I have main boards, power supplies, and so on as spare parts. But sometimes they spend several years in my workshop waiting for a customer. When I find the right customer, several times the boards were damaged, mostly because of corrosion.

How could I save the boards, obviously without damaging them (anticorrosion, silicon, and lacquer)?

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    \$\begingroup\$ Humidity /environment control is 90% of it , in taped anti static bags , and in extreme cases vacuum sealed with dessicant, but that is usually for raw parts \$\endgroup\$ – crasic Jan 28 at 16:15
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    \$\begingroup\$ Why not just tell us where you live? We won't come and steal your corroded boards. \$\endgroup\$ – Transistor Jan 28 at 16:40
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    \$\begingroup\$ @Transistor Speak for yourself. My black helicopters are on standby. \$\endgroup\$ – DKNguyen Jan 28 at 16:42
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    \$\begingroup\$ Jaja I dont live in USA. I'm from maracaibo , venezuela \$\endgroup\$ – NIN Jan 28 at 16:50
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    \$\begingroup\$ the most likely cause of the corrosion is the salt in the air from the ocean \$\endgroup\$ – jsotola Jan 28 at 17:05

When comparing environments care must be made with comparisons.
I am in New Zealand. In my city corrosion rates are high. Elsewhere in the country corrosion rates are much lower. While temperatures and rainfall can be similar or different the main factor is distance from the sea (!).

Note: Maracaibo climate is hot all year round (about 25C) and moderately wet in winter. It is on the ocean. Corrosive salt in the air is probably a major problem (as jsotola says). It is NOTHING like Las Vegas which is far from the sea, gets hotter and much colder and is very dry. ie it is always important to look at actual parameters

  1. Storage in an area fed with filtered contamination free and low humidity air can help.

    A very low airflow via a suitable filter is OK as long as overall you maintain even a slight "positive pressure" so the outside air is eliminated.

  2. A good quality conformal coating will provide an excellent solution, but car must be taken not to coat connectors and in some cases "wicking" into some sockets and similar can occur.

    As an example only, Dowsil 1-2577 is excellent but may not be readily available to you. This is expensive in small volumes, gets MUCH cheaper in moderate amounts and covers a large area - a film 0.1mm thick is adequate and can be applied by dipping brushing or spraying.

A cheap conformal coating which MAY be adequate - if using it you should test it on some target boards in your environment - is "polyurethane spray" / varnish / laquer. This is not as effective as eg 1-2577 but is very low cost and widely available. Polyurethanes usually set by absorbing moisture from the air - it would probably be wise to ensure that the moisture that is absorbed while drying is salt fee. As with any conformal coating, be aware of coating contacts and possible issues with "wicking" on connectors and sockets.

  1. Anticorrosion vapour emitting products have been mentioned. These can work well but have major problems if used with incompatible materials.

    i.e., Anti corrosion vapor emitters MAY be suitable BUT always ask the manufacturer - whether re Zerust or similar products.

From the Wikipedia article on Volatile Corrosion Inhibitor:

  • " ... Restrictions and limitations in the use of VCI. VCI materials will not protect all metals from corrosion; in fact, they appear to increase the rate of corrosion in certain metals. VCI materials must not be used to protect any assemblies containing optical systems or precision moving parts which have been coated with a preservative or lubricant, unless otherwise specified. Items protected with bonded films, such as molybdenum (a dry lubricant), are not included in this category . VCI materials are affected by heat and light. They lose their effectiveness as the temperature increases and they decompose if exposed to direct sunlight for extended periods. They also decompose in the presence of acids or strong alkalies. Precautions must be taken when VCI is used with items, assemblies, and subassemblies containing zinc plate, cadmium, zinc. base alloys, magnesium base alloys, lead base alloys, and alloys of other metals including solders and brazing alloys. If such items contain more than 30 percent of zinc or 9 percent of lead, they must not be preserved with VCI. In all cases direct contact of VCI with non ferrous metals except aluminum and aluminum-base alloys should be avoided unless specific permission has been granted. Care should also be taken with assemblies containing plastics, painted parts, or components of natural or synthetic rubber. Assemblies containing parts made of these materials should not be packed with VCI until proof is established that they have passed the compatibility test required by Specification Mn..-I-8574. ... "
  • \$\begingroup\$ Russell now I know the conformal coating. I'll search more about it. Thanks \$\endgroup\$ – NIN Jan 29 at 2:16

For long term storage, what I usually do is put the item in an anti-static plastic bag, put some desiccant packets if available, then seal it (video) using an impulse sealer. This method has yet to fail me.

