Sunday, June 5, 2011

Musing about board #3

I've started thinking about board #3 and working out what the goal will be.

Without much wind around at the moment it's a bit hard to set performance improvement goals for the board and son I think for board #3 the goals will be around improving the production techniques. In particular speeding the proces up and improving the finish quality.

The three features I want to change are potential working with a full woodcore, adding channels and pouring the rails.

Sources of delays

i) Waiting for resin to cure for inserts, building up the core and setting the rails in place at a minimum this adds a day to the process and with my set up ended up adding several days as I did each one seperately. it would be ideal to be able to create a 'kit' of the insert pieces that could then be put in place at the same time as doing the lay up. Using ABS plastic disks for all inserts cut perfectly to size seems to be the best way to do it other than using 5 minute epoxy if cost permits. ABS washers about 15mm would do for the footstrap inserts if 6mm flange nuts are are being used and they would be more than enough for the fin inserts. Handle inserts....we say no to handles!!!!
ii) Laying up the top and the bottom in seperate passes. This was partly due to my concern that I  would not be fast enough to do both sides because I was using 3 layers of cloth each side and I wanted to really work on reducing air bubbles. Ideally this would all be done in one pass and possibly using 2x8 oz layers of glass rather than 3x6oz each side. The limitation there is it won't be possible to do one of the layers at 45/45 degrees to make sure it is torsional stiffness......
iii) Cutting and forming the rails was another slow process but the issue was more the potential for having a poor rail, core bond. Pouring either epoxy or polyurethane would address this but would introduce waiting time so the tradeoff is not great. Using ABS ( or PVC) rails and then being able to clamp the rails to the core at the same time as laminating would be ideal. So long as only one side board has 3-d shaping then this would be doable by using a template of, roughly, the negative of the board cut down the centre and then using it to clamp the rails agains the core ( brokite style).
iv) Doing a seperate bagging to get the smooth finish on the board. This added an overnight wait for the curing. I suspect it would be faster to finish it by hand.


  1. I like warm box to speed up the things:


  2. Hey Dean. I'm going to use a hot box for post curing the resin this time. Everything i read in epoxy datasheets says that heating it to 50-60 degrees 24 hours after it cured increases the strength and flexibility. The downside to doing it while the resin is curing is that any air in the core material will be pushed out and can cause air bubbles in the resin. Jorge had this trouble in his last board which he heated during the curing process.

    On a seperate note, what a great shed this guys got. Loads of great tools to make some great stuff other than RC planes as well.

    How is you're board coming along? Any thoughts about kicking off a blog so we can follow along with you're progress??