Detergent for Washing PCBs in Dishwasher? - Page 1
Forum section: electronics / projects

author: MRiddickW
author_rank: Contributor
timestamp: August 12, 2021, 09:26:23 pm
content: Hi all,When washing PCBs in a dishwasher, does detergent brand/type matter? Are there any ingredients I should shy away from? I'll just use Cascade Complete gel if there's nothing to worry about.(And no, I would not be washing food dishes in the same washer.)We're troubleshooting a problem that we think may be board leakage, and inspired by Bob Pease, I'm ready to throw these in the dishwasher to see if that will help (Seethis threadto read the previous tangents into the specifics).In his bookTroubleshooting Analog Circuits, he says he "took a few boards home and set them in the dishwasher with the normal charge of Calgonite." I would just use Calgonite, but it's not longer made.I'm sure there's nothing magical about Calgonite in particular, but it did get me wondering if there's any ingredients I should avoid that would just make things worse. Specific perfumes, anti-spotting agents, etc.Any insight into this matter anyone can offer is much appreciated.Thanks!(Please feel free to move this thread if it fits better elsewhere. I looked at the different subforums and didn't see anywhere obvious.)

author: cdev
author_rank: Super Contributor
timestamp: August 12, 2021, 09:41:47 pm
content: I use this citrus (orange) cleaner degreaser stuff, its very strong and a little bit of it (like a few drops) is usually enough. I have a lifetime supply, (a gallon) of it downstairs, do you want its name? It wasn't expensive at all and it works really well for me. It will clean almost anything. It works great on greasy dirts, of all kinds. Given you use a clean rag or something to scrub it a bit. Its good for cleaning anything greasy off of your skin and hands too. If works well with PCBs for me so far, and rinses off.

author: Benta
author_rank: Super Contributor
timestamp: August 12, 2021, 09:57:09 pm
content: I suppose you're both single, right?I use either IPA or an ultrasonic cleaning bath.

author: floobydust
author_rank: Super Contributor
timestamp: August 12, 2021, 10:12:14 pm
content: It depends on the flux you used, but we just used water as a rinse.Don't use dishwasher detergents because they all contain rinse-aids to prevent water spots they leave a chemical residue, as well as perfumes.Maybe try hippy eco-friendly stuff, that is usually free of the additivies.

author: MRiddickW
author_rank: Contributor
timestamp: August 12, 2021, 11:32:43 pm
content: Quote from: Benta on August 12, 2021, 09:57:09 pmHa! I was planning on getting a countertop dishwasher that can be set up out of the way....But yes I am.Quote from: floobydust on August 12, 2021, 10:12:14 pmIt's rosin flux. I had already cleaned off all I could see with IPA so we threw it in the board washer set up for water-soluble flux for a cycle to unsurprisingly no effect (we discussed the concern of contaminating the water, no need to warn me).Yeah, the rinse-aids and scents is what gives me pause too.CascadeandSeventh Generationboth have "Free and Clear" products that might fit the bill.Quote from: cdev on August 12, 2021, 09:41:47 pmThe name would be great, thanks!

author: David Hess
author_rank: Super Contributor
timestamp: August 12, 2021, 11:34:20 pm
content: I've washed boards in the dishwasher with whatever dishwasher detergent that I had available, but that was *before* assembly, and I used reverse osmosis water.

author: KaneTW
author_rank: Frequent Contributor
timestamp: August 12, 2021, 11:42:01 pm
content: Pick whatever Alconox-esque product that's machine washer safe. Rinse with DI water.

author: tooki
author_rank: Super Contributor
timestamp: August 12, 2021, 11:51:52 pm
content: How about instead of the highly corrosive dishwasher detergents, maybe you use a detergent designed for machine washing PCBs? Like Electrolube Safewash F (low foam concentrate).

author: ejeffrey
author_rank: Super Contributor
timestamp: August 12, 2021, 11:53:46 pm
content: I doubt any residue left by dishwasher detergent will be worse than charred rosin flux. Rinse aids might actually help, they help the rinse water sheet off so it leaves less soap and dissolved solid residue.

