Q.
I'm just starting to research purchasing a spray gun to use for applying polyurethane. I've checked out the Apollo line of converted HVLP sprayers (I have a compressor), but haven't used a spray gun for this before, so any advice would be helpful.
2. Investigate the never-ending contibutions to the newsgroups on this subject by using the database archived at www.deja.com. Use the word "HVLP" as your search word.
3. Get a smattering of current opinions from the newsgroup at rec.woodworking, but keep in mind that people base their opinions on what they currently own, regardless of your needs and pocketbook.
4. Spend as much as you can on a decent system, and get at least a three-stage turbine.
5. If you can, think very carefully about whether you want a gun that continuously streams air (a bleeder) or one that only streams air when the trigger is depressed (a non-bleeder).
6. Weigh the cost of getting a decent turbine rig vs. that of a conversion gun, air line, filter/regulator and compressor powerful enough to drive that gun.
8. Be more specific in what, where, and how often you will be spraying. Do you have an area set up for spraying that is workable as well as safe?
9. Systems that work for career finishers may not be what you need. That is the advantage of the newsgroup; there are many fellow hobbyists there with whom you may have much more in common in terms of frequency of work, working conditions, materials, and projects.
I'd like to be of more help, but my advice about what you should get is just not relevant to you and your situation. If you do the legwork I have detailed above, you will be much better served than if I tell you what I do and how I do it. Besides, I do not spray polyurethane and I never have. I spray lacquer and catalyzed coatings (conversion varnish, catalyzed lacquer, etc.).
The best advice I can give you is to beware of people advising you who think that they know it all. They only know what works for them. That is why getting a consensus is a much wiser approach, and it will let you make an informed purchasing decision.
I just recently used polyurethane on a job to match an existing finish, and used my siphon-feed gun. I did have to crank up the air pressure, and had a lot of wasted material in overspray, but I recommend this over thinning material to use in an HVLP system.
If you have access to an airless system this would probably work best; just remember to clean the lines thoroughly. Polyurethane is very messy.
