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JohnH
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Group: Forum Members
Posts: 20,
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Hi again I have been working all last week on respraying and polishing the pattern again, so that I can make a new mould with wider flange. I have cut a new corex shroud out of two pieces (so that I get the correct width for the pattern, see photo) and taped these together with brown packing tape, then put a tape line around the pattern at the point that I going to encase the first half of the mould, this has been hot glue gunned to the pattern via the brown tape, then I added a fillet of wax from the underside which I have forced through the gap so that the corex is a snug fit around the pattern. I have now gel coated and epoxy puttied one half of the mould, so I am at the same stage as last time. I have removed the corex shroud (see photo)and I have to clean up the pattern and mould so that the second half can be moulded (hopefully later today) One thing I did come up against this time was epoxy putty got VERY HOT (exotherm?) so I had to take this outside to try to cool it, this may have been due to large amount of putty I used (3.5 kg) The resulting bottom mould is much cleaner than last time and I hope this will give a good result. |
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JohnH
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Group: Forum Members
Posts: 20,
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Hi I have now completed both moulds and have removed them from the pattern. The first half separated nice and easily, the other took a little more digging to get out, so there is some small damage to the bottom half of the mould which I will have make good. The moulds look very nice and smooth and I hope to get some nice mouldings from them, see the photo's. |
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JohnH
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Group: Forum Members
Posts: 20,
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Hi I am doing a trial run of one of the parts of the quad, (top part) a single layer of carbon cloth, plus peel ply, infusion mesh and bagging material, I have bagged everything up and infused the resin, so will see how it turns out tomorrow evening, I have left it in front of the log burner in my workshop to cook. I am using 2/2 twill 200gram, I suspect this is too heavy for what I need, I may need more layers of lighter material, we will see.
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JohnH
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Group: Forum Members
Posts: 20,
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I have taken the top part out of the mould, see attached pic
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Rootz
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Group: Forum Members
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Great idea, John! I was thinking about doing just this only a couple of days ago - So much cooler than made from CNC cut sheet. Only difference was that I was thinking about making the arm cross-section kinda thick wing shaped, on the basis that this would help with winds. Keep us updated on your progress. I might just be your first customer if you're gonna sell them!  |
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Joe
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Group: Forum Members
Posts: 310,
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If only my first try at CF would have been like that... Great project, keep us posted.
 A $1000 electronic device will always protect a 10 cents fuse
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JohnH
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Group: Forum Members
Posts: 20,
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Hi This is the latest of my attempts. I used one layer of 200 gram 2/2 twill on the bottom plus one layer of 2mm Soric, then another layer of 2/2 twill cloth, this was because I found it impossible to remove the Peel-Ply from the first moulded part, I did not use any peel-ply or infusion mesh on this go and relied on the Soric to pull the resin into the part. This worked OK but has left very small pin holes on the part, I presume this is because not enough resin has been drawn into the part on infusion, (perhaps pull the resin for longer?) On my next attempt I am going to use peel-ply pre treated with a release agent along with infusion mesh and see how this comes out. Another thing that I did on this attempt was to use a "tack spray" to hold the cloth in place whilst working on the lay-up, this was much easier to work on the part, whilst bagging but again leaves a slight residue on the exterior of the part, after taking to the guys at E.C. they confirm that this type of adhesive will do that, they are looking into sourcing a spray that is compatible with epoxy resin (good luck). Using the amount of cloth and Soric has resulted in a bombproof shell and should be plenty rigid enough for any abuse I may give it on the finished item.
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JohnH
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Group: Forum Members
Posts: 20,
Visits: 151
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I have decided to make a new set of moulds, with larger flanges and a better edge to the pattern, which i could not achieve using the blanking off method with Corex . I have cut the pattern in half so that this can be fixed to plate glass and then the mould will be cast from there in two sections, this will give me better edges and a parallel joining edge on the finished part. Also I will use two coats of Gelcoat which should give me a thicker layer. I have run out of space on the website for uploading photo's so I cannot show the latest.
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Wabba
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Group: Forum Members
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Hello John, Looks good. I have been developing a similar idea for the longest time, you work inspires me to begin to materialize it. Question, how is the finished airframe, do you bolt two of these together with separator or is there going to be a dome? I agree that these "3D" shapes look so much bette than the flat 2D shaped bolted together, which is the majority though. Keep us posted!
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JohnH
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Group: Forum Members
Posts: 20,
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Hi Wabba
I am bolting the upper and lower parts together using threaded spacers and dome headed screws, this will be seperated by a custom made silcon rubber "H" section which I am having made specially made which will align the parts.
There is also a dome canopy which will carry the GPS unit if required, you can see these parts in a previous post.
I have now made a new bottom mould which has larger flanges, which I am now VERY happy with, next is the top half.
I will post pictures as soon as I have the limit to my uploads increased.
Thanks for the good words.
John
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