Choosing spray-on finishes

[ironhat]

I've only played with spray finishing and none of it on a finished project because I never seem to be able to get the gun set right. I bought the HF HVLP (powered by a compressor- not the fan supplied model) but haven't done anything with that one yet. I've been reading about catalyzed laquer finishes and now understand the differences between pre and post cats and wondered if using the post - mixing it in the shop as opposed to at the distributor - is viable. Having it pre-mixed gives you only 120 days of shelf time which isn't long enough for my frequency and quantity of use. The finish I saw on some cabinet doors was just amazing and I wondered if any of you have been doing this (in house mixing, that is). BTW, you don't count, cabinetman. You use in one project what I would use in a year or longer.

[cabinetman]

I've always used pre-cat lacquer. I'm talking about the stuff that you don't add catalyst. Depending on the brand I get more than 120 days of life out of a can. That goes for nitrocellulose or acrylic (acetone based/lacquer thinner). If you buy post-cat (the kind you hafta add catalyst before using), you could mix only what you think you need, and possibly run out.

The only additives I add to my lacquer are retarder and lacquer thinner.

The HVLP guns that you run off of a compressor may require low air pressure, so you may need an on-the-gun regulator (one of those little ones) that will register low pressure. It will vary for different brands
.
I've switched to waterbased polyurethane lately because of health reasons, and didn't like dealing with the weather. I've got to say that I get as good a finish with WB as lacquer. And I'm not using one of those newfangled guns, but a Binks 7.

[ironhat]

Maybe the answer to this question is universally known except to me so here goes. Are all waterbased polyurethanes polyacrylics like the Minwax product? Minwax is the only one I'm familiar with. BTW, any reason the HVLP unit that I mentioned can't be used with the H2O based products? It's the only reliable gun I have going.

[wardprobst]

I think your gun will spray water base material but you'll probably need to clean it very well. Guns specifically designed for water base tend to use stainless steel for the "wetted' parts to reduce corrosion.
DP

[Thom2]

Chiz,

Here's a good informational write-up on lacquer that I keep bookmarked.

http://www.woodcentral.com/russ/finish11.shtml

I haven't done any lacquer with my HVLP yet, but when I do I plan on using automotive lacquer.
Two reasons for this
1.) the different temp thinners are much easier to get and give you more control when dealing with temperature. 2.) I just grew up around body work, work for a parts house and have been trained on automotive finishes and sold paint products for several years. (not that I remember any of it, but it's easier to remember than to relearn)

Hope you find some good info in that article, I feel it's a very good, very brief and to the point write-up with excellent info.

I'll also offer you a tip on getting used to the gun. If you're going to go straight to a clear product out of the gate, do not expect your best finish right away. Clear products on light wood make it extremely hard to see the coat.
To get a feel for the gun, I advise either contrasting paints for basecoat/topcoat or blow water thru it onto a big sheet of brown cardboard. Either of these will give you a general feel for what the gun is doing under different patterns and pressures.

[ironhat]

Good thinking on the water based precautions, Dale. I also have bookmarked that site, Thom. That pretty much covers every aspect of laquer. I'll be spending some time reading through his 'Corner' as well. I also just order Taunton's Complete Guide to Finishing today.

[Pappy]

I use a precat laquer on most projects. I buy a gal. and split it into qt cans to extend the shelf life.

[JimD]

Why not use a water based pre-cat? I really like Resisthane which I get from Hood finishing products for about $25/gallon plus shipping. I find it very easy to spray and I like the fact I clean up with water. I just rinse the cup in my laundry tub then spray water through the gun 2 or 3 times and put it away. I would be too cheap to use an equivalent amount of lacquer thinner.

Resisthane dries enough to sand in an hour. It is rated for kitchen cabinets so it is pretty tough. I have had good luck with both the gloss clear and am currently about done with a gallon of white. The clear needs no sanding sealer, they recommend a primer under the white.

I use a Wagner conversion gun - HVLP on a compressor. I've sprayed Minwax's water based poly with it but it was not nearly as easy as Resisthane.

Jim