Vacuum bag vs bolt force (fabricating a carbon fiber wing)

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SUMMARY

This discussion focuses on the fabrication of a carbon fiber wing using vacuum bagging versus bolt force methods. The user is attempting to achieve a solid bond between the top and bottom halves of the wing, with a 2mm gap filled with epoxy. Calculations indicate that vacuum bagging can generate a total force of 2170 lbs at 14 psi, while using bolts can theoretically apply 2280 lbs of force. The consensus is that vacuum bagging is preferred for even load distribution and minimal resin seepage.

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Hello, thanks in advance.

I'm trying to make a near 100% solid carbon fiber wing. I'm vacuum bagging the top half of the wing and the bottom half of the wing separate.
After making sure there is a thin 2mm gap b/w the center of both halves the goal is to put a very strong, thick epoxy between them and clamp the mold together.

I'm wondering if I should use the vacuum bag for this process or use a series of bolts and washers as seen in the attached picture?
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<Moderator's note: post edited to include the image. Please do not use external image servers.>

Questions:
1) The surface area of the top side of the mold is 80 sq in and the bottom is 75 sq in. If I draw a vacuum strong enough for 14psi is my total force 155 sq in x 14psi = 2170 lbs?
2) If I use 20 bolts with the a surface area of the washers touching the flange of .38 square inches each and each washer can apply a force to the flange of 300 psi is my
total force on the part theoretically 20 bolts x .38 sq in x 300psi = 2280 lbs?

*The above questions are assuming a near perfectly rigid mold. I'm just trying to see if my math is right.3) Will only the excess resin seep out of the seems of the parts if I vacuum bag the halves together or will the vacuum cause more resin to escape the mold? I think in theory the vacuum shouldn't cause excess to seep out.Thanks.
 
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I would think the vacuum method is preferred as it distributes the load evenly over the entire surface; whereas the bolt method would result in concentrated forces at/near the bolt locations only.
I don't think you need to worry about the resin seep-out as it will only need a thin coating to bond the two together. Generally, on a glue line...the thinner the better. (as long as all imperfections are filled).
In fabricating aluminum honey-cone wing sections for the F-86 and F-100 Fighter jets, we used a vacuum bag and applied pressure as well, using an autoclave pressurized to 100 psi (that was back in 1955).
I think your math is OK.
 
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