WPS CookBook Tom Jennings mru 28 June 2002 22 July 1998 This document contains Trade Secrets. Copyright Tom Jennings 1998. No portion may be copied or transmitted without explicit written permission. ----- title: Nixie display geometry date: 28 June 2002 desc: Optimum nixie spacing and mechanics. * 1 2 : 5 9 : 5 9 a a a b b Assuming 6844 type 1" round nixies: inter-digit spacing a= 1.5", b=2.0". Colons centered. Colon dots 0.5" apart (vertically). am/pm indicator centered between MS digits, approximately at the upper edge of the tube envelope. Panel hole for 1" tube is 1.125" nominal. Sub-panel assembly (plane of nixie sockets) should be 0.5" behind front panel, assuming nominal 1/8" panel. Tubes just protrude. title: Vellum/shellac printed cards date: 8 Dec 97 desc: Hard, flat card, slightly yellow card, text can be printed with DeskJet. Clean printhead. Print on vellum (K&E 195C Albanene works) at high resolution with "coated paper" setting. Dry quickly, desk lamp will do. (Avoids creep). DeskJet ink is water soluble -- seal with light mist of Low-shrink Butyrate airplane dope aerosol, otherwise shellac smears ink slightly. Cut white 60 lb. cardstock large; flow on thin, wet, perfect coat of shellac. Coat back of printed vellum with thin, wet, perfect coat of shellac. Let tack dry, about 5 min. Place vellum on shellacked cardstock, roll on smoothly, avoid airbubbles. Place *clean* paper over vellum, use hard flat surface and rubber roller to flatten and seal vellum and cardstock. Let air dry 1 - 5 min. Sandwich with clean paper, press flat between heavy and extremely flat & hard surfaces for 1 - 4 hours. Remove from press, allow solvents to air dry, repeat pressing until solvents gone. Cut to size. Apply additional coat of shellac to protect ink; additional bottom coat may reduce curling? title: Exposing & developing 3M Color Key III date: 19 Dec 96 desc: Make high-contrast, high-res photomask using DeskJet transparency. Reversal process. ( * ) 500W photoflood lamp in cheap ^ aluminum reflector | 18" | v glass ------------------------- positive ------------------------- image FACE DOWN Color Key3 ------------------------- emulsion (dull) UP glass ------------------------- Expose for 13 min (20 min slight over exposure) [15 min too long -- fine detail overexposed -- Sep97]. Needs fine tuning. Remove from glass stack. Do reasonably quickly -- *Completely wet or immerse* CK3 in developer (3M "Color Proofing III Developer"), then faintly wipe with developer-soaked toilet paper to remove developed emulsion. Lightly rub detail sections to clear. Don't rub too hard. Rinse in clear water, shake and dab water off, hang to dry. ----- title: Etched brass and copper using Datak negative photoemulsion. date: 21 Dec 96 - ongoing desc: Place resist mask on metal starting from transparent artwork. Process is negative eg. black artwork == no resist on metal. For front panels et al, do not drill holes until after etching is complete (avoid difficult masking and nasty undercutting). Uses ER-71 resist, ER-8 developer, used ER-8 developer, inkjet transparency, oven, photoflood lamp (500W, 120V GE PHOTO-ECT 3200 degree). Preparing metal surface, coating with resist. Prepare metal; sand with increasing grades (240, 400, 600, dead 600) of sandpaper moving paper/metal in *one direction* only. Make final passes light fast and smooth to make mirror polish. Must be extremely smooth even if final object is to be rough etched; resist/mask interface has to be sharp. Polish metal with cotton balls or clean rag and metal polish as shiny as possible. Final final with plastic polish. Rub final passes of polish linearly to eliminate swirls. Prepare clean carrier/substrate to handle metal after polishing; piece of wood will do. Wash spotless and grease and fingerprint free -- rub Ivory Liquid rubbed on hands then wash metal panel. Dry with clean paper towels, lint free and not touching surface. Place on carrier in oven. Handle only by carrier. OVEN DRYING: Preheat oven to 120-150 degrees F. Oven-dry for 20- 30 mins. Let metal cool to about 120F. AIR DRYING: Leave in dark drawer for 2+ hours. APPLYING RESIST: Bring metal and ER-71 spray bottle into dimly lit solvent-atmosphere-safe room. Tilt substrate and soak with ER-71 until evenly coated. Let excess run off a corner. blow slightly to remove drips. Lay flat in dark place to air dry and even out, approx. 10 minutes. Leave in a dark room or drawer to let film smooth itself and air dry, approx. 15 minutes. If fisheyes or bald spots, (sigh) strip with used ER-8 on a rag, go back to step 2. After 15 min. air drying, film should be utterly smooth and glossy. Judgement required whether flaws in resist film are harmful; if so, repeat. TO CURE INVISIBLE FLAWS IN RESIST COATING: THIS NEEDS TUNING. Allow to dry enough for second coat -- an hour or so. Apply second coat, same as the first. OVEN DRYING: dry in 120-150 degree oven for 20 - 30 minutes. AIR DRYING: dry in dark drawer for more than two hours. POSSIBLY LONGER WITH SECOND COAT. EXPOSING AND DEVELOPING PHOTORESIST: Warning: this generates nasty petro fumes. Print artwork onto HP Transparency (paper type: transparency, quality: best). Print *reversed* -- Illustrator, Select All, Object Transform Something flip horizontally. Let dry. Set up 500W photoflood lamp [120V 500W GE PHOTO-ECT, 3200 