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Not a t tail. Tail looks a little like the deepend. . .
I could happily make my own but time and money is a big factor. This is a cheap trial of things and testing the new workshop too. Will wait to hear from Dave where he gets his molding stuff as that could dictate whether i do poly or epoxy |
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Another way to go cheap would be to use the plug for the part. I've been doing it that way for a 60" glider called the Consortium designed by Tom Hunt. After the cure I slit the belly and use strip's of old X-ray film to seperate the lay-up from the plug and then pop it out. The feature article is out of the Nov. 1990 issue of Model Aviation magazine. The bare fuse weigh's an ounce.
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Quote:
Not really a copy if the layup has 10x more carbon, larger spars that make it fit for purpose; kinda like building a race car it may look like a street car but that's where the similarity ends |
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Hop onto kickstarter and I'm sure you'll get some funds
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No doubt, its still a copy, no matter what the layup. But I think theres no point worrying about copyright for a handful of planes when HK sells them by the hundreds. Its definitely a grey area though.
Another resin that might be worth considering Alex is Vinylester, if you can get it. I have been told it sits between polyester and epoxy in most of its attributes, including price. There are compatible gel coats available for it too. |
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Have a few places to visit locally now. Thanks Guys, going to visit Nuplex and PJ Hobbs tomorrow
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I have heard they can be a little more expensive, but if the customer service and knowledge of product is good, then it may save me money
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I agree with Joe's advice.
I made many moulds using Vinylester Resin. I think they all stuck to some extent or other - most to the point of destroying the plug. The challenge with Polyester and/or Vinylester Resins is avoiding heat build up. Even though I took careful measures to avoid this, it seems that I "cooked the paint" on the plug in at least one case. Single pack paints were involved here too, I hasten to mention, a mistake in itself. Conversely, all the epoxy moulds I made have released fine. At least one of them had single pack paint on the plug. This is not to suggest that Polyester/Vinylester resins will not work; clearly they will. However, particular care needs to be taken to avoid the above problems. If the design is good enough to justify moulding it, the mould is worthy of the best materials. Epoxy with sand or poraver fill and maybe backed with steel frame. I used a thin epoxy shell and a steel RHS frame backing for my Wompoo build, which was probably cheaper than a full laminate/epoxy - sand fill/ laminate sandwich mould. But then, I have welding facilities to weld the frame. This frame backing also served as a flat clamping surface to slide clamps along made for the job out of 30x30 RHS and threaded rod. This facilites quick clamp up on assembly prior to pressuring up the bladder. edit: The mould surface coat that I use is epoxy/graphite/colloidal silica/flocked cotton mix made up as recommended by Adam (WWWorks). It seems to work fine, but I have nothing to compare it to. |
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Last edited by Jim.Thompson; May 08, 2014 at 07:08 PM.
Reason: see edit.
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Vinyl Ester can cope with a lot more heat than Poly Ester as far as I am aware. The molds that Dave made are either Poly or Vinyl Ester with Gelcoat and we have had no problems with sticking.
I guess it depends on the price difference and how good you want the molds. If you are after DS fodder then cost is imperative but if you are after a long lasting mold that produces masterpieces then a bit of money spent here could make all the difference. I love your concept of getting more pilots enthusiastic. Let me know if there is anything that I can do to help Jono |
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http://www.nzfibreglass.co.nz/
is a cheap local supplier. i would suggest just coughing up and using epoxy.... its more stable, and its more practice in the material you will be using. buy a bit more and use the extra for making wings from. |
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What brand epoxies are available in New Zealand?
For a while here marine grade resins were available cheap from ebay and such. Then the mould could be started with a superior laminating resin (Araldite LC3600, Kinetex et.al.). The fill could be a cheaper resin mixed with a filler of choice (sand/Poraver etc). Then the final top layer could be the good resin/fabric again. However, last I checked, there was very little difference in the price of the two grades of resin and I've since stocked only LC3600 and use it for everything. If I order two or more packs at a time, it turns out to be reasonably priced. Transport is a huge percentage of the landed cost to where I am, as it's classified as "Dangerous Goods" and attracts a surcharge. I could get any number delivered at one time for the same surcharge. |
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I will use epoxy for the mold now, as you say, it is what I am used to and also plan to makes parts with. Will visit nuplex this coming week
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I have never had a problem with sticking, but in saying that it could happen.
with vinyl ester and poly, (vinyl better) wax very well and a few times with drying in between, the a good coat of spray pva, Mist slow and let dry, lots of coats. some guys that have stuck things have found that with pva you can add water and get unstuck. |
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