Does "washing" IPA need to be anhydrous?
I am fairly clueless about the operational details of using SLA. Does the "washing" IPA need to be anhydrous or will the inexpensive 70% or 91% solutions that are common in the US perform adequately?
Re: Does "washing" IPA need to be anhydrous?
Yes they do. There are resins around that wash off with soap water, if that is more convenient.
Re: Does "washing" IPA need to be anhydrous?
There are special water washable resins, but the 'normal' resins apparently don't do well when exposed to water before curing. IPA that is < 99% can make it brittle and micro-fracture a lot, from what I have read. Amazon has a seller, Florida Laboratories Inc (no affiliation) that is selling 4L of 99% IPA for about $75.
Re: Does "washing" IPA need to be anhydrous?
You can get 4 quarts for abotu $20. https://www.ebay.com/itm/ONE-GALLON-4-quarts-Isopropyl-Alcohol-IMAX-PURE-100-HIGH-PURITY-IPA-99-A/181635423475?hash=item2a4a509cf3:g:AA0AAOSwxyJaoNne:rk:7:pf:1
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Chuck H
3D Printer Review Blog
Re: Does "washing" IPA need to be anhydrous?
Photocentric, Wanhao & Anycubic resins work with 85+ IPA. I assume the same for similar mixes. No difference compared with IPA 99+. No brittleness, no sticky surface. I do not know why it should actually, you only remove the surface film and cure to get a nonsticky surface. The IPA would not really penetrate.
Photocentric clear turns yellowish if you use IPA instead of water. Also you need to realize IPA is very hygroscopic and needs to be handled accordingly. Exposed to air it will suck up water like crazy.