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Glass fibre mould from the slender plug

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vtsteam:
Pekka, what about finishing the plug well and then doing a plaster of Paris mold over? Then varnish the plaster, wax it and mold your sword material in that?

Actually, since you seem to do really nice work in wood, what's wrong with a wooden sword? Traditional for practice and children's swords, I believe.

If you really want, you could glass the outside for some wear protection. -- it does take more finish work, but far less mold work, so they're about even.

eskoilola:

--- Quote from: PekkaNF on June 12, 2018, 05:07:11 PM ---Yes. I tried vacuumforming 1 mm polycarbonate (for two halves) to make <snip>

--- End quote ---
Polycarbonate is not very good material for vacuumforming. I does not get really soft and when it does, it already starts to decompose. I made a swarf shield for my tiny lathe from this material and it was an excersise with heat gun. The result is not pleasing but it does the job.

I quess acryl or ordinary PVC might be better.

eskoilola:

--- Quote from: vtsteam on June 12, 2018, 11:44:54 PM ---<snip>
Actually, since you seem to do really nice work in wood, what's wrong with a wooden sword? Traditional for practice and children's swords, I believe.
<snip>

--- End quote ---
Do You actually believe that a small wooden sword would have any chances of survival in the hands of a viking ?
The idea of making the thing out of polycarbonate has some appeal to it as that material is virtually indestructible.
One might consider using the vacuum to fill in the particle wood sword with polyester resin. I have used the polyester resin to repair housings of old tube radios which were broken and were made out of the particle wood. The resulting composite is actually very strong.

PekkaNF:
I should have clarified few things:
* Both swords have to somewhat transparent, therefore something bit more opaque that wood is needed. I normally would make the core out of foam and epoxy glas fibre veil to it to give some strength and surface to finish, but that does not work on this one, because there is no transparent core material (or it is unobatanium).
* All anime props must be pretty harmles, they must have no "live" (read "real") metal and maximum strenght is "wood" or the prop is not allowed. Puts some limit on materials.

We made a halberd out of closed cell foam, plastic electrical conduit, some plywood on structurally critical parts. It's about 250 cm long and has all detachable spikes (three when assembled) and few spares. Weight very little and breaks if you poke anybody with it, but looks very menacing. That was easy.

Plaster of paris came to my mind, but the mould would be 1,2 m long, least 200 mm wide and some depth....probably shrinking would be a factor and on those dimenssions POP might need some serious inforcement. Think I'm going to go for polyester. Digged out the gelcoat, resin and noticed that the MEK bottle had leaked....what a mess. Luckily the plastic box I had all of them had contained the mess.

Pekka

vtsteam:
Hi Pekka, I think you meant translucent in the first and last post -- not opaque, hence the confusion.

eskoilola, re. "Do You actually believe that a small wooden sword would have any chances of survival in the hands of a viking ?"

Depends on the viking (or in this case samurai, not to mix up our cultures) and the type of prop use. If for costume show primarily, wood will certainly do. But if the proposal is for actual clashing with replica-looking blades, any hard plastic will also dent pretty bad and even break. Light weight hollow soft plastic like polypropylene would be more appropriate and safer.

And btw to go along with Japanese culture, bamboo swords are quite durable, even in practice battles. Not that they are particularly safe if of scale proportions. Tubular blades are much safer.

Pekka while you may not prefer to use plaster of Paris for other reasons, it can be reinforced just like any modern plastic resin would need to be -- and you can use easily obtained or scrap wire or screen or mesh, as well as set into a wooden box for support. It cures very quickly, and no, it does not shrink, which is why it is traditional for molding. Vaseline (petroleum jelly) is a great release for it, all easily obtained and inexpensive materials.

But of course everything we do must appeal to us, and if epoxies and glass fiber are what you want to work with, that's the way to go. I'm jus throwing out possibilities to consider.

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