A new one is coming!

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A new one is coming!

downunder
This post was updated on .
This time I am using Paulownia wood as a top layer. The idea is to make it under 2.5kg:) The core is still bamboo - hence Shinai name...

It wasn't easy tho. To make a top layer of narrow wood strips something like 45x5x900mm takes ages. And a lot of elbow grease with a hand tools

But I like using some forgotten tools:)



Applying some epoxy on sides:



Gluing wood strips together between two walls



This are two top layers on top of each other. If strips are glued well, there is no need to sand the bottom, only the top (exposed) side:



And now the new board resting on the rocker table under the vacuum:



The board is loosely cut all around to allow handling and varnishing.

Technically, this was pretty demanding board 
Since it is not for me but for the shop. It needs to be puuurfect to be accepted for sale.

Tomorrow glassing the bottom maybe even with some topsheet! I might still varnish this board so it's about a week to finish it, depending on my workload:)

Stay tuned coz this board will be THE one! I'm hoping for something never done before:)
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Re: A new one is coming!

Chris
Looking good :) does the wine glass help stabilise the vacuum bag?

Come on, do tell ;)
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Re: A new one is coming!

downunder
The wine is to find leaks:)

Ah, maybe this board is not The one

On the photo above, I've forgotten to use my roller on the line there the top layer bridges with the core.

I think this is a must to bridge the fiberglass properly. As a result the FG didn't bridge perfectly, good but not perfect.

Something to think about on a new build. Or I may dump the top layer and go with the triax + carbon and a veneer.

AND, the topsheet is not for faint hearted

I think more and more that the topsheet is good only for pressing with a pneumatic press. It is extremely hard to do the topsheet with a vacuum. The air pockets are bastards to fix. More elbow grease...
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Chris
Your bag is too tight, as you are using a breather fabric you can bunch the bag up around the changes in levels so you don't get bridging. The folds will not show on the final finish as you have the breather fabric, peel ply / mesh / release film under

Crappy photo but kind of shows the idea
2014-04-04 19.13.15

Pull 1/2 vac so you can still move the bag around and work the folds around the lumps so it won't bridge then pull the full vacuum.
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Re: A new one is coming!

downunder
Yes,
this was the cause, thanks for the tip.



On 5/13/14, Chris [via BoardBuilders Forum]
<[hidden email]> wrote:

>
>
> Your bag is too tight, as you are using a breather fabric you can bunch the
> bag up around the changes in levels so you don't get bridging. The folds
> will not show on the final finish as you have the breather fabric, peel ply
> / mesh / release film under
>
> Crappy photo but kind of shows the idea
> <img src="https://farm3.staticflickr.com/2848/13690352765_690252554b_z.jpg"
> width="640" height="360" alt="2014-04-04 19.13.15">
> <https://www.flickr.com/photos/landychris/13690352765>
>
> Pull 1/2 vac so you can still move the bag around and work the folds around
> the lumps so it won't bridge then pull the full vacuum.
>
>
>
> _______________________________________________
> If you reply to this email, your message will be added to the discussion
> below:
> http://boardbuilders-forum.1077691.n5.nabble.com/A-new-one-is-coming-tp1429p1438.html
>
> To unsubscribe from A new one is coming!, visit
>
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Re: A new one is coming!

downunder
I went with the top sheet (well, bottom actually). Had a few dramas with that like taking it off two times and that:( It is ultra shiny but still has got a protective film so can't take photos.

Ended up with 2826 grams before the final cut, varnish on top, etc.

I recon this is due to a bottom sheet, extra SS inserts (2) + almost 90 grams epoxy (50% more and was not enough, you need to "bath" a FG not to get some visible dry spots under the bottom sheet).

Used only 120g/m^2 FG which makes soft flex.

This is interesting since a foam top layer and biax carbon on top of the foam only (not the length of the board), makes more rigid board with the same bottom layout. Remember, my boards are "exposed" wood and every single mistake can't be hidden (ie. hidden with the graphics).

I'll double the FG for the bottom and use only 120g/m2 on top for my next one. The reason I've used 200g/m^2 on top has to be seen and I'm not ready to reveal that yet:)

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Re: A new one is coming!

Chris
have you tried wetting out the glass before laying up? then carefully laying up to reduce the initial air bubbles
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Re: A new one is coming!

downunder
Chris wrote
have you tried wetting out the glass before laying up? then carefully laying up to reduce the initial air bubbles

Yes. Not the first time I'm having issues with that and hate it. The problem is a concave tho. Takes a lot of hand roller to squeeze the air pockets out. Tiny air pockets are even more complicated.

I think Carved.de they drill tiny holes through the core and probably do everything in one go.
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Re: A new one is coming!

Chris
yes, holes are good. my foam has holes drilled at 50mm centres to allow air to escape and for infusion will allow the resin to permeate through and reduce voids and dry spots
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Re: A new one is coming!

downunder
In reply to this post by downunder
Hm,

did not get any better results with folding the plastic:



It is easier to work out the plastic around the bridging line but I think this is not the solution for the problem. It actually made it worse since more air is trapped as tiny air bubbles.

I think the cause of bridging problem is the perforated film (PF) which is under tension. Pulling some vacuum and work out the folds is good but not enough because the vac will tension PF again where the board core finishes:



One can work out the gap but not two gaps. Either way, one is always tensioned when one pressed.

My proposal is to cut the PF just before the board edge. Then a vac can't pull the PF and open the air gaps.

But than, is the whole idea of using the PF to have it tensioned???

Or the other method might be to perforate the PF on the bridging line to let the air escape (but PF will be still tensioned, and not pressed down to close the gap).

Ideas?

Of course, not having a step down like my 45 degrees routed lines, is a much better go. Like I did on my Carbon Shinai, about 30 degrees:



The above carbon top layer was made on a perspex table as well.

 

downunder wrote
Yes,
this was the cause, thanks for the tip.



On 5/13/14, Chris [via BoardBuilders Forum]
<[hidden email]> wrote:
>
>
> Your bag is too tight, as you are using a breather fabric you can bunch the
> bag up around the changes in levels so you don't get bridging. The folds
> will not show on the final finish as you have the breather fabric, peel ply
> / mesh / release film under
>
> Crappy photo but kind of shows the idea
>  width="640" height="360" alt="2014-04-04 19.13.15">
> <https://www.flickr.com/photos/landychris/13690352765>
>
> Pull 1/2 vac so you can still move the bag around and work the folds around
> the lumps so it won't bridge then pull the full vacuum.
>
>
>
> _______________________________________________
> If you reply to this email, your message will be added to the discussion
> below:
> http://boardbuilders-forum.1077691.n5.nabble.com/A-new-one-is-coming-tp1429p1438.html
>
> To unsubscribe from A new one is coming!, visit
> http://boardbuilders-forum.1077691.n5.nabble.com/template/NamlServlet.jtp?macro=unsubscribe_by_code&node=1429&code=YmFiaWNkZEBnbWFpbC5jb218MTQyOXwxNjIzMjkxODIy
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