author: WattsThat
author_rank: Frequent Contributor
timestamp: August 13, 2021, 12:45:24 am
content: Dishwasher detergents are caustic as all hell and will absolutely attack tin and copper. That’s a really, really bad idea.Quote from: tooki on August 12, 2021, 11:51:52 pmThis ^^^^^

author: jpanhalt
author_rank: Super Contributor
timestamp: August 13, 2021, 10:10:13 am
content: Alconox SDS still shows trisodiumphosphate. It was great in a chemistry lab with hot water.Calgonite now shows sodium silicate, which replaced phosphates in household detergents years ago. Don't know what it contained originally.Electrolube Safewash F SDS shows shows some ether-alcohols (e.g., alcohol ethoxylate and dipropylene glycol monomethyl ether), 2-aminoethanol (a good solvent), and alkylbenzene sulfonic acid sodium salt. The later is a strong acid like sulfuric and phosphoric acids.1) All are ionic and need to be rinsed well.2) There are several substitutes in the US to consider. Some people are fond of "Simple Green." I lke ZEP products that are available at Home Depot, Lowes, Menards, etc. ZEP Heavy Duty Floor Stripper might be a consideration. It is similar to Electrolube's product as it contains an alkoxy alcohol (butyl cellosolve) and 2-aminoethanol, but apparently lacks the sodium sulfonate salt. That is, it is non-ionic. I have not used it in a dish washer.3) I have used ZEP at room temperature and it works but evaporates slowly, so that has led to experiments with more volatile alkoxy alcohols.Note: My main PC died yesterday morning. I am using a very old PC that still had Google search (not Chrome). Doing anything with it is a struggle. Apologies for any misspellings.

author: KaneTW
author_rank: Frequent Contributor
timestamp: August 13, 2021, 11:08:57 pm
content: Dishwasher detergent are really not that caustic. The lab detergent I use is mildly alkaline at pH 10 and completely safe for most metals. Dishwasher detergent is pH 10-11.Both copper and tin are safe in alkaline solutions. Copper will form a copper oxide but it'll do that regardless with air exposure. Tin is only affected by hot concentrated alkali.

author: EPAIII
author_rank: Super Contributor
timestamp: August 14, 2021, 01:36:00 am
content: I love Bob Pease but I think his comments about using his home dishwasher was his way to say that the cleaning of PCBs should not be over-thought.I have cleaned a number of PCBs that were in a questionable condition but in most of those situations I did not have easy access to a dishwasher so I often just used a janitor's sink. One thing I look for first is the presence of any flux on the board. If that flux gets inside any parts that have mechanical contacts (switches, relays, etc.) it can be very difficult to remove.If there is any flux on the boards I would FIRST, CAREFULLY wash them with a flux remover. But the flux remover can carry the dissolved flux inside those parts with mechanical contacts. So, while doing this I made sure that all the flux remover drained in a direction away from any of those components. This often required cleaning different sections of the board with the board at different angles to promote drainage away from those parts.As for cleaning the boards in the dishwasher, I guess that would work. But today, ultrasonic cleaners are inexpensive. I have one in my home shop that is large enough for most PCBs that I have encountered. Some larger ones may need to be cleaned one half at a time but that works. I would use a simple cleaner like plain Dawn dish detergent.If you are really concerned, the major makers of the ultrasonic cleaners sell cleaners that are designed for electronic parts.https://www.all-spec.com/Product/100-955-914-6768https://www.google.com/search?q=Branson+ultrasonic+cleaning+solution+for+electronics&client=firefox-b-1-d&biw=1666&bih=851&sxsrf=ALeKk03W8pihXYNNIthbE8e9TTXy5W623Q%3A1628904335212&ei=jxsXYaG9DNaztQakgZYo&oq=Branson+ultrasonic+cleaning+solution+for+electronics&gs_lcp=Cgdnd3Mtd2l6EAwyBQgAEM0CMgUIABDNAjIFCAAQzQIyBQgAEM0COgcIIxCwAxAnOgcIABBHELADOhEIABCwAxCKAxC3AxDUAxDlAjoHCCMQsAIQJzoGCAAQBxAeOgUIABCGAzoICAAQDRAFEB5KBAhBGABQpscUWIPhFGCg-hRoAXACeACAAdADiAGqDZIBBzAuOC40LTGYAQCgAQHIAQrAAQE&sclient=gws-wiz&ved=0ahUKEwjhwJfCra_yAhXWWc0KHaSABQU4ChDh1QMIDQhttps://www.grainger.com/product/30XN22?ef_id=CjwKCAjwsNiIBhBdEiwAJK4khoaZYr3aHgJMYmjMWU1w9sAJqW9O3payf1VW5k38qNvZi4g2ZEtVIxoCqREQAvD_BwE:G:s&s_kwcid=AL!2966!3!264955916099!!!g!437519823839!&gucid=N:N:PS:Paid:GGL:CSM-2295:4P7A1P:20501231&gclid=CjwKCAjwsNiIBhBdEiwAJK4khoaZYr3aHgJMYmjMWU1w9sAJqW9O3payf1VW5k38qNvZi4g2ZEtVIxoCqREQAvD_BwE&gclsrc=aw.dsMany more hits:https://www.google.com/search?q=ultrasonic+cleaning+solution+for+electronics&client=firefox-b-1-d&biw=1666&bih=851&sxsrf=ALeKk02WNAHkQZ6QAbC41h0U31kZy0RLXg%3A1628904682461&ei=6hwXYYLYG5K7tQa06JWwDw&oq=ultrasonic+cleaning+solution+for+electronics&gs_lcp=Cgdnd3Mtd2l6EAEYADIECCMQJzIGCAAQBxAeMgUIABCGAzIFCAAQhgMyBQgAEIYDMgUIABCGAzoHCCMQsAMQJzoHCAAQRxCwAzoRCAAQsAMQigMQtwMQ1AMQ5QI6BwgjELACECdKBAhBGABQk7AFWNG3BWCzzwVoAnACeACAAYUEiAHcEpIBCzAuMS4zLjMuMC4xmAEAoAEByAEKwAEB&sclient=gws-wiz

