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South East USA
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Is there such a thing as a washable crystal?  I like to give my board a good hot soapy bath after soldering all the washable components on, and would like to use more components that are washable. I've always assumed SMD crystals are not washable. I use this one:
http://www.digikey.com/product-detail/en/ECS-160-20-3X-TR/XC1776CT-ND/2676640
The data sheet says nothing about washable. Anyone know much about crystals and/or of a washable type?
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I dont think any electronics is really washable, you risk shorting out due to water being held under parts and not exposed to air holding in there for long periods of time due to capillary action.

as far as washing flux off, a 99% alcohol bath does nicely and dries out super quick, otherwise use whatever and wait a couple weeks while hoping something doesn't short
« Last Edit: July 07, 2013, 08:21:29 pm by Osgeld » Logged


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@SouthernAtHeart:

In the Ol' days before everyone was concerned about ozone holes and global warning, we used a mix of alcohol and a fluorocarbon ... Today, some commercial products are similar but substitute to remain on the right side of Federal law:
http://www.zorotools.com/g/00060945/k-G0897163

You may experiment with other commercial products with large alcohol contents:
http://www.splashwash.com/Product.aspx?pid=9

Be aware, the evaporating alcohol will likely cause moisture condensation.

I read that an American supplier of Arduino breakout boards uses reflow soldering and then does bathe the boards... But then they put them in a low humidity controlled dryer for a timed period.
https://learn.sparkfun.com/tutorials/electronics-assembly/all
( see Washing - select from left pane menu)

I have made circuit boards for over 40 years and have never given my boards a water bath... But if you feel you must you should at least build or concoct some type of low humidity dryer.

- Ray
« Last Edit: July 07, 2013, 09:57:45 pm by mrburnette » Logged

Grand Blanc, MI, USA
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I've used tetrachloroethylene (brake cleaner) and it works well but is pretty pungent stuff. Denatured ethanol (in gallon cans in the paint department of your favorite big-box home improvement store) seems to work just as well and is not as noxious but as noted above there is usually some minor condensation. I use compressed air to dry the tetrachloroethylene or ethanol. I've also used a blow dryer with the ethanol as it helps deal with the condensation.

I know that a lot of the no-clean fluxes are said to be water soluble but for whatever reason I've never actually considered using water. OTOH, it would seem that anything that stands up to alcohol or tetrachloroethylene would be OK with water. Probably distilled or deionized water would be best.

I haven't used an SMT crystal like that, but it looks like the basic package is pretty similar to the typical through-hole types. Those look pretty well sealed up and I've never had a problem with them.
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Well since practically all SMT components are compatible with some form of wash solution, I'm not sure of the problem.

I guess the first order question is, what is it you wash YOUR boards with that damages components?
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I use hot water and soap. I used to use household alcohol, but it seemed to 'dull' the board --take away the nice shine. I use a flux that is 'water soluable'. I could see parts like the atmega328P-AU, 0803 CAps & Resistors, being unaffected by dipping in hot water but it seemed to me the crystal package would seep liquid into it?  Maybe not??
De-ionized water- will that clean the flux off good?  No soap?  Is that the same as distilled water or is it hard to come by?
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I knew someone who used hot water and soap and just let them dry out before use...

As for the crystal, surely it has to be sealed air tight?... -  I suppose you could always stick the board (after leaving it to dry) in an oven on a low setting
just to make sure there's absolutely no trace of water left, or even a heat gun, hair dryer?
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I've water washed boards for years.. It depends on the board and how it was assembled. Low clean no clean and water clean fluxes are both water soluble and hygroscopic to some extent, Some worse than others. All components are "Generally" watertight the notable differences being sensors. A crystal or resonator must be watertight in order to avoid the influence of the flux used in soldering the board and the board cleanup later or be susceptible to changes in frequency because of foreign material buildup.

Doc
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Well since practically all SMT components are compatible with some form of wash solution, I'm not sure of the problem.

so you say a SMT compent will be fine overnight in warm tap water with dish detergent then powered on cause the component is sealed?

btw if you are interested I have a 1 in 20 odds on some random amount of money, just spend all your production cost for the next month on that gamble, it should be fine

hint, who gives a crap if the part is sealed! its the leads that screw you up

my dell laptop at work got the roof leaked on, poured nearly 2 cups of water poured out of it, took nearly a month in the dry chamber, hard disk died just about one year later due to detergent growth, thing looks like a salt mine.

so sure go wash your boards in a dishwasher, it only took a year for rain water to kill my laptop, good luck
« Last Edit: July 08, 2013, 12:54:54 am by Osgeld » Logged


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Side issue:
You have to be careful with POTs and sockets (all things mechanical).
The washing can deposit flux into the mechanism and cause problems.
Some compressed air helps remove wash from under components.

I always install and solder POTs & sockets after I wash the board.
Flux can then be removed with Q-Tips & liquid.

The SMD crystal will be OK to wash.
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The way you have it in your schematic isn't the same as how you have it wired up!

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Quote
I've also used a blow dryer with the ethanol as it helps deal with the condensation.

CAVEAT: alcohols and petroleum distillates are combustible so if the fan motor in the dryer has brushes ... well, just be aware.  The other issue is that some of the fancy dryers of today have Ion generation, so one could get a spark or statically damage sensitive electronics although it is unlikely once they are in-circuit; but use caution.


- Ray
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When I was young, (Ok eons ago), I worked as a Wave Solder machine operator.  We used a solvent called 1,1,1-Trichloroethane to clean the boards after soldering and the parts would spend a few minutes completely engulfed in a cloud of the stuff while excess flux would drip off by itself.  Boards would emerge clear of all flux and residues.  Those perfect days are gone now that it was determined that chemicals like this (chlorofluorocarbons) effect the ozone layer.

Since that time, it is quite common to see Aqueous Cleaners in use at board shops.  Where I worked, we adopted a new line with water soluble flux and other water-soluble products while we tested out the washing machine and determined that it OK for the prototype shop that was building and testing the DEC PDP-11/23.
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Quote
I've also used a blow dryer with the ethanol as it helps deal with the condensation.

CAVEAT: alcohols and petroleum distillates are combustible so if the fan motor in the dryer has brushes ... well, just be aware.  The other issue is that some of the fancy dryers of today have Ion generation, so one could get a spark or statically damage sensitive electronics although it is unlikely once they are in-circuit; but use caution.

- Ray

Right, am aware. I give the boards a good shake and use the dryer away from the major concentrations of alcohol. I figured that what was left on the board wouldn't be too large a problem even if it did catch fire  smiley-wink

Was not aware of the ion generation dryers, thanks. Mine is ancient so shouldn't be a problem. This might explain all the bad-hair days though   smiley-grin
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Thanks for all the feedback. I like the denatured ethanol idea and might give it a try. With a good drying from an old hair dryer.
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I've also used a blow dryer with the ethanol as it helps deal with the condensation.


I hope you do that outdoors in the shade - ethanol flames are practically invisible in daylight and a
blow-dryer can occasionally generate sparks from bit of crud that hit the heating wires.
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