TheBaron Posted June 18, 2019 Share Posted June 18, 2019 15 hours ago, CedB said: Still confused about the mould though… Me too. But not doubting that whatever transpires will inspire! 1 Link to comment Share on other sites More sharing options...
stevehnz Posted June 18, 2019 Share Posted June 18, 2019 Is there a female mould to come from all this pfaffing around with resin & silicon? Steve. Link to comment Share on other sites More sharing options...
Fritag Posted June 18, 2019 Author Share Posted June 18, 2019 (edited) On 6/17/2019 at 6:01 PM, CedB said: Still confused about the mould though… 13 hours ago, TheBaron said: Me too. 11 hours ago, stevehnz said: Is there a female mould to come from all this pfaffing around with resin & silicon? Well it’s like this.... (1) My 18-month-old existing silicone mould got squashed and bent out of shape in a storage box and so went in the bin. (2) I wanted to cast some more resin masters. (3) Ergo - more silicone... And one of the reasons I wanted more resin masters was this: For vac-forming the canopy master has to include a base to lift the canopy away from the Dental vac perforated surface (so as to ensure that the softened plastic is pulled right onto all of the edges of the canopy). Here’s a master inside a roughly trimmed vac formed canopy to illustrate what I mean. You can see the canopy itself sits on a base , and then ends have also been extended. But I’ve found that the easiest way to then trim the canopy to the correct size and get nice neat edges, is simply to sand the edges of canopy on a flat sheet of glass paper, with a master inside to act both as a guide and a support. Like this: But obviously that master has to be just the correct canopy shape without the base etc. And so (finally) the reason I needed more resin masters was to be able to trim one or two down to just the canopy shape so as to be able to use them when sanding the canopies to size. Simples.......... Well done if you bothered to read all of that....... Edited June 18, 2019 by Fritag 21 Link to comment Share on other sites More sharing options...
giemme Posted June 18, 2019 Share Posted June 18, 2019 Ciao Link to comment Share on other sites More sharing options...
Courageous Posted June 18, 2019 Share Posted June 18, 2019 11 minutes ago, Fritag said: Well done if you bothered to read all of that....... I read all that, makes sense to me. Stuart Link to comment Share on other sites More sharing options...
keefr22 Posted June 18, 2019 Share Posted June 18, 2019 13 minutes ago, Fritag said: But I’ve found that the easiest way to then trim the canopy to the correct size and get nice neat edges, is simply to sand the edges of canopy on a flat sheet of glass paper, with a master inside to act both as a guide and a support. Like this: That's a great idea! I've made resin canopy moulds in the past, but to trim the canopies like that had never occured to me! Keith Link to comment Share on other sites More sharing options...
stevehnz Posted June 19, 2019 Share Posted June 19, 2019 5 hours ago, Fritag said: Well done if you bothered to read all of that....... So straight forward when you think about it, I can't think why I needed to ask. Steve. 1 Link to comment Share on other sites More sharing options...
CedB Posted June 19, 2019 Share Posted June 19, 2019 … and there we have it. Masterclass, as usual. Thanks Steve (Nice scissors by the way - they're great aren't they?) Link to comment Share on other sites More sharing options...
Fritag Posted June 19, 2019 Author Share Posted June 19, 2019 5 minutes ago, CedB said: (Nice scissors by the way - they're great aren't they?) I thought you might spot that. I included them in that photo just cos you'd posted a piccie of yours (and cos they're good for trimming vac canopies of course). I hadn't just rushed out and got them...Honest! Although it is right to say that my cupboard has its fair share of Ced inspired modelling tools (I had to re-write that a few times to avoid the word 'tool' resulting in a 'fnaar fnaar') Didn't know they were called conjunction conjecture conjunctival scissors tho' 9 Link to comment Share on other sites More sharing options...
perdu Posted June 19, 2019 Share Posted June 19, 2019 It is so good to have Fritag back teaching Such a consummate instructor/advisor/guru great moulding lesson, it scared me I saw the first image (obviously) and thought my blurry morning eyes just became worse 'til I realised I was seeing the mould in use with a canopy wowsa Link to comment Share on other sites More sharing options...
Terry1954 Posted June 19, 2019 Share Posted June 19, 2019 19 hours ago, Fritag said: Well done if you bothered to read all of that....... I did too, and it all became very clear (pardon the pun) Terry 1 Link to comment Share on other sites More sharing options...
