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Dezer
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Group: Forum Members
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Hello friends,
I made two pieces of carbon fiber by the hand lay up process + Vac bagging and I'm having problems with areas as per the picture. Defects such as air bubbles and dry regions. I am not using Gel coat because I will use clear coat when finalizing and I do not use tacky spray because it is a cosmetic piece.
I'm using material / resin ratio in 50:50 and vacuum at -28 in.
Where can I be going wrong?
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Dezer
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Group: Forum Members
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I could not post the photo here, follow the link in the photo: https://ibb.co/gW4bYa (Image hosted on imgbb.com site)
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Warren (Staff)
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I suspect your vac level is too high for a traditional wet lay vac bag. Assuming that area had plenty of resin to start with, the bag would be likely pulled tight over such a corner, more so than elsewhere, and thus excess vacuum would squeeze out too much resin giving the dry patches you have,
Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant
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Dezer
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Group: Forum Members
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+xI suspect your vac level is too high for a traditional wet lay vac bag. Assuming that area had plenty of resin to start with, the bag would be likely pulled tight over such a corner, more so than elsewhere, and thus excess vacuum would squeeze out too much resin giving the dry patches you have, Thanks for the answer Warren, Do you have any idea how to eliminate this problem? I had already realized that my vacuum was too strong for this process that I thought of inserting the vacuum and then turning off the vacuum pump to remove resin. If you have solutions to help me, I'll be grateful.
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Warren (Staff)
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Group: Administrators
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Ideally you would use a vacuum regulator such as our SMC Vacuum Regulator as it will keep the vacuum at a set level for you. However if you don't have the budget or access to such equipment, as long as you have a good seal on the bag, you will only need a vacuum gauge to find out what level is in the bag and turn the pump off and clamp the bag when the correct level is reached.
Warren PenalverEasy Composites / Carbon Mods - Technical Support Assistant
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Dezer
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Group: Forum Members
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+x[quote]Idealmente, você usaria um regulador de vácuo, como o nosso regulador de vácuo SMC , pois manterá o vácuo em um nível definido para você. No entanto, se você não tem o orçamento ou o acesso a esse equipamento, desde que tenha um bom selo no saco, você precisará apenas de um medidor de vácuo para descobrir qual o nível na bolsa e desligar a bomba e apertar o saco quando o nível correto é alcançado. I have the vacuum gauge to control the vacuum level. What is the ideal vacuum level? For all the parts that are doing are being removed more resin than necessary.
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Dravis
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Are you using a resin bleeder sheet /perforated release film? sometimes if I want to keep a wet lay part "resin rich", I use several layers of perforated film on top of each other, that reduces the amount of resin that the vacuum can remove from the part, while still allowing the vacuum to keep the fabric conforming to the mould.
"Sapere Aude"... Dare to KNOW!
The written word is the only truly efficient vehicle for transmitting a complex concept from mind to mind...
103% of all people do not understand statistics...
Do not adjust our mind, theres a fault in reality :-)
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Dezer
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Group: Forum Members
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+xAre you using a resin bleeder sheet /perforated release film? sometimes if I want to keep a wet lay part "resin rich", I use several layers of perforated film on top of each other, that reduces the amount of resin that the vacuum can remove from the part, while still allowing the vacuum to keep the fabric conforming to the mould. Hello Dravis, I use breather and perforated release film. I will test with more layers of perforated release film and reduced vacuum pressure. Soon post results. Grateful!
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Dezer
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Group: Forum Members
Posts: 74,
Visits: 1.8K
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+x+xAre you using a resin bleeder sheet /perforated release film? sometimes if I want to keep a wet lay part "resin rich", I use several layers of perforated film on top of each other, that reduces the amount of resin that the vacuum can remove from the part, while still allowing the vacuum to keep the fabric conforming to the mould. Hello Dravis, I use breather and perforated release film. I will test with more layers of perforated release film and reduced vacuum pressure. Soon post results. Grateful! I made another part with the following steps: - 3 layers of Mold release wax - 2 layers of separator MX 01 (hydrocarbon based release agent) - I applied a thin layer of Ampreg 26 + A26 Fast (Gurit) epoxy resin for tacky effect and better mold the carbon in the mold. - Laminated wet layup with resin Ampreg 26 + A26 Fast (Gurit) - Degassing resin - 3 layers of carbon fiber 3K - Peel Ply - 2 layers of perforated film release agent (as suggested above by Dravis) - Breather - Vacuum bag - And vacuum pressure this time reduced by -14 inHg. And yet I still have dry-effect problems and air bubbles in those specified areas of the part. Images:    I have no idea what I'm doing wrong. Any suggestion ?
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Dravis
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To me it looks like you are simply not making sure to get the corner areas of your layup wetted through enough
When doing wet-lay I always wet out each layer one at a time using PLENTY of resin and a stiff brush .
in wet-lay you can not calculate the amount of resin as 50-50 you will be lucky to get 55 resin and 45 fibre by weight ratio
The breather cloth will get rid of most of the excess resin, but compared to infusion you will still have a more resin rich part
"Sapere Aude"... Dare to KNOW!
The written word is the only truly efficient vehicle for transmitting a complex concept from mind to mind...
103% of all people do not understand statistics...
Do not adjust our mind, theres a fault in reality :-)
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