On Wed, 29 Feb 2012 07:37:31 -0800 (PST) "Peter C. Wallace" <p...@mesanet.com> wrote:
> On Tue, 28 Feb 2012, dave wrote: > > > Date: Tue, 28 Feb 2012 22:04:50 -0800 > > From: dave <dengv...@charter.net> > > Reply-To: "Enhanced Machine Controller (EMC)" > > <emc-users@lists.sourceforge.net> > > To: emc-users@lists.sourceforge.net > > Subject: Re: [Emc-users] Film Emulsion for Encoder Wheels? > > > > On Tue, 28 Feb 2012 20:06:25 -0600 > > Jon Elson <el...@pico-systems.com> wrote: > > > >> dave wrote: > >>> If anyone is really desperate I think I still have some KPR (Kodak > >>> photoresist) around. IIRC ... vacuum pull down the photomask over > >>> the substrate (board) expose with UV. Develop with toluene. Etch. > >>> > >>> Since I'm a packrat (I'm obviously relate to Neotoma cinerea ) ;-) > >>> the KPR is tucked away someplace. It may have auto-polemerized. > >>> > >> Arrgh! Horrible stuff, horrible chemistry, terrible exposure > >> control and repeatability. > >> Use dry film resist, all aqueous processing with mild chemicals. > >> Vastly better > >> exposure control (I've used both, as you might tell from the above) > >> visible results after development so you know if the resist > >> expose/develop step went well before you try etching. Think and > >> Tinker sells it in small quantities, I > >> believe. > >> > >> Jon > > > > Sorry you had such bad luck with it. I diluted it IIRC 1:1 with > > toluene, floated in on the copper, drained off any that would run > > off, let it dry, exposed it with a very intense UV lamp. Developed > > with toluene and then etched. Never had one fail. > > > > The UV lamp was the nasty part of it (about 1 KW); we used it to > > convert diethylstibesterol to a colored compound that could be > > measured in a spectrophotometer; not something one usually has > > laying around. > > > > Aqueous based chemicals are probably a safer way for most people to > > go. I did this a LONG time ago and was not aware of any > > alternatives. > > > > Dave > > > > I used KPR many years ago and it worked perfectly (not too surprising > as it was good enough for wafer masks. In fact I think the bottle I > had came from Fairchild Semi's surplus store). It had extremely sharp > line defnition and excellent development characteristics. I simply > dipped bare cards in the KPR, baked in the oven, contact printed > (sunlight!) with litho film I had exposed in a Speed Graphic 4x5 > camera with a copy machine lense. At this point the KPR make a color > change from greenish where unexposed to purplish where exposed. > > Then I developed in the Xylene Toluene mix, no problems at all. > > This is by no means a suggestion that anyone run out and buy some > carcinogenic solvents and play with them in their kitchen (as I did) I'm not so sure they are carcinogenic as hepatotoxic. For several years I helped the lab with hop certification. Fancy round blender bottles with hops plus benzene. Our hands were damp with benzene for about 6 weeks a year. In addition, anytime you can smell benzene you are above the inhalation limit. After many years we switched to toluene which is about ten times less toxic. Unless someone has managed to find a column and liquid phase that will separate the alpha and beta acids ( bittering ) in about 6 min with HPLC the industry is probably still using spectrophotomety for volume analysis; think 60-100 /da. That was > 45 years ago and I'm still kicking. The MSDS's have been cleaned up some the one for sugar (sucrose) used to recommend washing with water for 1/2 hour for dermal exposure. LOL Dave > > >> > >> ------------------------------------------------------------------------------ > >> Virtualization & Cloud Management Using Capacity Planning > >> Cloud computing makes use of virtualization - but cloud computing > >> also focuses on allowing computing to be delivered as a service. > >> http://www.accelacomm.com/jaw/sfnl/114/51521223/ > >> _______________________________________________ > >> Emc-users mailing list > >> Emc-users@lists.sourceforge.net > >> https://lists.sourceforge.net/lists/listinfo/emc-users > > > > > > ------------------------------------------------------------------------------ > > Virtualization & Cloud Management Using Capacity Planning > > Cloud computing makes use of virtualization - but cloud computing > > also focuses on allowing computing to be delivered as a service. > > http://www.accelacomm.com/jaw/sfnl/114/51521223/ > > _______________________________________________ > > Emc-users mailing list > > Emc-users@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > Peter Wallace > Mesa Electronics > > (\__/) > (='.'=) This is Bunny. Copy and paste bunny into your > (")_(") signature to help him gain world domination. > > > ------------------------------------------------------------------------------ > Virtualization & Cloud Management Using Capacity Planning > Cloud computing makes use of virtualization - but cloud computing > also focuses on allowing computing to be delivered as a service. > http://www.accelacomm.com/jaw/sfnl/114/51521223/ > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------------------------------------------------------ Virtualization & Cloud Management Using Capacity Planning Cloud computing makes use of virtualization - but cloud computing also focuses on allowing computing to be delivered as a service. http://www.accelacomm.com/jaw/sfnl/114/51521223/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
