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Old 10-17-2015, 11:25 AM   #21
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yup, i think thats gonna do it

if you wish to take the intensifiers out, you will have to make them out of silicone , i highly doubt they going to come out

look forward to the results !
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Old 10-17-2015, 12:49 PM   #22
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Quote:
Originally Posted by Blackrat View Post
yup, i think thats gonna do it

if you wish to take the intensifiers out, you will have to make them out of silicone , i highly doubt they going to come out

look forward to the results !
Hopefully they will, by bagging them they should be able to be extracted after the bladder is removed. I do have some shore 70 urethane that I was going to attempt to make a bladder out of, this may be a good material to use, it seems to not stick to the epoxy, but silicone may be much better. After determining the solution, different materials can be used to find the best fit.

Here is a thought; if I used urethane or silicone to construct intensifiers, could they then be molded into the bladder to make a single unit? Basically thinner in the bladder area and thicker areas in the corners to concentrate force?
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Old 10-19-2015, 10:49 AM   #23
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also be aware that silicone can expand significantly under heat and lead to even greater forces acting on the clamped mold.

your idea of thinner and thicker bladder areas sounds good imo.
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Old 10-19-2015, 11:34 AM   #24
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Hi

For you shape it might be worth trying qualax balloons. They are used a lot in the Rc glider building.
Making and end cap for your mould so you can use 2 spaced apart slightly to fill the but area or maybe one will fill out enough.
Use a long hollow fiberglass rod for air and one tiny hold at the far end as you need the balloon to fill from far end back , this will enable it to hopefully fill into your tight corners ok. Also you need to make nice round end on the shaft ( drilled marble works well) so your balloon doesn't pop from there.
They are very tough about $.50 each depending on what size you get. And will blow up to 1ft dia so conforming to your mould shouldn't be a drama.

For you tube
You might have to make it out of brass or something that you can bend to conform to the shape of your mould and get ballon around corners. That if you can not see end of mould line of sight

Tim

Like this.

Check out this video on YouTube:

http://youtu.be/zeLC-miXSwo
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Old 10-21-2015, 06:16 AM   #25
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And and ...
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Old 11-14-2015, 11:11 AM   #26
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Ok, I have some updates after attempting layup using the intensifiers, the improvements are significant. I chose to use the existing SL 800 bladders to avoid changing too many variables, and not knowing which one made the improvements, here are the results.

First image is of the most agressive corner on the mold, new part using the intensifiers is on the right. You can see the first two parts (left and center) both consistently have the same issues in similar locations.


Again, new part on the right




The next improvement is the bladder, I am currently molding a "anatomically correct" bladder out of shore 60 urethane, which should apply a fair amount of pressure in these problem areas. Thanks for all the input so far, the results are great!
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Old 11-15-2015, 06:19 AM   #27
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what a difference eh ....

funny enough, im struggling with the same problem , but im getting inconsistent results even with an intensifier :S
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Old 11-15-2015, 10:26 PM   #28
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That are just bridging problems. If you would lay the fibres more accurate you would not need an intensifier.
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Old 11-27-2015, 04:10 AM   #29
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Nice to see this beginning to work out as I am kinda thinking I might attempt something a bit similar.

But a question to all - how do you actually go about making a DIY silicone, latex or PU bladder? Pour into the mold and slush around, then pour out and build up layer by layer? I know you could brush it onto the tool/plug, but if you wanted to reduce the buildup in size could you actually do it in the mold as per above?

You may think it has been covered a lot, and it kinda has, just not down to the detail of actually making one;-).
(Except one poster mentions he "rotomolded" by hand with silicone inside the mold.)

Last edited by GeckoSub; 11-28-2015 at 02:50 AM.
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Old 11-28-2015, 11:46 AM   #30
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Quote:
Originally Posted by GeckoSub View Post
how do you actually go about making a DIY silicone, latex or PU bladder? Pour into the mold and slush around, then pour out and build up layer by layer? I know you could brush it onto the tool/plug, but if you wanted to reduce the buildup in size could you actually do it in the mold as per above?

I have been working on making bladders with shore 60 urethane, which is fairly rigid yet flexible. The issue is when I try to brush it in and then close the mold, when dry it wants to fail on the parting line. I think the way to do it would be to apply a thinner material (liquid silicone, etc) and attempt a "roto mold" to evenly distribute the material. You can brush it in, but you would definitely want to apply more and close it to bridge the two sides while curing.

I am working through the process, so pictures and updates will follow.
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