Greyhead

This is a way of producing small plastic mouldings without the need for any vac-forming.

The first stage of the process is to make a hardwood plug, the better the surface finish the better the final moulding will be. If you’re being pedantic make it smaller by the thickness of the plastic, but knowing what the finished thickness of the plastic will be after moulding would certainly tax my brain past the limit!

Then cut a corresponding hole in some plywood. The clearance between the plug and the hole should be about the thickness of the plastic you intend to use but it isn’t that critical.



Cut your plastic leaving plenty of spare and position it centrally over the hole; I find it helpful to pin the plastic in place to stop it curling when the heat is applied.

Heat the plastic using a heat gun; keep the heat gun moving to get as even a spread of heat as possible over the entire area of the plastic then quickly plunge the plug through the hole to the required depth.



Here are 2 tank sumps for my SE5a, one roughly trimmed.



Getting the right amount of heat takes a bit of trial and error and you will almost certainly have a few failures before you get it right but the plastic can be any thermo plastic from pop bottles to ice-cream containers so it costs nothing to experiment.

Bluewavestudios

Another useful idea, especially for doing smaller parts as shown.
Cheers for Posting Grahame.

Regards........Mark

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Greyhead

This is the first time I've tried this method although I've known about "for ever"! It really is only for small parts, for anything bigger vac-forming is the way to go and I'll certainly have to get round to making one as per your instructions but at the moment the SE5a is taking precedence.

Bluewavestudios

I can only agree with you there Grahame,
The SE5A must be getting close to completion now and I would do the same in giving that priority before starting anything new, it's always so easy to get sidetracked onto something else.

The Plunge moulding method certainly seems to have worked well for you and as stated, It is probably the better method for small parts where Vac-forming would be wasteful just for a couple of small bits.

The Sumps look good on the Model too.

Regards.......Mark

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I'm Only Here Coz I'm Not All There !!!

SilentWings

Thanks for this Grahame - like you I've known about this for a while but never actually tried it. Any idea as to how thick you could go when it comes to forming sheets in this way...would 1mm be out of the question?

Marudek

I used similar technique to make canopies for my Hornet and Pitts 1:33 card models. I simply formed canopy with paper parts, then filled paper canopy with Milliput. When it settled I removed paper and polished the “plug” (or matrix). Then I cut off the bottom of 2l Coca-cola plastic bottle and inserted my matrix mounted on a scrap wood block. I heated up the whole thing over the flame of gas cooker and let shrink. After it cooled down I just had to trim the canopy.

I’ll use this technique to make canopies for my 1:33 card Catalina (which is now waiting in a queue).

Regards,
Marudek

Greyhead

I've just measured the plastic I used, it's 0.7mm and that moulded easily so I don't think that 1mm would be too thick. It would take more heat to soften but it would "hold" the heat longer; it costs nothing to try so why not give it a go?

SilentWings

This sounds great!.

To be honest Grahame, I was thinking about making a simple vac-former for those parts of my canopy that have a compound curve - however, after reading this thread it would seem that plunge moulding will give me similar results for a lot less effort.

Thanks for the words of encouragement - I'll give it a go just as soon as I can.

fossil

Will try this for my M-55 Geophysica..... Thanks