Kodak Photo Resist (KPR)

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ajc-28
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Kodak Photo Resist (KPR)

Post by ajc-28 » Mon Dec 22, 2003 6:26 am

Does anyone here use Kodak Photo Resist, which is known as KPR, for making small quantities of printed circuit boards?

toejam
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Re: Kodak Photo Resist (KPR)

Post by toejam » Mon Dec 22, 2003 7:57 am

I used a spray on resist a few years ago You will have to determine the exposure time. I used an ultra violet sun lamp as a light source. It took me about eight hours to get that right. The developer is temperature sensitive, and requires constant agetation and the etching process requires the same.As an alternative, you might try expresspcb.com there you get a free layout software and they give you three 2.5x3.5 boards for fifty or so bucks.

Chris Foley
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Re: Kodak Photo Resist (KPR)

Post by Chris Foley » Tue Dec 23, 2003 7:08 am

I used the KPR process for etching several years back. When applying the photoresist to absolutely clean copper, I had the best luck either spraying (don't breathe in the mist -- use a very well ventilated workspace, and use a respirator) or just cutting the KPR with KPR thinner, and pouring the mix on a board, then spreading with a lint-free cloth or sponge, then letting excess drip off, then air drying. Either way, a dust-free and totally clean darkroom environment is critical. The original Kodak spec suggests a pre-bake at this point to help solidify the dried emulsion on the board, and that extra step really helped in ensuring board quality. After exposure, I would post-expose bake again at a slightly higher temp as recommended in the original Kodak spec, but that step isn't really necessary if you've done everything up to this point well. Etch the board (I used ferric chloride), then you use Kepro PRSK stripper to clean off the KPR from over the pads/traces (use gloves), and then detergent/green pad cleaning of boards to remove residues and remaining chemistry on boards. Kepro has gone on to its reward, but I understand the chemistry is still available from D&L Products, Inc. Phone: 314-575-7717 Fax: 636-861-9109 Email: [email protected] no address available on their website.<p>If you use ferric chloride or other etchant, be responsible and don't just dump it down the drain.<p>You had a question?<p>Chris<p>[ December 23, 2003: Message edited by: Chris Foley ]</p>

ajc-28
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Re: Kodak Photo Resist (KPR)

Post by ajc-28 » Sat Dec 27, 2003 8:00 am

Thanks for the informaion about KPR. I did have a question which was where I could purchase this material, which you answered. I use KPR to make small runs of PC boards, but it is getting very expensive.
AJC

Mike
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Re: Kodak Photo Resist (KPR)

Post by Mike » Sun Dec 28, 2003 6:08 am

Wait, Chris,<p>Aren't you supposed to dump feric chloride down a drain? Thats what the instructions from radioshack said to do.<p>If not, where are you supposed to dump it?<p>-Mike

Chris Foley
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Re: Kodak Photo Resist (KPR)

Post by Chris Foley » Thu Jan 01, 2004 6:06 pm

Sorry not to get back to you quickly. You can't pour used ferric chloride down the drain because of the copper you etched out -- it's in solution, and causes problems with your local sanitary district settling tanks, even in very minute concentrations. If you live in a rural area and use a septic tank, you'd find that it would kill off all the bacteria, and you'd have to drain it and start a new one. In addition, the solution is toxic.<p>Here's a link to a site which discusses proper disposal of used ferric chloride etchant.<p>MG Chemicals ferric chloride faq<p>This method is acceptable, and only requires the purchase of pH strips. Be sure to wear safety glasses when neutralizing the solution. It would probably mean a trip to the disposal facility once every year or so for a hobbyist. Acid neutralized etchant sludge will keep for a long time in plastic.<p>It's a pain, but proper disposal is necessary -- you can't see the damage fly dumping causes, but damage does happen. Grownups clean up after themselves.<p>Happy new year, and good luck
Chris<p>[ January 01, 2004: Message edited by: Chris Foley ]</p>

Mike
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Re: Kodak Photo Resist (KPR)

Post by Mike » Fri Jan 02, 2004 5:55 am

I have done this about 3 times and dumped it down the drain into my septic. Can this cause problems?<p>-Mike

russlk
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Re: Kodak Photo Resist (KPR)

Post by russlk » Fri Jan 02, 2004 7:13 am

I hope that a pint once a month will not be a problem, because I do it. Once a day is probably too much.

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Lenp
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Re: Kodak Photo Resist (KPR)

Post by Lenp » Thu Apr 23, 2020 12:14 pm

Here's some info from MG Chemicals!
Q. How do I dispose of Ferric Chloride Solution?
A. There are two ways:
Contact your local Hazardous Waste Disposal Company
The solution must not be put down the drain because of residual copper ions left in it. To make it safe for disposal, you can add sodium carbonate (washing soda) or sodium hydroxide to it to neutralize it, until the pH value goes up to between 7.0 and 8.0, testing it with indicator paper. Copper will be deposited as a sludge. Allow the sludge to settle, pour off the liquid, further dilute it with water and then it can be poured down the drain. Collect the sludge in plastic bags and dispose of it as required by your local waste authority.
Len

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