Fritag Posted June 22, 2019 Author Share Posted June 22, 2019 (edited) I saw over on @Courageous excellent Seafox thread that his Dental Vac former has arrived. Welcome to the vac-dabblers Stuart. Go on @limeypilot - you know you want one Ian. Anyways - I had a play with mine yesterday afternoon...... I did a test with 0.5mm PETG sheet and got a nice clear result; but to my mind the canopy was a bit thin and flimsy to work with. It may be because my resin masters are quite tall and so the 0.5mm sheet was being stretched a bit too far. Anyways, the Hawk canopy is quite a chunky beast as anyone who ever got their fingers trapped underneath it will testify. So I tried some 0.7mm sheet and was happier with that. I lost a couple of efforts to over-heating bubbles but then manage 4 acceptable ones on the trot. I keep thinking I should be scientific about the process; you know - do some tests raising the platform to a measured height and timing the heating with stopwatch and note the results. But I never do. I just raise the platform and peer at the plastic as it gets heated and when I think its sagged a bit and soft enough, but whilst the surface is still nice and smooth and shiny and no bubbles, I lower it and trigger the vac. Its a bit of a 'Muppet' technique really. I'm pleased with the results. There's a fait bit of fettling to do on the windscreen section before I'll know whether I'm happy with the fit and shape; but I think the main sections will do. I'm off on hols tomorrow. I'm hoping to gets these efforts trimmed before I go. Edited June 22, 2019 by Fritag 10 Link to comment Share on other sites More sharing options...
perdu Posted June 22, 2019 Share Posted June 22, 2019 Muppet? NO! Artisan methods? YES! pssssssshaww Off on holidays again? Oh well no doubt normal service will be resumed IN 2021... The mouldings look very 'top of the range' Steve, you should sell some of your finished ones (Of course the finished ones, do you think we could do them as well as the vacmeister?) Have a good jolly mate 1 4 Link to comment Share on other sites More sharing options...
Fritag Posted June 22, 2019 Author Share Posted June 22, 2019 (edited) On 6/11/2019 at 10:56 AM, 72linerlover said: If you noticed in the past some effect on the clear plastic, it was probably due to some release of the "polyol" of the resin that did not truly mix with the catalyzer. So let the master set for a pair of days, be gentle with plastic heating and quick in forming. Ta Eugenio, I meant to say... I did a test with an 18-month old master and a 2-day old one side by side, and the clear plastic was patchy/discoloured in spots with the new one and not the old. Interesting. I wonder if there is anything that can be done to hasten the release/drying out/whatever of a new resin master? Edited June 22, 2019 by Fritag 1 Link to comment Share on other sites More sharing options...
stevehnz Posted June 22, 2019 Share Posted June 22, 2019 37 minutes ago, Fritag said: I wonder if there is anything that can be done to hasten the release/drying out/whatever of a new resin master? Mould it before you go on holiday. Steve. 5 Link to comment Share on other sites More sharing options...
CedB Posted June 22, 2019 Share Posted June 22, 2019 Nice vac forming Steve - those look just the job. Hols again? Have a good one… 2 Link to comment Share on other sites More sharing options...
perdu Posted June 22, 2019 Share Posted June 22, 2019 2 hours ago, Fritag said: I wonder if there is anything that can be done to hasten the release/drying out/whatever of a new resin master? I doubt if anything could catalyse the new resin so it degasses earlier Make it before you... Ah 😉 2 Link to comment Share on other sites More sharing options...
giemme Posted June 22, 2019 Share Posted June 22, 2019 (edited) 5 hours ago, Fritag said: I'm off on hols tomorrow. You don't say! The vacformed canopies look great I'm quite surprised you had to go up to 0.7mm thickness, though; I normally get along pretty well with 0.3-0.35. But then it's APET, not PETG, so maybe they react differently Enjoy your hols! Ciao Edited June 22, 2019 by giemme Link to comment Share on other sites More sharing options...
Gene K Posted June 22, 2019 Share Posted June 22, 2019 7 hours ago, Fritag said: I did a test with 0.5mm PETG sheet and got a nice clear result; but to my mind the canopy was a bit thin and flimsy to work with. It may be because my resin masters are quite tall and so the 0.5mm sheet was being stretched a bit too far. What do you think would be the impact of raising the master so that the "walls" of the vac formed PETG is smaller (leaving more material for the canopies)? Gene K 1 Link to comment Share on other sites More sharing options...
perdu Posted June 22, 2019 Share Posted June 22, 2019 With the suction process you need a certain amount of flex for the undercut to mould properly but I would posit that the amount here shows he is simply showing off Flash git 😂😂😂😂😂😂😂😂😂😂 Wot me jealous? Hmmm maybe 😈 4 Link to comment Share on other sites More sharing options...
