IWPA POSITION STATEMENT:
OFFSHORE TROPICAL ROTARY CORE VENEER QUALITY - STATEMENT OF CONCERN
The IWPA Veneer Committee has concluded that there is growing concern about the diminishing quality of tropical rotary core veneer. This is particularly true as relates to “soft” hardwood species such as Ceiba pentandra (fuma, fromager, ceiba, sumauma, lapuna). The concern is coming from both end users and importers and has been deemed sufficient to warrant this “Statement of Concern” from the IWPA on behalf of its members and the industry as a whole.
I. Background Information:
North American hardwood plywood manufacturers have been using imported tropical rotary “core” veneer (also known as “corestock” veneer) since the late 1950’s when lauan core started to arrive from the Philippines. It was common for spliced lauan veneer to be sanded prior to shipment to North America. The availability of lauan veneer from the Philippines began to decline in the 1980’s and products from South America and West Africa have since taken its place.
Presently the majority of offshore corestock veneer is being used in the production of thin panels. Today, the average face and back veneer thickness is 1/42” (.6mm), with some faces being as thin as 1/50” (.5mm) or as thick as .7mm (1/36”) – depending, in good part, on species, type of cut (rotary or sliced), and country of origin. A long term and undeniable trend indicates that face and back veneer thicknesses will continue to get thinner. With ever-decreasing face and back veneer thicknesses, it would be ideal if the quality of offshore core veneer were to get smoother and better every year. Unfortunately, most agree that the opposite is occurring.
II. Quality Issues (as reported by importers and end users include the following, in order of importance/severity):
1. Extreme “Rough Cut” or “Torn Grain”: Often this issue makes the product unsuitable for overlaying with thin decorative veneers (its intended use) and sometimes it is so severe that, even when buried as an inner ply, a proper glue bond cannot be achieved.
2. Severe Buckle or Waviness: This issue causes lay-up problems, especially at the glue spreader and upon feeding into the press.
3. Poor Packaging/Marking:
a. Wet Pallet Lumber– This is a big problem, which causes condensation and ultimately “RAIN” inside the containers, causing damage to the veneer.
b. Weak Pallet Lumber/Loose Straps – Often the pallet lumber is so weak that it breaks during handling, causing damage to the veneer. Likewise loose strapping often causes units to fall apart or shift, causing damage to the veneer.
4. Poor Splicing:
a. Weak Joints – The splice joints do not hold and the sheet falls apart before reaching the glue spreader.
b. Staples/Tape – The only acceptable type of splice joint is a good sound strong glue joint. Stapled and taped joints are not allowed.
c. Staggered Joints – Often components are spliced with staggered joints which create edges that are ‘stair-stepped’ or ‘jogged’. This causes lay-up and trim-out issues.
d. Component Inconsistencies – When components of varied thickness and smoothness are spliced next to one another, a clear demarcation of the components telegraphs through to the face.
III. Suggestions for Improvement of the Major Issues:
- Rough Cut - It is generally accepted that log quality is not as good as it used to be. Thus, minimizing rough cut requires more attention be paid to lathe/knife set up and maintenance as well as log conditioning.
- Severe buckle - It is suggested that this is a result of “shock” drying and can be remedied with adjustments to the drying process.
- Poor Packaging/Marking – The IWPA Veneer Committee is working towards a comprehensive update of its packaging standard for veneer and platforms. In the meantime, it is recommended that all packaging lumber be dry and of a species with sufficient strength to remain intact and adequately protect the cargo during transport.
- Poor Splicing – Weak splice lines are the result of poor jointing and/or poor glue bond. It is recommended that suppliers who are splicing core veneer check the resistance of the splice lines and, if found to be unacceptable, confer with machinery and glue vendors to find a remedy.
Market feedback suggests that end users have become so frustrated with decreasing quality that they are looking to substitute veneer core with thin MDF or similar products wherever possible. It is generally accepted by members of the IWPA Veneer Committee that MDF and domestic core veneer, such as poplar, have already become common substitutes for imported core veneer. North American plywood manufacturers, and the market in general, tend to prefer to use good quality tropical offshore core veneer -especially in certain applications. There is a place in the North American market for tropical rotary core veneer. IWPA encourages overseas suppliers to work, together with IWPA, towards addressing the areas of concern.
Statement approved by IWPA Board of Directors, September 25, 2007