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Author Topic: 2 part silicone as a moulding rather than a mould  (Read 941 times)

RST

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2 part silicone as a moulding rather than a mould
« on: September 03, 2022, 09:42:28 pm »

Hi,

I am pondering an idea I have here:  I want some custom fendering that looks like the full-scale rubber blocks.  My 3-D printer prints nice and neat and I hashed up a quick mould to try omething last week:

I have plenty of blu-stuff 2-part silicone, I cast some parts using it (blue parts in image)I did soome googling and saw you can tint the silicone:  a) the method using oil based paints just didn't work b) the method using 8 drops of Tamiya acrylic in 8g (total) of silicone worked well-enough I think!

...I know well though that casting silicone is meant for the mould, not the moulding and that's how I always used it before.  But does anyone know if these will stand the test of time as mouldings or would they degrade with UV.  They should stick on my hull fine with the silicone adhesive I have.

Pic attached:

  • Top:  Quick ABS mould knocked up
  • Middle:  6 "virgin" silicone fender blocks
  • Bottom:  6 blackened silicone fender blocks

...They are to be honest just a little soft but not too bad, each one is 16mm long x 10mm wide x 6mm high.  I see there's a "thickener" available but that's expensive at £15.  Would talc work (not that I have any!)?  I heard corn flour works -which I have but am worried if it would rot over time.

Do I have any good chances here or am I just just wasting my time?  I can just print and paint the blocks but I thought it might be worth trying in silicone so at least they are something properly soft.

Thanks for any feedback from those who use similar stuff,

Richard

https://blu-stuff.com/
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nemesis

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Re: 2 part silicone as a moulding rather than a mould
« Reply #1 on: September 06, 2022, 06:28:22 pm »

make your mould in anything as long as it is NOT silicone, I made, years ago, silicone suspension units for my Hi Fi turntable and they still OK.nemesis
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T888

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Re: 2 part silicone as a moulding rather than a mould
« Reply #2 on: September 06, 2022, 07:52:50 pm »

RST


You can try CFS, I’ve found there tech help very very good if you tell them what your doing they may be able to help with a harder rubber. Sorry but there not cheap :((


https://www.cfsnet.co.uk/acatalog/CFS_Catalogue__RTV_Silicone_25_Shore_560.html
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ballastanksian

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Re: 2 part silicone as a moulding rather than a mould
« Reply #3 on: September 06, 2022, 11:15:59 pm »

The biggest thing that kills silicone rubber is the resin and its hardener, so as long as it isn't in bright sunlight all the time, it should be alright. Most things will perish in the sun eventually, but as your application isn't going to be stressed or hard wearing then that will favour it. Thickener (Thixotropic additive) only thickens it whilst green to allow you to build up layers that will not run whilst curing, it will not affect the rubber's shore hardness or the like once cured. You can get different grades of silicone, some very soft, or some that are hard, so it is wise to get advice from one or two suppliers and base your decisions on a consensus of their advice.
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Umi_Ryuzuki

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Re: 2 part silicone as a moulding rather than a mould
« Reply #4 on: September 06, 2022, 11:43:17 pm »

I pour a soft durometer polyurethane.

RST

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Re: 2 part silicone as a moulding rather than a mould
« Reply #5 on: September 07, 2022, 12:16:33 am »

Quote
Thickener (Thixotropic additive) only thickens it whilst green to allow you to build up layers that will not run whilst curing, it will not affect the rubber's shore hardness or the like once cured

...thanks ballastanksian.  That's kind of what I thought how it worked from the start.

...thanks T888 but if you look at the question I know that already.

...Nemesis I'm using that on something just now for something else.

...Umi-yes, that makes sense.

Sorry but I deal allot with polymers at work but the materials are easier and if course it's full-scale.  But it's always worth asking small-scale just in-case seoeone has done it before as nothing surprises me these days.

Thank you all for your feedback.  I think I'll pursue a different option and post-back later.
Rich
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Umi_Ryuzuki

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Re: 2 part silicone as a moulding rather than a mould
« Reply #6 on: September 07, 2022, 06:10:43 am »

Well, I must admit I do it quite a lot.  %)
http://modelsminiatures.com/fendering/
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