when I first published my first video mixing paint and filling a spray gun I used some old paint that was on the Shelf and thinned it by eye in this video I will take the thinning process a bit further by showing how waterborne paint reacts to thinning I had a new cabinet to spray inside so I purchased Glidden high endurance acrylic waterborne paint like in my previous video I'll be using a gravity feed gun with a 2 millimeter needle fluid nozzle and air cap configuration viscosity is simply the thickness of the material high viscosity is thick woah viscosity is thin it's like the old saying thick as molasses or thin as water I'm going to measure the viscosity of the paint using what is called a number for Ford Cup this is the one I'm most familiar with from my previous life with spraying cars for a living the viscosity is simply measured by filling the cup with paint and timing how long it takes the cup to empty I attempted to find a recommended viscosity for gravity feet guns and it seems to be information the manufacturers are stingy with or just don't think anyone like me would actually care about well I came up with a number of around 20 to 30 seconds in a number for Ford Cup is best to atomize paint and I'll show you just what that looks like it's a general rule that paint dries properly at 56 percent relative humidity and 72 degrees Fahrenheit well good luck waiting for that day so temperature matters make sure your pain is at least at room temperature and waterborne paint dries best when there is a lot of air movement don't be afraid to set up some fans to blow across your sprayed surfaces extenders are not thinners what they do is slow down the evaporation of solvents to allow the paint to flow to a smooth finish on a hot humid day it will certainly aid in eliminating orange peel and blushing in your final coat caution be very careful when spraying vertical services extenders will increase your possibility of getting runs in the paint to use the Ford Cup you need a stopwatch or a watch with the second hand the stopwatch is best to take a measurement fill the cup with the liquid and start the watch as soon as it is lifted out as soon as the paint starts to drip from the cup stop the watch it takes water just 6.5 seconds as I am about to demonstrate paint straight out of the can is an entirely different thing I measured the paint two times just to make sure I had a good measurement the paint was so thick like molasses it was hard to tell when the cup had emptied it took six minutes five seconds since I now own the Ford Cup I'll probably measure other brands of paint as I buy them just to see which manufacturers put the most material in the can note that I have a small pail of water set aside to immediately clean the cup water could change the chemistry of the paint in my research I didn't find anywhere where someone said water does change the chemistry but I'm still dubious about adding too much when spraying furniture it may be best to use acrylic enamel which can be substantially reduced without harming the materials properties a word of caution acrylic enamel is solvent based and should not be sprayed in a confined area where a spark could ignite it adding just 10% water could have the same effect as adding 25% thinner to a can of lacquer I measured 500 milliliter into a beaker and added 50 milliliter of water yes I'm using metric measurement simply because it's easier to use after thoroughly stirring I took the measurement two times and came up with a viscosity of two minutes nine seconds note that just 10% water made to paint 55% more viscose this mixture did not go through my gun very well so I went back to the bench and with a fresh uncut 500 milliliters of paint added 25% or 125 milliliter of water actually I made a mistake and went a little bit over my measurement is now 40 seconds and it does spray yes it is a far cry from the 6.5 seconds we measured for the water in conclusion if you are spraying a vertical surface make sure you spray a tack coat first and allow it to dry before applying your first full leg coat at 40 seconds I had to narrow the fan just a bit and remember I am using a gun with a 2 millimeter needle fluid and air cap combination you may have noticed that I hum not only a regulator but also a moisture filter on the end of my air hose in my opinion it makes the gun way too heavy I'll address the issue in another video there are currently four guns listed on my Amazon store with two millimeter tips that cost less than $50 so go check it out at Budman productions.com and if you care to do some of your own experimenting i've added a number for Ford Cup if you have any questions or comments about this video please post them and I'll certainly respond to you you make it a great day and thanks for watching