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Old Oct 16, 2012, 08:39 AM
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mikegbogh's Avatar
Roodepoort, South Africa
Joined Aug 2007
1,036 Posts
First half layup

Hi Guys,
Some more pics of the weekends layup. After the thin wipe of PVA it was time for gel coat, I am using a GC 1080 from AXXON products and it is polishable.
I mix about 50 gram at a time and lighty heat it to make mixing easier. The mixing is very thorough , often scraping down the sides of the cup , after a good few minutes the mixed gel coat is tranferred poured into a fresh cup and this is brushed on, the reason is I dont want any gel coat from the very bottom of the cup that is not fully mixed.

Once the plug is covered with a nice even layer it is left to gel, depending on ambient temp in my workshop that 1-2hrs. Once its setting but tacky the cotton flox mix gets contoured into the sharp corners as well as some around the wing roots and canopy lip.
Next I add a 2 x 80k carbon tows also to round the hollows and stiffen the mold edges. Next starts the light cloth 49/86 gr and I use as much off cuts as I can and plenty over the nose and wing root areas.

Next is bigger pieces of soft 163gr glass, about 2 layers all over, followed by 4 layers of thick stitched bi-axial cloth at 400gr this is precut into reasonable pieces and layers built up, it soaks up lots of resin, which I mix at 100 grams a shot , more starts heating before I can get it wet out, if U mix more.

Last layer is a thin one again, so the surface is easy on the hands it took 8 hrs, 2ltrs of epoxy and 20 latex gloves to get the pics to this point.
pictures below.
cheers
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Old Oct 16, 2012, 08:54 AM
Hunting for Goat Lifters
Titus ZA's Avatar
South Africa, GP, Randburg
Joined Jul 2012
109 Posts
One word, Inspirational!

Fantastic work as usual. Love your masterclasses

cheers
T
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Old Oct 16, 2012, 12:31 PM
Deniable plausibility
Shedofdread's Avatar
Derbyshire, UK
Joined Aug 2008
2,313 Posts
All looking very good Interesting you're using Axxon resin - we used to use their resins but went over to SP / Gurit stuff for some reason (probably price...). I rather fancy the Axxon was better - it certainly has a longer shelf life before it needs a heat cycle to re-liquefy it.
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Old Oct 17, 2012, 07:00 AM
Thermaholic Homoslopian
fuzzchucker's Avatar
Kempton Park, Gauteng, South Africa
Joined Dec 2003
41 Posts
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Originally Posted by mikegbogh View Post
Hi All

The beautifull shape you now see, is refered to as the "form" or shape, and once its been used it gets binned, sad really.
Mike, you could always stick some dummy wings on it and make a static display of the plug... Persuade AMT to buy it off you for display in their shop. You sure as hell spend enough money there building all these GBOGH gliders

Are you going to the Warthogs Aerotow event this weekend? I kitted my ASG29 with tow release last night. Would like to go and give it a try. Would be nice to fly her again, she's seen WAAAYYY to little slope action this year.

Cheers,
Izak
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Old Oct 17, 2012, 08:48 AM
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mikegbogh's Avatar
Roodepoort, South Africa
Joined Aug 2007
1,036 Posts
halfway not bad

Hi All,
So 3 days later , time to take off the splitter board. I made some small cuts in the chipboard, one at the nose and two by the tailfin, broke out the thin tailfin section and lifted off the one half.
It released with no problem and looks like the plug is still dead centre so thats great. I will start polishing and preparing to now layup the second half.
Once finished I will let it rest a few days then cut both the edges, and smooth them .
Cheers
Mike
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Old Oct 17, 2012, 10:56 AM
Registered User
Joined Nov 2008
184 Posts
Just incredible Mike but I can't bear the idea that you bin the mould at some point!

I'm doing an ASW/ASG29 re-furb thread on the UK Scale Soaring website but I'm much too embarrassed to post it on here! I will be shamelessly copying your wing building technique when you get to it though...

Simon
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Old Oct 18, 2012, 01:48 AM
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mikegbogh's Avatar
Roodepoort, South Africa
Joined Aug 2007
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Hi swarrans,
Just incredible Mike but I can't bear the idea that you bin the mould at some point!

Not quite right, we keep the mold and the plug becomes obselete.
The molds should be good for at least 10 fuselages.
Should make the first fuselage in about a week or two.
cheers
Mike
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Old Oct 18, 2012, 02:35 AM
Registered User
Joined Nov 2008
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Quote:
Originally Posted by mikegbogh View Post
Hi swarrans,
Just incredible Mike but I can't bear the idea that you bin the mould at some point!

Not quite right, we keep the mold and the plug becomes obselete.
The molds should be good for at least 10 fuselages.
Should make the first fuselage in about a week or two.
cheers
Mike
Yes, sorry that's what I meant to say - it's still a shame as it is such an object d'art!...
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Old Oct 18, 2012, 05:30 AM
KISS_KeepItSimpleStupid
philkiteflyer's Avatar
Invercargill, New Zealand
Joined Nov 2006
548 Posts
Quote:
Originally Posted by mikegbogh View Post
Hi All,
So 3 days later , time to take off the splitter board. I made some small cuts in the chipboard, one at the nose and two by the tailfin, broke out the thin tailfin section and lifted off the one half.
It released with no problem and looks like the plug is still dead centre so thats great. I will start polishing and preparing to now layup the second half.
Once finished I will let it rest a few days then cut both the edges, and smooth them .
Cheers
Mike
OK, thanks for the answer to my first silly question, answer accepted gratefully.
Now I'm trying to understand the second mold layup. You have removed the board and will be making the second half using the first mold as the splitting board? ? ? Have I got that right ? ?

