Boards coated in wax?

| Hey peoples, | We are working with the dairy industry out here and they asked us to start reworking all there boards for them. Of course we said yes, hehe. Only we didn't know what them farmers coated them boards with. It turned out to be wax, hmmmmm? Now I know I have so much to learn here but the wax thing has got me I must say. The farm equipment company (our new customer) told us that it keeps the moisture out. Sounds simple right? He also said it made it easier to rework? Well at face value it does. But here are my questions. | 1. Will the wax effect the solder flow? | | 2. When the wax reaches a temp that makes it sweat will it then become conductive? | | 3. I dont want to boo hoo the whole wax thing but isn't there a better sealant out there? One that you might know of that will alow us to do the same easy rework ability? | | These boards gotta live with the cows. But I think the wax is for the birds. < bad joke! I thought I would run this one past you guys and believe me I am open minded.I just can't seem to find bees wax in my book. So if ya all think wax is ok I will go with it! | Thanks alot if you can help................Jeff Sanchez |

To anwser your question 3,

Why don't you guys just use Conformal Coating? I would recommend a silicone-based, since it's the easiest to rework - especially the less viscous kind. I used to work with the Dow Corning's 4105 Silicone and you could just literally peel it right off.

Most Conformal Coatings have a very wide temperature range - if I remember correctly i believe it's in the -40 C to 260 C ballpark...i don't really remember since it's been awhile since I've looked at a Conformal Coating data sheet. Conformal Coating is NOT conductive, and its intended use is for Printed Circuit boards. MOst coatings out there act as both a dielectric and for environmental protection. I'd recommend that you get in touch with a conformal coating supplier and get some literature.

However, I would guess that wax is a hell of a lot cheaper.

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| | Hey peoples, | | We are working with the dairy industry out here and they asked us to start reworking all there boards for them. Of course we said yes, hehe. Only we didn't know what them farmers coated them boards with. It turned out to be wax, hmmmmm? Now I know I have so much to learn here but the wax thing has got me I must say. The farm equipment company (our new customer) told us that it keeps the moisture out. Sounds simple right? He also said it made it easier to rework? Well at face value it does. But here are my questions. | | 1. Will the wax effect the solder flow? | | | | 2. When the wax reaches a temp that makes it sweat will it then become conductive? | | | | 3. I dont want to boo hoo the whole wax thing but isn't there a better sealant out there? One that you might know of that will alow us to do the same easy rework ability? | | | | These boards gotta live with the cows. But I think the wax is for the birds. < bad joke! I thought I would run this one past you guys and believe me I am open minded.I just can't seem to find bees wax in my book. So if ya all think wax is ok I will go with it! | | Thanks alot if you can help................Jeff Sanchez | | | | To anwser your question 3, | | Why don't you guys just use Conformal Coating? I would recommend a silicone-based, since it's the easiest to rework - especially the less viscous kind. I used to work with the Dow Corning's 4105 Silicone and you could just literally peel it right off. | | Most Conformal Coatings have a very wide temperature range - if I remember correctly i believe it's in the -40 C to 260 C ballpark...i don't really remember since it's been awhile since I've looked at a Conformal Coating data sheet. Conformal Coating is NOT conductive, and its intended use is for Printed Circuit boards. MOst coatings out there act as both a dielectric and for environmental protection. I'd recommend that you get in touch with a conformal coating supplier and get some literature. | | However, I would guess that wax is a hell of a lot cheaper. | Jeff,

Herb is right, but I will post here the message I sent to your email address before I got brains enough to read your forum posting:

Jeff,

Good to see from you again. I hope everything is going well, except for the wax.

I saw your posting and really didn't pay much attention, but it did concern me. First, what kind of wax as what chemistry? Who applied it and how (supplier and process as coated, draped, dipped, or?). What is the metallized surface as bare copper, gold, or? Is the wax removed during soldering operations? If so, what is the recommended method (wax supplier specifications)? Is the wax compatible with your fluxes and other solder process chemistries (solder paste, wire solder, etc.)?

Beyond all this, have you tried soldering to a sample surface? If so, how did it solder wet?

What I'm getting to is what you know so well. All copper surfaces must be protected to prevent oxidation whether the coating is tin/lead, gold, tin, or organics. No matter the coating, it only is there to protect, not inhibit solder wetting. If this stuff does both these, it is fine. If one or the other is not done effectively, the coating is unacceptable.

I hope this helps and best regards,

Earl Moon

Now that I understand the wax is designed to be a post process protective coating, I must say most of the same questions above must be asked. My biggest concern now is whether the wax really protects as do so many other conformals as Herb mentioned. Again, I get back to what works and how well.

Enjoy,

Earl Moon

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