author: james_s
author_rank: Super Contributor
timestamp: August 14, 2021, 05:38:41 am
content: I've cleaned PCBs in the dishwasher lots of times. I've always just used normal detergent but typically only about 1/4 as much as I would normally use for a load of dishes.

author: David Hess
author_rank: Super Contributor
timestamp: August 14, 2021, 12:51:18 pm
content: Quote from: EPAIII on August 14, 2021, 01:36:00 amOr solder in those mechanical parts after cleaning. DIP switches had that problem.

author: MRiddickW
author_rank: Contributor
timestamp: August 16, 2021, 05:25:16 pm
content: Quote from: EPAIII on August 14, 2021, 01:36:00 amWell we can see how well that worked!Thank you for the recommendations everyone, it has certainly given me a lot to mull over.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: August 16, 2021, 06:24:54 pm
content: Quote from: ejeffrey on August 12, 2021, 11:53:46 pmIf it's charred, you have other problems. RMA residue is inert, I have decades-old boards with rosin residue and they work fine, and the residue is inert. Flies trapped in amber since the Mesozoic should be a testament to the unreactivity of this class of chemicals.

author: tooki
author_rank: Super Contributor
timestamp: August 16, 2021, 11:01:33 pm
content: Quote from: Alex Eisenhut on August 16, 2021, 06:24:54 pmWell it’s not the rosin that’d be of concern, but the activators. But indeed, RMA (and even RA) flux core is generally totally safe to leave on.In contrast, liquid or paste RA, RMA, and no-clean can all be quite corrosive if they haven’t beenfullyheated.

author: cdev
author_rank: Super Contributor
timestamp: August 24, 2021, 11:58:09 pm
content: Its Zep professional citrus cleaner degreaser and its bright orange. Its very strong so be sparing. I had been trying to find something about d-limonine's use on PCBs, and I found this.https://www.turi.org/content/download/3762/46108/file/techreport6.pdfEvidently its okay and seems preferable to other cleaners that have been in use. But its strong enough to be useful at very high dilutions, if you are using an ultrasonic cleaner.This may be the URL for the stuff I use. A gallon of it will last forever unless you make a LOT of PCBs.You don't have permission to access "http://www.homedepot.com/p/ZEP-1-Gallon-Heavy-Duty-Citrus-Degreaser-ZUCIT128/100676344" on this server.I wouldn't use it in a dishwasher. The smell might be really strong and it might effect rubber parts, I dont know. But I wouldn't be surprised..

