Sunday, May 1, 2011

Top Laminate goes on

Learning from my mistakes this morning I just finished laying up the top laminate with full compliment peel ply, bleeder and breather material.

I bought some proper peel ply instead of using the perforated rip stop nylon that I used in the first board. As soon as the peel ply went on it started wicking the resin up and within about a minute was almost completely wet out - presumably because there was excess resin around around on the top. The jury is still out on the ripstop nylon. It was a must stronger barrier to the resin flow than the peel ply which combined with the excessive amount of resin I used last time may have lead to pools of resin being trapped under it and leaving the surface uneven. I'm not entirely sure but this seems like the most likely culprit.

I put down a layer of plain cotton material over the top (which was originally going to be color material for bottom of the board) to soak up more of the excess and still covered the whole thing in paper towels and rags to keep the air channel open. Last board I used polyester wadding that is used for filling inside quilts. It seemed to work well and but the density of it was not uniform and so I had a suspicion that this may have contributed to the uneven finish on the previous board. Again not sure.

I spent a lot more time working the resin than I did on the previous board. A lot more pressure on the squeegee and worked it until all the crackling/popping that is apparently due to air bubbles being pushed out/popped. Around some of the tighter curves I used a paint brush with the bristles cut down so the bristles were very stiff and dabbed this over any area where it looked like there might have been air trapped. Once the vac film starting to clamp I ran my fingers around the rail/sidewall joins because last time this was were a lot of resin accumulated.
With 400gm resin and under 25inHg small amount squeezed out shows the resin/fibre mix is about right.

I replaced the vac film even though it looked like it was still in good condition. Last board I reused it and after about 2 hours I was still not able to seal off all the leaks and this resulted in the vac pump running continuously for about 10 hours rather than the few seconds every 10-15 minutes that possible with a better seal.

I clamped it under 25 inHG for a few minutes as I find that taking it way up in the first instance helps it self-seal off some of the small leaks at the tacky tap. Then I back it off a bit and leave it around 20 inHg. 

Curing away under the car port - Working in cooler temperatures has made for a less hurried process.

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