Volatile is an interesting word because it can mean two very different things. The first is that something will evaporate easily at room temperature, and the second describes a situation or action that can change rapidly and unpredictably in a bad way. In both senses, the spray booth is the most volatile part of the production process. Here we force a liquid to become a vapor, which is the physical process of evaporation. And this is also where days or weeks of work can get screwed up in one awful moment. A poor sanding job, uneven stain, dust, runs, poor color matching – there are so many ways that things can go wrong in a booth that it’s no wonder the boss is, well, a little bit volatile.
The spray booth is also the most regulated area of production, with municipal, state, federal and sometimes even global rules affecting how we finish and what we can buy and market.
The process itself is volatile: it’s constantly changing as we drift more and more toward eliminating VOCs, using low or no formaldehyde products, switching from stains and clearcoats to solid colors, and now learning about antibacterial additives.
Despite a switch to HVLP, overspray is still a problem. There is hope for the future here though, as robotics such as the EcoPaintJet from Durr take center stage. This system, already being used in automotive finishing, combines a robot, a very sophisticated measuring system and a strange-looking tip to deliver incredibly accurate coating. It uses sensors to measure the surface and then constantly calculates how the applicator should travel over the surface, and how much finish has to be dispensed. There’s no overspray. But there is a significant investment, so it may not be an option for smaller shops.
Other reasons a woodshop might want to reduce the amount of finishing it does are odors, noise, dust contamination and air make-up. These last two can get quite expensive as scrubbing the shop’s air or pre-heating or cooling it can chew up electricity.
A custom shop is never going to fully eliminate the finishing process, but it can significantly reduce it by passing the buck to suppliers. Outsourcing prefinished panels can shave a little off the payroll, help eliminate bottlenecks at the spray booth, avoid some costly mistakes and reduce the chance of surprises. Those include everything from orange peel to bounce-back (dry spray), uneven coating, drips, blotches, runs, slow dry times in humid or cold weather, moisture blushing, wrinkles … the list goes on.
Panel sizes and substrates
A woodshop can buy prefinished panels that include options such as primed for paint, stained, and/or UV top-coated. It can order standard full sheets through a manufacturer’s distributor or pay more and have sheets ripped and crosscut by an outsourcing supplier. The latter option allows the shop to order slightly oversized or perfectly sized cabinet backs, sides, drawer bottoms, shelves, door panels and so on. The more custom and less predictable a shop’s output, the higher the chance is that they’ll go for the full sheets. Time is the real issue here – prefinished panels can sometimes take a while to get (especially in less common species or sheens), so many shop owners like to keep an inventory on hand for future work. Without knowing the dimensions of jobs that haven’t appeared yet, the shop’s most sensible choice is to buy and warehouse full sheets.
Handling prefinished panels can be a challenge. A lot of shops just order one face prefinished where that will work, and they keep this one up during machining processes to avoid scratches. Some shops that don’t have sliding tables apply blue masking tape strips to the surface, especially around the blade insert. But that can mess with fine height adjustments, and if the edges start to curl it can roll up as the panel crosses it. To avoid tear-out, use plywood blades with lots of small teeth. Sometimes deep scratches just can’t be avoided, and a door panel or cabinet side will need to be sanded, stained and coated right before it goes to the loading bay. So, it’s a good idea to pre-test some stain and keep a quart on hand for those repairs. It’s also a good idea to keep some scraps of the prefinished panel handy and test different ways to fix scratches before the shop decides to go with a product.
Most scratch repairs to UV coatings are made with other, more conventional finishes. Technicians generally start by sanding a small area with lubricated wet/dry 600-grit paper, then they can often complete the job using a wax stick or a burn-in stick in the lightest shade of color they see in that area of the panel. If the repair involves tiny splinters or a slightly raised surface, it may be necessary to gently scrape it with a fine razor before sanding. Any excess from the wax stick can be removed with the edge of a credit card rather than a cabinet scraper. Topcoat with an aerosol designed to blend with the factory coating (your panel salesperson should be able to recommend one). Above all, practice on scrap before working on a customer’s cabinets. Very minor scratches on inside surfaces (cabinet sides, backs, etc.) probably won’t ever see a raking light, so they usually go unnoticed by both the woodworker and the end-user.
