Here is another off-list reply that I received about 3m 415 and that I'm posting with permission :
Objet : 3M 415 double sided tape I saw your note regarding the 3M tape and couldn't keep from replying to you. I am certainly concerned about the product as a seller of the material. I did have some thoughts though. First off all manufactured products have tolerances; the polyester has a +/- tolerance from the target, as well as the adhesive layers coated to both sides. On the 3M data sheet it states that the overall tape has a thickness of 0.004". I have no idea what the actual numbers are for the components but lets for argument's sake say the carrier is .002" and each of the adhesive layers are 0.001". For simplicity let's also say that each layer has a +/- 5% tolerance. This means that the carrier can be anywhere from .0019" to .0021", and the adhesive can be anywhere from .00095" to .000105" Normally each of these three layers will go somewhere within these ranges but every so often they can also stack all to one of the two extremes, making a tape feel unusually thick or thin compared to the "usual." I am not saying that this is the case and not a general change in manufacturing of the product, but it is a very viable scenario. And typically on a multi layer product such as this it is much less likely that all (three in this case) components land at one of the spectrum, so the likelihood that one has seen this Aaron Salik (Talas Bookbinding, Archival and Conservation Supplies) [email protected]<mailto:[email protected]> --- Karen Potje Chef, Conservation et Restauration Head, Conservation and Preservation Centre Canadien d'Architecture Canadian Centre for Architecture 1920, rue Baile, Montr?al, Qu?bec, Canada, H3H 2S6 +1 514 939 7001 x 1236 cca.qc.ca<https://www.cca.qc.ca/fr/?utm_source=fr_email_signature&utm_medium=email> Twitter<https://www.twitter.com/ccawire> | Instagram<https://www.instagram.com/canadiancentreforarchitecture/> | Facebook<https://www.facebook.com/cca.conversation> | YouTube<https://www.youtube.com/user/CCAchannel> Que signifie la notion de < maison > pour vous?<https://www.cca.qc.ca/fr/issues/27/le-bonheur-nous-trouvera-t-il/64854/le-bonheur-consolide?utm_source=fr_email_signature&utm_medium=email> What does home mean to you?<https://www.cca.qc.ca/en/issues/27/will-happiness-find-us/64854/consolidated-happiness?utm_source=en_email_signature&utm_medium=email> <https://www.cca.qc.ca/en/cca-c-o/index?utm_source=en_email_signature&utm_medium=email> Inscrivez-vous<https://www.cca.qc.ca/fr/?go=enews&utm_source=fr_email_signature&utm_medium=email> pour recevoir de nos nouvelles. Sign up<https://www.cca.qc.ca/en/?go=enews&utm_source=en_email_signature&utm_medium=email> to get news from us. ****** Unsubscribe by sending a message to [email protected] Searchable archives: http://cool.conservation-us.org/byform/mailing-lists/cdl/
