Do not use any knock offs a these will cost you more money and lots of headaches in the long run. You get what you pay for and when it comes to airbrush art you need to go with names that you can trust. A lot of knock offs also will give for a harder time finding replacement parts when they tear up. Knock offs will tear up quicker than the name brands. A person with dry skin will get more than 7 days usually from the tattoo. It does not matter though if they have dry or oily skin you should apply talc powder as soon as the airbrush art tattoo dries. Airbrush tattoos do cost money and customers are not going to spend that money if their tattoo does not last for at least close to what is expected. If you are doing a mural on a wood floor then use a hand floor sander. You don't want to mar the wood only remove any rough areas. If the wood has been waxed or has a gloss coat then sanding this will remove this and allow for the paint to stick to the surface. Skin should be cleaned with rubbing alcohol to remove any oils from the skin. Airbrush art is one way to take something and turn it into a master piece. Over hand painted art, airbrush art can be done in less time but with the same great effects if not better. There is more that you can do with airbrushing that you can not do with hand painting. You can take airbrushing and create a beautiful mural on a concrete wall to turn that once bland wall into a work of art worthy of some attention. The point at which they come together is in the head assembly. The external mix is where the air and paint come together outside of the head assembly or the fluid assembly. These airbrushes create a large dot pattern. Larger airbrushed areas are better done with the external mix. Since with the larger dot pattern you are able to spray more areas in less time. Also the time frames are shortened when the paintings are airbrushed versus hand painted. Family portraits can be airbrushed over hand painted as well to give for a more realistic painting. The interior of your home is also a place for airbrush art. You can go with a nice mural on your wall to give a room in your home an artsy feeling.