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Old Jan 16, 2013, 04:27 AM
Entropy is happening!
Jim.Thompson's Avatar
Bellingen NSW Australia
Joined Aug 2008
6,716 Posts
Thanks Josh.

I still have not figured out how I'm going to block the drilling guide holes in the fuse mould before laying up a part. If I don't, the inflation bladder will blow the layup out the holes.

The only way I can think of is to machine up a short length of the 10 mm steel bright rod with a square, flat face to fit the wing root face nicely. Then, it will have to be retained somehow outside the mould. Maybe if I cut these lengths of steel rod to the correct length to fit under the clamps. The clamps will be short lengths of RHS steel with threaded rod outside the mould. I might need shims to adjust them (the stubs of steel mandrel) to the correct height. And also, some tacky tape, or teflon tape wound round them to prevent them dropping in and delaminating the layup. It will be a bit of a fiddle, but possible.

Jim.
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Old Jan 16, 2013, 05:48 AM
Life begins at transition
Australia, VIC, Sale
Joined May 2007
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What about recessing the mould face, then using the head from a screw? It might need filling to avoid the x getting full of resin, but could work?
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Old Jan 16, 2013, 02:29 PM
Entropy is happening!
Jim.Thompson's Avatar
Bellingen NSW Australia
Joined Aug 2008
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Quote:
Originally Posted by Odysis View Post
What about recessing the mould face, then using the head from a screw? It might need filling to avoid the x getting full of resin, but could work?
Odysis,

It would not be open when it's very purpose is required. That is, to provide a positioning guide for the drill to drill out the joiner hole in the fuse!
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Old Jan 16, 2013, 04:47 PM
Entropy is happening!
Jim.Thompson's Avatar
Bellingen NSW Australia
Joined Aug 2008
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Parting board removed.

I have now removed the parting board from the first side.
There is some small spots of black 2 pack paint that came off the parting board with the mould half. Not a good sign!
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Old Jan 16, 2013, 04:51 PM
Dean
A10FLYR's Avatar
USA, CO, Littleton
Joined Apr 2005
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Just sand/ buff 'em down Jim.....
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Old Jan 16, 2013, 06:53 PM
Entropy is happening!
Jim.Thompson's Avatar
Bellingen NSW Australia
Joined Aug 2008
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Originally Posted by A10FLYR View Post
Just sand/ buff 'em down Jim.....
They are not a problem in themselves, in fact, they scrape off with my fingernail. It's just what they might portent between the plug and the mould!
However, I've since realised it is not a significant signal of problems to come at all. I did not prime the parting boards, but simply sprayed them with 2 pack as an after thought. Not good practice, but anyway, that's what I did. As a result, the paint has not adhered to the parting board in a convincing way. The paint on the plug itself will have much more integrity.
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Old Jan 16, 2013, 06:54 PM
Entropy is happening!
Jim.Thompson's Avatar
Bellingen NSW Australia
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Pictures failed.

I took two pictures of the welding of the steel backing frames and the placing of them on the mould half. They didn't turn out ok. So, I'll post some when I do the second half.
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Old Jan 16, 2013, 10:51 PM
Arrarrar!
josh18's Avatar
Australia, NSW, Wagga Wagga
Joined Jan 2010
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Glad you got it sorted Jim. How do you attatch your metal frame to the mould? Ive heard of using something flexible, like PU sealant or something, to avoid bowing etc.
Keep up the great work!
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Old Jan 17, 2013, 12:22 AM
Entropy is happening!
Jim.Thompson's Avatar
Bellingen NSW Australia
Joined Aug 2008
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Quote:
Originally Posted by josh18 View Post
Glad you got it sorted Jim. How do you attatch your metal frame to the mould? Ive heard of using something flexible, like PU sealant or something, to avoid bowing etc.
Keep up the great work!
I just scored up the contact face of the steel with the angle grinder and set it into a vinylester/"Q" cells splooge, with the odd piece of coremat where the clearance was excessive.
I have done this successfully with the epoxy moulds for the plank. I know that the vinylester resin is not such a good adhesive. So, I have my misgivings about this time around. If it separates, I'll use something like a good silicone or something. I've not thought about it yet.

