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vacuum bagging

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darippah
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vacuum bagging

Postby darippah » Tue Feb 11, 2014 3:38 am

new to the board building thing. Just shaped 4 boards out of 1/2" plywood and plan to experiment a bit to see what works for me

I originally planned to seal my boards with polyurethane , but now I'm considering using Fiberglass/ epoxy so that I can thin the boards a bit and gain some flex / strength

my question is it necessary to use vacuum bag process and what are the benefits ?

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Re: vacuum bagging

Postby downunder » Tue Feb 11, 2014 10:25 am

1/2" plywood?

What you building? A truck? :) My friend, any DIY is doomed if your board is heavier than 2.5-2.8kg.

You'll always reach for a lighter board in your quiver. Unless you're a heavy weight rider 100kgs +....

Other than that maybe using a search or:

http://boardbuilders-forum.1077691.n5.nabble.com/

or many more building sites. My advice is to re-think your board weight. To answer your question, yes, vacuum is a necessity. The benefits? Many. Try gluing some FG without it, see how it goes ;)

Good luck.

sijandy
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Re: vacuum bagging

Postby sijandy » Tue Feb 11, 2014 4:33 pm

downunder wrote: My friend, any DIY is doomed if your board is heavier than 2.5-2.8kg.

My advice is to re-think your board weight.
I would'nt worry about weight if your just experimenting and especially if using ply. It's not actually that important or critical to the performance of a kiteboard and is certainly not worth worrying too much about until you've done a few boards and start refining them. Vacuum bagging has a number of advantages but takes a bit of practice and a fair bit of setting up... you can do it without but the result won't be nearly as good (altho iv'e never tried without vac bagging).

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Re: vacuum bagging

Postby downunder » Wed Feb 12, 2014 2:53 am

Sure, than no need for a vac or sealing it ;)

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Re: vacuum bagging

Postby sijandy » Wed Feb 12, 2014 5:17 pm

downunder wrote:Sure, than no need for a vac or sealing it ;)
??? Not sure what your getting at, he is going to be sealing it with glass/epoxy he just wanted to know if it's doable without vacuum bagging unless i've misinterpreted his original post?

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Re: vacuum bagging

Postby downunder » Wed Feb 12, 2014 5:47 pm

Ok, my concern is weight. If you experimenting with a board on the water and brake a foot, is making a board more heavy really a good advice?
Sealing as I see it is not fiber glassing. One can seal a wood with any oil, with almost no added weight.
One can glass it and it can still be unsealed on many places. Think dry FG. That is not sealed:)
And dry spots can happen with and without a vac, me thinks.

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Re: vacuum bagging

Postby BWD » Wed Feb 12, 2014 6:33 pm

Short answer:
NO, not necessary at this stage.

Longer:
The following assumes, from what you wrote, that you have no glassing or composites building experience:
Vacuum bagging is good for more refined control of resin:fiber ratios and keeping weight down.
Can help with shaping also, by holding board to rocker table without extra jigs or fastening.
Unless your boards are going to weigh well under 2kg before glassing, it is probably not worth it to vacuum bag them in my opinion. The amount of weight saved is not that great. You should probably shoot for getting a 3kg board rather than the 4kg board it would be easy to make as a first-timer. Vacuum bagging, refined glassing, carefully tapered lightweight cores, carbon, etc are techniques to use to get you from 3kg builds to 2.5 or less. Each of these more advanced elements or techniques may save, on its own, a few hundred grams, or less. Putting it all together is what gives the superior result. Usually this requires experience.
My opinion is that you should first learn what are the basics and the mistakes to avoid, that will get you to a 3kg, useful board. Then you move on to awesome light boards.
Any extra $ spent on vac bag equipment could be put into cores, glass and epoxy instead, giving you more practice and experience.

If you have 4 boards that are significantly different in size and shape, finish them the same way and learn the differences. Then modify them and ride some more, etc. Keep a log of what you do.

Or, if you have 4 cores that are similar at this point, finish them in different ways to evaluate the differences in tapering, rails, amount and orientation of glass, fin position, etc.

Have fun.

PS: if you want to buy something, buy a powerplane, makes short work of tapering cores. Let the chips fly!
Last edited by BWD on Wed Feb 12, 2014 7:08 pm, edited 2 times in total.

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Re: vacuum bagging

Postby sijandy » Wed Feb 12, 2014 6:52 pm

downunder wrote:Ok, my concern is weight. If you experimenting with a board on the water and brake a foot, is making a board more heavy really a good advice?
What relevance does board weight have to breaking your feet? Especially when were talking a difference of maybe 1-1.5kg at the very most.
downunder wrote:
Sealing as I see it is not fiber glassing. One can seal a wood with any oil, with almost no added weight.
One can glass it and it can still be unsealed on many places. Think dry FG. That is not sealed:)
And dry spots can happen with and without a vac, me thinks.
Unless your getting really savage dry spots i think it's pretty safe to consider a glass/epoxy layer as sealing. I see where your coming from but i was just trying to keep it simple as i get the impression the guys new to board making.

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Re: vacuum bagging

Postby downunder » Thu Feb 13, 2014 3:40 am

Andy,

we are hijacking his thread:)

The moment of inertia is I=m*r^2 (2.5kg board with 0.68 radius, and 4kg board with same radius is
73% more inertia).

The heavy board might twist your ankle with a significant force if you stuff up even a small jump and your foot slips of bindings. Or don't jump, transition or anything other than lawn moving:)
Just yesterday I've met a guy with 8y experience and he broke his ankle 2mths ago.

1-1.5 difference is huge. As BWD says, the target should be 2.5-3kg max.

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darippah
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Re: vacuum bagging

Postby darippah » Thu Feb 13, 2014 6:58 am

thanks for all the tips guys. Keep em coming I got a lot to learn :thumb:

would love to make a usable foilboard but thats probably beyond my level at this point


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