TorbenD Posted August 20, 2016 Author Share Posted August 20, 2016 (edited) *&£@*$!!!! The supplied kit canopy had a small scuff mark at its apex from some in-pack rubbing/collision which definitely needed polishing out so out came micro mesh cloths to give the whole canopy a nice gentle shine and just after the final 12000 polish I noticed what looks like several patches of crazing in the clear plastic which catch the light from certain angles... and not in a good way This is my first time ever trying to polish a canopy - I assume these are some kind of micro stress fractures but I definitely handled with kid gloves and supported inside and followed all the on-line tutorials I could fine. They look pretty terminal too. 1. Any ideas what could have gone wrong? I genuinely believe I wasn't too vigorous/rough 2. Any ideas what I could do to save this? More polishing? Micro applications of Tamiya Extra Thin then re-polishing? Future dipping? Answers on a forum near you please.... I'd love to avoid having to seek out a replacement - my only other alternative seems to be using this as the basis for a plunge/vac-form mould (yet another new thing for me to learn!) Hopefully, Torben Edited August 10, 2017 by TorbenD BradG 1 Link to comment Share on other sites More sharing options...
mikeblack Posted August 20, 2016 Share Posted August 20, 2016 Torben - can you get an after-market canopy? Other than that I've got no technical suggestions Mike Link to comment Share on other sites More sharing options...
Shaka HI Posted August 20, 2016 Share Posted August 20, 2016 (edited) I'd get a replacement from the manufacturer. You can't fix that. Vacuum forming canopies is something I have yet to master -- I failed miserably on a rather simple one. Those are stress cracks and basically your "subtle" polishing caused it. I think you need something in the canopy to fill in and harden so it has some bracing before you start polishing. I tend to use a QTip and polish as lightly as possible with my finger on the opposite site. Edited August 20, 2016 by Shaka HI TorbenD, Joel_W and mikeblack 3 Link to comment Share on other sites More sharing options...
LSP_Kevin Posted August 20, 2016 Share Posted August 20, 2016 Wow, that's a bummer, Torben! About the only think I can suggest is to give it a couple of dips in Future (or other floor polish). If that doesn't improve the look of it, then I'm afraid it's a write-off. Kev TorbenD and mikeblack 2 Link to comment Share on other sites More sharing options...
Hubert Boillot Posted August 21, 2016 Share Posted August 21, 2016 Too bad for the micro-cracks. If you want to make a vac-copy, it's not that difficult, if you have a vacuform machine. in this case, you can make a female vac-form (i.e. sucking the plastic into a cavity) by making a mold around the plastic canopy. You need to drill ahole at the bottom of the mold to suck-in the air. The hole must no be any bigger than half the thickness of the plastic sheet to avoid any visible dimple. To do this hole, a simple trick is to glue a small rod, or some thick monofilament nylon to the existing canopy and pour the molding medium around the esisting canopy. plaster of Paris is Ok to make a mold for a few trials. If you do not have a vac-form machine (or a simple plywood box with holes in the top, connected to your vacuum cleaner), than the "plunge" method over the existing canopy will work, but you will end up with a slightly larger-than-original canopy, and the frame details will be softer than with the female mold method. Option 3 is to ask for a new one to SH. And finally option 4 is to get a generous soul to lend you a canopy from his kit. Keep fighting ! Hubert mozart and TorbenD 2 Link to comment Share on other sites More sharing options...
TorbenD Posted August 21, 2016 Author Share Posted August 21, 2016 Thanks All, much appreciated Yup, looking terminal - The original plastic is commendably thin so I'm thinking it must be a bit of accidental heavy handed BFI on my part on that one area Shame it wasn't packed with a bit more protection in the first place, just unlucky I guess. I've just dropped Special Hobby I line on their contact section for a replacement, cross-fingers I'll be a bit luckier with their customer service. Hubert, I hadn't considered a female method and thanks for the idea and heads up on technique... If no joy from SH I may consider trying that as an alternative to keep the size “bob on†as the original fit was great and hopefully shouldn't take too long to put a Vac-form box together me thinks... :hmmm:Quick question - Could I substitute RTV silicon mould for plaster of Paris or would that not be firm/rigid enough? Also what clear plastic material and weight/thickness would you recommend for this method? Cheers, Torben Link to comment Share on other sites More sharing options...
Shaka HI Posted August 21, 2016 Share Posted August 21, 2016 Right...I guess to form such a canopy, you will need to create a female-form for the perfect fit. Way too much work..LOL. My issue for my simple trials were the canopy framing...in just didn't look sharp enough. Probably cause I never got the clear plastic hot enough and/or the vacuum just didn't "suck" enough. I'm going to sand off all that stuff before forming when I give it another go and somehow create the frame over the copy -- which I'm not sure how cleanly I can do this...regardless, a lot work if done properly will look far better and in scale than most kit canopies. Good luck (and I can't answer your specific questions, I suck at this, but I doubt silicon will work and I would get various thickness of the clear plastic and try them -- I imagine you want the best form using getting something somewhat rigid? I used very thin PETG clear plastic -- it was much too thin scale wise.) TorbenD 1 Link to comment Share on other sites More sharing options...
