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Re: [PSUBS-MAILIST] Acrylic Molds
Mark & Doc
I for one would like to see this discussion stay "on-line". This is the kind
of chatter I want to hear; not this nuclear homebuilt bullshit. I think I've
deleted two hundred messages in the last three days from this list that were
complete nonsense.
JP
On Monday 06 January 2003 07:51 pm, Doc wrote:
> Hey Mark,
>
> If you blow or droop the part, you will have some thickness variation in
> the finished part. For uniformity Drape molding over a felt covered male
> mold is best. The size and thickness you're talking can easily be heated in
> the oven. You can contact me off list and I'll try to walk you through it.
> There are no dumb questions,,, dumb answers, that's another story.
>
>
> Doc
>
> Mark Steed wrote:
> > Doc: Wonderful! You are the man and thanks for getting back with me. I
> > have done some small forming but nothing close to what you have. I am
> > very interested in these techniques, especially the forming oven. Could
> > you elaborate sometime on the oven's construction, time and temperature,
> > etc ? What I would really like to do is make up a round port 6 to 8
> > inches across and 1 to 2 inches deep. All this is approximate. I do have
> > some 3/8 inch thick stock. Is this workable? Thanks Doc. If you want me
> > to conatct you off-list or whatever, I appreciate it. What I don't know
> > about this sort of thing would fill a warehouse so don't be surprised at
> > some dumb questions. Many thanks again and best regards, Mark
> >
> > ---------- Original Message ----------------------------------
> > From: Doc <doc@bionicdolphin.com>
> > Reply-To: personal_submersibles@psubs.org
> > Date: Mon, 06 Jan 2003 18:37:02 -0800
> >
> > >Mark;
> > > I've done considerable research and testing on different ways to form
> > > acrylic in the barn, from gravity to blow molding to drape forming of
> > > up to 1 inch thick over a male fiberglass mold. For blow molding or
> > > gravity forming, you can coat your separation points (ring) with a
> > > layer of epoxy resin or gelcoat and a thin coat of car wax. You can
> > > build a 4'X8' forming oven out of plywood or chip board, aluminum foil
> > > , a piece of 1/4" plate glass and a propane barbecue!
> > >
> > >Doc
> > >
> > >Mark Steed wrote:
> > >> Carsten: Somewhere in all my papers, I have some factory (Dupont)
> > >> technical reports on acrylic forming. For the life of me, I cannot
> > >> find them now-but I will. In the meantime, I remember one method they
> > >> reported on and it was to utilize steel rings instead of plywood in
> > >> the mold construction. These steel rings were to be coated in a high
> > >> temp. petroleum based grease to keep the acrylic from sticking. The
> > >> assembly was inverted in an oven, heated and then gravity was allowed
> > >> to form the sphere. There was no provision for an air line for
> > >> "blowing". I have a few large pieces of 3/8 inch thick acrylic sheets
> > >> that I would like to try this on but hate to waste any of it. Are you
> > >> familiar with anything like this? Any suggestions appreciated from
> > >> everyone. I toured the Euronaut again today on the website. Damn,what
> > >> an accomplishment,Herr Kapitan! Mark Steed
> > >>
> > >> ---------- Original Message ----------------------------------
> > >> From: MerlinSub@t-online.de (Carsten Standfuss)
> > >> Reply-To: personal_submersibles@psubs.org
> > >> Date: Mon, 06 Jan 2003 22:35:58 +0100
> > >>
> > >> >Michael B Holt schrieb:
> > >> >> On Mon, 06 Jan 2003 20:53:47 +0100 Carsten Standfuss writes:
> > >> >> >> Was the plywood being used as a mold; that is, was the acrylic
> > >> >> >> being formed against the plywood?
> > >> >> >
> > >> >> > _ _ plywood ring
> > >> >> > ---------- acrylic sheet
> > >> >> > - === plywood ring with air vale
> > >> >> > ---------- plywood plate
> > >> >>
> > >> >> That's the same method in the Markham plans. How well did
> > >> >> it work?
> > >> >
> > >> >It doesn't work well.. I put the unit out the oven during the time I
> > >> > saw that the acrlic sunk in the middle - short before it contact
> > >> > with his centerpoint the baseplate. Then I connected air wire from a
> > >> > airpump (a small electric 18 atmosph. compressor) to the vale and
> > >> > blow the bubble.. ..but lost to much air via the plywood - so the
> > >> > bubble make just some 20° degree and not the 180° I want.
> > >> >Also I found that the plywood isolate the acrylic in the rand areas
> > >> >to much from the heat .. next time I prefer to test a mold with
> > >> >aluminium rings and plates..
> > >> >The acrylic was about a half inch strong - and the plywood maybe not
> > >> > the best..
> > >> >
> > >> >How much will the pine planks cost ?
> > >> >And how much the overall project ?
> > >> >How much hours you will spend ?
> > >> >Have you think about after using the sub - to
> > >> >spent it for museums porpose ?
> > >> >
> > >> >The "..naut" in Euronaut is also a contribution to S.Lake..
> > >> >
> > >> >regards Carsten WWW.euronaut.org