I used the Model Master Flat Clear coat on my KV-II tank taht I’m working on now. It looked great, until I wanted to weather my model. When I used the Water color/vinegar/water/soap method which I love to use, it just beaded right off the model, instead of adhearing to the model.
Anyways, I’m not happy with that…any other thoughts on that? or suggestions?
That doesn’t sound good. Thanks for the warning.
Sounds like you may have just had too much soap mixed in. Try it with a little less and see how it works.
It doesn’t sound like it caused any damage so model on Andy !!!
An acrylic wash might work. Acrylics have very good adhesion. Just more difficult to remove if you make a mistake.
I had the exact same issue before! I read about using the same technique and just couldn’t get it to work for me at all. Very disappointed… 
I tried with less soap and didn’t get any better luck. I finally took the model in the house and ran it under the faucet, let it mostly dry and tried again with better results.
I always use enamels for my washes now btw. I generally use water-based acrylics for the main color and dry-brushing so I use enamels for the wash so that I don’t have any issues about the paint coming off.
If you seal w/flat coat - you should use an oil based wash - enamel paint mixed w/thinner.
I use oil base washes because they give you a little more time and it will bond to the sealer
or
use acrylic wash w/rubbing alcohol as thinner - not water - be careful that may also eat through the sealer if worked too much
Good luck