Troy Smith Posted April 3, 2018 Share Posted April 3, 2018 Thread title may not be the best phrased question. Ages ago I discussed this with @Colin @ Freightdog Models He mentioned the material for canopy moulds was a resin with added aluminium, some googling got me this http://www.easycomposites.co.uk/#!/resin-gel-silicone-adhesive/casting-resin/vac-cast-epoxy-vacuum-forming-casting-resin.html Vac cast is an aluminium filled epoxy casting resin designed for high temperature tooling applications such as vacuum forming tools. which looks to fit the description, but you will note in the link that the small tub is 5.3kg, I'm wondering if anyone knows if smaller quantities of a similar material are available? Looking at vac canopies, eg Falcon, Rob Taurus, I note they use female moulds. Part of the reason I'm asking to make use yellowed vac canopies as masters, google is not turning up many answers. When I talked to Colin about this, a long time ago, he said he'd had problem because he'd not made airhols, and the resin was very hard to drill due to the metal content, so would casting in airholes, ie adding pins with mould release to the master work? Anyone know more, or can add some links? I've not seen @John Aero on here in a while, but perhaps a notification may get through, as I think he'd know more. thank in advance Link to comment Share on other sites More sharing options...
Alex Gordon Posted April 9, 2018 Share Posted April 9, 2018 Sorry Troy,I've only just seen this thread.I've got away with Plaster of Paris quite happily for the few bits I've had cause to replace.I would think that the mould would be good for a handful of pops at least. I like the idea of female moulds (cavity moulds is what I tell my little dears at school,I have no wish to explain the difference) if you are making a copy it makes the external dimensions the same as the original. Airholes,I've found that it is easier to drill through the mould after casting rather than inserting pins that are difficult to remove once the mould has set.On a cavity mould this makes life interesting keeping the drilling dust out of the of the cavity,something always sticks,fully conversant with that at this end. I've no piccies to show now but leave it with me. 1 Link to comment Share on other sites More sharing options...
Troy Smith Posted January 13, 2019 Author Share Posted January 13, 2019 I'm going to bump this, in case now @John Aero as posting again he could add some information, or if @Alex Gordon perhaps turned up some info in the menawhile. cheers T Link to comment Share on other sites More sharing options...
Pin Posted January 13, 2019 Share Posted January 13, 2019 Simple question, are you going to form one canopy to replace yours yellowed one or to mass produce them? The reason to use fillers such as alluminium for resin forms is to harden them so that the formd could withstand multiple (several dosens) cycles of vacforming being in contact with hot plastic. If you only going to form a single (or a couple) replace canopy you don't need to harden the form. This is what I have done: Here I have tried to make a negative form, but I'm not quite happy with the result, I suspect I have applied silicon release agent incorrectly 1 Link to comment Share on other sites More sharing options...
Plasto Posted January 13, 2019 Share Posted January 13, 2019 (edited) Troy, I made a resin master to vac form a canopy for my ongoing 1/32 Typhoon. Here you can see the RTV mould the vac form ‘buck’ and the PETG canopy I vac formed. I used regular casting resin and a home made vac table for the job. I think you would want reinforced resin on the vac form master if you were running many many copies. I vac formed around 20 canopies on my resin master without any issues. If if it’s a commercial venture then I have no experience of reinforced resin casting.. HTH.. Edited January 13, 2019 by Plasto 1 Link to comment Share on other sites More sharing options...
Black Knight Posted January 14, 2019 Share Posted January 14, 2019 For just one or a few copies I've used Keramin moulding plaster or Polymer Clay for the buck 1 Link to comment Share on other sites More sharing options...
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