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Old Nov 26, 2010, 11:57 AM
Entropy is happening!
Jim.Thompson's Avatar
Australia, NSW, Bellingen
Joined Aug 2008
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Filler

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Originally Posted by TexasThermalKing View Post
What white filler did you use on the foam core? Is there a full top to bottom spar, or is it laid on the foam core?
The white filler is "Fuller's" brand powdered filler (spackle by another name), mixed with 'Q" cells. I am using the traditional powdered variety again. I found the premixed stuff too hard to sand. And I can mix the powder with the filler cells to desired ratio depending upon the job etc.

The spar is not full depth. It is only top and bottom inserts of carbon tow as previously described. I suppose this becomes an augmented stressed skin type of wing. Anyone like to clarify this for me? I would guess that the foam does act to some extent as a shear web.

Jim.
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Old Nov 29, 2010, 11:44 PM
Registered User
United States, CA, Berkeley
Joined Feb 2007
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bunny suit...

this is what I meant, the 'clean room' bunny suits. I got booties too, but I dont use them.

Jim... send us some detail pics of your planned servo install, sounds intriguing. Why install that way, style points ?

What plank is that? Looks like fun.

Ben
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Old Nov 30, 2010, 02:10 AM
Entropy is happening!
Jim.Thompson's Avatar
Australia, NSW, Bellingen
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servo install

Quote:
Originally Posted by skinnydoc this[/URL
is what I meant, the 'clean room' bunny suits. I got booties too, but I dont use them.

Jim... send us some detail pics of your planned servo install, sounds intriguing. Why install that way, style points ?
What plank is that? Looks like fun.

Ben
Ben,

The bunny suits are a good idea, especially for spraying 2 pack (which I will not be doing for reasons already explained). I have visited 2 spray painting outfits in the last week, and they all seem to use them.

Servo installation:
This it a time I wish I could draw a diagram, but words will have to suffice.
In a top of the wing installation with top hinged and top horn set up, the servo will go in upside down. ie. with the horn facing towards the bottom of the wing. The servo itself will be fixed to the flat top cover, which will be fastened with 4 screws. The pushrod will transit diagonally through the wing to pass out the top skin approx half way to the horn. The horn and short length of exposed pushrod can be faired with a simple moulded glass or carbon tunnel, or left uncovered. Unfortuately, these fairing tunnels (or hoods) cannot be seen in the picture I took of my plank. I have seen this system used on some moulded production gliders. Less airstream obstruction etc.

The plank is my latest "homebrew", self designed creation. Waiting for a good southerly wind to maiden it. Should be quite a missile! PW51 airfoil and 1.6 kg @ 1400mm span.

Jim.
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Last edited by Jim.Thompson; Nov 30, 2010 at 04:03 PM. Reason: additional information
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Old Dec 04, 2010, 01:47 PM
Entropy is happening!
Jim.Thompson's Avatar
Australia, NSW, Bellingen
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Plug

I have finally finished the preparation of the plug, now ready for the fibreglasser to spray it with polyester gel coat for me. I expect to collect it sometime next week. The parting board has been prepared complete with a box around it to retain the layup. When I get the plug back, it will need wet sanding with finer and finer grit paper, and finally abrasive automotive rubbing compound to a high polished finish. Then allowed to cure sufficiently before setting in the parting board ready for one side of the mould to be built.

Jim.
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Last edited by Jim.Thompson; Dec 05, 2010 at 12:04 PM. Reason: addition of picture
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Old Dec 06, 2010, 06:02 PM
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Eureka, CA
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Nice work Jim!!

That should make an easy to handle square mold, are you going to do the splooge edge or the clay?

Smart move on letting others spray your plug for you, I still regret every time I have to spray 2k. I need to get a fresh air system before I start doing lot of 2k work again.

Alex
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Old Dec 06, 2010, 08:26 PM
Entropy is happening!
Jim.Thompson's Avatar
Australia, NSW, Bellingen
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Quote:
Originally Posted by alexhaben View Post
Nice work Jim!!

That should make an easy to handle square mold, are you going to do the splooge edge or the clay?
Alex
Alex,

I am thinking of doing the splooge edge. I will go back over the threads that describe it (yours I think?) and decide.

and:

"Smart move on letting others spray your plug for you, I still regret every time I have to spray 2k. I need to get a fresh air system before I start doing lot of 2k work again." Quote Alex.

Did you look at the link for supplied air respirator systems that Adam posted for me? It looks very good, and the price is certainly ok. Postage to Aus is $132 which is ok. Locally supplied 3M units are many times that price. I am needing to limit my exposure more and more due to my health condition.

