polycore

Some quick ideas, fixes, resins and joinery hints and building tips
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gunnadoo
Posts: 11
Joined: Thu Nov 20, 2008 12:19 am
Location: Innisfail Qld

polycore

Post by gunnadoo » Thu Nov 20, 2008 5:15 am

Hi all, another newbie to the site - great one, by the way. I have been playing with polycore, bought a few sheets and put a dinghy together, am fairly impressed with the product. While I like ply, my problem with it is that my (wet tropics) part of the planet and no shed would make building in ply difficult. I have been looking at Mike Waller's 1100, and reckon that it would be a good candidate for polycore construction. This stuff can be ordered preglassed and cut using DXF files, so I could order in all bulkheads glassed and pre-cut, and panels not glassed, in one piece for other areas. And, no rot worries. A second option would be to use polycore bulkheads, furniture, etc, and ply hull panels. Any thoughts?

madaz
Posts: 527
Joined: Thu Apr 26, 2007 7:47 am
Location: Hobart, Tasmania

polycore

Post by madaz » Thu Nov 20, 2008 6:56 am

I am building one of Mike boats myself, there is also a few 1100 being built now which you can check the progress on this site and at http://www.mahnamahna.com.au and follow the link to "nine lives"



More updates please Paul..... :P



I don know much about Poly core apart from the little piece I have lying around here. it seems to have its merits.



You may find some resistance with designers when you suggest building something designed for ply, foam. duflex and substituting the core material. i know Miek isnt much of a fan of using combinations of materials to make one boat. i.e. poly core and ply.



From my limited knowledge of it I think the only people doing boat designs out of it are the ones peddling it also? So perhaps alot of designers would be reluctant to specify it due to their limited knowledge of it, and its relative new status as a building material?



Further down the track that may also effect you in terms of re sale if you have a boat built out of something that not many people have heard of. I'm not knocking it though, but building from a tried and trusted material has its benefits also.



You could ask Mike directly, he will be more than happy to give you a response and is a wealth of knowledge.



Many ply boats have been built in the tropics to? where theres a will theres a way, there are a number of builders who have temporary plastic barn type sheds that have lasted the life of there project for a very small outlay compared to renting space somewhere. You could also pre coat all your sheets when they are delivered with something like Wattyl Timber Preserver, or thinned epoxy. Sounds dramatic but in the grand timeframe of building a boat the time taken to do it is negligable.



I have the opposite problem, its so cold half the year that epoxy doesnt dry so well..

mahnamahna
Posts: 580
Joined: Wed Aug 02, 2006 4:48 pm
Location: Gosford NSW

polycore

Post by mahnamahna » Thu Nov 20, 2008 8:04 am

Hi Guys,



Sorry about the lack of posts for Nine Lives, the Mike Waller 1100 being built in my shed. There has not been a lot of visible change and the owner and original builders have parted company...however the fairing and painting crew have been busy final prepping the boat for paint so I should have something to shoot soon, and there has also been some fitting of deck hardware, but this will be off again for painting...but again as soon as I have some visual change I will post pics.

Regarding polycore, I will be using Nidacore for my furniture, I have a duflex boat and would not be keen to make anything structural out of the polycore not because I doubt its worth but because the engineering for the boat was done based on the core material the designer specified (balsa). Due to running out of duracore balsa panels I was forced to use a little nidacore on the edge of my roof but over the cockpit that is non structural and I found it set hard once glassed both sides and holds the roof shape properly so I am happy with it. Once bogged you wouldnt know unless I told you that the core was any different.

