I just purchased an astro EuroPro EUROHVT1 after i purchased a warwick mini hvlp. The issue i am having is both of these guns DO NOT come with an internal filter between the cup and body (but warwick shoots nice!). I have not had this experience with Sharpe, or other cheaper guns that I have been using. It is a very good idea since it is one more defense against junk in the paint. Is this common to not have a internal filter?? Is there a way to rig one up? The channel is too small to use one of another gun.