I’ve searched and read everything I can find about this topic, but haven’t found the answers I’m looking for, mostly due to the serious/production-based comments.
90% of the work I’m doing is with water-based finishes, and 100% is sprayed in my garage/shop. The only use for oil I have right now is priming MDF where I can’t get away with real wood. So, I’m looking for a system that can spray latex and WB poly (ie: diamond coat), and will give me options down the road for finer finishing products (likely still WB). Going to oil based for finish coats isn’t an option without proper ventilation, so I’m not even contemplating it at the moment.
Here’s what I’m considering thus far, and the pro/con hightlights (for what I’m doing):
1. Bigger compressor and stick with the conversion HVLP guns. Pros include affordable multiple gun setups for different finishes and cost is reasonable for a half-decent 110V oil lube unit. Downside is that a proper system can’t really be had on 110V and that’s what I’ve got.
2. HVLP turbine systems. Entry level units seem to be geared at thinner finishes, and will likely need a steady supply of Floetrol or similar to make latex spray. Cost for a better system seems to be north of $1k, which is above what I’m looking to invest for hobby work.
3. Airless or AAA pumps. Geared at high volumes and work well for thicker finishes. Not sure how well they’ll dial down to the small quantities or thinner finishes I’d be looking to spray. Cost seems to be a plus on the airless, not sure yet about the AAA systems. Overspray – have no idea what to expect from such a unit.
Any thoughts? Most of the work I’m spraying is cabinetry, shelving and some smaller furniture, and tends to be opaque finishes (hence the latex).
Replies
Given that you're not a production shop, I don't think you'd have a problem finding a suitable 110v compressor. Something like a 60-gal, 8CFM@90 psi unit should be plenty.
The key is to use guns that don't require high CFMs - with a compressor rated at 8 CFM, you could go up to a 10 CFM gun. Wood finishing doesn't require a 100% duty cycle - you generally spray small pieces or panels one at a time, with pauses in between. You could even use higher CFM guns (say, up to 13 CFM) with a decent-sized tank, you'd just have to wait for the compressor now and then. My suggestion would be a gravity gun that has a good selection of tips, and to use the 3M H/O PPS system (PPS with pressure) for spraying the higher viscosity finishes (i.e. latex). I spray latex through two different LCFM guns, using 1.3 or 1/4 needle/nozzle sets and the H/O PPS. Thin the latex 10% with water and add 5% Floetrol, and the latex lays out like glass with both guns.
The guns spray other finishes (everything from thin shellac to acrylic primer) very well, just need to select the correct n/n set and feed system (pressure / non-pressure) depending on a finish's viscosity.
No one system is best for all finishes. The "latex" wall paint designed walls isn't suitable. These tend to "block", where objects stick to the surface even after it has cured for months and since they are formulated for brushing or rolling have a high viscosity. To spray calls for the air assisted airless spraying--and that's expensive..The 100% acyrlic enamels (such as Pro Classic) which would perform OK and be relatively tough and free from blocking, but are still formulated with high viscosity for brushing.
But, there are a number of waterborne acyrlic finishes, both clear and opaque that are designed specifically for spraying with both lower viscosity and faster drying times. HVLP conversion guns are the way to go here. I'd be seeking out a line of these. Your Sherwin Williams pro or industrial oriented dealer will have products that fit as will MC Campbell distributors. In addition there are on line sources for Target and Enduro finishes that would fit into this category, again both clear and opaque. I think this is the way to go instead of starting off with the DIY oriented products and then trying to later shift to professional oriented materials.
By the way, getting 220 isn't usually a big challenge. If you have a dedicated 110 circuit--ie. only one outlet box--it can be easily converted to 220 by changing the breaker in the box to a pair of 220 breakers. These are often available in half size breakers so the two breakers can fit the space of one 110 breaker. (The amperage capacity will, in general be the same as the amperage of the 110 circuit and is based on the wire size--14 gauge wire is limited to 15 amp circuits and 20 amp requires 12 gauge wires.) If you aren't comfortable working in the box, this is an easy task for an electrician and not all that expensive if no new wires have to be run. Still, as was mentioned a 110 compressor will do the job--just go for a large tank and an effecient gun.
Jeff Jewitt at http://www.homesteadfinishingproducts.com has a good selection and in particular good information about HVLP guns. Look at the finishing products he carries as well. I've used custom pigmented finish from him in the past.
latex curing solution
Just a comment on the curing/sticking issue with latex paints that are formulated for walls. In some cases, these paints are all one needs, and about as safe as they come for spraying in a home shop. I've finished built-in work with a finish coat (3-4 coats typically) of WB poly (diamond coat), and the finished product has an even finish, is completely cured, and probably 100x harder than the latex paint would be. Sticking/curing issue solved.
Thanks for the input on the conversion guns - I've like them so far. FYI, the best 110V option I've found is about 7 CFM at 40 PSI, which is an improvement from what I hobbled through the last project, but seems a bit low. Anything higher is 220V or 20A. I've looked at the wiring for this application, and it's a non-starter. A new panel is in the plans, but there's much to do to make any electrical upgrades happen (and no split plugs).
Sure you can solve the problem--but with an additional 3-4 coats of finish.
But the other issue is that to gear up to spray heavy bodied latex calls for quite a bit different equipment than to spray professional level finishes. To do both well requires two nearly separate set-ups--air assisted airless for the heavy bodied and HVLP for the less viscous materials.. Not much safety difference between the wall paint and the professional acyrlics except where some of the higher end finishes add cross-llinker compounds that are more toxic. Still not flammable though. And in either case you need personal protection since the solvent in these acyrlic paints are basically a form of ethylene glycol that you don't want to be breathing freely anyway.
HVLP with latex paint
A few months back, I helped my neighbor build some utility shelves in a closet. His wife wanted white shelves, so we used conventional latex enamel from Lowes, sprayed with my Earlex HVLP after thinning to the sprayer's specs. It applied nicely, and dried as indicated in the paint's instructions. No reports of sticking from the wife. Did I do something wrong?
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