Prefinished hardwood edge tape can simplify things too, and that can be coated in-house with an aerosol can if you don’t have a spray booth, but it’s also easy to outsource. For example, EdgeCo Inc. in Bay Shore, N.Y. offers prefinished edge tape with UV clear coating in 7/8” x 500’ rolls in many domestic species. The company has master coils in stock for slitting to custom widths, and tape can be auto, pre-glued or peel and stick (EeeZeeEdge).
The most common clear coat on veneered panels is an epoxy acrylate, which is generally very low in VOCs. It’s cured by ultraviolet light, so it doesn’t release significant VOCs or other hazardous air pollutants during manufacturing, or later in a client’s home.
A good example is Echo Wood PFP from Hardwoods Inc. which operates 24 distribution centers across the U.S. and Canada. Echo Wood is a two-sided sheet that is consistent from cabinet to cabinet, and multiple fabricators can supply the identical look for large-scale installations. It has a 15-percent matte sheen, and the coating is a UV-cured enamel that contains no VHAPS (volatile hazardous air pollutants) and is extremely low in VOCs. The panels are made to order (10-sheet minimum) with a 3-4 week lead time, and are available in 1/4” and 3/4” thicknesses in 4x8 or 4x10 formats on MDF. Hardwoods Inc. supplies matching edge tape in veneer and ABS, and Echo Wood is LEED Credit supported (MR4, 5, 7 and IEQ 4.4), and is available as an FSC-certified panel.
Columbia Forest Products offers UV Wood panels with a modified acrylate finish that resists scrapes, chips and the effects of solvent wipe-down. This product illustrates the main advantage of buying prefinished: it allows a woodshop to offer customers a real wood alternative to a melamine interior and do so at a competitive cost. UV Wood is available in low, satin, medium and high gloss; can be finished on one or two sides, and comes on any core, grade and species combination.
Timber Products Co. offers prefinished panels that are available as FSC-certified, and its RhinoCoat UV-cured coating contains no formaldehyde or VOCs. The panels are available in a wide range of sizes, thicknesses (from 5/32” to 1-1/2”), veneer species (essentially unlimited), core materials (veneer core, Pro-Core, particleboard, MDF) and gloss levels.
Roberts Plywood is a family-owned business in Long Island, N.Y. that carries a wide variety of architectural quality plywood and veneers. The company has added pre-primed and prefinished plywood.
Highland Hardwoods in Brentwood, N.H. can special order prefinished maple plywood and carries a wide assortment of hardwood edge tape in stock. The company is very committed to environmental values – since 2015, it has operated exclusively on solar power.
Northwest Hardwoods in Tacoma, Wash. and offers a UV clear finish on all plywood for any species. The company carries 14 North American hardwood species in standard and proprietary grades, and more than 25 exotic species plus a wide range of imported plywood products. Northwest has distribution centers across the country and also ships worldwide.
The Nova Peak panel from States Industries in Eugene, Ore. lets a shop buy small quantities of popular wood species and colors on higher grades of veneer. These are stock, not custom, and the options are 10 colors on four species – two on oak, three on maple, three on cherry, and two on mahogany.
Roseburg Forest Products operates two prefinished panel facilities, one in Dillard, Ore., and the other in Missoula, Mont. Its SkyPly hardwood plywood panels are finished using an epoxy acrylate UV coating and are available in four standard gloss reflection levels. Available thicknesses are 5.2mm, 1/4”, 3/8”, 1/2”, 5/8”, 3/4”, 1”, 1-1/8”, 1-1/4”, and the panels come in both 4x8 and 4x10 sizes. A shop can order one or two faces finished on a variety of cores such as veneer, HXB, MDF, Multi-Ply, particleboard and CFC.
For woodshops looking for prefinished panels that curve, Surfacing Solution in Chaska, Minn. manufactures a line of flexible wood tambour panels that can be used for walls, ceilings, pole wraps, wainscoting and doors. Panel options include solid wood, wood veneer, metallic and colored panels, and the company can provide custom color match staining and Class A fire-rated varnishes. A number of profiles are available, and lengths can be up to 12’.
This article originally appeared in the August 2020 issue.