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Peter_B

Waterproofing

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I spent some of Sunday trying to race my Boomerang on the very wet track at this years Iconic Revival. With all of the water having possibly killed some of the electrics I thought I'd start a topic  to find out what people do to try and waterproof things.

I'm asking from the "racing the Boomerang" point of view, but it would apply to other models and

There are some obvious answers such as fitting waterproof electrics to start with and putting receivers into balloons etc Those kind of things require a bit of foresight and planning (both of which I was severely lacking :))

One thing that occurred to me on the way to the Revivial was the balance plugs on my Core RC stick lipos - I was fairly sure I didn't want them getting wet, but I didn't know what to do about it. I ended up wrapping them with some electrical tape.

Also with the motor being exposed and having vent holes and an exposed sensor cable/port, what's the best way to keep that clear of water?

So what are your top tips for waterproofing?

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I used Blutac on my receiver.  A thick blob where the plugs go in, and a slim line around where the plastic joins.  I wouldn't expect it to survive being properly submerged for more than a few seconds but has done a good job of keeping racing splashes out.

Servos are a big harder because it's not easy to seal.  Having said that, I have completely submerged cars before and never had a servo fail due to water ingress.  I tend to use mid-price servos (< £20) but I've also submerged some basic ones.

On Sunday I swapped out my HobbyKing brushless ESC for an ETronix Probe WP in my Top Force because I couldn't face destroying a brushless ESC in the wet, and the Probe is waterproof.  I ran a brushed Super Stock BZ - brushed motors don't care much about getting wet as long as you oil the bearings after use - but although it was fine in my Fox, it was really underpowered in the Top Force.  In the end I took an old 9T sensorless brushless system out of my Truck of Many Wheels (which was disappointing as I wanted to run it in the monster truck race) because the motor itself was a sealed type and the ESC didn't have much exposed electrics.

I'm not entirely familiar with the Boomerang chassis, but the Hotshot has a sealed tub.  As long as you don't drive underwater, it should keep the worst out.  The Fox has a sealed tub too and didn't really get any moisture inside on Saturday.  That said I should probably open it up just to be sure!

I've never worried about water getting over the balance leads.  I'm no electrical engineer but I don't think there's sufficient voltage to make a circuit across that much distance.  I think the issue with water ingress is more related to PCBs where it can short between pins and damage semiconductors.  It can also cause PCBs to corrode and stop working.  Also water can get into switches and connections and instead of shorting due to being a conductor, it can leave deposits that become insulators.  At last year's G6 Recon I ran my SCX10 underwater (with a Blu-tac'd ORX receiver) and it stopped working.  I thought I had killed the receiver, but it turned out some water had got into a choc-block that I had used to distribute power to various components.  A quick wiggle of the wires and it came back to life.

The only electrical component that has been rendered dead due to water is an old Nosram Evil brushless ESC that had no external components, but got submerged while drifting in the rain at WLRC.  It actually ran fine after being submerged but wouldn't work a week later - I expect moisture in the case corroded the PCB.

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Additional - a friend recently mentioned to me a new product on the market.  I don't know what it's called, but apparently it's a putty-like gel that can be moulded around wires and electrics and then dries into a squidgy rubber.  Which is fine until you have a Sunday like I did and you end up changing ESC and steering servo multiple times and have to keep pulling off and re-applying your Blu-tac.  I wouldn't like to do that with a single-use product.

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7 hours ago, Mad Ax said:

Additional - a friend recently mentioned to me a new product on the market.  I don't know what it's called, but apparently it's a putty-like gel that can be moulded around wires and electrics and then dries into a squidgy rubber.  Which is fine until you have a Sunday like I did and you end up changing ESC and steering servo multiple times and have to keep pulling off and re-applying your Blu-tac.  I wouldn't like to do that with a single-use product.

I think you mean https://sugru.com/

I’ve heard of a spray you can use to waterproof electronics, not sure what it’s called yet. Involves taking the plastic case off the receivers, dipping/spraying with this stuff. 

