Has anyone had success painting an engine bay with a Preval sprayer or a cheap harbor freight touch up gun with a disposable filter attached to the bottom of the gun? I'm just trying to clean all the gunk off, spot prime the bare spots, and scuff the rest. Taping off pieces I can't readily remove but the engine is out. Will use automotive paint. Obviously not looking for concours result just presentable. I don't own a compressor and would probably have to rent one. Open to suggestions. Thanks.