I have just completed a very large maple bookcase which is 9 feet tall and 9 feet wide, consisting of 6 sections, being 3 upper bookcases which are 3 feet by 6 feet and 3 lower cabinets with 2 raised panel doors in each. I am now at the finishing stage and have never used spray equipment before. I am nervous about using such a large piece as my first experience, but I also know that hand finishing this piece will take many hours. I plan on staining and using polyurethane as the finish. I have a compressor and want advice on 1. Whether I should forget about using this piece as my first venture into spraying, 2. Whether I should buy an HVLP sprayer or somehow convert my compressor into an HVLP system and what I would need to do that. I have done some research and am a little confused on what is needed in order to use my compressor in an HVLP system. Also, I don’t know how much experience is usually needed to become adept enough to tackle a big job like this. Thanks for your help.
Cutnup
Replies
That's a big piece to screw up. Spraying isn't inherently difficult, but it does require some practice. I finish everything with a LVLP gun from Iwata with 30 gal. compressor.
I suggest you try on some scrap and see if the results are going to be good enough.
I use a hvlp gun with a pressure pot. I a;ways spray a cat lacquer. It take a bit of getting used to but you will be happy with the results once you get a few behind you.
Mark Rhodes
Vinworx.com
I suggest Spray Finishing by Andy Charron (Tauton Press) as basic reading.
Past that, my first suggestion is to give up the idea of using an oil based polyurethane for your top coat. Waterborne finishes designed specifically for spraying are likely to be your best choice. They come at about the right viscosity for spraying, and dry fast enough that overspray is less of a problem. (With oil based varnish, overspray become a sticky mess over everything.) Solvent based finishes such as lacquer require a booth or suitable outdoor places coupled with the serious cooperation of mother nature. In any event assure your self that the top cote is compatible with the stain that you choose.
You will want to practice first with water, and then with your finish. How long is hard to say.
. Whether you use your compressor as the base for a spray system depends somewhat on it's capacities. If you are talking about a portable pancake compressor that would be very limiting, but with a larger compressor using a HVLP conversion gun makes a lot of sense. Besides the gun, you need presure regulators and filters, and a place to spray that lets you move air past the item being sprayed to tame the overspray, and which keeps overspray off of places it shouldn't be. They don't need to be fancy with waterbornes. With solvent based finishes such as lacquer, or shellac, you need to be concerned about the flammabiliyt of the finishes being sprayed and the problems escalate.
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