Conformal, plasdip, drydrone seem to come up in searches. Never used any of them, I’ve just done the balloon/tape thing.

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10 hours ago, jupitertwo said:

I think you mean https://sugru.com/

Ooh, maybe that's the stuff?  Anyway I'm glad you mentioned that because someone totally different recommended it to cover the sticky grips on my ageing Nikon D70S bodies.

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https://www.ebay.de/p/Graupner-Wet-protect-50ml-Feuchtigkeitsschutz-968-50/2255560184?iid=201314546303&chn=ps&norover=1&mkevt=1&mkrid=707-134425-41852-0&mkcid=2&itemid=201314546303&targetid=516711886960&device=c&mktype=pla&googleloc=9042762&poi=&campaignid=1794477010&mkgroupid=68164081406&rlsatarget=aud-495842438326:pla-516711886960&abcId=1139186&merchantid=7765452&gclid=Cj0KCQjwhdTqBRDNARIsABsOl98rC8uOwlLJzRFshaRs5cKOwxJbD9BJmlhDt49XT2T7Qes59yaAKn4aAj6FEALw_wcB

I guess the spray mentioned is called "wet protect". Really useful for a quick rain run. Friend of mine drove his touring car with sensored brushless esc in a wet race, only spraying the electronics with it. No worries, everything was fine the whole day. Really impressive. But you have to renew it from time to time, and it leaves a film on the parts. It´s even possible to spray an already soaked electronic board, and it will repell the water, getting the ellectronic to work again. (If it didn´t die completely by short circuits).

In my M-Chassis, which sees regularly wet races, I use waterprrof receivers and ESC´s. (Sanwa/Carson). 

 

 

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Fresh water generally does not bother sensorless motors or batteries as it not very conductive and batteries and motors normally deal with huge currents. They will not care that a few milliamps of current is flowing through some water when there are normally tens or hundreds of amps flowing through the main circuit.
What will be a show stopper is if water gets into the low current circuits of the receiver, ESC, hall effect sensors on a sensored motor, or steering servo. When that happens you may find your car turning or accelerating out of control, or if the sensor system is effected the ESC could apply the wrong sequence to the motor causing the magic smoke to be released from motor, esc and/or battery.

The problem with the sprays is that you can't always get it into the parts that matter. Better off fully dismantling the parts and applying epoxy resin to fully encapsulate the electronics. You'd probably also want to put dielectric grease into the sensor connectors in a sensored system.

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Ive just fried a 1060 waterproof ESC just by running my dynamog through a shallow puddle to claen the mud off the wheels!!!! Some watere splashed up onto the ESC and sttled in thd well that all the wires came out of, soon to be followed by white smoke. I quickly disconnected the battery and carried eveything home:angry: I dried it out in a warm oven then dismantled it. It seemed all ok so I put it back together and sealed it with shoegoo. Plugged it in and all I got was forwards, no reverse or brakes, also within 20 seconts I could not touch the heatsink it was so hot. Its in the bin. My question that I was going to ask is can I put an ESC inside a bladder like a receiver or would heat br an issue. Im using a Tamiya tble-02 but only in the dry. If not a bladder what about a receiver box. Im not trying to submerge it just sensible wet conditions

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You could put the ESC in a bladder but that would cause heat issues as it would prevent air getting to the heatsink.

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Here's a recent vid about using an acrylic conformal coating on the internal board in a receiver. Worried to hear that the 1060 esc isn't as waterproof as claimed though.

 

 

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6 minutes ago, deangaffney said:

Worried to hear that the 1060 esc isn't as waterproof as claimed though.

Not sure it was a Kosher one???

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10 minutes ago, Busdriver said:

Not sure it was a Kosher one???

Ah yes, inspecting ebay closely I have deduced that if it's for sale at less than £15 it's not a proper one.

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