Wednesday, 8 February 2012

Sometimes things do not quite work as well as you hoped

I decided to try out my 'using boiling water to mould Plasticard around a former' technique today to see if I could produce consistent results. I had already prepared suitable moulds/formers for the hull ...


... and superstructure.


I then placed a piece of Plasticard that had been cut to fit into the hull mould/former ...


and then clamped the piece of Plasticard that was going to be used to be the superstructure ...


... to the wooden superstructure former.


I then immersed both in a pan of boiling water for forty five seconds, and after they had been taken out and allowed to cool, the Plasticard had taken on the required shape.

I repeated this four times, and got four hulls and superstructures.


However ...

... the process of immersing the wooden moulds/formers into the boiling water caused them to begin to deform and for the glue that I had used to put them together to lose all its strength. By the time I removed the last of the Plasticard from the moulds/formers the latter were on the verge of coming apart completely.

So what has this exercise taught me? That I can produce consistent results using my 'boiling water to mould Plasticard around a former' technique, BUT that I need to make the moulds/formers from something that is more heat resistant than the wood and glue I used for these moulds/formers.

This is something I need to think about in more details.

14 comments:

  1. Glue and Screw Bob, any joiner will tell you that!!

    Jim

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  2. Jim Duncan,

    Thanks for the advice.

    I suspect that you are correct. I will certainly try to rebuild my existing moulds/formers if I can l ... but using both screws and glue this time.

    All the best,

    Bob

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  3. You have the hull mould so that at least you can cast in resin or plaster???

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  4. Steve-the-Wargamer,

    I have never had much luck with either resin or plaster ... but they are options that I should certainly consider.

    All the best,

    Bob

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  5. Waterproof glue is half the answer. Did you use normal white glue? Try cascamite, needs mixing but don't collapse in water. Plus screws, as mentioned, and probably some sort of protection for the wood surface (vaseline?)
    Had you thought of vacuum forming? Probably too much work involving hoovers etc., for the job in hand.

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  6. Joppy,

    Thanks for the advice. I did use what claimed to be both water and heat-proof glue ... but turned out to be neither.

    I will certainly treat the wood (and screw the pieces together) next time, but I think that building a vacuum forming machine might be a step too far ... at the moment!

    All the best,

    Bob

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  7. I have had some success with using a heat gun to mould and draw form ABS. I see no reason why it wouldn't work on styrene.

    One has better control over where the heat goes but handling the warm plastic in your current setup could be difficult.

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  8. Pat G,

    Thanks for your suggestion.

    The only time I have used a heat gun, it was to strip paint ... and I don't know if it has the sort of temperature control I would need to use with Plasticard without melting it or setting the wooden components on fire.

    I do have a vague idea forming in my mind for a possible way forward, and I may give it a try tomorrow if I can. If it works, I will write a blog entry about it ... and if it doesn't I will probably write one anyway!

    All the best,

    Bob

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  9. Using a heat gun needs practice and a lot of judicious "wafting" Bob, but once you have the hang of it, it is quick and reliable. I use it for modifying insoles for patients.

    My suggestion would be to warm the plastic until it just starts to become softer, fold it around the former and clamp it, then warm it a bit more to take the stress out. Plunge it quickly into cold water to set it, then air cool. You could skip the water cool stage and it should still work.

    Kind regards, Chris

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  10. Hi Bob,

    I am really forward to seeing what those hulls are going to look like with the 'fixtures and fittings' added - there also seems to be rather a lot of them!

    MoBaS Tsushima maybe?

    All the best,

    DC

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  11. Chris Kemp,

    Thanks for the very helpful advice.

    For the moment I am going to try using the boiling water technique in a slightly different way ... but if that does not work I will give serious consideration to using a hot air gun.

    All the best,

    Bob

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  12. David Crook,

    Once I have the production method for the hulls sorted out I intend to move on to actually adding the 'fixtures and fittings'.

    As to how many 'Monopoly' battleships I am going to end up building ... well, who knows?

    MOBAS Tsushima? I suppose that it might be a possibility.

    All the best,

    Bob

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  13. Agree with cascamite - used it to build 1:1 scale boats up to 22 foot in length!

    You could try coating the wood in sanding sealer and then varnish to give a more water durable surface.

    I assume steam will not heat the card up enough?

    If you go the sucker method (sic) try http://www.instructables.com/id/How-to-Make-Your-Own-Prototypes-%3A-How-to-make-your/

    Note you can get granular plastic that will melt in water - maybe a change in mould shape and try this http://www.craft-products.com/polyform-plastic.asp

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  14. ADB,

    Thanks very much for your advice and the links (which were extremely helpful). Cascamite sounds like its a very potent adhesive.

    I have tried using steam to shape Plasticard ... but it took too long for the Plasticard to 'take' to the shape (and I parboiled my hands as well!).

    I am about to try another method ... and will write a blog entry about its success (or failure).

    All the best,

    Bob

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