New Repro D-Mask with Type 19 Mic.

New Repro D-Mask with Type 19 Mic.

Joined: September 8th, 2004, 10:02 pm

July 23rd, 2009, 6:56 pm #1

Hello chaps,
I am considering reproducing a D-Type oxygen mask with a Type 19 mic. I currently have a Type 19 in pieces for restoration so it would be a golden opportunity to make some molds of the front and back.
This is where I need somebodys help I want to understand the best method for producing home molded parts such as in resin. I would want to be able to reuse a mold for a production run.
I know some of you out there mold items in resin, etc how is it done?
I understand model shops may have kits for molding resin, etc. But I would like your feedback on what is best.
My idea is to make this repro as simple as possible to keep costs down but for it to look correct too.
This item will be part of a catalogue of items I am working on. The other items are mae west bladders and a 32 patt mae west, etc. These are still in work.
Thanks!
Neil B.
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Joined: July 21st, 2008, 7:16 pm

July 23rd, 2009, 8:29 pm #2

I seem to say this a lot, but considering he made reproduction ones before Stephen Silburn might be worth contacting...
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Joined: August 23rd, 2003, 10:11 pm

July 23rd, 2009, 9:08 pm #3

Hello chaps,
I am considering reproducing a D-Type oxygen mask with a Type 19 mic. I currently have a Type 19 in pieces for restoration so it would be a golden opportunity to make some molds of the front and back.
This is where I need somebodys help I want to understand the best method for producing home molded parts such as in resin. I would want to be able to reuse a mold for a production run.
I know some of you out there mold items in resin, etc how is it done?
I understand model shops may have kits for molding resin, etc. But I would like your feedback on what is best.
My idea is to make this repro as simple as possible to keep costs down but for it to look correct too.
This item will be part of a catalogue of items I am working on. The other items are mae west bladders and a 32 patt mae west, etc. These are still in work.
Thanks!
Neil B.
As I have some experience in casting stuff, I can give you some advise.
What you're after seems to me a tad more difficult than what I've done. You need a 2 part mold to casts the mic in one go. There are 'manuals' on the net about that (I've never done 2 part molds).
The resulting mics would be fairly heavy and I don't think you'll be able to get the thinner parts done.

I'd suggest a three stage approach: the mic housing can be vacuum formed:
http://www.stanford.edu/group/prl/prl_s ... rming.html
http://www.warmplastic.com/avf.html

The mic itself (I think) can be made using a one part mold. I use Smoot-On products. Smooth-Cast 305 for the resin part.
http://www.smooth-on.com/
http://www.youtube.com/watch?v=sOyBawt1-Ec (a tutorial on brush-on molds, which yuoi wouldn't need, but it gives you an idea of what can be done)

The parts on the outside I have never seen 'live' so I couldn't comment on what to do with that. I suppose it can be a combination?

Good luck!

Cheers, Toine
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Joined: October 19th, 2003, 6:40 pm

July 24th, 2009, 7:02 am #4

Hello chaps,
I am considering reproducing a D-Type oxygen mask with a Type 19 mic. I currently have a Type 19 in pieces for restoration so it would be a golden opportunity to make some molds of the front and back.
This is where I need somebodys help I want to understand the best method for producing home molded parts such as in resin. I would want to be able to reuse a mold for a production run.
I know some of you out there mold items in resin, etc how is it done?
I understand model shops may have kits for molding resin, etc. But I would like your feedback on what is best.
My idea is to make this repro as simple as possible to keep costs down but for it to look correct too.
This item will be part of a catalogue of items I am working on. The other items are mae west bladders and a 32 patt mae west, etc. These are still in work.
Thanks!
Neil B.
There is a chap in the UK who makes resin replica weapons and he uses a mould of plasticene held within a Lego block former.

I have cast small insignia very well by using play-doh in small boxes but the mould is not reusable. The way to mass produce is to use several repeated impressions and one batch of resin.

Always cheap and cheerful, I used vehicle body repair resin!
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Joined: September 8th, 2004, 10:02 pm

July 24th, 2009, 2:46 pm #5

Thanks chaps.
Thanks for the links and advice Toine.
I am determined to do this!
With the complexity of the mic body, I thought too that I would have to make it out of two separate moldings (Front and back). As far as the weight of the resin - this would help as the dear old Type 19 is quite heavy for its size.
Toine, I like the idea of vac forming. My only concern is the fragility of thin plastic.
To make this cost effective I would have to drop some of the details. It wouldn't open and the mic would be permanently attached to the mask etc. BUT it will look right.
It will have a chamois covering and real or lookalike green wool and chammy interior.
I'll keep you posted.
Cheers
Neil
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Joined: August 23rd, 2003, 10:11 pm

July 24th, 2009, 8:19 pm #6

Hi Neil,

It's the fragility that made me think of vacuum forming.
The mic housing has to enclose the oxygen inlet ring, so there's not much margin to strengthen/thicken the (originally) sheet aluminum body.
Cast resin is very strong in substance, but very brittle when cast to thin sheets.

Polystyrene is a surprisingly strong material, specially when formed into a cup-like form.

Anyway, good luck with the project! Looking forward to seeing pics of the prototypes!

Cheers, Toine
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Joined: September 8th, 2004, 10:02 pm

July 25th, 2009, 12:45 am #7

Hi Toine,
Yes, I see what you mean. So for the ring I could use some aluminium pipe. OR, as I don't intend to make the mic hinge open, I could disguise the thickness of the inlet ring. It could be made thicker for strength and made so it won't be seen.
I'll let you know how it goes.
Cheers
Neil
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Joined: March 10th, 2008, 7:41 pm

July 25th, 2009, 9:14 pm #8

Smooth-On that Toine mentioned is good stuff by reputation (and his personal experience). I have used Alumilite resin before and am happy with it. It isn't as brittle as epoxy resins like the 30 minute repair types. It is available in a couple of different colors too, so you may be able to avoid dying the resin or painting after the part is made.
The company also sells the silicone RTV for making the molds, a polyurethane rubber for making softer parts, and other needed bits for casting.
Carol there is very helpful, and the staff quite knowledgeable about what they sell.
www.alumilite.com/
Good luck and keep us posted!
Jeremy
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Joined: September 8th, 2004, 10:02 pm

July 27th, 2009, 7:02 pm #9

Thanks for the info Jeremy.
I shall investigate these products.
I am feeling very optimistic about the outcome.
Cheers
Neil
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Joined: June 4th, 2009, 8:58 pm

September 13th, 2009, 11:00 pm #10

Hi Neil,

It's the fragility that made me think of vacuum forming.
The mic housing has to enclose the oxygen inlet ring, so there's not much margin to strengthen/thicken the (originally) sheet aluminum body.
Cast resin is very strong in substance, but very brittle when cast to thin sheets.

Polystyrene is a surprisingly strong material, specially when formed into a cup-like form.

Anyway, good luck with the project! Looking forward to seeing pics of the prototypes!

Cheers, Toine
There is always the option of getting someone who runs a full casting facility to do the job for you !!!
look on ebay for g masks and escape boxes.
if you want to look into getting parts made and have patterns (or parts near to pattern quality) get in touch with me
regards maecus
am still looking into receivers for b type helmets
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