PDA

View Full Version : How to keep electronics dry????


Henry111
11-17-2009, 05:07 AM
I am preparing to purchase a Seabee Twin from G&P Sales. I have no experience with seaplans, so I am very concerned about keeping the electronics dry--while at the same time providing sufficient cooling. As you probably know, the single-engine Seabee is a pusher. But on the twin, the motors (mounted on the wing) face forward in the "normal" fashion. My tentitive plan is to put the batteries in the fuselage, and the ESCs behind the motors in the motor pods. This Seabee twin has a 72" wing span. Any suggestions for keeping "stuff" dry and at the same time provide cooling will be sincerely appreciated.
You can see photos of the model at G&P Sale here:
http://www.rcairplane.net/index3.html

Larry3215
11-17-2009, 07:19 AM
Hi Henry,

I highly recommend using a product called CorrosionX.

No matter how hard you try to protect your gear - condoms, balloons, baggies, hot glue, etc etc - if you end up going down in the water it will get into something and kill it.

I have tried every option over the years and then I read about CorrosionX, tried it and have never even considered going back.

Check out my post #3 in this thread for a full discription of how it works and how to use it.

http://www.wattflyer.com/forums/showthread.php?t=26120

Trust me, if you do it correctly you will never have to worry about blowing an ESC or Rx by dunking in the water again. I have actually ran motors, esc's, rx's while they were under water.

The old TV commercial for this product shows them treating an old tube type TV set. Then they plug it into an extension cord and toss it into a swimming pool. Some diver is then shown watching tv under water.

I treat everything EXCEPT servos. Some guys have reported that they open up the servos and treat only the circuit board. Thats too much trouble for me. I have had servos quit while they were wet but they have always come back after drying out.

The stuff works.

Henry111
11-17-2009, 06:19 PM
Larry, thanks.
After I posted my question I discovered your post on the question. Big relief for me.
Thanks again.
Henry

Larry3215
11-17-2009, 07:34 PM
Be sure to thourghly coat every sq mm of all sides of the circuit boards.

The only time I had a failure, the tech at Castle told me I had missed a spot on the BEC circuit - and thats the part that failed.

So dunk and re-dunk and swirl and be sure the CorrosionX gets everywhere :)

Good luck!

Henry111
11-17-2009, 08:10 PM
Larry, one more question:
Before treating the ESC do you remove the factory shrink wrap?

Larry3215
11-17-2009, 08:29 PM
That would probably make it easier but I never do. If you have more heat shrink to replace it afterwards I dont see it being a problem though.

One good reason to remove the shrink it that velcro would stick to it much better if it wasn't coated with CorrosionX.

Henry111
11-18-2009, 02:09 AM
Larry, regarding velcro sticking. That is a thought because I alway use it to mount my ESCs. So take off the factory shrink wrap. Treat with CorrosionX. Then put on new shrink wrap?????

Larry3215
11-18-2009, 03:02 AM
I see no problem with that.

MaxAdventure
11-18-2009, 04:58 PM
Well Larry, you really have some great information, suggestions, etc you've shared over the years and I really appreciate it!

I read some of your threads on the Corrosion X and realized I'm LONG overdue for using it. I have a cub I've started float flying, started a PBY5A project and I'm thinking about a Mars project next year.

At any rate, I looked all over Ace and couldn't find any, managed to get to the infamous McGuckin's Hardware in Boulder (they have everything, like - really everything) http://www.mcguckin.com/ and still couldn't find it, but I did find Boeshield T-9 developed by Boeing that seemed like the same stuff (and a couple of other corrosion inhibitor brands) decided if it was good enough for Boeing, might be good enough for my planes.... kinda hurt at $20US for a 16oz and $10 for the 4oz. I decided the 4oz would last me for some time and took it home.

As usual, I did my post purchase shopping research and found this which I thought was really interesting:

http://www.thehulltruth.com/boating-forum/37823-corrosion-x.html

My take away is that probably all three products work, and concidering my receiver is not exposed to the elements, I wouldn't be able to tell which worked 'best', but as long as it saves me RX and ESC, I'm happy! I'm curious if anyone else has an opinion between them, or Larry if you've tried the others for our applications.

