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Old 06-18-2013, 11:27 AM   #1
Cleuck

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Default Paste adhesive curing pressure

I have a few reasonably large (few inches wide x few inches tall) stiffener hats I would like to paste adhesive bond down to a large flat plate. In respect to bondline control, what kind of pressure should I expect to need per sq inch of bondline to achieve full squeeze out to my desired bondline thickness? I plan on using hysol ea9394. Everything I have read (mostly grad work) gives me the window of 5-50 psi, not exactly a clear cut answer. Any help is appreciated!
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Old 06-18-2013, 12:29 PM   #2
herman

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It is dependent on viscosity (temperature) and overall bond line dimensions and design, and desired bond line thickness.

If you are aiming for a certain thickness, use some shims of the proper thickness, and use that for bond line thickness control. Alternatively mix your glue with glass beads of the proper diameter.

In both cases, you can press as hard as you like, bond line will stay as designed.
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Old 06-19-2013, 08:38 AM   #3
Cleuck

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I guess my question was slightly ambiguous, I understand the pressure to achieve squeeze out is entirely dependent on everything that you had listed. I suppose I am looking for a rule of thumb based upon an estimated pressure required per sq" at a given bondline.

I may run some small tests 1sq" 2sq" 3sq" and so on to get a base line and see if things scale linearly

Thanks again
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Old 06-20-2013, 01:45 PM   #4
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Unless it's very cold where you're working the creep properties of the mixed adhesive should allow the parts to be bonded properly with normal clamping techniques (toggle clamps, spring clamps, clecoes, etc). Just make sure to use some sort of bondline thickness control method as Herman suggested.
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Old 06-24-2013, 06:35 AM   #5
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Isn't 9394 filled with bondline control particles? If not, as Herman said, I would try glass beads, or even wire.
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Old 06-25-2013, 05:44 PM   #6
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We've ruled out this architecture, but just to clarify we would have been going from a case where we had 50ish sq inches of total bondline. Where we use sand bags, bags of shot etc.. To a case where we would have had hundreds of square inches of bondline, thus my inquiry
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