Jim.
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Old Dec 07, 2010, 01:26 AM
scratch build everything
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South Africa, KwaZulu-Natal, Botha's Hill
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Hmmm, i don't have a problem spraying 2k without a respirator. I do spray in a ventilated area though. Maybe I just have cast iron lungs.
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Old Dec 07, 2010, 01:35 AM
Dean
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USA, CO, Littleton
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Quote:
Originally Posted by DudleyLeRoux View Post
Hmmm, i don't have a problem spraying 2k without a respirator. I do spray in a ventilated area though. Maybe I just have cast iron lungs.
When I was younger I thought the same thing....NOW I know better but its too late to reverse the damage! For petes sake take EVERY precaution you can!!!
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Old Dec 07, 2010, 05:25 PM
Entropy is happening!
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Australia, NSW, Bellingen
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Young and tough

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Originally Posted by DudleyLeRoux View Post
Hmmm, i don't have a problem spraying 2k without a respirator. I do spray in a ventilated area though. Maybe I just have cast iron lungs.
Dudley,

I am guessing that you are still young and tough! I am 65 years old, and my liver is sending out signals that it is approaching its "use by date". It requires care with all I that I put in my mouth and exposed myself to in the way of volatile solvents etc.

Even though immediate or short term effects might not be evident, there is still likely long term effects.

Jim.
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Old Dec 07, 2010, 05:36 PM
Entropy is happening!
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Splooge or Clay edge?

After looking at Alex's thread regarding the sploogeing of the parting board/plug intersection, I have decided to use clay.
I think that splooge is the superior way to go and most certainly would do it that way if I was also painting in the mould. Since I will not be, I'll use the clay for simplicity. That way, I will not have to strip the parting board of the dam to do so, and to cut the board into two to separate it to remove the plug for surfacing etc.

This fuselage will have glued on tail surfaces and wing as it is to be a one piece glider. So lots of additional reinforcement and filling/sanding of fillets in these areas. This would spoil any nice "Paint in the mould" finish.

Besides, I am planning on priming and surfacing the whole model, then (hopefully) doing a major airbrush job on it as bird look alike.

Jim.
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Old Dec 07, 2010, 05:46 PM
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Cody, WY
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Jim, I use clay to make molds that produce parts that will be post-painted. The only time that I use sploog is for making molds that produce PITM parts or primo-naked carbon stuff.

Good call.

Adam
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Old Dec 07, 2010, 07:21 PM
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Clay/plasticene.

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Originally Posted by wyowindworks View Post
Jim, I use clay to make molds that produce parts that will be post-painted. The only time that I use sploog is for making molds that produce PITM parts or primo-naked carbon stuff.

Good call.

Adam
Thanks for that confirmation Adam! The stuff I have from my local suppliers is called plasticene. I am assuming it is the same material?

Jim.
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Old Dec 15, 2010, 05:05 PM
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Wings bagged

I bagged the wings yesterday and this morning I pulled them out. I had primed the mylars with grey automotive primer except for the middle of the top where they will be glued onto the fuse. They came out looking really good with the primer filling all (or any) pinholes, which will make for easy follow up paint preparation. With only the primer, there is no noticeable waviness which I usually get!
There are a bit heavier than I planned at 490 grams! However, a bit of extra weight on the slope is no real problem. They feel really strong and stiff!
The layup, all "E" glass was:
1 layer of 76 gsm cloth @ 90 deg.
1 layer of 76 gsm cloth @ 45 deg.
1 layer (doubler) 1/3 span 76 gsm cloth @ 90 deg.

I did use plenty of epoxy and also rolled epoxy on the cores before assembly, to be sure, to be sure! This is one of the bubble avioding strategies that I have adopted. I also rolled the entire layed up assembly while it was under vacuum with a hard roller from middle to LE and TE to remove any entrapped air. I think I got this tip from Joemach1.

Anyway, I will now do an extension on my hot box to fit the one part wings into the box and get it cooking with gradually rising temperature. That will be the acid test for any tendency to bubble will show after some cooking.

I will post a picture of one my Endorphin wings with some of the bubbles that I am trying to avoid. As well as a pic of the new wings out of the bag this morning. Allways a good experience to pull a wing or a moulded part out and find it has been a success!

Jim.
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Old Dec 16, 2010, 01:10 AM
Entropy is happening!
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Hot box

The wings are now in the hot box. I am raising the temperature gradually. The temp is now around 45 deg. C.

What is the recommended max. temp. that I should elevate it to, can someone please advise?

Jim.
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Old Dec 16, 2010, 01:13 AM
Just fly it!
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Cody, WY
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Blue foam can off gas at higher temps and create blisters. I typically don't take my cores above 110-115*F - 43-46*C.

Secondly, I leave the mylars on until the post-cure is complete. This reduces the amount of fabric print-thru.

That's me anyway. I'm sure you will find some differing opinions out there.
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