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Feb 01, 2005, 09:50 AM
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Florrain's Avatar
It's not that easy to take pictures of a white surface but here are the results on the plugs.
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Feb 01, 2005, 10:00 AM
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Florrain's Avatar
Next step:

5 coats of wax with 4 hours between each coats and 24hrs between last coat of wax and gelcoat.

@devmonkey:

Yes the mold will be filled with "moldpasta" I don't really know what it is made of but my guess is it's made of resin+chopped fiber+ sand.

it's heavy and expensive but it is rock solid and very stable.
The layup will be: gelcoat+ 58gr glass+ 3x 160gr glass + 3 cm thick moldpasta + 3x160gr glass + 58gr glass
Feb 01, 2005, 10:04 AM
Need 4 Speed!
pdawg's Avatar
Wow!!! what a nice plug. After all this preparation on the plug, will you still have to polish the mold when its done? Incredible work,... just incredible
Latest blog entry: original Y/A F-18 Kit
Feb 01, 2005, 02:07 PM
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Quote:
Originally Posted by Florrain
Next step:

5 coats of wax with 4 hours between each coats and 24hrs between last coat of wax and gelcoat.
What wax system do you use? Different system or same on plug/mold versus part/mold layup? How do you like it in terms of pre-painting in the mold for parts layup?

Will you be integrating the slight depression for tape used for aileron wipers?
Feb 01, 2005, 05:48 PM
Registered User
Hi ptxman,

the wax he and i uses is PAT921 that is an polymer based release wax that is very tough and when multiple layers are aplied it hold for several releases without the need for waxing for every lay-up.
I normally pull about 5 releases from an mold before aplying one new layer of wax,i use it with vorgelat and with 2K paint without problems.
the best ruud
Feb 01, 2005, 07:16 PM
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Quote:
Originally Posted by ruud zandvliet
Hi ptxman,

the wax he and i uses is PAT921 that is an polymer based release wax that is very tough and when multiple layers are aplied it hold for several releases without the need for waxing for every lay-up. ruud
Do you mind telling me where PAT921 is available from? I typed it in my search engine & only your website came up! Maybe you are cooking your own recipie? Do you find the initial coat of paint beads up very much on the wax, or is it kind of formulated for this purpose.
Feb 02, 2005, 06:35 AM
Registered User
Hi ptxman,

Recipiene stainless steel high pressure cookingpan,multiple pure pyrex mixing bottles,safety gear,some nasty chemicals.
Or look at the german site from wurth this is an firm that makes release waxes,is also sold by me or by emc-vega.
i have no problems with paint,or gelcoat that it beads up,just spray it on in an nice closed film.
There is no problem with masking tape this al works well,and the release goes easy.
the best ruud
Feb 02, 2005, 05:17 PM
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Florrain's Avatar
Hi again,

No pictures today because I have been waxing and buffing and waxing again and again so nothing much interresting except i can back up Ruud's comment on the wax being very strong when dry.

I have been a litle heavy handed on the first layer and It took me several hours to buff it afterwards. It is very,very strong when dry.

I only found the right amount on the third layer and you really need very litle wax to cover large areas. the result is much cleaner and easyer to buff out.

I have also been playing around with my airbrush and 50/50 diluted PVA on a sample board and it looks promizing. I might use it as a back up on the plugs.
I'm still hesitating about this.

Any feedback from somebody with airbrushing PVA experience?
Feb 06, 2005, 02:03 PM
Pylon freak
Paulus's Avatar
A quick update on the Nemesis.

Today I flew the Nemesis with a B40 FAI 9 cell motor on 9 GP2200 cells and an APC 5x5 prop. I also shifted the CG to 55 mm. No CG problems with the lighter motor by the way.

I had some problems keeping the batteries hot in the cool wheather but after a few rounds the Nemesis really began to move! The runtime was pretty short. I think it can complete 10 rounds but just barely. I wanted to compare this with my B50 setup but the ESC was giving troubles but todays setup appeared to little faster.
With the CG on 55 mm cornering is way better then on the maiden flight. It really bounces out of turns. Holding knife edge was also very good. Flying the Nemesis feels much better than my Avionik D99 or Tokoloschi.

Paul
Feb 09, 2005, 06:25 AM
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Florrain's Avatar
Hello again,

We have been working hard on making the Jibe's mold.
Here is a small picture story about it:

We first filled the groove around the leading adge with special clay called Plastiline
Feb 09, 2005, 06:43 AM
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Florrain's Avatar
next we filled the trailing edge groove with a 4mm x 8mm rectangular section PVC strip which we spot glued in the previously waxed groove.

A few "ejection bolts" were also made and glued on the parting plane in strategic locations.
These ejectors are made of a special bolt, a tube and an aluminium plate.
The idea is to screw a long screw in the drawned bolt which will push on the floating aluminium plate which in turn will push the mold away from the plug.
Feb 09, 2005, 07:20 AM
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Florrain's Avatar
the boxes are then closed around the plugs and triangular strips of PVC are spot glued on the edges.
Clay is added to smooth the corners and the alignment pins are located in there positions by tapping them with a small hammer.

On the last picture, the plug is ready for gelcoat and is placed vertically for easyer access.
Feb 09, 2005, 07:32 AM
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Florrain's Avatar
Now the messy work starts with hard gelcoat.
Hard gelcoat is used on the edges of the mold an on the parting plane.
The problem with metal filled gelcoat is that it doesn't polish well so it's use has to be limited to the edges and it has to be applied very precisely to avoid overlapping to much on the form itself.

It took us almost 3 hours to cover the 2 wing plugs and the 2 tailplane plugs with hard gelcoat.
The max overlap on the leading and trailing edge is +-1mm and Novy did an excellant job with it.

Note: The metal particles in the gelcoat are very abrasive and if you spill some on a part that has to stay clean, you have to leave it there or very very carefully remove it with the tip of a clean brush. I you wipe it clean with a cloth, you are sanding the wax layer with the metal particles and you are in trouble...
Feb 09, 2005, 07:38 AM
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Florrain's Avatar
after hard gelcoat has been applied and has started to gel, softer polishable gelcoat is brushed ontop of the all plug.

When the gelcoat starts to gel, dry cotton is spread over it to form a coupling layer and after some more waiting for the gelcoat to cure a litle more, more cotton is applied and wetted with epoxy in the corners and everywhere a filet is needed for the glasscloth to conform nicely to the shape of the plug.
Feb 09, 2005, 07:44 AM
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Florrain's Avatar
After the cotton application, the glass cloth are applied.

For the wings, we used 1 layer of 58gr + 1 layer of 160gr + 2 layers of 200gr

The last layer is applied very wet and the box is filled with moldpasta.
Moldpasta is a ready mix of chopped fibre,sand and epoxy. It's very strong and very stable but it is also very expensive.

We used about 3cm thick layer of mold pasta which is about 16kg for both wings and both tailplane mold.


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