Check out pacific multi hulls, http://www.pacificmultihulls.com/index.cfm?menukey=41 they are designing kits utilizing poly core. As for my experience with polycore so far, it is easy to work with, either cold forming shapes and glassing to shape or flat glassing panels and using them as firm glassed panels. They are resin thirsty though, the scrim needs about 400g of resin per sq meter, the same as equivalent area of 400g glass so if you are glassing each side with 400gsm glass you will need roughly 1.5kgs of resin (you use slightly less resin on wetting glass as some wicks back out of scrim into glass. Having said that, you dont necessarily need to use 400gsm glass, on most of the furniture I will only use 400gsm on the outside so as to have some scuff strength but use 200gsm on the inside. But I have costed glass, resin and the core sheets and combined it is cheaper than buying panels of duflex or featherlite (ATL's pre glassed furniture panels) but then I am doing the labor of glassing that the preglassed panels would not require but right now, time I got, glass I got, resin I am running out of but have budgeted for and time I also have so this is the course I am taking. I plan on a lot of dry forming shapes of furniture on the boat so glassing is not an issue for me, I would be doing it after kerfing featherlite if I was using the preferred furniture material anyway. So it is much cheaper for me this way. Although it is a lot more work free forming my own furniture design compared to using a pre cut furniture kit, it is going to be about half the cost and without going into specific costs I will save about $5000 forming my own furniture. My finances have changed a lot since I started the boat so cost cutting became a necessity to finish but I am happy with the way things have gone so far. Ok enough rambling.....



Cheers,



Paul



Cheers,



Paul

gunnadoo
Posts: 11
Joined: Thu Nov 20, 2008 12:19 am
Location: Innisfail Qld

polycore

Post by gunnadoo » Fri Nov 21, 2008 1:08 am

Thanks guys, much appreciated. I had written to Mike, sadly, he no longer designs in composites. I suppose I am a bit jaded with ply - I have spent more than a little time maintaining my current cat, inluding removing a spot or 3 of the dreaded rot, fortunately not in too difficult an area to fix. That boat is epoxy ply, and only eight years old, so please forgive me my doubts about the material. Balsa fits into that area of suspicion as well. I had hoped to sell that boat, and get into building a new cat ready for retirement. The idea of buying panels pre-cut and glassed would have saved me a lot of time, and given a panel with no joins - Mike's DXF cutting files would have supported that. Anyway, in the absence of any design support, it looks unlikely to go ahead. I had looked at Pacific 40 - cant quite get my head around the costing - the price I paid for sheets of the stuff sure doesn't run out to more than about 30% of the kit, allowing for epoxy and glass. Thanks again, all the best for your endeavours.

mahnamahna
Posts: 580
Joined: Wed Aug 02, 2006 4:48 pm
Location: Gosford NSW

polycore

Post by mahnamahna » Fri Nov 21, 2008 4:43 am

Dont give up gunnadoo, try asking pacific multihulls if you can buy plans only that include lofting sheets and glassing schedules and no kit and buy unglassed core panels, glass and resin, make a vacuum table and make your own. (you can make panels without vacuum bagging but you wont get the same results they do or use as little resin). I reckon you can make a 1200x2400 panel including core (say 20mm), glass (say 600gsm x both sides) and epoxy resin for under $200 a sheet, about half the price of a factory glassed sheet, and with vacuum bagging or some kind of press to ensure that where 2 core panels butt together you achieve a smooth transition when you glass and I would think you would achieve as good a result. The designers that offer kits make money on the plans and the kit. If you let them know that no matter what you will only pay for plans, then a plan sale is better than no sale (or no sail?). The trick will be to nest hull panels and bulkheads so that you use the minimum of sheets. Once you have all of the panels made you have a kit. Its a lot more work, but if the work (read time) saves you money you don't have, it may make an impossible dream possible. Cheers, Paul

44c
Posts: 1148
Joined: Tue Aug 08, 2006 5:08 am
Location: Hervey Bay, Qld

polycore

Post by 44c » Fri Nov 21, 2008 4:55 pm

Maybe talk to Bob Oram. I'm sure he'd be able to help. All you really need is the lofting plans for the parts and a core and laminate schedule. He'd do that, I'm sure. He has a good 40 foot design, similar in appearance to a Spirited 380, but a foot and a bit longer. (The 39C)



Duflex is also available with foam cores but it is more exxy.



http://www.boboramdesign.com.au/

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