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Old 09-30-2016, 07:54 PM   #41
20_rc51_00

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How have things turned out for you?
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Old 10-01-2016, 11:35 AM   #42
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Originally Posted by 20_rc51_00 View Post
How have things turned out for you?

I have constructed new silicone bladders with intensifiers molded into them, which has helped a lot. The new bladders are slightly smaller than the mold, so they match the interior dimension of the laminate. So far I have been wetting out the material, inserting the bladder and placing the mold in a vacuum bag, followed by inflating the bladder. I may switch to prepreg to see if that will solve some of the issues I'm having with hand layup. Here is a pic of the more recent results, still have a few small voids and pin holes, but it's moving in the right direction.


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Old 10-01-2016, 12:54 PM   #43
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good to hear!

Are you still using the smooth on product?
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Old 10-01-2016, 04:36 PM   #44
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good to hear!

Are you still using the smooth on product?
First bladder was made using Smooth-On Dragon Skin, but have since switched to their brush on vacuum bagging silicone, seems to be working great so far.
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Old 10-02-2016, 02:22 AM   #45
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Do you have some photos with your bagging silicone application. Dont want to make a fault using this idea , your experience may help here..
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Old 10-02-2016, 11:29 AM   #46
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Same as in this pic, but the bladder is slightly smaller than the mold surface.

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Old 10-03-2016, 10:21 AM   #47
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I'm in the process of getting back on my silicone bladder project as well. Compositeman- how many uses are you getting out of those bladders? I assume you are making them by laying sheet wax in the mold to replicate the laminate thickness, carefully bushing both halves, and the putting them together and waiting for cure?

Also, what temp are you curing at? I am planning to do aluminum molds with a fairly hot cure temp to get parts in and out in about 2.5 hours. I would assume cure temp and bladder life are going to be directly related.
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Old 10-03-2016, 08:29 PM   #48
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Compositeman- how many uses are you getting out of those bladders? I assume you are making them by laying sheet wax in the mold to replicate the laminate thickness, carefully bushing both halves, and the putting them together and waiting for cure?

Also, what temp are you curing at?
Current mold construction is epoxy and glass laminate molds using wet lay up and a mild 150 F cure temp. The bladder is easily removed when collapsed using vacuum. So far only 10 parts have been made using these bladders, but no damage yet. I will be attempting the same process on aluminum molds with cure temps around 300 F, we will see how they hold up.

For constructing the bladders, I used a old mold that had been cycled to it's limit. By laminating multiple layers of 5.6oz glass to obtain the interior dimension, I can make bladders on a separate mold without the need to stop production of the final molds. Both halves are brushed on separately, then a bridging bead applied to each side and the mold closed. The mold was room temp cured and then post cured in the oven, cooled and demolded and instantly put into production.
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Old 10-10-2016, 05:38 AM   #49
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Could you explain this step :'The bladder is easily removed when collapsed using vacuum".
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Old 10-12-2016, 04:36 AM   #50
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Quote:
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Could you explain this step :'The bladder is easily removed when collapsed using vacuum".
I'm pretty sure that he means that once the part is cured, he pulls vacuum on the bladder (instead of positive pressure). This vacuum will suck the bladder in on itself (collapsing) and away from the insides of the part. And then, once collapsed, it will be easy to pull out of the part.
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