Blalh -- blah
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The test tubes were in the lower (larger oven). The convection oven setting was used to try to keep a more even temperature.
A thermocouple was used to
Samples of regular PEX (red), CPVC (white), and Pex-Al-Pex (orange) were set out on a piece of half inch plywood.
A K type thermocouple was used to measure temperature (its the wire coming in from the right). The thermocouple was logged on an Onset Computer logger (see plot below).
I was kind of amazed how awful a job the oven does of keeping an even temperature -- it was perfectly happy at times for the oven to be 30F lower than the set temperature. I finally gave up on trying to set a temperature on the oven, and just manually set the temp well above what I wanted, waited until the thermocouple said the oven was a bit above what I wanted, and then set a low temperature and let the oven drift down through the desired temperature range.
At each of the temperatures listed below, I opened the oven door and had a look at each of the samples, assessed whether they had suffered any deformation, and then picked them up and tried to bend them with just finger pressure.
At 150F, all of the tubes were fine. Essentially no real change from room temperature.
At 4:30pm opened oven door and examined the tubes. Oven temperature 260 F -- having drifted down from about 268 F over the past 5 minutes.
The CPVC showed some warping in shape for the first time.
All tubes quite flexible.
This is probably hotter than they should ever get in service.