author: bdunham7
author_rank: Super Contributor
timestamp: August 25, 2021, 12:11:58 am
content: Regular dishwasher soap in a normal cycle generally won't hurt copper, steel, stainless steel, tin or gold, but it is hell on aluminum or zinc. I don't know about the Safewash stuff. Obviously they intend it for dishwasher use. Also, ask about the optimum temperature and don't assume that hotter is better.

author: jpanhalt
author_rank: Super Contributor
timestamp: August 25, 2021, 09:42:29 am
content: @cdev That link worked fo me. Here's the SDS in it:https://images.thdstatic.com/catalog/pdfImages/4b/4b9eb9b0-9111-4d93-ad19-b24e6dc101c6.pdfNotice the ethoxylated alcohols C9-11 and the sulfonic acid sodium salts. Citrous extract is just for smell. Same basic stuff as some of the others I mentioned earlier. The pH is shown as 11-12, which probably less than those detergents with sodium silicate. Sulfonic acids are quite strong organic acids. Hence, their sodium salts are less alkaline.

author: cdev
author_rank: Super Contributor
timestamp: August 25, 2021, 01:40:36 pm
content: Here is a tech report on d-limonine in electronics manufacturing - its old but its fairly positive about it. The Zep degreaser I got was bought at Home Depot and it was fairly cheap. It's active ingredient is d-limonene.I have no doubt that if it was sold as an electronics cleaner it would cost an arm and a leg and probably be exactly the same.One gallon is basically a lifetime supply for me. A few drops does it.It works well on windows /glass too.Does anybody have a suggestion on an affordable ultrasonic cleaner? Maybe $50 or less. It will be used for small PCBs.

author: tooki
author_rank: Super Contributor
timestamp: August 25, 2021, 03:06:19 pm
content: Quote from: bdunham7 on August 25, 2021, 12:11:58 amThe datasheets say right on them what the optimum temperature is.Quote from: cdev on August 25, 2021, 01:40:36 pmA lot of modern (non-aqueous) flux cleaners contain orange terpenes. (More common than a few years ago.) So I doubt citrus ingredients are problematic. I still wouldn’t use janitorial cleaners for electronics, since they may contain additives or impurities that aren’t good for electronics. Especially not given how inexpensive (in absolute terms) electronics cleaner concentrate is. (Sure, Zep is several times cheaper, but several times practically nothing per load is still practically nothing per load.)

author: KaneTW
author_rank: Frequent Contributor
timestamp: August 25, 2021, 03:44:35 pm
content: Quote from: cdev on August 25, 2021, 01:40:36 pmhttps://www.aliexpress.com/item/1005001382418911.html?or similar. Do your own market research though

author: Bassman59
author_rank: Super Contributor
timestamp: August 25, 2021, 09:24:18 pm
content: On the flip side of the "washing PCBs in a dishwasher" coin, the last time I drank communal/"office" coffee was two jobs ago. It was right before learning that the lab support tech was washing the coffee carafe in the PCB washer.

author: Kjelt
author_rank: Super Contributor
timestamp: August 26, 2021, 06:17:20 am
content: This is what dishwasher powder did to my german breadknife.My wife does not listen to me saying do not put knives in the dishwasherSure it took a few years still it is corrosive.

author: KaneTW
author_rank: Frequent Contributor
timestamp: August 26, 2021, 02:41:50 pm
content: Yes, Aluminum will corrode in alkaline environments. Know your materials before you clean them.

author: Bassman59
author_rank: Super Contributor
timestamp: August 26, 2021, 03:37:06 pm
content: Quote from: Kjelt on August 26, 2021, 06:17:20 amThe superhot water in a dishwasher combined with the detergent really does a number on wooden knife handles.

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: August 26, 2021, 05:05:16 pm
content: I don't know about the best detergents, but if you want seriously low leakage you have to rinse well with DI water, probably several times.

author: tooki
author_rank: Super Contributor
timestamp: August 28, 2021, 09:31:01 am
content: Quote from: Bassman59 on August 26, 2021, 03:37:06 pmThat’s not wood in the picture.

author: cdev
author_rank: Super Contributor
timestamp: August 29, 2021, 12:40:00 am
content: Is it Bakelite, or some similar very hard black heat-tolerant material??