If so, then I now understand and going to have to have a go myself . . .someday . . . when I've got time . . .and more room in the workshop . . . . a better understanding of what to do . . . and can decide on JUST ONE MODEL.
So much to learn, so little time. Ah well such is life.

Mike, I'm enjoying your build and your commentary, it is very informative.

Thanks for sharing,
Phillip C
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Old Oct 18, 2012, 06:04 AM
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mikegbogh's Avatar
Roodepoort, South Africa
Joined Aug 2007
1,036 Posts
Hi there,
Quote
OK, thanks for the answer to my first silly question, answer accepted gratefully.
Now I'm trying to understand the second mold layup. You have removed the board and will be making the second half using the first mold as the splitting board? ? ? Have I got that right ? ?


Yes thats it without removing the plug the now exposed mold surface is waxed as well as the plug again. The plug is then buffed to a shine and a PVA coat applied.
Hopefully after laying up the second half , ie gel coat, light glass heavy glass the shape is perfecty reproduced with a nice clean join line down the middle.

The locating holes will be gel coated and filled with some flox mix and later when they lock in place the products will all be exactly the same.

Thats the plan anyway, we will see what happens next week when the plug is removed. I have seen guys remove the one half at this stage and then re-insert it back into the mold half, but by doing that you break the midline seal , and it is possible that when you do the second half , the plug could shift ever so slightly.

thanks for watching and asking questions , always welcome contributions, ideas and questions.
cheers
Mike
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Old Oct 19, 2012, 04:00 AM
Stirring the pot
johannlochner's Avatar
Port Elizabeth South Africa
Joined Jun 2008
4,013 Posts
I need to spend more time here on the Scale Sailplane forum!

I have been missing out.....
Well done so far Mike!

J
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Old Oct 19, 2012, 04:39 AM
KISS_KeepItSimpleStupid
philkiteflyer's Avatar
Invercargill, New Zealand
Joined Nov 2006
548 Posts
Quote:
Originally Posted by mikegbogh View Post
Hi there,

Yes thats it without removing the plug the now exposed mold surface is waxed as well as the plug again. The plug is then buffed to a shine and a PVA coat applied.
Hopefully after laying up the second half , ie gel coat, light glass heavy glass the shape is perfecty reproduced with a nice clean join line down the middle.

The locating holes will be gel coated and filled with some flox mix and later when they lock in place the products will all be exactly the same.

Thats the plan anyway, we will see what happens next week when the plug is removed. I have seen guys remove the one half at this stage and then re-insert it back into the mold half, but by doing that you break the midline seal , and it is possible that when you do the second half , the plug could shift ever so slightly.

thanks for watching and asking questions , always welcome contributions, ideas and questions.
cheers
Mike
Thanks, now I understand.
Good luck with part two . .

Phillip C
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Old Oct 22, 2012, 06:20 AM
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mikegbogh's Avatar
Roodepoort, South Africa
Joined Aug 2007
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Phase 1 Part2 or first part.

Hi guys,
Well saterday I got started early and after one more layer of release wax, gave only the plug a good shine, next was a wipe with the PVA, which by the way is my new best friend.
Painted on the gel coat and after a short break (lunch) it was time to start the process again, namely , flox/resin across all sharp transitions, hollows and canopy lip, next two carbon tows tip to tail , followed by light glass , medium glass and about 4 layers of Bi-axial cloth.
Final layer of fine cloth sealed everything off at 17:00 hours.
Left overnite it was nicely cured sunday morn, as the sun was trying to come out and I was off for an aerotowing event , I left the mold out in the sun in some black bags to ramp up the temperature for the day and do a little postcuring.
The aerotow went real badly for me and so I was home early, decided to crack open the molds and see what was inside.
regards
Mike
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Old Oct 22, 2012, 06:44 AM
scratch build everything
DudleyLeRoux's Avatar
South Africa, KwaZulu-Natal, Botha's Hill
Joined Aug 2009
1,219 Posts
Nice work Mike, Just let me know when you read to talk about releasing some of those fuse's into the world.

I am going to hazard a guess that the aerotow ended in a broken tail boom, landing at that attitude is never going to be pretty for those long fuselages.
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Old Oct 22, 2012, 07:06 AM
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mikegbogh's Avatar
Roodepoort, South Africa
Joined Aug 2007
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Originally Posted by DudleyLeRoux View Post
Nice work Mike, Just let me know when you read to talk about releasing some of those fuse's into the world.

I am going to hazard a guess that the aerotow ended in a broken tail boom, landing at that attitude is never going to be pretty for those long fuselages.
Hi Dudley,
Nice to hear from you, these fuselages wont just be released, I would rather scale pilots get them, there will be a few complete aircraft built , but there is a lot of interest, including some fullsize JS 1 owners.
and I know 4 complete planes already have homes, fuselages are the easy part. Oh and I also have a real job as well, lol

Your guess ....well this was only the begining of the pear shape so yes and no
ha ha
regards
Mike
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Last edited by mikegbogh; Oct 22, 2012 at 07:40 AM.
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