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Hanaldo
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+x+xAnd you're not bleeding out too much resin without a perforated film between the peel ply and the breather? Good question that...I'm pretty new at this so I appreciate you asking it. This is a complex three part closed mold and I let the resin get almost tacky before putting it together which helps with trimming and extensive seams. And I don't use a lot of pressure, just closing down the seam and compressing the fiber a bit. The appearance is very good so I hope I'm not removing to much resin. If it looks good then you're fine, the surface finish will suffer before anything else does. You may in fact still be quite resin rich, hard to say. If you wanted to know, you could weigh your carbon before starting, then weigh the finished piece afterwards and subtract the weight of the carbon. That would tell you how much resin is left in the piece and you could calculate your fibre:resin fraction. +xJust out of curiosity, how many cycles do you expect from your bladders? Depends on a lot of things, complexity of the part, how difficult it is to release the bladder after, etc. With epoxy, typically only 15-20 pulls before the silicone starts to break down.
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chriscnf
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+xYeh its unfortunate that epoxy dries silicone out so severely. Ive tried Mann Ease Release 200 as well as Stoner E236, E455, A324, and E497. I wouldn't say I noticed any very real extension of the silicones working life with any of them, perhaps a few extra cycles with E497 and A324 but its difficult to say if this was due to the release agent or because I was using a more forgiving process. Really none of them prevent the interaction between the epoxy and the silicone, so the silicone still dries out. PVA is really what you would need, which of course won't work. The good news is none of these transferred to the part, so I do still tend to treat all my silicone moulds just in case it does help at all. If you find something that definitely works to extent the life of the silicone then please let us know, I'd love to get indefinite usage from my rubber tools! Just out of curiosity, how many cycles do you expect from your bladders?
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chriscnf
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Group: Forum Members
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+xAnd you're not bleeding out too much resin without a perforated film between the peel ply and the breather? Good question that...I'm pretty new at this so I appreciate you asking it. This is a complex three part closed mold and I let the resin get almost tacky before putting it together which helps with trimming and extensive seams. And I don't use a lot of pressure, just closing down the seam and compressing the fiber a bit. The appearance is very good so I hope I'm not removing to much resin.
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Hanaldo
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Group: Forum Members
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And you're not bleeding out too much resin without a perforated film between the peel ply and the breather?
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chriscnf
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Group: Forum Members
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+xAre you using pre-preg or wet-lay? The non-perforated release film you see in that bike video is really for pre-preg only, where the resin content is already controlled. If you're doing wet-lay, you wouldn't use that film because as you say, you can't remove excess resin. You could use a perforated release film though? Would have the same benefits that they used it for in the bike vid, but would allow some resin bleed. Wet layup and I'm using the red stripe peel ply with a layer of breather cloth tacked to that. Resin bleeds through and absorbs into the breather cloth. So I'm reducing weight and contact with the bladder to some extent. The original reason was to allow the balloons to move freely when. Have to be careful with setup though or the ply is hard to remove. If release agent doesn't protect the silicone I might give a brush on latex a try, latex balloons come out reasonably well without release agent. I do have some weather balloons on the way from China to try out as well.
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Hanaldo
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Group: Forum Members
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Are you using pre-preg or wet-lay? The non-perforated release film you see in that bike video is really for pre-preg only, where the resin content is already controlled. If you're doing wet-lay, you wouldn't use that film because as you say, you can't remove excess resin.
You could use a perforated release film though? Would have the same benefits that they used it for in the bike vid, but would allow some resin bleed.
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chriscnf
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Group: Forum Members
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+xYeh its unfortunate that epoxy dries silicone out so severely. Ive tried Mann Ease Release 200 as well as Stoner E236, E455, A324, and E497. I wouldn't say I noticed any very real extension of the silicones working life with any of them, perhaps a few extra cycles with E497 and A324 but its difficult to say if this was due to the release agent or because I was using a more forgiving process. Really none of them prevent the interaction between the epoxy and the silicone, so the silicone still dries out. PVA is really what you would need, which of course won't work. The good news is none of these transferred to the part, so I do still tend to treat all my silicone moulds just in case it does help at all. If you find something that definitely works to extent the life of the silicone then please let us know, I'd love to get indefinite usage from my rubber tools! I built my bladder undersized enough that I can use peel ply and thin breather cloth which will reduce the the contact with epoxy. Its a work in progress but I fold back a tail of peel ply from the farthest point and it will pull out of the finished product giving me a lighter piece and a good surface to adhere to. I see that in the bike frame video EC put up that the vacuum bag is separated from the prepreg with a plastic film of some sort to enable the bag to move. I have done that and it pulls out of the work easily but doesn't have the advantage of removing excess epoxy.
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Hanaldo
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Group: Forum Members
Posts: 2.5K,
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Yeh its unfortunate that epoxy dries silicone out so severely. Ive tried Mann Ease Release 200 as well as Stoner E236, E455, A324, and E497. I wouldn't say I noticed any very real extension of the silicones working life with any of them, perhaps a few extra cycles with E497 and A324 but its difficult to say if this was due to the release agent or because I was using a more forgiving process. Really none of them prevent the interaction between the epoxy and the silicone, so the silicone still dries out. PVA is really what you would need, which of course won't work.
The good news is none of these transferred to the part, so I do still tend to treat all my silicone moulds just in case it does help at all. If you find something that definitely works to extent the life of the silicone then please let us know, I'd love to get indefinite usage from my rubber tools!
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chriscnf
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Group: Forum Members
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+xI always found pulling a vacuum on the air fitting made pretty short work of removing the bladder afterwards. Pictures? I will get some shots up. The bladder is coming out easily but I want to preserve its life. I pour epoxy into silicone molds and just had my first failure as the silicone changed color and lost some of its self release. Spay on release is just another cost in the process but I may have to go that way. I massively appreciate your input to this forum...Chris
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Hanaldo
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Group: Forum Members
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I always found pulling a vacuum on the air fitting made pretty short work of removing the bladder afterwards.
Pictures?
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