Doc.316

Howdy;
Been setting up my Vintage radio...with a modern reciever to go fly it. I had to reverse wire a couple of servos. Bet a couple of you remember doing this....well back in the day it was easy swap the pot wires and the motor wires and you were off to the field. Just found out that new servos are not made to do this since they have boards directly connected to the motor...(sigh)...after opening several I finally found two that I could reverse....whew!

Now that the background is over....when reassembling back in the day...I am not too old so 30 or so years....we potted the servos with "Weldwood contact cement"..no other brand. A local ham came up with it.....and it worked well... I see that it is still out there.

Is there something better?

Thanks,
Steve

Oh...there isn't much to stick together (only 1 IC on the board) but the servos I found DID have wires going to the motor and pot that could do with a good "potting"...

iflyj3

My Feedback: (7)

I use a glue that is for gluing tennis shoes. It can be found in the shoe department of K-Mart, Walmart or Meijers etc. Depending on the store it is called Shoe Goo or Sport Shoe Glue. It is also available in the glue department under several names but the one I like is by Loctite called Stik'n Seal. It comes in a 1 oz tube and is a little thinner than Shoe Goo but is the same stuff. This glue is electrically innert and does not contain chemicals that harm electronics. It stays a little plyable and can be removed when needed.

Another solution is GC Electronics Silcone part number 19-155 that can be gotten from electronic supply houses. It is an electronic grade sealant/adhesive. Do not use the silcone glue from the hardware store as it is caustic to the circuits.

Doc.316

Okies...thanks Dan...I will look for it. Yea, that is why we only used the weldwood stuff also...(others were bad on the electronics)...shoe goo ougha do it...I will get the wife to get me some when she go's to walmart.

mickvk

My Feedback: (1)

thank you for the information - I'm looking to pot a receiver myself. I was going to use 3M Scotch-Weld Epoxy Adhesive DP270 specifically formulated for potting. But since Shoo Goo is transparent that would be a big advantage (to see the bind light). I am surprised that it's a neutral cure, but I'll give it a go.

HighPlains

My Feedback: (1)

Actually department silicone glues are acidic, bases are caustic.

N1EDM

My Feedback: (2)

HIghPlains,

I remember using some gasket insulator silicone on the junction of a ham radio antenna that I made, to keep it 'dry' in the rain. About a year later, I had to peel it off because the antenna wasn't working well any more. WHen you mention caustic, you aren't kidding... the copper was about eaten away.

However, if you really want to try using silicone, try using some bathroom caulk from the home center. Get a brand name. I am not sure if that was as strong of an acid or not, but it didn't seem to corrode my copper wires any more. Maybe it's a different mixture.

For some reason, the smell reminded me of celery. Someone told me that it was acetic acid. Experiment first!!

Just my $.02

Bob

engrv7

If it smells like vinegar...don't use it.

Stan

LesUyeda

"Actually department silicone glues are acidic"

That's what makes them work so well.

Les

Frank Schwartz

My Feedback: (1)

As sfor potting electronics...I remember a Space Control that I bought many years ago after seeing Zel Ritchie demostrate it at the DCRC Symposium.
I bought a set...took months to deliver it...and it crashed every plane I put it in...I'd send it back and wait months and call and beg Ritchie to fix it and return it.....I finally gave up and sold it for peanuts to a collector......
However, I digress....the pc board on the Space Control was covered in some sort of epoxy clear potting. You could see the parts through the potting material. I am sorry I do not know what it was. Perhaps someone knows who reads these things...but I can tell you for sure it was NOT silicone....
Frank Schwartz
P.S. Later I saw Hal DeBolt fly his Acrobat Bipe with a Space Control and I marveled that it worked at all....I thought I was a good electronics man, but he must have known something that I did not...mine constantly drifted off center and his did not....ant the Sampey I bought later drifted, too....finally got a good digital set when they came out and quit losing planes to bad radio design...only dumb thumbs....

N1EDM

My Feedback: (2)

That clear coating was most likely something called a conformal coating, a dip or spray that is used to keep the electronics free of moisture. It would be sprayed everywhere except for things like connector contacts or microchips that were in removable housings. Were you thinking about doing something like this to your RC equipment?

Bob

Frank Schwartz

My Feedback: (1)

Idoubt that it was a spray. The coating appeared to have been poured on and was quite thick and really covered every part on the pc board...and the coating was not flexible or rubbery...was hard to see the values of the components.
Frank

iflyj3

My Feedback: (7)

Here are some pic's I just took of my old Space Control receiver brick. Frank is correct it is some type of epoxy. See how it has aged and cracked.

N1EDM

My Feedback: (2)

OK, if it's not a spray for waterproofing, then the epoxy (as the photos show) is on there is for holding the components in place, usually for vibration, and to keep them from leaning into each other and shorting out if some of the leads were exposed.

mickvk

My Feedback: (1)

Wow, that Space Control is a blast from the past.

For others who are getting to this information for the first time I'll add this - "conformal" in electronics just means a protective coating. It could be a hard laquer, an epoxy, a rubber, or an oil. Wikipedia has this page the does a great job of describing them. en.wikipedia.org/wiki/Conformal_coating

I have used Corrion-x on receivers, ESCs, and other electronics by doing a dull dip (repeated annually) with no problems and very good results in terms of water resistance (never fried a wet ESC. And I have dunked quite a few.

If Iuse a product to permanently encase a receiver, I will be certain to use something specifically designated as nonreactive, neutral cure or made for the purpose of potting. Tub and tile caulk is known to damage electronics. I wouldn't do that.

N1EDM

My Feedback: (2)

Hi Mickvk,

I agree with you about your definition of conformal coating - that is what I was trying to get at as well. Also, if you overdo a protective coating (i.e., put it on too thick) , some components could overheat and change values, which could detune the rx. I'm not sure if this would actually happen in our rx's or not, but it might not be work the risk of finding out the hard way.

Just a thought...

Bob

Michaelj2k

Here's a page from Micro Measurements. It's probably not exactly what you are looking for but there are data sheets that can be downloaded to get an idea of what to use. http://www.vishaypg.com/micro-measur...tive-coatings/

When we make a circuit board to balance strain gages for temperature compensation, we use 5 minute epoxy to pot the electronics which operate between 5v to 15v excitation.

sidgates

My Feedback: (2)

Frank, I think I know you. We always used Pliobond contact cement on hook up wires where they exited the pc boards or on motor terminals at Royal Electronics. We also used a clear spray on pc boards if we wanted moisture protection, I don't remember the brand, my have been Krylon.

Frank Schwartz

My Feedback: (1)

Sid: You have a good memory. I worked for Hobby Lobby from 1976 to 1979 and then a few years later for Rivergate Hobbies as sales manager. Bought a lot of your stuff at Royal, kits and electronics...
Regards,
Frank

sidgates

My Feedback: (2)

Frank,
I didn't remember who you worked with back then. Hobby Lobby was a good customer. I was in Nashville area last Oct. and when I was getting off the free way to go to our hotel what did I see but Hobby Lobby sign on the side of a building. Of course I had to visit before we left town.
I also got to visit an old friend who I had met in Denver many years ago, John Valentine.

Very good to hear from you. If ever in Denver please save time to stop by. My direct email is:
[email protected]
I have a scratch build project on my web that might surprise you:
http://sidgates.us