Thursday, January 26, 2012

Core setup

Today I cut the core out and did the first dry fitting of all the bits I put together so far.

The overarching goal for this evolved to be more about getting the process of making the board run smoother and try to eliminate the multiple curing cycles needed for inserts, rails etc by being able to do them all in one go. While in principal the approach of putting a kit of pieces together and then gluing everything together at the same time as doing the glassing is right approach, I've come to realise that efficiency is lost if the pieces you create are not within very tight tolerances. For example, i used the same size speed bore for the moulds to make the inserts as I did for drilling the insert holes in the template for the board. However, it turns out the the moulds for the inserts where not drilled vertically, just a little bit off but enough that each of the inserts needed to be sanded to fit and I lost about 1 hours and did lots of fiddly dusty work. So, next time round I'm going to focus on getting the tolerances on everything very tight.

Anyhow, had a chance to tinker today. Cut the core and did a dry lay up of the core 'kit' and tried a new reusable vac bag made from thick vinyl.

First thing was to put double sided tape down to hold the loose planks while i routed around the template

Then without any sanding I did a dry fitting to see how tighly the whole thing would hold together and if enough pressure was being applied to hold the rails on.

The pieces of the mould are pulled together using gaffer tape. Soon after this shot, the tape tore under the pressure. Then I had the ah moment and stuck some Velcro ( hook and loop) at both end. Worked like a charm. Was adjustable, strong and when is clamped down inside the bag, it hold tight.

The core needed a bit of trimming here and there. This was because I made a mistake when I got the rails material cut. I got 10mm strips but my router bit is 9.5mm. This was enough to require re-routing the moulds to accommodate the larger rails and of course the freehand work was a mess so the rails were not a tight fit straight away. After about 1/2 of work it was all good.

I put the mould and core inside a full bag mag of thick vinyl. The long sides I sealed with tacky tape but just used masking tape at the opening where I put the board into. Sealed very well and was easy to under. I went with the thick vinyl because the plan is to lay it up flat, put it in the bag and evacuate it and then form it in the jig. Having the full bag means that I won't have the problem of the table surface bending because this time the clamping pressure is on both sides. There will be a lot of pressure on the bag at the points where it lays on the jigs so I thought that think vinyl was the way to go.

I made the bag very oversized. The vinyl seals to itself very well and so the oversized bag, I suspect, help get a really good seal.

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