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Re: [PSUBS-MAILIST] Acrylic Molds




Doc: Will do and thanks a million.  Mark Steed


---------- Original Message ----------------------------------
From: Doc <doc@bionicdolphin.com>
Reply-To: personal_submersibles@psubs.org
Date:  Mon, 06 Jan 2003 19:51:41 -0800

>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
>> >> >
>> >> >
>> >>
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