Thanks again for the advice Larry!

donjiskra
12-06-2009, 03:06 PM
Corrosion Block
This is a new product to me, so I looked it up:
http://www.nocorrosion.com/how-corro...trol-works.htm (http://www.nocorrosion.com/how-corrosion-control-works.htm)
Sounds good and I like the fact that it doesn't leave a "gummy residue" unlike Corrosion X
A 12oz spray can costs $15.00 and a 6oz is $7.00

Mailing Address:

Midwest Corrosion Products
2813 193rd Street
Lansing, IL 60438

Modifier
12-06-2009, 04:13 PM
For sealing servos, I have used "Tool dip" that has been thinned down.
http://www.toolmarts.com/performix_18Z01.html

Dunk (or brush) the servo right up to the output shaft area, but not on the shaft or splines obviously.

For sealing the output shaft/case gap, you can spread a big bead of dielectric grease (or your favorite) around that area, then push your servo horn on. It probably wont completely seal from extended immersion, but it will withstand splashes and dunks.

I know what you are going to post, "the grease will cut once the servo turns", but as the servo turns back, it smears the grease back the other way. It lasts for a suprisingly long time before you need to reapply.

I have done both tricks for years for boats and trucks, even with O-ringed servos, both ideas have worked good and saved me money.

Moxus
12-06-2009, 08:21 PM
i use condoms, then put a splash of silicone around the wires there they enter the condom, and then a strip around the outside.
that is, unlike most other methods, absolutely watertight. you can dip it in water and your electronics stay dry.
this dont work for servos of course, but you can save your reciever this way, and esc too.
just make sure you got a safety margin on the esc rated power, to the actual power draw. that will make up for the loss in cooling.

another option i havent tried in rc, but i know it works from other electronic applications is plastic paint.
in electronics stores (not those that sells you tvs. those that sell you individual transistors) they got spray bottles with plastic paint, to protect electronics.
thats absolutely watertight, and a printed circuit sprayed with that will work evne if submerged in brine.
again, this probably wont work on servos, because you cant protect the pot meters and motors inside the servo with this.

Larry3215
12-06-2009, 08:58 PM
MaxAdventure and Don - that Corrosion Block stuff sounds interesting. I may give that a test one of these days. Lets us know how it works for you.

If you have a spare esc you dont mind the risk of loosing - try running a motor while the esc is under water. I know that test works with CorrosionX :D

Moxus - you need to be sure your using a silicone sealant thats certified safe for electronics. If not - the fumes can damage the printed circuit boards. Dont use normal household silicone sealants like you get from the home improvement store.

You also need to be carefull as you can still get condensation inside your condom/balloon when the thing hits cold water. Many guys who use that technique also put water absorbent beads in with the rx/esc.

I have not found that technique to be very reliable when I tried it - especially around an rx with lots of servo leads, but maybe I wasnt carfull enough sealing.

nascarwings
12-07-2009, 01:02 AM
this is all i use.... http://www.mgchemicals.com/products/422a.html?PHPSESSID=55ba20abaf5248155a1d25e1ca769e db trust me its been well tested ...lol. i have corrosion x it works but it is a mess to work with....

cyclops2
12-07-2009, 07:30 PM
Originally ALL pcb when completed were sealed with either Varnish or Shellac. For military specifications.

Rich

cyclops2
12-26-2009, 05:40 PM
Because I am older than both of them. And they were too young to remember.

:ws:

Rich

AirmanAirhead
01-19-2010, 03:09 AM
I like the idea of coating the esc especially with either plastic paint mentioned by Moxus, or the shellac/varnish. I've used Corr X. and I've had mixed results, but I fly in brackish water and I know that creates much more problems that fresh water. My most recent experiment is using a Turnegy ESC leaving the shrink tube on, and blocking the ends with hot glue. Since it's winter, I don't have a cooling problem, the summer will be a different deal. Having said that it's hard to argue with Larry, he seems to be the man. But again my issue is the brackish water.

AA

MaxAdventure
01-19-2010, 06:36 AM
I've been flying in the snow and started applying the Boeshield T-9 to my exposed ESC on my Swift II (first use of the T-9). It's right on the bottom and I had to pull off the shrink to re-solder the signal lead that ripped free so I'll be dunking it in the snow every missed catch - I'll holler if the Boeshield doesn't work. This seems as good a real-life test as any!

Larry3215
01-19-2010, 07:04 AM
Keep us posted MaxAdventure.

Don Jiskra - how is that Corrosion Block stuff working out?