<html><head></head><body><p dir="ltr">Brian, cast acrylic will exhibit some natural shrinkage as you approach thermoforming temperatures - it could be that you are seeing the beginning of this at your annealing temperature. Is the discrepancy in thickness only, or are your diameters off as well?</p>
<p dir="ltr">Barring any obvious visual abberation, I'd be inclined to use the windows as per the minimum measured thickness. If there is visual distortion, you might want to flatten it and then run it through annealing again. Once the shrinkage has occurred, you shouldn't see it again.</p>
<p dir="ltr">Sean<br>
</p>
<br><br><div class="gmail_quote">On October 16, 2014 2:45:18 PM MDT, Brian Cox via Personal_Submersibles <personal_submersibles@psubs.org> wrote:<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
<div style="font-family:Arial, sans-serif; font-size:10pt;"><div>Hi All,</div><div> Been annealing my disks, I've been just standing them on end in the oven. I'm seeing a tiny variation of the thickness of the acrylic, at first I thought it was because of standing them on end , but I think there is actually some variation in the thickness of the original material. The most I've seen is .020 . I guess it's nothing to be concerned about. Anyone have any info on this?</div><div> </div><div>Brian</div></div>
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