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Fibreglass, Carbon Fibre, Paper Mache - The composites chat thread

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Not sure if I should get some epoxy or try to rangi up a vacuum system or just carry on as I am..

Did some reading about prepreg but seems like the cost skyrockets / is not really novice spec.

20181209_093404.jpg

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Keep doing what you're doing, looks great! 

I mean, your first thing you've done and it looks marvelous. Can only get better from here as you go! 

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Headlight blanks in and made a lid for my air box.

The air box was 3 layers of carbon laid onto a thin sheet of aluminium with 2 quick coats of wax. It was a little over rolled / short on resin. I wonder if a little more cure time in the pot would have stopped the resin extruding.

 

20190120_105414.jpg

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Airbox lid.. in the post below for some reason.

Does anyone have a good adhesive to gluing stuff to the carbon.. like mounting tabs etc..

 

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1 hour ago, mjrstar said:

 

Does anyone have a good adhesive to gluing stuff to the carbon.. like mounting tabs etc..

 

We used a loctite instant adhesive at work for plastic vortex’s to fibreglass, can’t remember which one tho sorry

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9 hours ago, mjrstar said:

Airbox lid.. in the post below for some reason.

Does anyone have a good adhesive to gluing stuff to the carbon.. like mounting tabs etc..

 

The same epoxy you made the panel from would be a good start, make sure you key up the panel in the area you're trying to bond and even more sure that all the release wax has been cleaned off

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Starting on a new mould for some 4AGE ITB trumpets but learning from some previous mistakes. 

Problems from the past are that I've had too little draft angle on some parts that are quite long. Also that some of the excess untrimmed parts end up folding over something and locking the part in place. Also trying to use only 2 pieces when theres no reason not to use more if it makes life easier. 
Annndddd I think it will be a good idea to add some tabs so I can twist the halves relative to each other to try get the part free.
Previously I've damaged the moulds by needing to smash a screwdriver in (or whatever) to get the halves apart. 
Hopefully this will help! I'm hoping I can make at least four, or even eight from the one set of moulds.
I'll also try drill some little holes in the moulds, fill them with wax and then so afterwards I can use some compressed air to blow the halves apart hopefully if they are stuck. 
The center part of the bell shape still needs to be dissolved out, but cant think how else to get that sweet sweet return angle on it.
Worth it... Fingers crossed! 
 
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Fingers crossed! 

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So that was a win and a fail. 

It was a win because getting the moulds polished up from 360 grit up to 2000 made for a nice result and the moulds popped apart super easy and definitely reusable without any damage inflicted to separate them.

It was a lose though because my design didnt work too well. 
Trying to fold the carbon fiber up around the radius of the bell didnt really work, this is where the sheet needs to kinda do some pleats to make the turn. So its hard to hold it all in place while trying to push the top down, which due to tight tolerances would then just want to squish it all back out the sides anyway.

So I think I need something else which pushes in from the sides instead of just down from the top. So maybe split into 120 degree segments or something. 

Aaaaahhhhhhhh frustrating but learned something from it.

Also with some further consideration I need to remake them a smaller size anyway. 
This is why I'm glad 3D printing exists, it would suck a whole lot more to make these moulds any other way then have to restart a bunch of times! 

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you need to accept that 3d printing isn't part of the solution- use an air bladder or a vac bag rather than a 2 part mold. Literally done over and over for parts like these.

 

Do you need someone to share the youtube videos again :-D

 

edit:

Sounded real shit. Love your work xx

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Printed moulds are legit! 
User error/inexperience not bad tools. 
One of my previous ones (rear one) formed the bell shape just fine.
I tried something different and it didnt work. So now I know what else to try instead.

Even as per below it's just being bit of a fuss pot to get that full return on it.

20190224_164147.jpg.5964cb9dfe06c5e0d7c86459f5f6e6b8.jpg
 

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