If you were in a store that sells air conditioning supplies, probably not.
Otherwise, you're probably OK, but it still best to see what the manual recommends.

The separator needs to be hung vertically on a wall or some other immovable object. It doesn't have to be close to the paint spray gun in order to work.

As for the oil for your compressor, what exactly is your concern? If you saw a product that says it is formulated for air compressors, it should be just fine.

Compressor oil is non detergent. Detergent oil is not necessary in a compressor, will foam in the pump, and raise heck in paint. Ideally, you want oil free air, especially for painting, but no separator is perfect.

These oil/water separators work well don't they. Perhaps I could install a oil/water separator at the air compressor connection and then install a Disposable In-Line Filters for water that condenses in the pipes. Will this be effective. Thanks

If you have "dry" air going into the pipes, what is going to condense in them?

Something about the hose being cooler than the tank or something. I think the tank, because of the engine sitting on top of it, will be warmer than the hoses so when the air enters the hose you can get condensation in the hose.

Well, that is what I read someplace anyhow. Thanks

The advice you receive here is only as good as the information you provide.

You seem overly concerned about the quality of air coming from your hose. Why? What are you doing that needs this level of air quality?

You have probably already done this but it is a good idea to drain the compressor air tank too.

I did not know that mine had a drain valve until recently. Used it for 30 years without draining. My drain plug is under the tank and not visible without getting down there and looking underneath. Mine had about a half cup of water in there.

I also put a water separator in the line many years ago and it does trap a little water.

spraying oil-based paint. Nothing worse than getting water a finish. I believe. Thanks

Water in compressed air happens when humidity levels are high. For the purposes you outline, getting moisture out of the air is not rocket science. Drain your compressor before starting to spray paint and buy a decent water/oil/contaminent seperator made by a well-known manufacturer that specializes in compressed air.

Go to any local body shop and ask them what they are using. If it works for them, it will work for you.

Here some things we have learned about water and compressors from years in the compressor sales and service business.
Depending on the temp and humidity a compressor can make a gallon of water per horsepower per day.

Water traps collect only condensed moisture. This is important because when a compressor is under sized and runs all the time most of the water will stay in vapor form and condense in the lines or the end usage spot. So two traps (one at the tank andone at the point of use) will get a lot of folks by.

You can get air as dry as you are willing to pay for. A compressor with an aftercooler can use a basic refrig dryer. A compressor without and aftercooler needs a hi temp or 3 in 1 dryer to be effective. An aftercooler can get about 50% of the water out and cools it so it is easier to condense and trap.

Draining the tank is good to do for the life of the tank but unless you fill the tank up that water does not end up down the line.

That is unfortunate the oil/water separators will not get out condensed moisture but only water traps will. The aftercooler etc thing is to expensive for me.

Know of any good water traps online for a good price that I can purchase?

Also if I do go with a water trap are the oil/water separators necessary. Thanks

An oil water seperator is a water trap. Oil and water seperators will only remove condensed water not water vapor. No trap removes vapor.
There are good water traps and there are cheap water traps.
Cheap traps have a glass or poly bowl and only handle up to 150 PSI. Good traps are metal bowls and handle 250 PSI.

I get it know. Never heard the term water trap used for water/oil separator before. Thanks for your help.

You can make a pretty decent air dryer for spraying out of a garbage can, copper tubing, fittings, and tap water.

You put a coil of copper tubing in a garbage can full of water, with a flow of cold water into the can to keep it cold. Put a drip leg on the bottom of the coil, poked out the side with a bit of a container and drain. Run your air through the copper and it will come out at a dewpoint very near your cold water temp (usually low 50's around here). If you need it colder, you can put ice in the water and get to under 40 degree dewpoint air, which will spray very well with even the toughest to use paints.

I have used several of these setups that friends have built, and the work really well.

If you are totally paranoid on moisture, you can also add a desicant filter just before the gun.

Coalescing fiters are the best oil traps. Thye have a paper filter that absorbs the oil mist. Desiccant filters work real well but be careful. Add a trap after the desiccant. The desiccant can get propelled down line and reek havoc with paint guns bu they are very effective until saturated.
There are also coalescing filter that screw right on to a paint gun. They will trap any residual oil and the last condensed water at the tool. Usually a good one is about 14.95.