<html><body><div style="font-family: Arial; font-size: 12pt; color: #000000"><div>According to the Wiki article the 'film was developed in the mid-1950s,' which could mean original BN1/2/3(shout out to Patrick)/4 pumps might not have it. Though 'old school' petrol didn't have ethanol in it, I suspect the distillation process of the time allowed other nasty stuff in the fuel, and gasoline itself is a pretty good solvent. Maybe some other barrier material was used?<br></div><div><br></div><div>Geez ... you know you're a 'Healey Nut' when you have to know what the plastic film on SU pump diaphragms was made of (I did major in chemistry for a couple years and still have a passing interest--that's my story anyway).<br></div><div><br></div><div><br></div><hr id="zwchr"><div style="color:#000;font-weight:normal;font-style:normal;text-decoration:none;font-family:Helvetica,Arial,sans-serif;font-size:12pt;"><b>From: </b>"Oudesluys" <coudesluijs@chello.nl><br><b>To: </b>"Bob Spidell" <bspidell@comcast.net><br><b>Cc: </b>josef-eckert@t-online.de, "Austin Healeys List" <austinhealeyslist@gmail.com>, "healeys" <healeys@autox.team.net><br><b>Sent: </b>Wednesday, November 23, 2016 6:22:12 AM<br><b>Subject: </b>Re: [Healeys] su pumps again<br><div><br></div>
<div class="moz-cite-prefix">Could well be although I am not sure
how long mylar has been commercially available. The SU pump may
predate the days of mylar?<br>
Kees Oudesluijs<br>
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Op 23-11-2016 om 15:14 schreef Bob Spidell:<br>
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<div>re: "...The plastic foil is on the bottom of the diaphragm
opposite the stem ..."<br>
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<div>That's where it's been on every old pump I've disassembled;
the newer diaphragms I've bought didn't have it. I've always
assumed the 'plastic foil' was mylar: <a href="https://en.wikipedia.org/wiki/BoPET" target="_blank">https://en.wikipedia.org/wiki/BoPET</a><br>
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<div>Bob<br>
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