble mold release you can pump low pressure water inplace of air.

4. don't forget to add stiffeners and supports to your mold or it will warp sitting around waiting to be used. learned that one the hard way.

[Pogo]

Yep, all true, but thought it might be worth mentioning that last one applies to strip-built boat parts too. The wise builder will keep the hull and/or deck on the forms, or use spreader sticks, to maintain the desired shape, etc. If you don't the fiberglass "wanders". Plywood's intrinsic stability minimizes this in S&G boats. Fiberglass boat molds in factories are built and reinforced extremely heavily, almost appear fortified.

[Too Busy]

Yep, all true, but thought it might be worth mentioning that last one applies to strip-built boat parts too. The wise builder will keep the hull and/or deck on the forms, or use spreader sticks, to maintain the desired shape, etc.

yep
I didn't take my Wee Lassie off the forms until the outside was glassed and the gunwales were in place. Then glassed the inside and put a temporary spreader in place while the glass cured. I stored it on the molds between work sessions until the inwales and thwart went in.

[bowgarguide]

Too Busy
Has it right with the air and water ports we also had a sling made to attach at several points with overhead electric hoist , and sometimes they still hung up.
From design to poping your first boat out they use to say it took 10,000 man hours.
Ron

[neon14]

Sounds like to much work to me lol. Thanks for the input guys, maybe this winter I will try a stitch and glue or something. I really like those small one person canoes.