David Hall 9 Posted November 3, 2021 Share Posted November 3, 2021 I have to repair a couple of my moldie F5J gliders, each with damage to the leading edge, with a chunk missing back to the spar. Fortunately, the structure is still sound enough, so I simply need to fill and the skin the wings (one is glass fibre, the other is carbon fibre skinned. For the point at which the wing repair is skinned, I have previously applied CF/GF cloth and sanded down the lumps later. This time, I plan to apply a plastic sheet to the wet cloth and hold in place/shape to give the cured cloth a smooth finish. Can anyone recommend a suitable treatment for the plastic (Acetate/PVC) sheet to release the cured resin? .. Recent efforts with furniture polish have only been partially successful with many specs still stuck the the sheet when removed. Quote Link to comment Share on other sites More sharing options...
Allan Bennett Posted November 3, 2021 Share Posted November 3, 2021 When moulding glass or carbon fibre my release agent is two-stage. First there's the wax, which I think is simply beeswax, then there's a liquid pva release agent like this one https://www.ecfibreglasssupplies.co.uk/product/clear-matt-pva-release-agent brushed on and allowed to dry. It's water soluble, so is easy to clean off the finished item. 1 Quote Link to comment Share on other sites More sharing options...
Graham R Posted November 3, 2021 Share Posted November 3, 2021 I was also going to suggest pvc release agent. Quote Link to comment Share on other sites More sharing options...
David Hall 9 Posted November 4, 2021 Author Share Posted November 4, 2021 Thanks for the pointers, I'll go with that. Quote Link to comment Share on other sites More sharing options...
John Lee Posted November 4, 2021 Share Posted November 4, 2021 I've not had an opportunity to try it myself but I've seen "Peel-ply' used for exactly what you want, David. https://www.cstsales.com/peel-plies.html https://www.instructables.com/Peel-Ply-for-Smooth-Fiberglass-Surfaces/ Quote Link to comment Share on other sites More sharing options...
David Hall 9 Posted November 4, 2021 Author Share Posted November 4, 2021 Thanks for the info... It occurred to me that, if I use a sheet of (prepared) acetate as the external surface that will give the CF/GF wetted fabric it's shape and finish, might I be better applying the resin and fabric to the sheet, then holding the loaded sheet in place on the wing until set. That would give it a smoother finish? Quote Link to comment Share on other sites More sharing options...
Martin Fraser Posted November 4, 2021 Share Posted November 4, 2021 The PVA release agent doesn't always lie flat and smooth but being blue at least you can see where it is. There are chemical agents but I've not been very impressed with them so my favourite is Meguiar's mould release wax or similar Miracle Gloss Mould Release Wax - Easy Composites Cheers, Marty 1 Quote Link to comment Share on other sites More sharing options...
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