The plastic, desiccant, and impulse sealer can be acquired for cheap, at least in the Philippines.

enter image description here

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    \$\begingroup\$ I'm surprised this wasn't the first suggestion. It's not perfect - no inherent temperature control, for example - but provided you can get enough bags of the size you need, then it should do the job. Reusable bags will reduce the waste too. \$\endgroup\$ – Dan Jan 29 at 11:51
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    \$\begingroup\$ @Dan I don't really own electronics that are sensitive enough for me to care about e.g. temperature control or gas diffusion (a concern for some MEMS components). I agree that it's good enough for most cases, especially consumer electronic parts. \$\endgroup\$ – PNDA Jan 29 at 14:57
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    \$\begingroup\$ Absolutely. I've stored computer boards in resealable anti-static bags for years with a little dessicant sachet. Never any issues. \$\endgroup\$ – Dan Jan 29 at 15:55

I think you can stick them in an airtight box with rust inhibiting vapour block.


Just make sure your box isn't a plastic box ridden with static charge.

  • \$\begingroup\$ Perfect. . Thats great, and another "chemical options" ( maybe silicon ). I've seen several power supplies TV's (mostly from samsung) protected with silicon \$\endgroup\$ – NIN Jan 28 at 16:44
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    \$\begingroup\$ @NIN Silicone will block connectors and solder and silicone oil is really bad as it prevents anything from adhering to anything else. Stay away. Silicone connformal coating is fine but that is for long term permanent protection and takes effort to apply and cure. \$\endgroup\$ – DKNguyen Jan 28 at 16:45
  • \$\begingroup\$ Antiestatics bags ? \$\endgroup\$ – NIN Jan 28 at 17:38
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    \$\begingroup\$ @NIN That was what was mentioned earlier when by crasic when he mentioned anti-static bags. You can get a heat sealer for those bags too. You can also add in dessicant pouches before you heat seal or in extreme cases you can vacuum seal it. \$\endgroup\$ – DKNguyen Jan 28 at 17:38
  • \$\begingroup\$ DKNguyen your answer was awesome. You made me know that incredible tools. Even thought answer of Russell help me to find out the " conformal coating" . This time I'll give the puntage to russell because is more closely to my thought. . Thank you. \$\endgroup\$ – NIN Jan 29 at 2:14

Former service manager here. If your job is protecting these repair parts, then you don't get to shrug off your local climate being what it is. It is your job to maintain climate control in the storeroom 24x7, both temperature and humidity. If you can't do that, then you need to date stock and redline it past a certain number of months.

Mind you, you don't have to clmate control a whole room or building. Just the stock. If you can get it done with an old refrigerator rigged to keep things at 25C, with an incandescent bulb to heat when ambient temperature falls below 15C (and gosh, most refrigerators have a light bulb socket already in them), and manual dessicant packs to remove humidity... good enough.

Good way to store welding rods, too.

Intentionally having the refrigeration coils and the light bulb fight each other is a good way to dry out the air. You wouldn't want to do that continuously, just turn the light bulb on anytime the humidity is too high and let the thermostat turn on the compressor.

  • \$\begingroup\$ @Nin This answer is worth noting. \$\endgroup\$ – Russell McMahon Jan 29 at 9:31

The gold standard for long term storage of sensitive electronics is dry nitrogen. But that's probably not cost effective for what you want to do.

I would recommend a sealed off storage area with conditioned air into it - either a separate AC unit or a dehumidifier. There's a sweet spot for electronics in so far as relative humidity goes. You want the air dry enough so that you're well away for the dew point temperature (where moisture condensed out of the air), but moist enough so that static buildup (ESD) is not a problem. I think that range is something like 40% to 70% RH (30%-60%?), but don't quote me on those exact numbers.

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    \$\begingroup\$ I don't see why that would be that hard. You just need a glove box (hack a $60 Canadian Tire sandblast cabinet) and ziploc bags. I've thought of doing that for paint, so I don't get a "skin" on my half full paint cans. \$\endgroup\$ – Harper - Reinstate Monica Jan 29 at 1:52

I repair Apple devices and I use Anti-Static bags stored in plastic bins. I often throw in some desiccant for good measure.


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