Keeping the carbon on the flanges during layup

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Keeping the carbon on the flanges during layup

Keeping the carbon on the flanges during layup

Author	Message
mrlindeman	mrlindeman posted 9 Years Ago HOT Topic Details
Group: Forum Members Posts: 10, Visits: 61	I have been running into a persistent issue with some proof in concept work I am doing. Materials: C&J Composites epoxy 2-1 part resin. 2 X 2 3K 5.7 OZ carbon fabric. 6 inch by 3 inch half round mold. This mold is taken off of a tube. Its a 1 piece half round shape. It is a gel coat finish with one inch flanges. The mold is prepped with a thin coat of resin and 2nd stage cured to tack. Then the first layer of carbon goes in. The problem I am having with this and many other molds is, that once the carbon is pressed into the mold and the edges are folded over to tack to the flanges; there is lifting in the bend which caused voids on the edges. Even at full tack it still lifts. When more layers and resin is applied the issue gets worse. The remainder of the part looks almost perfect but any contours like this cause the fabric to peel slightly and cure with dry areas. This is a hand layup and with vacuum it would not be an issue, but I am trying to figure out how this is done successfully in a strictly hand layup process. Thanks for any help. My digi-cam is dead so unfortunately pics are not an option. Air Bubbles, Pin Holes, & Voids are my worst enemy. I am committed to their permanent prevention at all costs.
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*VVS*	*VVS* posted 9 Years Ago HOT Post Details
Group: Moderators Posts: 226, Visits: 334	You kind of answered your own problem in that wet lay is not quit cutting the mustard. But there are a million ways to work around this using anything and every thing about the house. You can add weight using things like hot water bottle, bag of flour etc only thing to figure is something to stop it sticking. I've had great success cutting plastic milk cartons up and using this as it self releases, also I like to clamp this with cheap plastic ratchet clamps from the diy store. You can literally use anything that works.
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mrlindeman	mrlindeman posted 9 Years Ago HOT Post Details
Group: Forum Members Posts: 10, Visits: 61	I see what your saying! I was thinking that a bag full of flour or sand could be used to place in the mold and apply pressure to the stubborn areas. Air Bubbles, Pin Holes, & Voids are my worst enemy. I am committed to their permanent prevention at all costs.
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George Sychrovsky	George Sychrovsky posted 9 Years Ago HOT Post Details
Group: Forum Members Posts: 24, Visits: 1.6K	put thin plastic film like cling wrap over the lay up squeegee all air out and should stay put --------------------------------------------------------------------- Disclaimer opinions of others will vary depending on what they are selling
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Dravis	Dravis posted 9 Years Ago HOT Post Details
Group: Forum Members Posts: 592, Visits: 1.9K	Hi! I use plastic bags full of hot water, for the "bowl-shaped" or irregular shaped parts -- Not only does it conform completely to the surfaces, but it also speeds up initial cure. I even use this technique with vacuum bagging and infusion -- Bags of loose dry sand works as well, and it is a bit heavier, but the water I can take directly from the hot water tap . When doing wet lay, i have often used cut out pieces of bagging film .. it releases very easily .. And I have a large roll of it hanging on the wall .. "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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mrlindeman	mrlindeman posted 9 Years Ago HOT Post Details
Group: Forum Members Posts: 10, Visits: 61	Ok guys, the progress is as follows. I remade the part and followed the previous layup. Taking into consideration the ideas in this thread i went with using a zip lock bag with enough water in it to fill the mold and rest nicely. I used a this sheet of acetate plastic and as a barrier between the epoxy covered CF and the bag. I filled the bag with warm water. 85 F. The part was at full cure within 8 hours and was ready to pluck from the mold. The bag came out easily as did the acetate sheet. I flexed the mold and out popped a near perfect CF part. What was also awesome is the flanges stayed down due to the water bag enveloping the top flange of the mold slightly. No air pockets or voids anywhere except a tiny area at the top of the flange which will be cut away anyways. I am so grateful for the help. I wish I could post a picture but as before the camera is kaput. Thanks for the help. Air Bubbles, Pin Holes, & Voids are my worst enemy. I am committed to their permanent prevention at all costs.
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Zebra	Zebra posted 9 Years Ago HOT Post Details
Group: Forum Members Posts: 14, Visits: 32	Plastic bags of water to apply pressure to the mold cavity is a great idea. I have been using rigid bladders cast from resin or gypsum with heavy weights on top (or clamps). Bags of waters seems like a quick way of achieving the same. My molds have small cavities and sharp edges so I am curious to known if a bag of water will provide enough pressure against some of the tiny right angles that cause me problems. For a bowl shape, I bet an inflated balloon could work too (if there was enough pressure). I am a big fan of compression molding instead of a vacuum bagging process for complex parts that I have to make multiple times. I always seem to screw up vacuum bagging on anything except simple relatively flat parts. That says more about my skill level than the effectiveness of vacuum bagging though. Compressing the cf between a rigid mold surface and a heavy rigid bladder in the shape of the part has produced the most consistent results for me.
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Fasta	Fasta posted 9 Years Ago HOT Post Details
Group: Forum Members Posts: 468, Visits: 3.5K	You could also consider a silicone intensifier where you would have an inner silicone block that clamps on the back of the laminate until cured. Layup a dummy part in your mould to match the finished part thickness and then pour cast a silicone into the back of the part, even include the flange if you dam the edges to stop it flowing out. The silicone block can be clamped down with something flat like plywood or other. Something else to try is maybe looking at your laminate orientation. If the the fibres are running directly square over your flange corners then this is a more difficult and sharper corner for the fibre than if your material were at 45 degrees. The softer angle across the corners is easier for the fibres. Also maybe finding lighter/softer fabrics. Finishing the last ply with fibreglass instead of carbon or just adding a little thickening addative to the resin will make it a bit sticker and help it stay in place. Fastacraft Facebook page
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