Shel wrote: > The bottle is made of #7 plastic. Is this a poor choice > for darkroom chemicals?
Hi Shel, The #7 designation is apparently a recycling catch-all for "all other resins". Here's what I learned from a State of Indiana website I just found. (That just happened to be the first one on the list of search results.) Plastics #1 through #6 are: ~ #1 PET (often marked "PETE"), used for soda pop bottles and carpet fibers; ~ #2 high-density polyethylene (HDPE), used for many laundry detergent bottles; ~ #3 PVC, used for plastic plumbing pipe and fittings; ~ #4 low-density polyethylene, used for plastic bags; ~ #5 polypropylene, used for hard plastic bottles; ~ #6 polystyrene, also used for hard plastic bottles. Reagent-grade laboratory chemicals are often packaged in #2 plastic containers (HDPE). God only knows what's in any particular plastics formulator's #7 blend. Some blends might be fine for chemicals; others might not be. Perhaps if Kalt is trying to save money by using a cheap resin, they might also try to save money by using a less expensive contractor to do their molding. Maybe a cheaper shop might be less attentive to cleanliness? Maybe these bottles are more likely to sit in dustier environments before final sale, and thus are more likely to have schmutz and bio-schmutz on the inside surfaces? I think I'd worry as much about this as I would about the actual chemical composition of the resin. Bill Peifer Rochester, NY - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