degrees], timer and glass. Lamp should be 18" over table. Prepare ER-8 and two glass or metal trays just large enough for metal object -- folded aluminum foil works fine. Place reversed artwork *image down* onto coated metal, clean glass over artwork -- quickly and in dim light. Expose artwork/resist for 4 min. Do not touch resist during development process, until completed and remaining resist has dried and hardened. Handle only be edges! Place object in tray #1; pour on used ER-8 to cover. Immerse for 45 seconds, agitating (tilting) every 5 seconds. This does not seem critical. Remove from ER-8, tilt to drain; hold piece of toilet paper to bottom edge to wick off bulk of solvent. Not critical, 5 - 10 seconds is plenty. Place in tray #2, cover minimally with new, unused ER-8. Immerse for 10 seconds, tilting back and forth. This step removes any residual "dirty" ER-8 from the actual development step that would cause a smear of unwanted resist and wreck detail. Drain object, wick ER-8 with toilet paper on edge, do not touch resist pattern. Resist pattern is invisible; becomes faintly visible when dry. Let dry for unknown amount of time. 30 minutes? Resist can be tested by placing object in etching tray filled with water containing a *few drops* of FeCl; the faint, slow etch will increase contrast, and won't be deep enough to wreck the metal (though if resist is bad, you'll have to start with 600-grit sandpaper and repeat the whole process). Paint the reverse to avoid eating by FeCl. Edges, etc. ----- title: GC Positive Etch Resist date: 9 Nov 98 desc: Apply resist mask to brass/copper for etching using GC Electronics (Rockford IL) PCS "Etch Resist Sensitizer", cat #22-077 PCS "P.C. Board Developer Concentrate", cat #22-225 From instruction circular in developer box: EXPOSURE: UNTESTED Sunlight "on a clear day" (sic) 3-8 minutes. Fluorescent blacklight, 15W, two bulbs 3" distance, 8-10 minutes. GC Exposure Light (cat #21-397) for 90 seconds. Ordinary fluorescent, 15W, two bulbs 3" distance, 20 minutes. DEVELOPING: UNTESTED Mix 1 part developer conc. with 9 parts water. Immerse exposed material, agitate until image appears; continue until background gone. Rinse under room temp water. NOTE UNDER "STRIPPING" Recommends GC #22-240 stripper; however says "Re-exposing board to light source without artwork and then developing will also work" -- does this mean resist remains light-sensitive after development?! Eg. during etching?! 500W photoflood 12" filament to emulsion inconsistent results 18" distance exposures 1,2,3,4..8 minutes Developer at 10:1 didn't seem to work; randomly increased, appeared more or less linear. Probably reusable, 3:1 probably simply faster. Test-etched with consumed FeCl for a few minutes. LIGHT=REMOVE EMULSION 8 minutes showed pitting in emulsion (black ink on mask == emulsion left on substrate) 6 maybe slight undercut, possible pitting? very small if so (may show under extended etch) 4,5 minutes looks good, but bad shadowing on mask? Filament orientation? 3 minutes bad shadow, but .004" line is good. 1,2 minutes did not work (emulsion did not lift) *** Probably should use two coats of emulsion. Development is delicate -- do just enough to remove exposed resist. Thick resist will not wash off easy enough -- spray lightly, tilt, let drip off corner, lay flat to dry slowly and evenly. *** Exposed 4 minutes @18". Try 3.5min. 23 Nov Repeated attempts at 3 - 4 minutes all fail; the resist develops too slowly; exposed areas aren't developed by the time other areas are long-done. Drying time is actually only a few hours for the wet resist. Interpretations of initial test probably wrong; will try 8 minutes next -- the pitting in the 8 min test may simply have been bad preparation, as the mylar papertape exposure shows much more solid holes than the 3 minute test, and the tiny text is very clean at 8 minutes. (Will do another progressive test up to 20 minutes or so.) 15 Nov (approx) Coating method: (.025" brass sheet) sanded well with 600 grit & soapy water; dried. Sprayed photoresist on horizontal substrate. Blew on lightly to break bubbles. Tipped to edge to drain excess; wicked off puddle at edge of substrate. Laid flat, let dry (> 4 hours). 6 minutes worked OK. Should do another progressive test! 8 dec 98 18" height 7 minute exposure, with HP transparency emulsion baked in oven at 150 degrees FAILED -- did baking screw it up? Will repeat with previous coating method. Baked did screw it up. Almost worked OK with room temp dry, but emulsion was not perfectly flat and letters may have been overexposed? Next try with perfect coating, R.T. dry, 6 minute exposure. 9 Dec 98 Found one jar of developer 22-225 that is clear: for 22-074, 22-077 (in use here), dilute developer 3:1 tap water. Do not heat. 9:1 is for some presensitized boards. Don't leave in tray more than 1-2 hours, store in closed jar. Three more 6 minute attempts failed; will do progressive test next. 10 Dec 98 Should have done test long ago! progressive test, 2 - 18 minutes: 18 excellent 14 excellent 12 excellent 10 excellent 8 fair 6 poor 4 essentially unexposed 2 unexposed Will repeat original WPS LE-2 with 15 minute exposure. 15 minutes failed; developed OK, then all the image fell off. Will try again at 10 minutes. All tests failed, emulsion either doesn't develop or developed detail slides off.