When contamination strikes, it leaves a crater in the finish, known as a “fisheye.” There can be one
or two or, literally, thousands, caused by a drastic change in surface tension where coating flowed
away from the contaminant and literally piled up around it.

There are things that we can’t see with our eyes or feel with the tips of our fingers, yet they can cause us distress when we apply a finish. This section on finishing is about some of those gremlins that rise up, and how to avoid them. It’s also about ways to keep those gremlins in check,. My article is followed by some background and resources to help you get off to a clean finish.

Shrouds, such as this custom unit from Nederman,
gatherdust for collection by central or local vacuum

Gremlins in the finish shop are true terrors because they are invisible. They come down the pipe from the compressor or float across the shop on the breeze. They come from the oil on your skin, from hairspray, makeup, or even from clothing, etc.

When contamination strikes, it leaves a crater in the finish, known as a “fisheye.” There can be one or two or there can be, literally, thousands. By the time you see them, they are under the coat that you just applied. Something caused a drastic change in the surface tension at that spot and the coating flowed away from that contaminant and literally piled up around it. Don’t confuse these with pin holes in open grained woods. That’s another issue altogether.

Silicone is the ultimate gremlin. If someone across the shop is spraying silicone on the saw table, planer bed, or jointer, some of it may still be on the wood milled at that machine when you apply finish. If someone sprays it on plastic laminate before routing an edge, the air currents in the shop can move it all around the production area.

Once it’s loose, it can hang around for a long time. It seems that these tiny guys just love to land on something and hang on for dear life, because they are hard to remove.

Lots of folks with fisheye issues call and ask me if we sell fisheye eliminator. They experience contamination one day and they want a quick and easy fix. Fisheye eliminator sounds like a silver bullet. Not so! Fisheye eliminator is a solution of 100 percent silicone. It may indeed help to get rid of issues on that one job. But by using it once, you open Pandora’s Box. Yes, there are shops that use fish eye eliminator with every job they spray. They have to. Doing otherwise would increase the chance of fisheyes in an ever-increasingly contaminated environment. Once you have atomized those silicones, they will land whereever the air currents carry them.

Silicones are not the only bad guys. Try Googling “fisheye contamination.” Read a while, and you will see what I mean. There are lots and lots of issues. There are even certain under-arm deodorants that have been linked to fisheye contamination.

Compressed air
Make certain you set up your compressed air delivery system to include proper water traps, drops and filters to remove residual chemicals in that delivery stream. If you have never experienced fisheye due to blow-by from compressor crankcase oil then you have something yet to experience. It is truly disheartening but very preventable.

Replace that worn pump. Engineer your compressed air piping so that at least the first 25 feet leading from the compressor go downhill to a water trap with a blow-off valve. Put a trap at the end of every branch and some kind of filter there to collect residual oil and water. Compressing air causes moisture in that air to condense. Invest in whole-system filtration after that initial 25 feet as your first line of defense.

Contamination doesn’t care if it comes out of a nail gun, a blow gun, a sander, or a spray gun. All it has to do is get on the wood. Think of it this way…high volume air usage minus filtration equals, “Katie, bar the door.” Blow guns and air powered sanders can really spread things around!

Read the specs for the filters that you are buying and spend some serious money for filtration that filters out the smallest micron sizes. In conclusion, contamination can be even worse with waterborne coatings. Also, water and oil don’t mix. But they are both vehicles for spreading contamination.

Refinishers deal with all kinds of contamination every day. My hat is off to them. They never know what is lurking in the pores of the wood they are refinishing. Chances are some type of furniture polish or wax is hiding there. Stripping or just washing and refinishing often releases these contaminants. Obviously, the first line of defense in every shop is a dogged approach to prevention. But refinishers have to take what they get.

Barrier coats
Think of vinyl sealers as Saran Wrap. They help to keep in the good and keep out the bad. Want to keep water out? Use a vinyl sealer. Want to seal down contamination? Vinyl resins can help with that. They are also sticky. They help with adhesion.

There are lots of vinyl resins and just because it says vinyl on the can doesn’t necessarily mean that what you have is a really the best for a barrier coat. Look for a sealer that is non-yellowing. Also, look for one that can be catalyzed to improve its performance. Those are going to contain the best resins for barrier coats.

