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Posted by: 914Sixer Jan 17 2009, 06:38 PM

What type of sealer should I use on the bottom of these?


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Posted by: StratPlayer Jan 17 2009, 07:51 PM

Use liquid electrical tape... You can get it a home depot, stuff works great for that application. I've done 2 boards using liquid electrical tape.

Posted by: McMark Jan 17 2009, 09:05 PM

Good idea!

Posted by: 914Sixer Jan 18 2009, 09:00 AM

I tried that earlier and it just ran off the copper. I will try cleaning it with lacquer cleaner and see if it will stick.

Posted by: KevinP Jan 18 2009, 09:08 AM

I have been using an aircraft grade expoxie that has been on the relay board for about 14 years now. No problems yet.

KP

Posted by: rfuerst911sc Jan 18 2009, 09:14 AM

A good electrical parts store might sell you a small amount of conformal coat which is what is used today on almost all boards. This would be what I would use as the first step to seal the board traces from corrosion. I don't know if you need anything after the conformal coat to strengthen the board so it doesn't flex? I'm guessing maybe that's why Porsche used the goop they did.

Posted by: John Jentz Jan 18 2009, 10:42 AM

What did you clean the traces with so the solder would flow?

Posted by: kwales Jan 18 2009, 11:38 AM

What you want is what the electrical guys call "potting compound". Comes in silicone and epoxy and is used to "pot" or seal electrical components. Comes in conducting and nonconducting. We want nonconducting.

Some types have a self leveling feature (low viscoscity) so it will ooze across the board and create a level pool. This is what we want.

Potting compounds used to be silicone, but epoxies are used a lot now. To my way of thinking, this is a 30 year old car and the potting compound may need to be removed later for another fix. Silicone is much easier to dig out than epoxy, so I would suggest silicone.

Searching silicone potting compound prices turned up this linky for $18 a tube.

http://mro2go.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=51240405

Ken

Posted by: StratPlayer Jan 18 2009, 11:52 AM

Hmmmm it ran off the copper,,,, did you use a spray version of that. I used the liquid tape that had to be brushed on. Never had such a problem using it.

Posted by: 9146986 Jan 18 2009, 12:05 PM

Dave Shepard and Glenn Stazak used to use a two part potting epoxy that worked good.

Posted by: Phoenix 914-6GT Jan 18 2009, 12:17 PM

QUOTE(kwales @ Jan 18 2009, 09:38 AM)

Posted by: restore2seater Jan 18 2009, 01:28 PM

QUOTE(Phoenix 914-6GT @ Jan 18 2009, 12:17 PM)

QUOTE(kwales @ Jan 18 2009, 09:38 AM)

What you want is what the electrical guys call "potting compound". Comes in silicone and epoxy and is used to "pot" or seal electrical components. Comes in conducting and nonconducting. We want nonconducting.

Some types have a self leveling feature (low viscoscity) so it will ooze across the board and create a level pool. This is what we want.

Potting compounds used to be silicone, but epoxies are used a lot now. To my way of thinking, this is a 30 year old car and the potting compound may need to be removed later for another fix. Silicone is much easier to dig out than epoxy, so I would suggest silicone.

Searching silicone potting compound prices turned up this linky for $18 a tube.

http://url=http://mro2go.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=51240405]Silicone Potting compound linky[/url]

Ken

Ken, the link says it is broken. Can you redo it please. I would love to see what this stuff is.

Posted by: Aaron Cox Jan 18 2009, 07:36 PM

Potting compound works well.

I used Black RTV, and it is still good

Posted by: Bartlett 914 Jan 20 2009, 09:22 AM

There is a thread on Roadglue that covers this. I have seen this material and I think this is the best solution. This is as close to the original material as you will get. I don't think RTV is the best because some of these outgas corrosive vapors.

http://www.roadglue.com/forum/showthread.php?t=653

Posted by: underthetire Jan 20 2009, 10:35 AM

Just my 2 cents but usually any silicon has ammonia in it. NOT GOOD FOR TRACES. We use a product called 3 bond for sealing. No ammonia but takes longer to dry. Epoxy once cured is always good. ( PS. i repair CNC equipment, so waterproofing is very important!).