I am building with Polyore, under vacuum, but not infusing (too much hassle for small panels). If it was not for the desire to get a mould finish on the outside, I would not have bothered bagging it. I would not infuse Polycore or Nida for the reasons stated earlier, and would not infuse foam unless there were time constraints. The 15m lee hull will be built in one panel, 7m x 15m, hand laid and vac bagged, not infused.
George
I am planning on sending off for samples of various core materials to evaluate. My first project with these will likeley be a 10' catamaran dinghy, but it is all in prepartion of building a 40-50' harryproa. Can you give me some information on what thicknesses I should be looking at for the different core materials. I am currently considering:
Rob
The 10 footer can be 6mm H80, the 50'ter will be 15 and 20mm H80. Plain, no cuts, or scrim. You will need to perforate it by drilling 1mm holes at 100mm/4" centres through the stack of sheets. Apart Divynicell/Termanto foam you have covered the options I would consider.
I use high density polystyrene for the bows. Yellow Pages should throw up half a dozen local suppliers. You can use any closed cell foam, but polystyrene is easy to glue and sand, light and cheap. The sides of the hull are flat panels up to 500mm/20" from the bow, below the waterline foam goes back further, depending on how narrow the hulls are.
George
Rob
Woven cloth is not used much these days as knitted cloth is preferred. This is two layers of uni knitted together which keeps the fibres straight and theoretically puts les strain on the resin. Harry has 400 gsm/12 oz, Vis 600 gsm/18 ounce.
Regular cloth is one tow woven over one, under one. Twill is two tows woven over two/under two. Twill looks hornier and the fibres have less crimp, but it is hard to keep the edge s neat as it frays very easily.
Core is the expensive part, which is why strip planking is (was in a lot of places) lower cost. That is cheap carbon. Could use it on both sides (not one) if the cost is affordable. Problem with infusing carbon is that it is very difficult to tell the wet bits from the dry bits. I would test with glass first.
Your questions are not too basic. I certainly don't mind answering them. There are a number of books which have some of the information in them. Google and the supplier's web suites are another good source.
Regards,
Rob
Hi Rob,
I thought you have recently been building with a honeycomb core. Have you been infusing that on just one side at a time, or is it different enough from nida core that you can do both sides at once?- GardnerOn Tue, Dec 23, 2008 at 9:18 PM, Rob Denney <harryproa@gmail.com > wrote:
G'day,
Glad it went well, George. Infusing Nida is tricky. I would not drill holes in the core, you will use a fair bit of extra resin. George's suggestion would be better. The big problem is the edges. Exposed edges could be tapered using a hot household iron, but joined edges will be messy as you don't want a solid resin edge for weight, bending and stress reasons. A solution would be to taper them both at 45 and overlap them. On big boats, you could leave a gap and join the inner and outer skins. You could also bog the edges before infusing. None of these are ideal. Unless there are labour/time considerations, i would lay it all up wet and bag it. I would also talk to Nida and ask for their advice. It is possible that a thicker layer of scrim would act as a transfer medium
Funny story: I got a phone call yesterday from the guy that bought the 420 sqm/450 sq' Outleader kite. He makes boating movies for a living. He has chartered Brindabella (80' maxi) for Sydney Hobart, sold half the crew positions ($10,000 each!) and because the forecast is for fresh northerlies, wants to fly the kite in the race and film it for a future TV show. Could I come over and show them how to work the kite?
So, I leave here at 0005 on Boxing day, fly to Sydney, get to the boat at 0900 and we cast off at 1100, race starts at 1300. A beat out of the harbour, then bear away, drop the main and hoist the kite. Next stop Hobart. A boat full of kite virgins, including the inevitable few who think they know what they are doing and the world's biggest traction kite. Add in the stress of the race, the on board cameras, a dozen media helicopters, huge spectator fleet and we have the recipe for a flawless display. ;-) I will let you know how it went when i get back.
regards,
RobOn Wed, Dec 24, 2008 at 12:31 AM, Gardner Pomper <gardner@networknow.org > wrote:
Hi,
I got my first hands on demonstration of vacuum resin infusion from George Kuck of this forum last weekend. Thanks George! He was using core cell and had drilled holes through to allow infusion of both sides of the panels. I an now looking to start trying some samples myself and I wanted to try out nidacore. My question is, can you still infuse both sides at once on honeycomb? I can't tell how big the cells are, but it would seem to me that drilling through might open a couple and you would end up with a big block of resin. Is that ok? I would think it would be a stress point.- GardnerYork, PA
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