Water proof feature and repair
Is there a way to keep the iphone 7 water proof after repair? im also asking the same question for galaxy s7.
Technically its not water proof. No such electronic is water proof.....more it's water resistant. Anytime you open the phone you're lessening it's water resistant seal.
How far down the rabbit hole would you like to go?
The iPhone is "waterproofed" with half black tape, half plumber's tape. Its not hard to get a seal that is about the same as what Apple put on it stock. For Samsung, its basically black tape all the way around the front and back. I prefer using the precut adhesive for the S7, so its technically OEM waterproofing.
But I have no way to check to see if it really is waterproof. I can't advertise that it still is and I can't drop a phone in a bowl of water for hours. If I wanted to advertise as waterproof, I would have to buy the $15k nano coating machine and spray every phone. That would be waterproof but is it worth the money?
Instead, I try to make the phone as close to OEM as possible but tell people that its not waterproof. That way its more than likely pretty watertight, the customer will try to not get it wet and won't come back to me upset if it does get wet and dies.
Buy new adhesive, clean the old one completely and apply new one carefully every time you open it. Do not even consider reusing old adhesive. If any external parts are replaced, check all openings (for example speaker holes) on them to make sure they are as good as the original parts.
In this way you should be able to make it still properly sealed after repair. I have no idea on how to test it for sure though. Sony has special equipment and procedure to test their waterproof gadgets after repair. Generally there is an inspection port, you remove the sticker on that port, use a hand vacuum pump to suck air out and see if the air pressure leaks back into it. iPhone 7 has a baro vent so this method does not work.