What Causes Veneer Checking: Part III

By Bernie Bottens | Posted: 03/28/2013 2:00PM

 

Bernie Bottens how to finish wood This week we look at environmental changes and how they may impact the veneer. I mentioned environment beginning in the second paragraph of the first installment of this article. Please refer back to parts 1 and 2 of this series so that you are aware of what has been said thus far.

Read: What Causes Veneer Checking?

Read: How to Make Wood Veneer

 

Climate is central to understanding that which creates the stress that makes veneer checking happen. Let’s take the Northwest as an example. Winters in the northwest and west of the Cascades are cloudy, cool, and wet with annual rainfall in Portland between 36 inches and 42 inches being common. The summers are warm and much dryer. Winters east of the Cascades are cold and often snowy. Summers are much warmer and very dry.

Now let’s say that you own a shop in Portland and that you have just won a big contract to supply the interior panels for elevator lobbies in a new Las Vegas building (annual rainfall of 5 inches). The papers are signed and you need to jump on this project because there are deadlines that must be met for installation. You get right to the task of ordering the materials. It’s a big project but, then again, it’s fairly repetitious as each lobby has the same footprint.

As the project progresses and the building in Vegas goes up, you have installation deadlines for each floor starting with the ground floor.To keep this long story short, let’s fast forward to the point where you have done the first few lobbies. Let’s look back at what has transpired up through the first delivery trip.

It’s been difficult to acquire the number of sheets necessary in the species of veneer that was specified for the job. You have had to pull from several sources and will continue to have to do so as the project progresses. Material costs have been high because you have had to have some of the veneer air freighted from back east in order to meet your production deadlines. Next-day air has been your salvation in spite of the cold and snowy weather in the central states. Today, you’ve received the veneer early enough in the day to drop it at the panel shop so they can get directly to work gluing up the veneer on the substrate. You are literally able to start cutout 48 hours after the veneer lands at the airport.

Let’s fast forward again to the shipping deadline. It’s a typical cold, rainy Portland day when the truck backs up to your dock to load. You are concerned because this same weather front is moving through northern California like a slow freight train. Snow is falling from Klamath Falls almost all the way to Reno. The good news is that south of Reno, the storm dies out and the weather dries up.

Fast forward again and we see that the truck made it to Las Vegas but not without having spent an extra night on the road due to bad road conditions. The truck spent that night in the parking lot of a hotel along the way. The install crew met the truck in Vegas and got right to work. The project went together well on site and you moved on to staying ahead of the next deadlines. No disasters to report today!

Not so fast. Let’s drop anchor here and take a look at what has happened environmentally (temperature and humidity) that could well put stress upon the veneer.

1. Some of the veneer was sourced out of the Midwest and from several suppliers in that region.

2. Winters in the heartland of America are often very cold. That weather is brought south from the cold, dry Arctic.

3. Air freight was used to create a just-in-time arrival.

4. The Northwest in the winter is cool but very wet.

5. The veneer went from the supplier’s warehouse (cold and dry) to the plane (dry air) to delivery truck (cool and wet), to the panel fabricators.

6. The panel fabricator went right to work gluing up the panels (cool and wet).

7. The panels went directly from fabricator to your shop for cutout and build (cool and wet).

8. The finishing process followed right on the heels of the build.

9. The truck for the trip to Vegas was waiting the morning following the final coat of finish (cool and wet).

10. As soon as pack and wrap could happen, the truck was loaded (cool & wet).

11. There was an extra night on the road in an unheated truck due to cold, snowy conditions on the road (cool, wet to cold and snowy).

12. We all know that the new hotel in Vegas is air conditioned and that relative humidity is much lower there than anywhere else that the veneer has been in recent history.

Eventually, the panels and the veneer will become one with their new environment in the Las Vegas building where they are installed. You can rest assured that the relative humidity in that building will be very predictable.

Next week we are going to look a bit deeper into what all of the above could mean for the veneer. There may well be stress-caused consequences to all of this. Please stay tuned!

Until next time…spray on!


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About the Author

Bernie Bottens

Bernie Bottens (WoodworkingNetwork.com/blogs)writes and teaches on the subject of wood and wood finishing in industrial woodworking. He and his wife, Carol, live in Vancouver, WA. Bernie has been teaching wood finishing to shop owners, shop foremen, spray technicians and finishers all over Oregon, southwest Washington, and northern California for the past 9 years. Prior to that, he owned his own cabinet shop. His shop credentials include apprenticing and becoming a journeyman exhibit builder. Before that he taught in the public schools for 20 years. Bernie is the owner of Kapellmeister Enterprises, Inc. and Kap Coatings Consulting. Reach him at kapenterprises@msn.com.

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