Vinyl gets a lot of attention these days. They can be really good and they sound high tech. But don’t forget the low-tech barrier coat. I’m talking about shellac. It’s been around forever. It is dissolved only by alcohol so you usually don’t have to worry about it being rewetted by the topcoat and causing contamination there. However, always look for 100% de-waxed shellac. That is especially important with water-borne top coats. Waxes and water don’t get along.

When using vinyl or shellac, a little goes a long way. Fog the sealer on in several light, dry coats. Flooding it on tends to help the contamination float up. Fogging helps to bridge the contamination. You may have to sand the surface smooth when you’re done so be mindful of how much you apply. On the other hand, vinyls are also soft and you want to watch out how much “soft” you put down under a harder topcoat. Think of it as spreading creamy peanut butter and then putting a plate of window glass on top of it. Think the glass might break under pressure? I have people tell me that they flood on two or three coats of vinyl before they apply their final finish. Always question this concept: if one is good, two is better and three must be heavenly.

Bernie Bottens teaches wood finishing in industrial woodworking all over the Pacific Northwest. Meet him at the AWFS Fair July 20-23 in the Woodworking Network Booth 2139, sponsored by M.L. Campbell.

Centralizing dust collection
By Rob Williamson, Nederman USA

Custom shrouds can be tailored to fit most other common hand tools, allowing them to be tied to
both central and portable high vacuum systems using pipe, hoses, swing arms, valves and tool
balancers. Nederman, which provides such shrouds, says it will recommend certain manufacturers
that they feel offer the most functional hand tools according to application.

Working in an environment that creates wood dust during the production process. The presence of this dust necessitates the use of an efficient system to reduce, collect and remove the dust to help meet OSHA General Statute requirements to provide a safe work environment. There are also additional National Fire Protection Association (NFPA) dust control guidelines that are used as requirements by OSHA. Failure to meet these requirements could result in down production and/or substantial fines.
How your plant collects or handles dust can have negative effects beyond potential OSHA fines. Dust can be a serious health and safety hazard if not properly controlled. Dust can cause respiratory, skin or eye problems for employees. It can also contaminate your products, shorten equipment life and even create a potential combustion situation.

Many manufacturers still are sweeping up or blowing the dust away from work areas. This only makes the problem worse. The best place to handle dust is at the source where it is produced and vacuuming is the best method to capture and remove it.

In a typical production facility, large production equipment has hoods, manifolds or other attachments that extract/vacuum the dust produced by the equipment during the production process. However, other equipment and processes can also produce or spread dusts and other contaminates. These can include hand tools and your dust cleaning process.

Dust produced by hand tools is often collected by low-vacuum systems on tables where the work is performed. This is ineffective, leaving too much dust behind to spread in the air or be trapped in the table area. Low-vacuum systems use more energy because they require a high air volume, but produce a low capture velocity (100 – 5,000 fpm). Low-vacuum systems use a 4-6-inch diameter hose and are inflexible due to the hose size and because the hose is connected to the table, not the tool which is the source of the dust.

The most effective and efficient method to capture dust produced by hand tools is to use high vacuum dust extraction systems that are connected to the tool (also known as on-tool extraction). This method is up to 99 percent efficient and almost any tool (grinders, sanders, cutters, drills, welding torches, etc.) can be fitted with a manifold for at-the-source dust extraction. High vacuum dust extraction systems are also more energy efficient, utilizing a collection hose of only about 2 inches in diameter. The system requires only a low air volume but produces a high capture velocity of 10,000 - 15,000 fpm. The small and flexible hose allows the use of boom arms and hose reels, which enables the worker to use the on-tool extraction in a large area. High-vacuum extraction systems can be mobile, portable or stationary. These systems also can offer HEPA filters and auto start/stop vacuum as options.

High-vacuum systems can handle multiple drops, so you can add hoses to vacuum when and where it is needed – whether for use on hand tools or for cleaning production areas. The high-vacuum filter unit also can be placed in a separate room, allowing quiet operation. The filter cleans the air before it is released into the atmosphere.

