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Archive for December, 2012
Posted by Jim.Thompson | Dec 22, 2012 @ 08:19 PM | 13,509 Views
I did my very first vac resin infusion tests yesterday and the results were quite good. I had leaks on the first tests, but it did not seem to spoil the composite plate that I was making. Probably because the leak seem to bypass the layup.

I waxed up some thick glass plate after taping the edges to keep them clean so that the acrylic filler would adhere to retain the bag later. Then I cut out two cores, one out of 1.5mm LRC (low resin content) Soric.
The second one, I cut the same size core out of Coremat, which is a regular fibreglassing core filler which I just happened to have in stock. I place a layer of heavy glass cloth (295 gsm) on top and bottom of each of these and positioned them on the glass plate. Then added a layer of peel ply, with the ends wrapped around pieces of spiral wrap in the usual way. I finished off the stack with a layer of infusion mesh. Inlet and outlet hoses were inserted the spiral wrap, one to pull the vacuum and the other to supply the resin.
I used a spray paint pot as a resin trap, copying "Ant's" example described in an earlier infusion thread.
I used Araldite LC3600 (it goes by several numbers??), and the ambient temperature at the time was 35 deg. C, so I didn't bother warming the resin.

I had some difficulty chasing leaks, but after they were (mostly) tracked down, the infusion went smoothly and plenty quick enough.
The bag was opened and the samples stripped from the glass this morning and look good. What was...Continue Reading
Posted by Jim.Thompson | Dec 08, 2012 @ 03:08 AM | 11,263 Views
I made a quick joiner mould today using two pieces of 12x12 RHS aluminiun and one piece of 40x40 aluminium RHS.
I used the 40x40 to space the smaller sections accurately. I waxed this to ensure it would stick to the assembly. Then I cleaned a piece of 8mm plate glass with acetone and masked off the 40 mm wide strip that would form the mould interior. Then I carefully ground the glass slightly to provide a good key for the epoxy that I was to glue the 12 x 12mm strips to, with my angle grinder. The 12x12 strips were cleaned with acetone and sanded rough on one face to provide a key.
Then I removed the masking tape and glued and clamped the thinner strips to the glass using the large piece as an accurate spacer. I glued them with epoxy and West Systems 403 added.
When the glue had mostly set, I removed the 40 x40 and cleaned the surplus epoxy that had exuded slightly out the inside corned of the joins with a chisel.
Now I have my mould for a 12 x 40 joiner bar!
Any combination of scrap sized material could be juggled to suit the application. This saves much time and money.

Jim.

When fully cured, I waxed and PVA treated the mould. Then when the PVA was totally dry, I layed in the bottom of the mould 12 rows of 50k carbon tow, suitably wet out with laminating resin and rolled as flat as possible.
The next day, I glued in a foam core with included plywood shearweb that I have previously cut to 9x36mm using my hot wire gear. This was carefully spaced equidistant from...Continue Reading
Posted by Jim.Thompson | Dec 04, 2012 @ 03:29 AM | 10,153 Views
I layed up a couple of new nose cones for my 2 mtr. Endorphin over the last couple of days.
The first one came out very well. I used wax and PVA. The second one is in the mould with the bladder at around 15 -20 psi pressure. This one has wax only and is the first time I have used only wax. The mould is well seasoned now and has produced 3 or more parts.

I'll pull it tomorrow morning and check the results. This one is 3 layers of 185gsm glass cloth.

edit: The second one done without PVA (wax only) pulled nicely! One of the benefits of a seasoned mould!

Jim.

edit: In the third pic below, the bladder can be seen folded to avoid it interfering with the lap join on the bottom of the part. Much simpler than making an insertion tube and fitting the bladder after the mould is assembled I think. A few dabs of glue stick will keep the plastic bladder folder untill it is inflated. I have not had one become sandwiched in the lap join.