bracesport
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@Wildthing - watching too many YouTube videos!
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bracesport
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First test of the moulds this morning - this is the fibre glass nose cone - I am working up to the more complex carbon parts! There is three layers of very light FG cloth - the middle layer is with the grain and the outer layers are biased to the grain - it seems to work pretty well just using a brush to dab everything into place - the extra glass on one half is obviously for the joining seam - the balloon seems to be holding pressure well - so far so good.
Wildthing
Legendary member
Slick
bracesport
Legendary member
@Wildthing - best case - the parts will release from the mounds - I don't want to think about the worse case! 
bracesport
Legendary member
Well, it was a success and a failure - the success was the 3D printed moulds worked and de-moulded - the failure was my fibre glass was too light (25g/m2) and even three layers ended up to be way way to thin with no structure - Oh well, lesson learned, I have ordered some thicker FG (100g/m2) - I should imagine the carbon fibre will be better as it is 80-100g/m2.
Also I think my balloon failed with the tube line being soft silicon, so I changed that to a hard PVC line and added a one way valve - the inside layer of FG had pulled away from the wall indicating the balloon lost pressure.
We live and learn!
Also I think my balloon failed with the tube line being soft silicon, so I changed that to a hard PVC line and added a one way valve - the inside layer of FG had pulled away from the wall indicating the balloon lost pressure.
We live and learn!
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bracesport
Legendary member
getting ready for round two - my 10g fibreglass has arrived, and I am prepping two pool cues for booms - I plan to make two different booms to compare - one with bidirectional cloth covered with a braided sock, and one with two layers of bidirectional cloth - I put the cling film onto the pool cues longitudinally this time - it should give me a smoother boom (top coat is only as good as the undercoat)!
bracesport
Legendary member
The nose cone is in the mould again - this time with 3 layers of 100g fibre glass - I put a 4th strip at the opening to give me a bit more meat to tune the fit if needed - the balloon seems to behaving itself so far - the first boom is done too, it consists of 1 layer of 80g 90deg woven cloth to give me lateral stiffness and 1 layer of 3K braided sleeve.
bracesport
Legendary member
I put down another section of the fuse into the moulds - this time it is the main fuse section which supports the wing and attaches to the boom - I used two layers of carbon fibre and two layers of fibre glass - sorry one of the pictures is blurry but you get the idea!
bracesport
Legendary member
Wildthing
Legendary member
Do you grease up the molds at all so the pieces come out easy?
bracesport
Legendary member
@Wildthing - I just use three coats of the PVA mould release directly onto the moulds - I did not sand the moulds either!
bracesport
Legendary member
My biggest issue is I’m bursting the balloons during curing, I suspect I am using too much pressure unnecessarily! As long as I get 4hrs curing it seems to be ok but it would be good to perfect the system!
Wildthing
Legendary member
Possibly the heat generated is actually melting or weakening them causing it to burst. There must be different quality of balloons out there, never looked myself but I know over the years you would get some that would break and you hadn't even blown it up totally yet.
bracesport
Legendary member
YAY - the second fuse part moulded very well - the part came out easily again and the finish is way better than my original effort where I used the inner and outer moulds but had the cling wrap as the release agent - I am loving this process!
Just thinking about the weight, as I am sure I will be over doing it again - my Carbon ship target - 270g target - 68g fuse - 140g wing - 15g tail feathers - 32g 6 servos - 5g receiver - 10g battery - with the first two fuse parts moulded (un sanded) I am at 44g which is a bit heavy, so this will be interesting as I sort the last two pieces (servo tray and boom).
Just thinking about the weight, as I am sure I will be over doing it again - my Carbon ship target - 270g target - 68g fuse - 140g wing - 15g tail feathers - 32g 6 servos - 5g receiver - 10g battery - with the first two fuse parts moulded (un sanded) I am at 44g which is a bit heavy, so this will be interesting as I sort the last two pieces (servo tray and boom).
Wildthing
Legendary member
Do I remember right you said you don't sand the molds on the inside? If not I think I would try that on the next one, I just see all the little wrinkles and imperfections which I know you sand and clean up to perfection but I hate sanding so if I can cut my time in half by doing the mold first and my actual piece comes out with a smooth surface I would be happier . Don't get me wrong, you are a master at this and I love watching the progress so it isn't any sort of insult in any way.
. Don't get me wrong, you are a master at this and I love watching the progress so it isn't any sort of insult in any way.
bracesport
Legendary member
@Wildthing - yes, after this round (and given it works) I will definitely make the moulds even better! I originally thought the parts would not release that easily, but given the success the process can be improved incrementally - I also have to perfect the amount of material used to make the parts lighter!
Wildthing
Legendary member
When are you going to start selling them ?@Wildthing - yes, after this round (and given it works) I will definitely make the moulds even better! I originally thought the parts would not release that easily, but given the success the process can be improved incrementally - I also have to perfect the amount of material used to make the parts lighter!
bracesport
Legendary member
@Wildthing - there is much water to go under the bridge to finish this one! I am looking forward to retirement and a time when I will have more time for the hobby - currently I can only grab a hour here and there! That being said how cool would it be to sell your handy work!
I managed to lay up another boom at lunchtime, so fingers crossed it will release this time (if not I will try the PVA)!
I managed to lay up another boom at lunchtime, so fingers crossed it will release this time (if not I will try the PVA)!
bracesport
Legendary member
I did not photograph the next mould being prepared - it is the servo tray/nose section of the main fuse - again, it has 2 layers of 100g carbon 30 deg bias cloth and two layers of 100g fibreglass cloth - I lowered the balloon pressure and it is currently holding pressure after one hour.
bracesport
Legendary member
Ok this is getting exciting now - the servo tray is moulded, and given it was the most complex of the moulds I am very happy with the results - the servo tray section will sleeve into and glue to the main fuse section - the nose cone will then sleeve over the servo tray - I need to get the boom glued into the main fuse body before glueing in the servo tray.
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