Waterproofing HC-SR04 Ultrasonic

I'm looking for a way to weather-proof the HC-SR04 ultrasonic range finder. There are probably times where it might end up underwater, but generally I just want it to handle splashes of water and some dirt, and not completely screw up because of those.

I bought some 40KHz waterproof transducers, but unfortunately I can't figure out how to de-solder the old transducers. The solder goes in too deep for the wick to pick it up.

I like the price point and operation of these units, so I was wondering if anyone knows of a variation of this board that either doesn't come with transducers, or, comes with waterproof ones.

On another note, I know that part of the challenge in terms of designing these sensors is amplifying the voltage and interpreting the signal. Based on the fundamentals of how US works, it doesn't seem that difficult. I get the impression that what makes the schematics so complex is the fact that it has to amplify 5v to 12v while still giving 8 pulses of a clean 40KHz square wave, and then the circuitry to read the signal and transmit it to the arduino in a way that's easy to use.
I have a 12v power source, some transistors, H-bridges, and op-amps to my disposal. Assuming I get the arduino to do most of the work (including creating a 40KHz square wave and interpreting the signal), does anybody know of a basic design I could use?

To desolder stuff like the transducers, heat up the pins, putting new leaded solder in the joint, move the soldering iron from one pin to the other in a succession until both joints are molten, and pull out the transducer.

Also, have a look here http://uglyduck.ath.cx/ep/archive/2014/01/Making_a_better_HC_SR04_Echo_Locator.html

// Per.

I'm going to see if someone with more skill than me can try the de-soldering. If you haven't figured it out, I'm kind of a noob when it comes to electronics, so I don't feel too confident in being able to follow that link you provided. Thanks for pointing it out though.

This is an old post that didn't get much discussion or any real answers but schmidtbag is asking the same question what I would like answered which is:

schmidtbag:
I'm looking for a way to weather-proof the HC-SR04 ultrasonic range finder.

I'm also wondering if anyone here has used these sensors for back up sensors and if anyone thinks they can be waterproofed or should I be looking at another one that would be better suited for a back up sensor? I'm sure others have searched for this and might have found this post only to find it to be a dead end (this site seems to have a lot of dead ends), so rather than starting another post that might or could probably end as another dead end I thought I'd revive this post and hopefully someone can answer this.

Thanks in advance
jessey