Re: [PSUBS-MAILIST] Acrylic bubble port construction techniques?

[Mike Young <tvcmikey@yahoo.com>]

Hey Nate,
Are you old enough to remember this stupid toy we had
when I was growing up? It consisted of two acrylic
resin balls on strings, which one click-clacked away
like some paddle ball. As I remember, some kids would
be playing with these things, and they blew up in the
kids' face. :{0>

Mike from Malaysia


--- Nathanael Henderson <jude@pconline.com> wrote:
> 
>     My question isn't the obvious one, ie. 'how do
> I.'   Rather, what I'm
> wondering is if certain methods are dangerous (would
> compromise the
> structural integrity of the plastic.)
> 
>     The most immediate option that springs to mind
> is milling from a big
> solid block of cast acrylic.   I can't imagine any
> objections to the
> strength of the resulting product, but it would be a
> bit expensive to buy
> a huge block just to carve out most of it, plus the
> considerable headache
> of trying to mill out the dome (a lathe of some sort
> perhaps.)
> 
>     Second option:   A laminated block.    You could
> cut rings of acrylic
> out of thinner sheet and fit them together into a
> rough dome shape, fusing
> the sheets with solvent 'glue' (methyl chloride?). 
> Advantage:   Easy to
> obtain sheet acrylic, reduced cost, easier final
> finishing of the dome.
> The big question:   How would the laminated aproach
> affect final strength
> of the plastic?   Probably safe with sufficient
> de-rating, but I'd feel
> better hearing from somebody more knowledgeable. 
> :-)
> 
>     Third option:   Thermoforming, particularly
> force forming onto a mold.
> Probably the cheapest route in terms of plastic
> costs, but would require
> more elaborate equipment and be less predictable in
> terms of the final
> thickness of the plastic.  Limitations on the
> size/thickness of the dome.
> 
>     Fourth option:   Conventional casting into a
> mold using acrylic
> resins.   Advantage:  Efficient, high quality high
> precision resulting
> product.   Ideal for mass production, but possibly
> very high cost of
> equipment to produce them.  Probably not practical
> for a once-off.
> 
>      Fifth option:  Dammit, go buy one.  :-)    How
> expensive are
> commercially manufactured domes?   (Any size prices
> would be usefull.)
> 
> 
> 
> 
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