Don’t continue to just move the dust around when there are solutions that will allow you to efficiently collect and remove it. Protect your employees and avoid OSHA fines, down production and contamination of your equipment by removing the dust at the source.

Rob Williamson is Technical Director for Nederman USA (formerly Dantherm Filtration). He can be reached at 800-533-5286 ext. 823 or rob.williamson@nederman.com.

Curtain Partitions Cut Dust


Wood Designs Inc. provides displays to high-end retailers, working in wood, metal, glass, laminate and fabric. The Oklahoma City firm’s reputation is really skin deep and depends on the quality of the displays’ finish. With much of the work custom, organizing plant workflow is very important, especially for major roll-outs, such as Macy’s stores national rebranding.

A process layout consultant suggested Wood Designs use curtain partitions for its finishing area. Wood Designs opted for Goff’s Curtain Walls to section off the areas, with Goff’s vinyl strip curtains to provide access into the sectioned off finishing areas. “The nice thing about the Goff’s Curtain Walls is they are designed to go up fast,” says Wood Designs senior VP Scott Griffin. A heavy-duty galvanized track that hangs from the ceiling establishes the area to be enclosed by the curtains. Curtain Wall sections attach to the roller system using No. 2 brass tooth grommets on 1-foot centers, which glide along the track. The Curtain Walls are made of 14 ounces reinforced vinyl, with lower hems chain-weighted to prevent air currents from flaring them up. See-through windows provide visibility in each panel. “We were able to use our new finishing area in no time,” says Griffin.

For a recent 30,000 square foot plant added in Atoka, OK, they used the same approach. “When we moved into our latest plant in Atoka we again specified Goff’s Curtain Walls,” says Griffin. “Though we had a totally new crew here, when the box arrived we just laid it out on the floor. The guys quickly figured out how to hang the Curtain Walls and over a week of their spare time the enclosure for this large area was up and ready.”

In Wood Designs’ main Oklahoma City plant, the curtain partitions separate five large paint booths, where an automotive finish is applied to ensure longevity of the display products. There are ventilation systems in each section. Once the finish is applied, the product moves by hand carts into the finishing area, where it remains to set up and dry until debris will not stick to the surfaces. Within the 5,000 square feet of the curtained off area, half is a work area, and the other portion for inventory. Dry displays are next moved into a post-assembly area where hardware, fabric and attachments are added.

The plant ceiling reaches 40 feet high. A 300-inch diameter sock air makeup system is part of a $750,000 central dust collection system. “The area within the Curtain Wall is the most dust-free in the plant,” says Griffin. He credits the finishing area created by the Curtain Walls with cutting down on rework costs, since the curtains contain airborne contaminants. Griffin also likes the visibility the window provides for safety, supervision and product flow. VIDEO of Curtain Walls at woodworkingnet

Redbook Finishing Resources
Following is a list of suppliers that sell dust collection equipment and products. Visit RedBookOnline.com for a complete list of dust collection related products.

O2 Filtration LLC - o2filtration.com

AAF International  - aafintl.com

Aget Mfg. Co. - agetmfg.com

Air Handling Systems - airhand.com

Air Systems Mfg. of Lenoir Inc. - airsystemsmfg.com

Camfil Farr APC Dust Collectors - farrapc.com

Chemco Mfg. Co. Inc. - chemcomfg.com

Donaldson Torit - donaldsontorit.com

Felder USA - feldergroupusa.com

General International USA Inc. - general.ca

Honeyville Metal Inc. - honeyvillemetal.com

ITW Air Management - itw-air.com

Koger/Air Corp. - kogerair.com

Midwest Group One - midwestgroupone.com

Nederman (formerly Dantherm) - nedermanfilters.com

Nordfab Ducting - nordfab.com

Oneida Air Systems Inc. - oneida-air.com

Powermatic WMH Tool Group - wmhtoolgroup.com, powermatic.com

Penn State Industries - pennstateind.com

SandMan Products LLC - sandmanproducts.com

Scientific Dust Collectors - scientificdustcollectors.com

Western Pneumatics Inc. - westernp.com

Woodstock International Inc. - woodstockint.com

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