Found two of them digging my old stuff storage.
Do anyone still use these for guitar finishing in the era of HVLP and turbines?
Can you recommend a compressor specs for these guns? Nitro finishes, sealers.
My little Badger 400 has been a great gun for touch up or smaller spray jobs like a neck. You can get by with about any modest compressor, the gun doesn't use much air volume, you don't need a large compressor.. I generally use a regulated pressure of between 15 - 25 lbs., depending mostly on the viscosity of whatever I'm spraying. You should have a moisture and oil trap/filter to deal with air quality for finish work. I have been using Behlen products but there are other choices out there.
I don't use it for instrument work but I use a 400 extensively for finishing scale models. It should work fine as Paul says. As far as compressors, I have an oil-less model from Harbor Freight with a 3 gallon tank that cost me less than $50 (look for a sale!) and is great. It has a good gauge and regulator and having the tank eliminates any pulsing. It's also less than 1/3 the cost of a dedicated airbrush compressor which will pulse a bit if it doesn't have a tank. A moisture trap is essential, even in a dry climate like Arizona.
A larger than minimal compressor will allow use of an air eraser, too if you need that capability.