Hubert Boillot Posted August 21, 2016 Share Posted August 21, 2016 I wouldn't know how a silicone rubber mold would react when used as a female mold. My gut instinct is to go for something more rigid like resin, plaster or even epoxy paste like Milliput or the ones you find in DIY stores (coating the master with vaseline should prevent any sticking of the mold material) Female vac-forming is definitely a lot better than male vac-forming : you know where the limit part/backing sheet is without doubt, the sheet is sucked in the details, which are therefore sharper, and finally no need when doing a master to make complex adjustments to integrate the thickness of the vac-formed material. The Nieuport Sesquiplane I am working on now was vac-formed in this way ( as are the Welsh Models 1/144 liners which were mastered by our own Derek) and the quality is really close to a short-run IM kit, surface-wise. As for the material, I'd recommend acrylic sheet in 0.75 / 1 mm thickness (0.5 may be doable, with some trials). Acrylic ages well (not as UV-sensitive as the PVC used in old vac kits, which yellowed over time) and is very clear. Clear PS is too sensitive to heat conditions, and may end-up not as transparent. The best materials are PMMA ( Perspex ) but it requires high temperatures (and therefore more risk in manipulation - I know one French Modeller who softens it in boiling oil ... not something I'd be wanting to try personnally), and preheating for a few hours at about 60° C to eliminate moisture trapped in it - which results in nasty bubbles in the plastic when heated, or polycarbonate (PC) which is the material used for headlamps of most modern cars now, but probably too complex to use in a makeshift home environment. Btw, you may have the issue of bubbles with acrylic sheet, solved by oven-curing just like PMMA. Hope this helps. Hubert mozart and Shaka HI 2 Link to comment Share on other sites More sharing options...
Hubert Boillot Posted August 22, 2016 Share Posted August 22, 2016 (edited) If you want, I have everything to do this for you, but the canopy. If you are willing to send it to me, I can try it, and if it works as I am describing : a) I will have put my actions where my mouth is , and you will have a better-looking canopy (but then I know it works because I have done so for a 1/72 XC-142 kit ) Hubert Edited August 22, 2016 by MostlyRacers Joel_W, Shaka HI, mozart and 2 others 5 Link to comment Share on other sites More sharing options...
TorbenD Posted August 22, 2016 Author Share Posted August 22, 2016 If you want, I have everything to do this for you, but the canopy. If you are willing to send it to me, I can try it, and if it works as I am describing : a) I will have put my actions where my mouth is , and you will have a better-looking canopy (but then I know it works because I have done so for a 1/72 XC-142 kit ) Hubert Wow... such a kind and generous offer Hubert, I don't know quite what to say... A massive thank you, for a start! This post arrived only 15 minutes after Special Hobby got back to me via email saying they'd happily help out and send me a replacement as soon as the chap who looks after such things gets back from holiday next week. So far so fab with their customer service So, unless things go unexpectedly awry on that front I'll take the SH replacement option on this occasion, especially as the kit part was nice and thin and I was pleased with it apart from the original scuff damage. Thanks again so much for your offer - I have to say the support and advice in these LSP forums gladdens the heart in what can be a largely solitary pursuit. My other reason for taking this option is I would rather see your modelling time used on that beautiful Nieuport Sesquiplane.. more please!!! All that said, I love learning new things and the way you describe the female vac form technique has got me thinking I want to give that a go myself at some point before to long. I'm certain I'll need it some day - so a big thanks for that earlier post too and the inspiration attached to it Hubert Much respect. Cheers, Torben mozart, Shaka HI, mikeblack and 1 other 4 Link to comment Share on other sites More sharing options...
mozart Posted August 23, 2016 Share Posted August 23, 2016 Hope SH come through for you Torben, looking promising so far, but what a generous offer from Hubert....isn't the LSP community wonderful?! Max Joel_W, TorbenD, mikeblack and 1 other 4 Link to comment Share on other sites More sharing options...
TorbenD Posted August 23, 2016 Author Share Posted August 23, 2016 Hope SH come through for you Torben, looking promising so far, but what a generous offer from Hubert....isn't the LSP community wonderful?! Max i couldn't agree more Max Torben mikeblack 1 Link to comment Share on other sites More sharing options...
mpk Posted September 15, 2016 Share Posted September 15, 2016 This is an awesome build. Especially considering you have been away so long Torben. Just a note on polishing canopies. I used to use toothpaste on a tissue. Worked every time. Can hardly wait to see the rest of this build. Hard to believe I have spent most of the day on this site gaining influence, knowledge and enjoyment. In between I have done a little modeling myself. This community spares no expense when it comes to inspiration. So glad I joined. I also joined another forum which has several fine people on board but for some reason I keep coming back here.... mozart, TorbenD and Shaka HI 3 Link to comment Share on other sites More sharing options...
TorbenD Posted September 15, 2016 Author Share Posted September 15, 2016 Thanks for your kind words mate. You're right there's a cracking bunch on this forum - it's full of encouragement, inspiration, information and top notch modelling! I've had to take a temporary break from this build due to some of those pesky work and various “life†pressures but hope to restart this weekend. I've just received the replacement canopy from Special Hobby so have one less excuse now! Cheers, Torben Shaka HI and mikeblack 2 Link to comment Share on other sites More sharing options...
mpk Posted September 16, 2016 Share Posted September 16, 2016 Thanks for your kind words mate. You're right there's a cracking bunch on this forum - it's full of encouragement, inspiration, information and top notch modelling! I've had to take a temporary break from this build due to some of those pesky work and various “life†pressures but hope to restart this weekend. I've just received the replacement canopy from Special Hobby so have one less excuse now! Cheers, Torben Very cool that they looked after you so well. Link to comment Share on other sites More sharing options...
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