Pickygit Posted July 1, 2018 Share Posted July 1, 2018 Anyone have ideas on how to renovate a badly yellowed canopy on my P47 please? I suspect this is just and age or sunlight degradation issue. Quote Link to comment Share on other sites More sharing options...
onetenor Posted July 2, 2018 Share Posted July 2, 2018 You could try a wipe with thinners or Acetone or ethyl acetate (also known as Amyl Acetate ) just a light wipe as it may be soluble which is why it could work. Some people say polish it with metal polish but I've not had this work for me as it's as much a chemical change as anything. If you do try polishing do this first as there is nothing to lose from it. you may have to renew it in the end but finding a replacement could be hard. You could make your own by press moulding or vacuum moulding. There is lots of info online.( Facebook, instructables etc ) on how to do it. You could use the old one to make a casting from., If it doesn't fall apart, In epoxy or body filler or even plaster. Smear with vaseline as a release agent. Once dry/set add another 1/4" deep layer to give you enough draw depth. Good luck Edited By onetenor on 02/07/2018 02:54:12 Quote Link to comment Share on other sites More sharing options...
Allan Bennett Posted July 2, 2018 Share Posted July 2, 2018 I'd be concerned about using solvents, as they may make matters worse if they attack the plastic. An alternative route (or an insurance in case the solvent causes a problem) is to remove the canopy, make a plaster-of-paris mould of it, then have someone vacuum-form a replacement for you. I've done this in the past with a cracked canopy by using duck-tape to repair the conopy and then duck-tape and thin balsa around the bottom of the canopy to raise its height (to ensure it moulds fully), placing it upside down in a box of sand to stop it deforming too much, then filling it with plaster. When set, I demould it and leave it to dry for a few days before sanding the bottom flat with my Permagrit, so it sits nicely in the vacuum forming machine. In the case of a repaired canopy you can also sand out any blemishes in the plaster plug before using it to mould the replacement. I used to have a friendly local model shop who would do the forming for the price of a sheet of clear acrylic, or whatever the material is. Quote Link to comment Share on other sites More sharing options...
The Wright Stuff Posted July 2, 2018 Share Posted July 2, 2018 I have to say that I suspect solvents won't work because the yellowing is a chemical change within the material, not a surface residue. I expect that if you try acetone, the best result will be a white frosty colour. At worst, it will dissolve and distort it. Other than replacement, all I can suggest is painting it black or silver. It won't be the effect you are looking for, but it might be a temporary improvement... Quote Link to comment Share on other sites More sharing options...
Pickygit Posted July 2, 2018 Author Share Posted July 2, 2018 Thanks for the input, guys. I think I'll have to try the vac forming route but concerned about using vaseline as a release agent. Is there anything else less messy and more easily cleaned off that I can use? Quote Link to comment Share on other sites More sharing options...
Ernie Posted July 2, 2018 Share Posted July 2, 2018 Hi Pickygit, Why not tint it darker instead of trying to clarify it I've used dark blue dylon in the past It can look really cool, like the pilot is big celebrty. ernie Quote Link to comment Share on other sites More sharing options...
Robert Cracknell Posted July 2, 2018 Share Posted July 2, 2018 Whenever I have needed a release agent either when using silicone or plaster moulds I have used either neat washing up liquid brushed on thinly and allowed to dry or a mix of 50/50 PVA glue and water again brushed on thinly and allowed to dry. In each case a soak in warm water will yield a release and you just need to wash the moulded item to get rid of the release agent and allow to dry. Proprietary release agents are available here **LINK** ...but I have found mine to work just as good. Quote Link to comment Share on other sites More sharing options...
Pickygit Posted July 2, 2018 Author Share Posted July 2, 2018 Thanks again for your input guys. Quote Link to comment Share on other sites More sharing options...
The Wright Stuff Posted July 2, 2018 Share Posted July 2, 2018 Posted by Ernie on 02/07/2018 13:04:12: Hi Pickygit, Why not tint it darker instead of trying to clarify it I've used dark blue dylon in the past It can look really cool, like the pilot is big celebrty. That is an awesome suggestion, Ernie. It it fast / robust, or do you need to gloss varnish after dying it? Quote Link to comment Share on other sites More sharing options...
McG 6969 Posted July 2, 2018 Share Posted July 2, 2018 Hi Pickygit, I think Ernie's idea is worth a try, why not, it could give a very 'cool' effect. Regarding your choice of release agent if you have a go with making a plug, I wouldn't use Polyvinyl Alcohol. It works fine for large glass fiber moulds, but it can be a mess on small plugs as you have to peel it off. I would simply suggest some natural bee wax. Apply it thinly, let it dry and polish it up with a cotton pad. Repeat the procedure at least 2 or 3 times. Being polished, it also improves the surface a lot. Good luck Cheers Chris Quote Link to comment Share on other sites More sharing options...
Engine Doctor Posted July 2, 2018 Share Posted July 2, 2018 If it's gone brown it's also probably gone brittle. Thinners etc won't help as said it can make matters worse. Tinting it can also cause more damage due to the solvents in tint. Think on the line of replacing it and possibly use it for a mold for a plug as already suggested. I painted a canopy on a Kyosho Majestic wit laquer and glittered the inside with metal flake custom car glitter. looked great in sunlight but went as brittle as egg shell after two years !! Quote Link to comment Share on other sites More sharing options...
kc Posted July 2, 2018 Share Posted July 2, 2018 Vortex Vacform sell several P47 canopies ( as well as many others) so if all else fails they may have one to sell you or make one for you from the old one. Quote Link to comment Share on other sites More sharing options...
will -0 Posted July 2, 2018 Share Posted July 2, 2018 If you fly the model it will be far enough away that you don't notice.... Quote Link to comment Share on other sites More sharing options...
Allan Bennett Posted July 2, 2018 Share Posted July 2, 2018 Posted by Pickygit on 02/07/2018 12:44:19: Thanks for the input, guys. I think I'll have to try the vac forming route but concerned about using vaseline as a release agent. Is there anything else less messy and more easily cleaned off that I can use? I've never used any release agent when making plaster of paris plugs for vac forming. Even the balsa-and-tape 'skirt' I add to the damaged item seems to release cleanly from the plaster. Quote Link to comment Share on other sites More sharing options...
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