Uni-Mould distortion

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Uni-Mould distortion

Author	Message
Robert72	R Robert72 posted 5 Years Ago Topic Details
R Group: Forum Members Posts: 57, Visits: 151	Hello all, I have made a mould for my telescope tube (300mm dia x 1500mm) using the Uni-Mould system and it has suffered from slight distortion (slightly off circular on one side). I cannot post cure the mould as I dont have an oven big enough. I have clamped the mould back onto the pattern. Is there anyway I can reinforce it to hold it in shape? I was thinking bands between the flange bolts. Maybe two layers of 5mm pvc foam strips with a couple of layers of carbon/epoxy? Any suggestions welcome.
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Robert72	R Robert72 posted 5 Years Ago Post Details
R Group: Forum Members Posts: 57, Visits: 151	+x Robert72 - 12/1/2019 1:45:04 PM Hello all, I have made a mould for my telescope tube (300mm dia x 1500mm) using the Uni-Mould system and it has suffered from slight distortion (slightly off circular on one side). I cannot post cure the mould as I dont have an oven big enough. I have clamped the mould back onto the pattern. Is there anyway I can reinforce it to hold it in shape? I was thinking bands between the flange bolts. Maybe two layers of 5mm pvc foam strips with a couple of layers of carbon/epoxy? Any suggestions welcome. So I have decided to make external formers to stiffen up the mould. The pattern has been placed back into the mould and bolted tight. The intention is to bond 9 ply/styrofoam/ply formers, externally to each half. These will then be glassed over, and with any luck the mould will retain its shape.
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Warren (Staff)	Warren (Staff) posted 5 Years Ago Post Details
Group: Administrators Posts: 2.5K, Visits: 7.9K	Additional stiffening would help but care needs to be taken not to make it worse. You can wrap it in release film or similar and use an electric blanket to get a mild post cure which should help. The release film will stop the blanket sticking. Warren Penalver Easy Composites / Carbon Mods - Technical Support Assistant
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Robert72	R Robert72 posted 5 Years Ago Post Details
R Group: Forum Members Posts: 57, Visits: 151	+x Warren (Staff) - 12/4/2019 9:58:01 AM Additional stiffening would help but care needs to be taken not to make it worse. You can wrap it in release film or similar and use an electric blanket to get a mild post cure which should help. The release film will stop the blanket sticking. Thanks for the reply Warren. Does the additional stiffening potentially make it worse due to stress concentrations? I have noticed that the flanges running down each half are not parallel (due to the slight ovalisation of the mould?). In order to make the flanges meet each other and close the split, the flange bolts have to pull the flanges back to parallel. Attachments 20191103_152349.jpg (178 views, 2.00 MB) 20191102_201901.jpg (156 views, 2.00 MB)
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