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Old Nov 11, 2012, 10:04 PM
deltas are cool
AIR SALLY's Avatar
Tehachapi ,CA.
Joined Apr 2006
19,993 Posts
amazing is this your first time making molds ? if so you are a quick learner ,nice work ,heres a tip in case you need one ,when i do shapes that are not flat ,like your cowl and fuses i cut the glass on a 45 degree angle and it sure makes doing the lay ups a lot easier,also if you use a darker tool coat or dye the white to a darker color it makes doing the lay up a little better cause you can see air bubbles and voids a lot easier. nice work ...keep at it
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Old Nov 11, 2012, 11:07 PM
Dean
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USA, CO, Littleton
Joined Apr 2005
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Definatley not a beginner, for sure!
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Old Nov 12, 2012, 06:49 AM
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acesimmer's Avatar
United States, NV, Fernley
Joined Oct 2011
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Thanks for the tip Roger keep them coming. Yes, I know about the angle layups to allow the cloth to flow around curves much better. I have made molds in the past but was thirty years ago and only made a couple of planes plus model boats. One was a large BA Hawk and the other a large Saab Viggen then a 5ft PT17 Jap Torpedo boat. These came out pretty good by pure luck.... laugh. Now it is so much easier to get info due to the internet.

This is my first large detailed scale mold set using all the modern resins etc. I wanted to tint my tool coat but it is the first time using this brand and type so did not want to risk anything on this layup.

I do have a lot of experience making molds with silicone/RTV rubbers etc. When I was restoring my Spider I had to make all of my own badging due to availability. I will be casting a lot of the scale parts for this model also.

Regards Stranded mat. It is working great for a stiffen layer. I pull it apart to loosen the strands then lay it as patches that overlap so they bind together. I use it only on the final and last layer.
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Old Nov 12, 2012, 10:49 AM
Go small or go home
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Old Nov 12, 2012, 01:19 PM
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United States, OR, Portland
Joined Jan 2008
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What a great How-To!

Just out of curiosity, was the Spider an Alfa, Ferrari or some other two-seater?
I remember casting dash knobs for my 750 series Sprint twenty years ago.

Are you thinking you'll do composite skinned wings as well? It would be so nice to maintain this level of detail in the wing and control surface skins.

-Joe
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Old Nov 12, 2012, 01:38 PM
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United States, HI, Kamuela
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I would hope you would paint the beauty in 1965 - 1966 VIET NAM color's! I was there, Saw aerial support with the T-28. Thanks Bob Hansen
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Old Nov 12, 2012, 06:01 PM
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United States, NV, Fernley
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Quote:
Originally Posted by Joe Kollmann View Post
What a great How-To!

Just out of curiosity, was the Spider an Alfa, Ferrari or some other two-seater?
I remember casting dash knobs for my 750 series Sprint twenty years ago.

Are you thinking you'll do composite skinned wings as well? It would be so nice to maintain this level of detail in the wing and control surface skins.

-Joe
81 Fiat.... Used to have a Ferrari Dino years ago and hated it. Slip the clutch a couple of times and its replacement time....Crunch a gear and you know what... Yuck

Yes, I'm doing a full top and bottom scale detailed wing. Going to try a couple of methods. Standard foam hot wire with the skin. And the other is 2K urethane expandable foam under compression whilst the skins are in the mold with a spar added. Done a few experiments and it looks very promising.

I just laid up a cowl to test the new release agents before continuing. One half with the old method and the other with the new stuff. Will see if any difference in part release. I would hate to finish the molds and find it does not part out... I did remove the rear parting plane and it just popped off super easy so maybe hope yet. I had read this morning that some peeps had issue with the new stuff then some loved it. So will see.... Also finished the rear parting plane and ready to mold that section tomorrow.
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Old Nov 12, 2012, 06:03 PM
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United States, NV, Fernley
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Quote:
Originally Posted by Robert Hansen View Post
I would hope you would paint the beauty in 1965 - 1966 VIET NAM color's! I was there, Saw aerial support with the T-28. Thanks Bob Hansen

I'll be doing several builds with a range of schemes. I must look that one up.
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Old Nov 12, 2012, 08:18 PM
No Hangar Queens!
Maryland
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Quote:
Originally Posted by acesimmer View Post
2K urethane expandable foam under compression whilst the skins are in the mold with a spar added.
That sounds like a BRILLIANT idea.
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Old Nov 13, 2012, 07:57 PM
Now in TN!
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Chapel Hill, TN USA
Joined Apr 2001
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You're moving right along Ace.

J
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Old Nov 13, 2012, 09:37 PM
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United States, HI, Kamuela
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Squadron Signal has Era books on the aircraft in Viet Nam, in color, and various group Logos. Thanks Bob Hansen
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Old Nov 13, 2012, 10:55 PM
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Australia, NSW, Plumpton
Joined Jan 2008
381 Posts
good to see this but need your help im material ...

if i want to make moulding what should i use material and can you list them with purpose ???

thanks in advace for helping...
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Old Nov 13, 2012, 11:24 PM
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United States, NV, Fernley
Joined Oct 2011
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I'll Try.......

I used a foam plug and covered it in 2oz cloth using a laminating epoxy resin. Then covered in a 2K quality hi build automotive primer

Wet sand down 240, 300,400, wet/dry paper
Used a two part putty scratch filler then repeated until close to perfect. Then wet sanded to a hi sheen with 800, 1200 then 1600 paper.

Add rivets if wanted using hi quality carpenters glue with around 50% water. Google for lots of ideas!

For the mold

Used 100% pure Canuba wax buffing on several coats. Then spray with PVA mold release

Check my picks or Google for parting planes.

Used an epoxy tooling coat with two thin layers
Then clear epoxy laminating resin over 1oz cloth and build up sharp edges/corners until rounded off.
Then same resin with 2oz cloth several layers over those corners/edges.
Then cover entire plug with 2oz cloth and resin
Then several coats of 6oz cloth and resin
Final coat is the heavier stranded mat or 10oz cloth.
Allow to cure for 24 hrs above 70 deg F

Best to google and check out the real experts. Lots of vids on YouTube.
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Old Nov 14, 2012, 07:32 PM
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The outside temps got much better today so with minimal heat in the shop I was able to layup the rear tail section. So she is half complete. I had a heck of a time with some of the sharp outside and inside corners. Especially around the hinge blocks and the elevator stub. Even using 3/4oz I was having issues due to the outer hinge block being very small and sharp. So I mixed up some tool coat and added cotton flock to make a paste. I inserted the flock paste into a large syringe and used it like a mini calk gun. Works like a champ and I was able to get at all the sharp bits and soften them up. I still think that I may have a few bubbles but will fix those in the mold face if required.

Tomorrow will remove parting planes and clean edges ready for the final layup on Friday. I sure hope these new materials work and the plug releases easy without being destroyed. One good thing about doing the mold in quarters instead of two halves is if one piece came out bad I could just remold that section assuming the plug survives....GULP!!
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