Cheap waterproofing that works!

[ozzie-crawl]

I wonder when the ESC manufacturers are gonna truly waterproof their products!? It would certainly be worth an extra $20 or so!

this is one of the reasons i wont spend big $$$ on a esc,if your going to pay $200-$400 for a esc thats made for marine use it should be water proof

[BHChieftain]

When Doug R was still with us he ordered small little plastic boxes...I still have 5 of them. We got them for the rec and they snapped shut and then you run the wires out and seal the holes. Worked well.

Sure....why not have a small box for the ESC....make sense to me.

I'll see if I can rig that up for my Syncron newbie build thread I started the other day...

-Chief

[DISAR]

I have a Hydra 240 which has an integrated watercooler and has a plastic wrap around it-- it states it is water resistant. What's the best method to waterproof this one?
-Chief

In case you waterproof it with something over the boards the warranty won't be valid any more (probably). I had mine immersed in sea water which is much worse for electronics than fresh water, and it got burned-shorted. They replaced it free of charge!

Rearding the total waterproofing of the esc, it might not prevent the esc from burning in case the boat accumulates too much water especially sea water which is very conductive. The shortening can happen from the connectors too.

The total encapsulation of the esc can cause heat build up and makes the esc unrepairable. But also if burned-shorted is unrepairable. the choice is yours
The ideal waterproofing for me is like a box with the esc inside and all cables sealed at the ends. I have my hydra in one of them made by fiberglass plates and silicone seal the cables and in-out tubes
MGM has introduced a new option for total waterproofed esc.

[Jeff Wohlt]

So what about a small lipo bag that seals good. now when it burns you are protected from flames and burned areas in the hull?

[7500RPM]

I have been using MG Chemicals Conformal coating for many years with great results, and they do make it in an aerosol format.

http://www.mgchemicals.com/products/422b.html

[ncornacchi]

There are potting compounds out there for encapsulating electronic circuits, like the Aquacraft ESC's. I'm not sure why we aren't building a little box, putting the esc in it, and pouring it with the compound! Any comments?

That's also a really good idea...we use potting compound in in-ground uplights, pools,etc...and it bonds to the silicone conductors, so, no wicking. On the CC240 clear wrap, that was the first thing to go as it did nothing more than trap moisture for me

[ray schrauwen]

You would want a thermally conductive epoxy that is non- conductive and won't ruin electronics.

....Again MG chemicals.

When you encapsulate, it can hold heat in, you will need good water cooling!!!

I'm using the Silicone Confoormal from MG listed earlier in this thread, it's like water and I apply it with an eye dropper.

it is also UV Indicating so if you get a Black light you can see any missed spots....

[ray schrauwen]

The guy has guts to run in submerged. I won't even do that with a $30 esc, lol... Cheapoooo

[daveives]

Putting it all together...

Thanks to the informative responses to this thread I now think that I might understand what is going on. Consider the following scenario:

You waterproof the ESC with your favorite method.
The ESC gets used, so it gets warmer.
The higher than ambient air pressure inside the sealed ESC expands the seal between the silicone wire insulation and the sealant, breaking the seal.
The ESC cools down after running.
The air pressure inside the ESC decreases below ambient (remember, some air got out when the ESC heated up.)
If there is water outside the ESC at this time, it gets wicked in aided by capillary action.
The lower air pressure inside the ESC empties the capillary flow into the interior of the ESC.
The next time you run the ESC, it smokes.

Now when can some stage of this process not happen, so the ESC is unharmed?

If you have a single board ESC there is no lower air pressure inside since there is no "inside". This is why what works for a single board ESC does not work for a multiple board ESC. If the seal gets broken the water stops at the interior end of the wick and does not hurt the ESC since it can likely evaporate before the next use. You must have an internal void to draw water through the wick and not stop by filling just the wick.

If your sealant is really strongly adhered to the silicone wire insulation coming out of your ESC, the seal never gets broken, so for multilayer ESCs you must choose the sealant with the strongest bond to the silicone wires. Thus if you can glue a silicone wire to a board with your sealant and then pull it free, the sealant is likely not good enough. The strongest sealant I have found is "Permatex Ultra Blue RTV Silicone Sensor-Safe Gasket Maker Item# 81724". Just try to pull a silicone wire glued to a board with the Ultra Blue after it has set; you are in for a surprise.

Another possibility for even more safety might be to build a box, lined inside with Teflon tape, and fill the entire ESC with Ultra Blue sealant and use a vacuum pump to remove all air from the encapsulation. A post mortem on ESCs encapsulated using heated Zpoxy finishing resin (without using a vacuum pump) shows large internal voids even though the epoxy was very easy flowing - like water in consistency.

If you use silicone conformal coating on a multi layer ESC it might work if you are meticulous about covering absolutely everything - I tried it once triple coated and it did not work for me. Even though the spray was water-thin I must have missed something (I did not know about the black light inspection.)

[sailr]

I think we might be overthinking this situation?

[ray schrauwen]

He does make some good points. Explains why the ESC in the video works fine submerged for a short period.

Try doing that after a year of bashing in an rc car, water will wick in there eventually.

The good bond is most important. That tool coating stuff is just that, a coating, not a good bond at all, specially on silicone wire.

[Steven Vaccaro]

I think we might be overthinking this situation?

Dave is a guru on water proofing esc's.

Learn from what he says. He literally runs his esc's on the outside transom of most of his boats!

[bustitup]

There is a big difference between water resistant and water proof.

Water resistant may be good enough for boats that only occasionally get a few drops of water inside an enclosure which contains an ESC.

Water proof is needed for ESCs that normally run under water, such as some of my OPC outboard tunnel hulls with the ESC mounted on the cavitation plate of the outboard engine. The ESC is underwater when the boat is not moving!

From my experience:

Epoxy DOES NOT reliably waterproof an ESC - eventually water will seep in along the flexible silicon leads.

I now use Permatex Ultra Blue RTV Silicone Sensor-Safe Gasket Maker Item# 81724. This stuff really is strong and adheres very well to plastic, wood and silicone insulation. Just try a gob over some silicone wire or silicone tubing to wood or plexiglass; you likely will not be able to pull it apart!

I tried tool-dip, then liquid tape (2 different brands), then Zap thin finishing epoxy heated, then conformal coating (3 coatings) , and combinations of these to waterproof ESC's that get submerged in normal operation. All of these waterproofing efforts failed. It takes silicone to bond correctly to the silicone wire insulation and silicone cooling tubing. Epoxy (and all the other waterproofing methods I tried before the Sensor-Safe Silicone) eventually leaks along the silicone wire insulation, killing the esc. These methods eventually fail for me after typically 8 sessions or so at the pond.

I also have had good luck so far with Permatex Sensor-Safe Blue Silicone Gasket Maker which costs under $4 at Wal-Mart for 3 ounces, but the Ultra seems stronger for just a couple of dollars more.

My thanks go to the unidentified rescuer at the 2009 NEAT Fair who told me about the Ultra Blue.

I also have had better luck with my motors which HAVE NOT been water waterproofed at all, just squirted with Corrosion Plus after running. With a motor, waterproofing leads to capturing the water from an inevitable small leak which does not dry out, causing corrosion over time.

At least this is what works best for me, and I have about a dozen blown ESCs of experience behind these recommendations.

do you have a photo of one of your esc's that has been treated or coated with this Item# 81724?

thank you sir in advance