hendie Posted June 22, 2019 Share Posted June 22, 2019 That's way better results than anything I've ever got with clear plastic. 5 hours ago, Fritag said: I wonder if there is anything that can be done to hasten the release/drying out/whatever of a new resin master? Only a couple of things I can think of in that respect - Heat being one of them. Perhaps a lightbulb as a heat source or if you want to get fancy, you could use one of those heat pads for home brewing. They are generally very low powered so shouldn't damage the resin part. The other thing is to reduce the volume of the resin. Instead of using resin for the entire part, if you fill most of the cavity, then insert for example, a balsa plug in the rear to take up remaining volume, there will be less resin overall to off-gas. 3 Link to comment Share on other sites More sharing options...
Courageous Posted June 22, 2019 Share Posted June 22, 2019 14 hours ago, Fritag said: Welcome to the vac-dabblers Stuart. Thanks Steve. Just taken delivery of an A3 sheet of 0.5mm PETG, so I'm hoping that it doesn't end up too thin after your own efforts. All I've got to do now is make a master mold... Good show with your own glazing. Looking forward to seeing further progress when you get back. Stuart 1 Link to comment Share on other sites More sharing options...
72linerlover Posted June 23, 2019 Share Posted June 23, 2019 On 6/22/2019 at 10:51 AM, Fritag said: I wonder if there is anything that can be done to hasten the release/drying out/whatever of a new resin master? Hi, Fritag. For my resin masters I used a cheap "Prochima" 1:1 resin and I was simply lucky waiting only two or three days. Never done before, but perhaps a gentle buffing with a rubbing alcohol dumped cloth could help. Or simply with water and soap. About the final thickness after forming, I'll tell you that I use plunge forming, without vacuum and hold the clear plastic by two side clamps. This way you get an almost constant thickness. Ok, not very scientific or industrial, but I'm happy with that. I seem to remember to have done this way working with Silvano anh his Chipmunk too. Cheers Eugenio 1 Link to comment Share on other sites More sharing options...
keefr22 Posted June 23, 2019 Share Posted June 23, 2019 Steve, last time I did some primitive smash and crash plunge moulding, instead of using resin for the master I tried using hydrocal dental plaster (it's like a smoother, harder plaster of paris) It came out of the mould with a few air bubbles in the surface, but mixing up a little more and rubbing it into them, then smoothing down with some 1200 grit wet and dry, gave a lovely smooth surface. It then worked really nicely for a mould. Keith 2 Link to comment Share on other sites More sharing options...
Fritag Posted July 11, 2019 Author Share Posted July 11, 2019 (edited) On 6/23/2019 at 10:45 AM, 72linerlover said: Never done before, but perhaps a gentle buffing with a rubbing alcohol dumped cloth could help. Or simply with water and soap. About the final thickness after forming, I'll tell you that I use plunge forming, without vacuum and hold the clear plastic by two side clamps. This way you get an almost constant thickness. ...... Cheers Eugenio Ta Eugenio I've since found that giving the moulded canopy a good polish with car polish (I used a felt-wheel in the little Tamiya battery router for the job) seems to clear away the discolouration - so it's not the problem I thought it was anyway. I'm getting pretty constant canopy thickness using the dental vac. I think probably just prefer a slightly thicker canopy than, say, Giorgio does. On 6/23/2019 at 2:54 PM, keefr22 said: tried using hydrocal dental plaster I bought and tried some modellers hydrocal plaster some time ago Keith but I found that it was quite soft after it set and the edges of the moulded canopy crumbled. P'raps the dental plaster sets harder? Or P'raps I got the mix wrong? Or P'raps I was incompetent in any one of a myriad of ways I have not as yet figured out........ Anyways. After a good deal of faffing and avoidance activity I think I've got there there with the canopies. One of the potential problems is that pulling or vac-forming a canopy directly over the kit supplied canopy results in a very slightly over-size canopy. Doesn't matter much of the time but it was causing me problems getting a decent fit/look on the Hawks. Particularly the windscreens. So I've had to allow for this by making slightly undersize masters. Here's the final windscreen master; with the second, cut-down, master I used to help me sand the moulded windscreen to size and a couple of almost finished screen and a - yet to be trimmed -spare And here's one test fitted. And here's a canopy. I'm happy with shape; although it's about 0.5mm to tall still so the sides need a tad more sanding down and this one needs a bit more polishing for better clarity. The canopies hinge open on the starboard side, and I'm gonna pose them open, so actually a precision fit is probably not vital. Edited July 11, 2019 by Fritag 17 Link to comment Share on other sites More sharing options...
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