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Old Jan 02, 2013, 07:38 PM
Arrarrar!
josh18's Avatar
Australia, NSW, Wagga Wagga
Joined Jan 2010
3,317 Posts
Thanks adam, Thats exactly the snswer I was looking for.
Jim- are you using just wax, wax and pva, or frekote for your moulds?
The biggest thing I dont like about my current moulds is that they have pva swirls in them. I think the next set I make I'll go with semi permanent releases like frekote etc. Sounds like its well worth the investment.
Cheers
josh
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Old Jan 02, 2013, 07:41 PM
Entropy is happening!
Jim.Thompson's Avatar
Bellingen NSW Australia
Joined Aug 2008
6,716 Posts
One or the other.

Quote:
Originally Posted by josh18 View Post
................ I know Adam recomends it but I though I'd heard him say in the past that he doesn't like epoxy based tooling coats because they are hard to polish. .......................
Just repeating what I may have answered before here Josh: if you want to mould as "professionally as possible", as you mentioned previously, you need to make the necessary decisions. One or the other. From start to finish.
That is why I suggested you follow Adam's recommendation to the last detail. If you require polishing at the mould stage, the plug finishing and/or the release system has been compromised - by definition.. Not professional in the fullest meaning of the word, I would suggest.
My methods and my skills are still well and truly developing. I continue to use wax and PVA, which a more professional moulder would not. When and if I gain the necessary skills to avoid the more fundamental pitfalls and I can afford the semi-permanent release systems, I will progress to using them.
However, there are mitigating circumstances, I have no one around me within 500 klms who might share a 5 ltr. container of Frekote or Marbocote, both of which I understand have a limited shelf life. These economic factors have to be taken into consideration before making the crucial decision. I'm a retired pensioner with a limited budget.

If you really want a polishable mould, use polyester gel coat followed up with Vinylester Resin and chopped strand mat. I've used it for fuse moulds and will be using for the fuse for this plane. I understand that the gel coat is polishable.
After all, how many parts do you expect to manufacture from your proposed moulds? This is relevant to the set of choices too!

Jim.

edit: I was posting at the same time you were. Some of the above may be irrelevant or out of order. My apologies if that is so.
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Last edited by Jim.Thompson; Jan 02, 2013 at 07:43 PM. Reason: see edit.
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Old Jan 03, 2013, 02:33 AM
Arrarrar!
josh18's Avatar
Australia, NSW, Wagga Wagga
Joined Jan 2010
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No worries Jim, Ive just been confused for a while, but what Adam said pretty much cleared it up.
Cheers Jim
Josh
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Old Jan 03, 2013, 12:32 PM
ETS....Energy retention system
timbuck's Avatar
gold coast australia
Joined Aug 2008
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What happened to jimbello...? Where did he go..
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Old Jan 03, 2013, 01:58 PM
Entropy is happening!
Jim.Thompson's Avatar
Bellingen NSW Australia
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Quote:
Originally Posted by timbuck View Post
What happened to jimbello...? Where did he go..
Ohh! We put him out to retirement. After all, he was getting a bit old you know!

New Year, fresh start, new name.

Jim.
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Old Jan 03, 2013, 07:54 PM
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Jim.Thompson's Avatar
Bellingen NSW Australia
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Air injection fittings.

I've got the air fittings ready for the fuse mould.

The nut and hose tail will be cast in the wing root of the mould. I will put some teflon tape around the exposed part of the thread to protect if from resin contamination. A small ball of plasticene will be stuck in the end, which will also stick in place long enough to get the first coat of gel coat to retain it. When all layed up and cured, the hose tail can be removed and replaced with the plug as in the pic on the right. Some plasicence can be used to fill in any gaps etc. on the inside of the root face.

When ready to pull the part, I only have to change the tail for the plug, put a hose on it and apply a few psi of air pressure.

Jim.

edit: That should read: "the plug for the tail".
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Old Jan 05, 2013, 07:51 PM
Entropy is happening!
Jim.Thompson's Avatar
Bellingen NSW Australia
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Good spray painting conditions.

