Model Railroading > Weathering question

I use weathering chalks to age my small fleet of motive power. Has anyone ever found a product that you can spray on a model and not lose the weathering effect? I has always used dulcoat or something very similar and after adding a coat to the weathered moderls, it fads or completly makes the chalks dissapear. I have just recently gotten back into the hobby and don't know what all (product wise) is out there. I'm just tyring to find something that will SEAL the chalk weathering without fading it.

Check this out,

https://www.trainorders.com/discussion/read.php?3,5069479