Avoiding Overspray Problems Inside Small Cabinet Boxes
Small boxes such as cubbyholes present an overspray concern. Here are some tips. April 10, 2008
I'm looking for some tips on how to spray this cabinet without any overspray. The cabinet is 98"w x 32h x 16d and is divided into 12 equal cubbies. It needs to be finished on all sides. There is a quirk reveal where the face frame meets the cabinet, so if there needed to be masking off done, it is a possibility. While I have figured a number of ways to do it by masking sections off, I am interested in doing it without those additional steps. Any suggestions?
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From contributor L:
Quick spraying and lots of retarder.
From contributor D:
Airmix for sure. Low overspray to begin with and it covers fast.
From contributor P:
Spray inner surfaces prior to assembly. Then mask and spray exterior. Too late for this one, I know...
From contributor A:
Any way you could finish it some other way than spray?
From contributor J:
If you're looking for technique, I might be able to help you. But I think that experience is more important here and if you're asking how, I think you will get a lot of runs with the way I will describe.
Spraying from left to right, top to bottom, the left being furthest from the spray booth. I would start in the center back of the top left cube, spraying clockwise all the way around back to the spot you started at. Then, since your arm is connected, you need to bring your arm back, so I would move a little forward and spray the next section closest to the front, repeating until the box was done, then I would spray the front edges of the two boxes I am working on. When I start the bottom left lower box, I start on the top center in the front and work my way backwards. When I do the next two, I spray the front edges of those two, start on the center top front one and work my way back. The bottom I start in the back and work my way front again. So on and so forth.
I did a bookcase that looked exactly like this one except it had 10 across and 10 down and took me 45 minutes to spray nonstop. I remember I had to spray extremely heavy - "right-on-the-edge-of-getting-serious-runs" heavy. Plus I needed a ladder to get to the top.
From contributor B:
I had to do one very similar (4'x8'), but was subdivided into all different sized box openings. I unfortunately have a HVLP turbine siphon cup and knew I could not keep a wet edge throughout the whole process. So I did it exactly like the past poster, by spraying from the back of the individual boxes and moving forward. However, I couldn't keep the front of the face frame wet, so I sprayed the interiors and lipped onto the inside edge of the face frame. I then let that dry completely. Upon drying went back and masked from the back interior edge of the face frame to the back of the opening. I used good old blue tape and thin roll paper. It'll add about an hour to mask, but no over-spray or drips from heavy spraying. Spending the extra time to mask may be worth it if you're not as good as the pros on this site. I wasn't... So I guess give it a shot and see if you can keep a wet edge on the face frame. If not, let it dry and mask it. No shame in the latter. Mine came out real slick.
From contributor C:
What finish are you using? Is this an open unit or are there doors?
From the original questioner:
I am using Chemcraft pre-cat and spraying with a Kremlin. Unfortunately there are no doors on this one. I have added quite a bit of retarder and will do my best. I have several years in the spray booth and have done units similar, but I usually mask some part off (i.e. spray cubbies separate from exterior). Thank you for all the pointers.
From contributor E:
When using a pre-cat, use as much retarder as practical. But if it still gets some overspray, it can be remelted into the finish afterward by keeping a gun handy with a 1 to 1 mixture of high quality lacquer thinner and butyl cellosolve (retarder). After you finish spraying the piece, inspect for overspray and spray the solvent mix lightly over these areas. This should rewet the overspray and let it melt back into the finish. This works better if the finish is still a bit tacky and works better with some pre-cats than others. Basically you need to get at it before the catalyst starts to kick in for the finish to rewet nicely.
From contributor N:
I have sprayed loads of similar units. They do suck. I lay them on their back, spray the face, let that dry, tape that off. Mine were 2" wide, so a piece of low tack 2" tape worked well. Then spray the insides, lay pieces of cardboard on top as you spray to catch any overspray. I know you don't want to mess with taping, but I found this to be the best method. Or use two people to spray each side, working your way down.
From contributor M:
I trick I learned a few years back... the brown paper bag! If some overspray occurs, use a brown paper lunch sack, and rub it out. I didn't believe it when I heard it, but it works well!
From contributor Z:
2000 grit 3M wet/dry paper also works great for removing light overspray roughness without leaving any noticeable scratches.
A lot of overspray trouble is avoided by the order of your routine and adjusting the position of the piece being sprayed to take full advantage of the direction of airflow such that your overspray is not drawn back over surfaces you sprayed previously. If you map it out right, you should have only very light overspray to deal with.
You certainly have good equipment for the task, though I don't think anyone has mentioned tip size. With a Kremlin I find it really helps to have a selection of tips so you can always choose one that gives you the best result and in this case, one that lets you move fast.
I'm not sure I would agree that slowing down the flash off time of your product is always the best solution. That can lead to runs and curing problems, and as long as the product is wet, there is more likelihood of trash settling into it, as most of us are not working in situations of good dust control.
From contributor V:
I have done many of these. I always give two topcoats, so on my first coat spray, the whole thing is normal, then second coat, topcoat face frame by itself and sides if finished, let sit overnight, mask them off. Takes minor time, scuff sand boxes, topcoat them, done. If there is a tape edge, break it easy with 1000 grit - easy when totally cured overnight. I use Resistant with the Kremlin. I do two topcoats because that's what my boss prefers to give the customer.