I just started the second side of the fuse layup. I've sorted out the difficulty of laying up around the wing fillets. More or less like Adam describes. Also using band-aid sized "straps" (for want of a better description), which are folded over the sharp external corners or arris's and retain the layup in good contact with the gel coat.
On the nose of the fillet, I also found that a small stip of drop sheet plastic stretched over the offending area, retained it all nicely. The surface tension of the plastic on the wet layup is al that is required to keep it tight and for it to do it's job.

Jim.

edit: Of course, I did thoroughly degrease the steel first!
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Last edited by Jim.Thompson; Jan 17, 2013 at 12:23 AM. Reason: See edit.
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Old Jan 17, 2013, 05:32 AM
Life begins at transition
Australia, VIC, Sale
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Originally Posted by Jim.Thompson View Post
Odysis,

It would not be open when it's very purpose is required. That is, to provide a positioning guide for the drill to drill out the joiner hole in the fuse!
My bad - I was thinking for the air release nipples, not the drill guide!
Clay and a bit of sticky tape sounds like a plan...
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Old Jan 17, 2013, 04:58 PM
Entropy is happening!
Jim.Thompson's Avatar
Bellingen NSW Australia
Joined Aug 2008
6,716 Posts
Torsional stiffness - drag spars

Josh and Tim,

After more thought, I've realised that the tube spars for drag spars and LE control surface spars will have much more torsional stiffness than flat ones! Obvious to me now. I guess I just have to think about such things more thoroughly.

Odysis,
I have some nice little threaded plugs to fill the air injection holes. See picture (not very good) in post #411.

Jim.
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Old Jan 19, 2013, 03:07 PM
Entropy is happening!
Jim.Thompson's Avatar
Bellingen NSW Australia
Joined Aug 2008
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Soric - b****y Soric!

I have now built the second half. I just have to weld up the steel backing frame and build up the flange where required to achieve a flat contact surface with it.

I ran out of coremat for and used up some Soric which I had in stock. I consider this stuff to be a waste of money for my uses. It is far to heavy and weak for flying parts as I found out as a result of a series of vacuum resin infusion tests I conducted. All details on my blog. The short story is that the conventional hand layup balsa cored samples were far lighter and stronger than any resin infused samples that I did. The Soric cored samples were the weakest and heaviest by far. These samples failed along the hexagonal divisions when I applied a light bending force to them.

So I decided to use it up for the hand layup second side of this mould. This also was something of a mistake as the Soric has no geometric stability when wet out like the coremat has! It stretches and slides all over the place. I wish I had never even heard about it. It was expensive to get here too!

Oh well, the price of learning essential lessons is often high!

I also forgot to take pictures along the way. I'll take some of the steel work when the rain stops.

Meanwhile, it's rain, beautiful fire stopping rain here!

Jim.
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Last edited by Jim.Thompson; Jan 19, 2013 at 08:06 PM. Reason: additional information.
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Old Jan 19, 2013, 07:17 PM
Just fly it!
wyowindworks's Avatar
Cody, WY
Joined Nov 2007
6,915 Posts
Quote:
Originally Posted by Jim.Thompson View Post

Oh well, the price of learning essential lessons is often high!
Unfortunately, this is often a reality when working with composites. I have tried some processes over 30 times before I concluded that they wouldn't work.

At least it's cheaper than college.

Adam
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Old Jan 19, 2013, 08:03 PM
Entropy is happening!
Jim.Thompson's Avatar
Bellingen NSW Australia
Joined Aug 2008
6,716 Posts
Cheaper than College.

Quote:
Originally Posted by wyowindworks View Post
Unfortunately, this is often a reality when working with composites. I have tried some processes over 30 times before I concluded that they wouldn't work.

At least it's cheaper than college.

Adam
Very true Adam!

I just waiting to read further information and reports about Soric's performance from other builders. Other than the few subjective claims that I've read so far.
I'm doing my best to keep an open mind about it, but with samples in hand that perform so poor..........it's hard not to.

Jim.
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Last edited by Jim.Thompson; Jan 19, 2013 at 08:04 PM. Reason: Spelling/syntax
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Old Jan 20, 2013, 03:02 AM
Arrarrar!
josh18's Avatar
Australia, NSW, Wagga Wagga
Joined Jan 2010
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Shane and Ant from down my way (rcjunkie and anthonyd) have had some great results infusing soric. They do say its heavier though.
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