The gun runs for a sixth of the cycle
Run the defaults and the booth is occupied for three and a half hours, of which thirty two minutes is spraying. Everything else is masking, waiting for a coat to flash, waiting for heat, waiting for the panel to be cool enough to touch, and getting the next vehicle in. That ratio is not a sign of a badly run shop. It is what refinishing is: a sequence of short applications separated by periods where the only correct action is to leave it alone.
Understanding that changes what you do about throughput. The instinct when a booth is the bottleneck is to want another booth, and another booth is the most expensive answer available. The cheaper ones come out of the same arithmetic. Move masking and unmasking into a prep bay and an hour comes off the booth cycle without touching the paint process at all. Reduce the turnaround by having the next vehicle staged and ready. Neither of those touches a flash time, which is the part you cannot negotiate.
Flash time is not yours to shorten
The flash figures in this calculator are inputs because they belong to the product and the conditions, and they are the one part of the cycle where trying to save minutes costs you the job. Solvent that has not left the film before the next coat goes on is trapped, and trapped solvent leaves later, through everything on top of it, as dieback, as solvent pop, or as a wrinkle that appears after the vehicle has been delivered.
The figures also move with the weather. Cold air and high humidity both stretch the flash, sometimes considerably, and a schedule that has worked all summer stops working in the first cold week of autumn. This is exactly why the data sheet gives a window rather than a number, and why it states the temperature the window applies at.
Where the whole-job constraint really sits
| Change | Effect on the default cycle | Effect on jobs per day |
|---|---|---|
| One minute off each of three flash steps | 3 minutes | None |
| Bake hold removed | 30 minutes | Usually none on its own |
| Masking moved out of the booth | 60 minutes | Often a whole extra job |
The reason the table looks like that is that jobs per day is a floor function. Minutes saved do nothing at all until they add up to a whole cycle, and then they add a job all at once. Chasing three minutes here and five there feels productive and changes the output not at all, while a single change that removes an hour crosses the threshold. The calculator prints the whole-job effect rather than the minutes for exactly that reason.
What this does not model
It schedules one booth and one job at a time. It has nothing to say about a shop where the prep bay is the real constraint, where parts arrive late, or where a colour has to be sprayed out and checked before the job can start. It also assumes the job goes right the first time: a run that needs to be flatted back and resprayed puts the vehicle through the whole cycle again, and one of those in a day costs more throughput than any amount of flash trimming will recover.
Booth construction, ventilation rates, filtration, make-up air and the electrical installation are governed by rules that vary by jurisdiction and by insurer, and by the manufacturer of the equipment. This page schedules minutes. It has no opinion on whether a space is a suitable place to spray, and it should not be read as one. For the air movement side of a room in general terms, the CFM and air changes calculator covers the arithmetic of volume and air changes without touching what any of it should be.
Questions people ask
Should the bake hold include the ramp up?
No, and the calculator keeps them separate because they behave differently. The hold at temperature is the figure the data sheet specifies and it is fixed by the material. The ramp is a property of your equipment and the mass of the vehicle in it, and a booth that takes twenty minutes to reach temperature is adding twenty minutes to every job in the shop. Timing your own ramp with a vehicle in the booth rather than empty is worth doing once.
Why does saving a few minutes not add a job?
Because jobs per day is a whole number. If the cycle is two hundred and ten minutes and the day is four hundred and eighty, you get two jobs and sixty minutes of nothing. Saving five minutes gives you two jobs and seventy minutes of nothing. To get a third job the cycle has to come down to a hundred and sixty, which is a fifty minute change. The calculator shows the whole-job outcome of each change for that reason, rather than reporting a saving that has no effect on output.
Is spray time per coat a real figure I can measure?
Yes, and you should. Time a coat on an actual job, gun in hand, from first trigger to last. It is usually longer than people estimate because it includes moving around the vehicle, doing the jambs, changing position and checking the wet edge. For a full vehicle it will be very different from a single panel, which is the main reason a shop cycle time varies so much from job to job.
How do I handle a job with no bake?
Put zero in the bake hold and the cure section is just ramp and cool down, and you can zero those too if the job is genuinely air drying in the booth. What air drying does to the schedule is push the waiting elsewhere: the vehicle either occupies the booth for far longer, or it comes out and occupies floor space that also has a cost. Neither shows up as a shorter cycle unless you account for where the vehicle went.
Can I use this to decide whether to buy a second booth?
It will tell you the throughput a booth can reach and which parts of the cycle are consuming it, which is the input to that decision rather than the decision. Before a second booth, the arithmetic usually points to the things that occupy booth time without needing a booth: masking, unmasking, staging and turnaround. Whether the capital case works depends on demand, staffing and the rest of the shop, none of which this page can see.