I'm now waiting for some suitable condtions to spray the plugs with 2 pack black paint.
It has been very humid where I am, the normal conditions of summer. We have some moderated humidity forecast for Tuesday.
So, I'm hoping that will be the day these get painted.
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Old Jan 06, 2013, 09:27 PM
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Bellingen NSW Australia
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Drilling guides.

The drilling guides have been machined ready to go when required.
They can be seen fitted on the bright mild rod stock that will serve as the positioning guide. Two sizes of course.

All I need to do is paint the plugs, wait a few days for it to cure, then start on the fuse moulding.

The excitment is building...............

Jim.
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Old Jan 08, 2013, 03:11 PM
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Bellingen NSW Australia
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Painting frames.

I made some simple painting frames to support and hold the wings.
The weather is looking good for painting later this morning. Humidity dropping and the breeze is also forecast to drop.

Should be a goer!
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Old Jan 08, 2013, 03:13 PM
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Bellingen NSW Australia
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Square joiner question.

Quote:
Originally Posted by wyowindworks View Post
Oh, sorry, Jim. I see that you are parting the fuse the other way....which is just fine. You would just layup the mold halves around the drill guides.
Which brings to mind Adam, in the case of a square or rectangular joiner, would you use some of the joiner box (or tube if you like), to do the same job?
Except of course that you would not drill out the hole, but scribe it for later cutting out after pulling the part out of the mould I am guessing?

Jim.
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Old Jan 08, 2013, 03:40 PM
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Whitchurch,Shropshire. UK
Joined Jul 2008
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Hi Jim,
Thought I would post my results from a Quick Test of Adams recipe for Tooling coat'
Using an old plug as a surface to test the coat on I reapplied two coats of Freekote.
I then mixed up some laminating resin and hardener, too this I added 25% WS 404 and 8% Graphite.
This was applied to an area at a thickness of approx 0.5 to 0.75 mm and allowed to go tacky.
Another mix was applied in a similar fashion and thickness and again allowed to go tacky again.
Two or three layers of 100 gsm glass where applied with laminating resin / hardner mix and allowed to harden over night.
The area was pulled from the plug with very little effort and produced an excellent surface free from air bubble voids.
Whilist I was applying the first layer of the tooling coat no problem what so ever was encountered with the coat Fisheyeing. This is not the case with the commercial Tooling gel coat that I have been using to date.
Hope this encourages others to use Adams recipe for tooling coat.
Chris
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Old Jan 08, 2013, 07:57 PM
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Bellingen NSW Australia
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That all sounds like good news Chris!
Did you use only the Frekote? Or did you use the "sealer" first, then the Frekote?
If I got it right, Adam uses the sealer first. Not sure.
I kinda envy you builders who can obtain some Frekote. It must be the way to go.

I wonder if I asked one of my friends in the north? .......

Jim.
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Old Jan 08, 2013, 08:12 PM
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Bellingen NSW Australia
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Plugs painted!

I had a lucky short break in the weather and got the plugs all spray painted with 2 pack glass paint. Two hours later, the wind was blowing, and now at lunch time, there was even a few spots of rain.
Anyway, it went very well, despite me confusing the reducer for the hardener! By the time I had added the correct quantity of hardener, I had the paint thinned to more like 50% instead of around the recommended 15%. It did not seem to matter as the paint went on very easily. Apart from some slight orange peel on the wings, the job is the best I've done anyway. It will polish up quite ok I think.

I improvised some frames to suspend the wings in for painting. They worked ok.

I used a supplied air respiration helmet and wore a spray painters coveralls. It was a bit hot in the mid morning 35 deg. C.

Jim.
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Old Jan 08, 2013, 08:31 PM
ETS....Energy retention system
timbuck's Avatar
gold coast australia
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Glad to hear it went well Jim.
At least thin paint spreads easy. and flashes off quick.
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Old Jan 08, 2013, 09:00 PM
Entropy is happening!
Jim.Thompson's Avatar
Bellingen NSW Australia
Joined Aug 2008
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Yes Tim. It does seem that for a beginner like me, thinner than recommended is possibly a good way to start. I know it results in a thinner paint thickness, but that can be built up.

Jim
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