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Re: [PSUBS-MAILIST] Acrylic Molds
Jeff: I am in total agreement and for my part, the discussion can stay on-line. I'll leave the final call with Doc. If he is game, I sure am. I would love to be able to form some acrylic domes that are actually useful instead of the small experimental ones I have tried (and ruined). I have a tremendous amount to learn about the subject and with Doc's expertise, and the rest of this multi-talented group, no telling what can develop. Hey, did you get the corrosion paper OK? Marco got his in New Zealand. Best regards, Mark
---------- Original Message ----------------------------------
From: JP <jeffpost@rawbw.com>
Reply-To: personal_submersibles@psubs.org
Date: Tue, 7 Jan 2003 18:13:55 -0800
>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
>
>