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Author Topic: Neoprene Source  (Read 1489 times)

BarryM

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Neoprene Source
« on: December 24, 2008, 09:28:39 AM »

Given that there are guys on here that know their synthetics, can they confirm or otherwise that bicycle inner tube patches are made from neoprene?  I need a very small piece of 1/16th or 1.5mm thickness for a diaphragm and patches were suggested as a readily available source.

Thanks

Barry M
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andrewh

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Re: Neoprene Source
« Reply #1 on: December 24, 2008, 09:55:06 AM »

Barry,

They may well be made of neoprene, but are more likely Butyl rubber - which is what the tubes are made of

Can I ask why you need neoprene?  Its a good general rubber but not specially good for any particular thing

Firms like SBA sell sheets but that would probably be expensive.  All the suppliers of industrial rubber make and sell sheets of all sorts of rubber.  In neoprene there would be a range of thicknesses, colours and all the hardnesses from 20 Shore A to 95.

If you are considering a tube patch, perhaps a bit of tube would do the trick?  This is always butyl rubber, not very elastic, but good for high temperatures and everlasting in air, water and ozone.

andrew
 
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BarryM

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Re: Neoprene Source
« Reply #2 on: December 24, 2008, 09:58:38 AM »

Andrew,

As mentioned, need is for a small diaphragm in a regulator that will have steam on one side and gas on the other.

Barry M
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andrewh

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Re: Neoprene Source
« Reply #3 on: December 24, 2008, 11:01:18 AM »

Barry
Sorry,  missed it.  I see where you are coming from now

Assuming the gas is LP gas - probably a butane/propane mix you will find that neoprene has a limited resistance to it, it will swell and soften a bit, but not enough to stop it working.

Depending on how thick you need it - I'm guessing about 1/2 to 1mm you might find some industrial gloves which would donate material to you.  I have a few sheets - mainly of silicone and some exotic materials, and if you PM me with a size I will see if I have owt suitable.

regards,

andrew
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andrewh

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Re: Neoprene Source
« Reply #4 on: December 24, 2008, 11:08:45 AM »

Just remembered :}

RS do sheets of several sorts of rubber sheeting - in 12inch squares.  You probably want to aim for about 70ShoreA if there is a choice of hardness

Lordy, I havn't said this in years:
Shore hardnesses (durometer if you are american)
Ball of your thumb: about 20 (Shore A)
Staedler rubber; 80 shore A
bathplug:  90 to 92 shore A

For amusement: hard steel is about 98 or 99 Shore A
hope it helps

andrew
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derekwarner

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Re: Neoprene Source
« Reply #5 on: December 31, 2008, 11:55:45 PM »

Hi all.....yes BarryM...I have a French ANTON V71 gas regulator & when supplied, Fabrice also included a replacement seal kit which comprised two small nitrile [NBR] o-rings & a 20 diameter x 1.5 mm thick nitrile [NBR] diaphragm

I questioned the diaphragm material with Fabrice....& his explanation after translation via Babble Fish to the best of my ability  :o :(( was .......

The pilot pressure from the boiler is not steam from the top of the boiler but water from a lower boiler tapping  @ ~~~~~ may well be @ 140 PSI, but only @ approx 100 degrees C - it is important not to lag this pilot line to the regulator so as to get further surface cooling & hence further water temperature reduction

On the other side of the diaphragm we have LP 70/30 gas - the nitrile [NBR] elastomer has total compatability with this gas & so a section from a bicycle tube would appear OK....  :-)) just make sure that it is not perished

It is important to be able to bleed the trapped air from the water pilot line as close to the regulator as possible...otherwise the air acts as an accumulator & can cause a fluttering effect on the diaphragm & hence irregular gas supply to the burner...........Derek
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Derek Warner

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BarryM

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Re: Neoprene Source
« Reply #6 on: January 01, 2009, 10:25:27 AM »

Derek,
Thanks for info especially about the need for a bleed point. I had not included the need for a bleed but I will now.

Happy new Year,

Barry M
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derekwarner

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Re: Neoprene Source
« Reply #7 on: January 03, 2009, 07:16:46 AM »

Hi all....BarryM...my comment re the source of the gas regulator pilot pressure & non lagging ...etc were based on the recommendations of others ...but here we see that Bernard has used the boiler top as the pilot source & has lagged the pilot line...which are clearly a part of a beautifully detailed steam build  :-)) ...with the orientation of the ANTON V 71 regulator [pilot lin into the top] certainly would make air bleeding of the pilot line much easier  O0


It also appears that the boiler lower tapping is used for an alternate function....a blow down device????????   ............Derek
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Derek Warner

Honorary Secretary [Retired]
Illawarra Live Steamers Co-op
Australia
www.ils.org.au

BarryM

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Re: Neoprene Source
« Reply #8 on: January 03, 2009, 09:39:42 AM »

Derek,
Given the pipe run there would be, as you say, no need for a bleed point. I suspect that the regulator's maker does not advise lagging the sensor line in order to avoid the possibility that the diaphragm has steam on one side rather than condensate (same idea as the syphon on a pressure gauge). Lagging the line would appear to reduce heat loss in general but is unlikely to prevent condensate forming at the regulator end and so it looks like the maker is just being cautious.

What the other bleed is for I have no idea but perhaps Bernard will advise us?

Barry M
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