Nice webpage Harvey!
http://www.dragonworks.info/index.htm I liked the stepper motor control box and the oscilliscope rework!
here's mine, a few good things but haven't been working on any site update for a while now. coding html without Dreamweaver is like designing a circuit board with not even a freeware vector art program, slow! every time a table is moved or changed in the slightest everything goes out of whack...
but the page design and subject material (mostly my artwork and some hobby) are good (I'd like to think anyway).
http://ocean-arts-hobby.tripod.com/index.htmland here's more on a free art hosting site
http://casino13.deviantart.com/gallery/Robert
I'll get around to
--- In Homebrew_PCBs@yahoogroups.com, Harvey White <madyn@...> wrote:
>
> On Tue, 27 Dec 2011 03:44:08 -0000, you wrote:
>
> >Thanks for all the input!
> >
> >So then avoid KPR even though it works well, is that because it's toxic? explosive? staining? if it works then maybe using proper precautions, but then on the other hand if there are safer alternatives that work as well (or better?) then of course that would be the logical preference.
>
> KPR has xylene, possibly MEK and the like in it. Much nastier stuff
> to deal with than film resist, precoated boards, and sodium carbonate
> (?) developer.
>
> You'd need KPR, the developer, the dye (very needed!) to make the
> boards. Short wave UV (nasty!) to expose the boards. From then on,
> it's as good as any other negative photoresist in terms of what you
> have to do.
>
>
> >
> >
> >I see that some commercial equipment use dispensing pumps and "spinners" to apply the stuff, I've been a painter by trade most of my adult years so I have plenty of airbrushes, small detail guns and a supply of clean dry air I could use, possibly, for even distribution of material...
>
> That'll work too. an old record player, if you could find one, might
> make a good spinner at 78 RPM. Otherwise, easy to make one.
>
> >
> >actually on that note I should mention that I have an account with Paasche, they make a lot of custom spray heads for use in automation, I can get them at cost, about 40-60% off, if anyone wants.
>
> Nice. Not sure that you need to spray on the resist, though. Depends
> on what kind you have.
>
> >
> >
> >wishing it were so with MEGA Electronics, as they have the nicest UV units I've seen (in pictures) so far. perhaps modeling a homeaid unit something like their products would be the best alternative to buying outright.
>
> Home made is fine. Main thing is finding and matching the lamps to
> the resist. Generally, 15 watt tubes are fine.
>
> >
> >Mega has everything for producing quality boards, through hole rivit kits, pcb drills and routers, a lot of ancillary items that are very specialized, and very expensive...
> >
> >http://www.megauk.com/
> >http://www.megauk.com/uv_exposure_units.php
> >http://www.megauk.com/pcb_drilling_machines.php
> >http://www.megauk.com/through_hole_rivets.php
> >
> >there seems a certain "drool" factor in considering their products, but alas I fear they are all far to expensive for mua!
>
> Ditto.
>
> >
> >one item I do think is very reasonable however is a small drill press from Micro-Mark, it appears to be a spot on copy of the German proxxon at about $100 less cost, and comes in "cleanroom" white.
> >
> >http://www.micromark.com/MicroLux-3-Speed-Mini-Drill-Press,7797.html
> >
>
> The higher the RPM the better. Aim for about 20K or more if you can.
>
> >
> >
> >I'm interested in the possible use of a photoplotter for making the positive or negative transparency plate also,
>
> Photoplotter would be fine, you want as opaque a black as you can get.
> The old Kodalith was wonderful for this (the line version, not the
> dot).
>
> >
> >not really too familiar with them and trying to understand the benifit, I have some idea now, thanks!
> >
> >still, I was looking at some used equipment like that on ebay but determined that it was too bulky, expensive, (and maybe even possibly could become somewhat antiquated as things tend to go, new technolgy and what all coming around so fast these days), it just seems easier to have just a decent printer to check the actual size of the board for parts fit, errors missed on screen (computer), etc. and bringing a flash drive somewhere (where they might have a photoplotter?) to have a transparency made. I saw a video where someone taped 2 identical overlapping transparencies together and thought sure that will work but there is a chance to distort if not perfectly aligned and so such methods can introduce greater possibility for error, but novel in it's simplicity and using far less expensive equipment.
>
> True enough, but if you're doing 144 pin TQFP devices, with 0.5 mm
> spacing and 10 mil tracks, then you want accurate.
>
>
> >
> >
> >As a painter I used to use a lot of leaded enamels (glad that's passed), lacquer and acrylic urethanes (Dupont Chromabase), and working at a factory that produced surfboards I worked with polyester resins, epoxys, acetone, etc. and much later ended it all with a move completly to waterbased material or I wouldn't take the job.
> >
> >for hobby in small quantity or even very light limited production though I can't see a big problem with chemicals, though again I would prefer any safer alternatives, so I'm interested in the elmers glue resist mentioned also!
> >
> >
> >I'd like to try both methods for myself anyway but want to hear any thoughts or suggestions in any case, I might have better luck succeeding that way I reckon maybe...
>
> Try toner transfer as a thought. Works for many a project, no nasty
> chemicals, you will need a laminator.
>
> Some details of what I do at www.dragonworks.info in the electronics
> section. You can get good results once you iron out the process
> properly.
>
> Harvey
>
>
> >
> >
> >Thanks again!
> >
> >Very Kind regards,
> >Robert
> >
> >
> >
> >
> >
>