No matter what gun you have, if it's dirty it will not spray right. Always better to spend an hour making it as clean as possible, than having it spit or otherwise fuck up when you have a full cup of material. I learned that the hard way early on. I lost a quart of reduced material since it started to cure before I got the gun clean, plus I had to wait until the material that was already down was dry. Then I had to wet sand the panel to get rid of the fuck up. An expensive, time consuming lesson that I will never forget. I always seem to learn the most from my fuck ups, when everything goes smoothly I used to mistakenly let my guard down. Now, I always assume that I missed something and become hyper observant.