The influence of mechanical surface preparation methods on southern pine and spotted gum wood properties: Wettability and permeability

The demand for engineered wood products (EWPs) continues to rise internationally. However, for some important Australian commercial timbers such as plantation grown southern pine and native forest sourced spotted gum, a major impediment to achieving commercially viable EWP production is difficulties experienced in gluing – particularly for sawn laminate based EWPs such as glulam. Wettability and permeability have a major influence on wood adhesion. This study investigated the efficacy of different surface machining preparations on the wettability and permeability of southern pine and spotted gum. For both species, planing resulted in poor wettability, whereas face milling and sanding treatments post-planing improved wettability. Wettability increased in southern pine earlywood compared to latewood; and wettability decreased for both species with increased time post-surface machining. Planing resulted in the highest permeability for southern pine but the lowest permeability for spotted gum. Face milling resulted in higher permeability compared to sanding treatments.

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Influence of mechanical surface preparation methods on the bonding of southern pine and spotted gum: Tensile shear strength of lap joints

BioResources ◽

10.15376/biores.16.1.46-61 ◽

2020 ◽

Vol 16 (1) ◽

pp. 46-61

Author(s):

William Leggate ◽

Robert L. McGavin ◽

Andrew Outhwaite ◽

Chandan Kumar ◽

Adam Faircloth ◽

...

Keyword(s):

Shear Strength ◽

Lap Joints ◽

Face Milling ◽

Wood Products ◽

Feed Speed ◽

Tensile Shear Strength ◽

Tensile Shear ◽

Southern Pine ◽

Surface Machining ◽

Lap Shear

Southern pine and spotted gum are two of Australia’s most important locally produced commercial timbers. However, internationally, they are amongst the most problematic species to glue cost-effectively, especially for sawn-laminate-based structural engineered wood products, such as glulam and cross-laminated timber. This study investigated the efficacy of different pre-gluing wood surface machining preparations on the tensile shear strength of lap shear samples prepared from both species. Surface machining methods tested included planing, face milling, and sanding post-planing with 40 and 80 grit sandpaper. Wood face milling is not currently used commercially in Australia and has not previously been adequately tested on Australian commercial timbers to improve wood adhesion. Planing is currently the most common method used internationally for preparing wood surfaces for gluing. For both species, face milling with fast feed speed (45 m/min), slow cutter speed (57 m/s), and sanding treatments post-planing resulted in significantly higher tensile shear strength compared to planing for lap shear samples that had been subjected to an accelerated weathering process. Performance differences in tensile shear strength between surface machining methods are likely to be related to the effects of these machining methods on surface roughness, fibrillation, and sub-surface cell damage.

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Examination of wood adhesive bonds via MicroCT: The influence of pre-gluing surface machining treatments for southern pine, spotted gum, and Darwin stringybark timbers

BioResources ◽

10.15376/biores.16.3.5058-5082 ◽

2021 ◽

Vol 16 (3) ◽

pp. 5058-5082

Author(s):

William Leggate ◽

Maryam Shirmohammadi ◽

Robert L. McGavin ◽

Andrew Outhwaite ◽

Mark Knackstedt ◽

...

Keyword(s):

Adhesive Bond ◽

Wood Adhesive ◽

Face Milling ◽

Southern Pine ◽

Surface Machining ◽

Bond Performance ◽

Hardwood Species ◽

Extremely High Frequency ◽

Adhesive Penetration ◽

Face Mill

The successful manufacturing of glulam from several important Australian commercial timbers is quite challenging due to difficulties in gluing. Improvements in adhesive bond performance of spotted gum, Darwin stringybark, and southern pine timber have been achieved using alternative pre-gluing surface machining methods, e.g., face milling and sanding-post planing, when compared to conventional planing methods. In order to improve the understanding of the effects that different surface machining methods have on adhesive bond performance, this study used micro X-ray computed tomography and microscopy to assess key adhesive bond criteria. There was a considerable loss in the amount of adhesive after the wet and dry test cycles for all species. There was also an extremely high frequency of voids in the glue lines for all species, which would negatively impact bond strength and durability. Face mill prepared timber boards resulted in thicker glue lines and greater resistance to adhesion loss, compared to boards prepared via planing. For the two hardwood species, face milling also resulted in greater adhesive penetration; however, for southern pine, there were no significant differences in adhesive penetration between the three surface machining treatments. Adhesive penetration was much deeper in southern pine compared to spotted gum and Darwin stringybark.

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Preparation of steel substrates before application of paints and related products. Surface preparation methods

10.3403/02387807u ◽

2015 ◽

Keyword(s):

Surface Preparation ◽

Preparation Methods ◽

Steel Substrates

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Preparation of steel substrates before application of paints and related products - Surface preparation methods

10.3403/02400405u ◽

2019 ◽

Keyword(s):

Surface Preparation ◽

Preparation Methods ◽

Steel Substrates

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Preparation of steel substrates before application of paints and related products. Surface preparation methods

10.3403/02400405 ◽

2000 ◽

Keyword(s):

Surface Preparation ◽

Preparation Methods ◽

Steel Substrates

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Preparation of steel substrates before application of paints and related products - Surface preparation methods

10.3403/bseniso8504 ◽

2015 ◽

Keyword(s):

Surface Preparation ◽

Preparation Methods ◽

Steel Substrates

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Recommended Practices For Shop Cleaning And Priming

CORROSION ◽

10.5006/0010-9312-17.8.119 ◽

1961 ◽

Vol 17 (8) ◽

pp. 413t-414t

Author(s):

◽

Keyword(s):

Surface Preparation ◽

Preparation Methods ◽

White Metal ◽

Application Methods ◽

Recommended Practices ◽

Methods Of Application

Abstract Recommendations for shop cleaning and priming practices are broken down into seven categories: methods of surface preparation, methods of application, workmanship, supervision, inspection, priming, and fabrication. Surface preparation methods discussed include solvent cleaning, hand cleaning, power tool cleaning, flame cleaning, brush-off blast cleaning, commercial blast cleaning, white metal blast cleaning, and pickling. Application methods considered include brush, spray, hot spray, airless spray, roller, and dip. 5.9.1, 1.7.1, 5.4.7

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Hybrid Approach for Wood Modification: Characterization and Evaluation of Weathering Resistance of Coatings on Acetylated Wood

Coatings ◽

10.3390/coatings11060658 ◽

2021 ◽

Vol 11 (6) ◽

pp. 658

Author(s):

Anna Sandak ◽

Edit Földvári-Nagy ◽

Faksawat Poohphajai ◽

Rene Herrera Diaz ◽

Oihana Gordobil ◽

...

Keyword(s):

Service Life ◽

Hybrid Approach ◽

Wood Properties ◽

Wood Products ◽

Superior Performance ◽

Surface Erosion ◽

Coating Film ◽

Chemical Treatments ◽

Cellular Wall ◽

Bulk Substrate

Wood, as a biological material, is sensitive to environmental conditions and microorganisms; therefore, wood products require protective measures to extend their service life in outdoor applications. Several modification processes are available for the improvement of wood properties, including commercially available solutions. Among the chemical treatments, acetylation by acetic anhydride is one of the most effective methods to induce chemical changes in the constitutive polymers at the cellular wall level. Acetylation reduces wood shrinkage-swelling, increases its durability against biotic agents, improves UV resistance and reduces surface erosion. However, even if the expected service life for external cladding of acetylated wood is estimated to be 60 years, the aesthetics change rapidly during the first years of exposure. Hybrid, or fusion, modification includes processes where the positive effect of a single treatment can be multiplied by merging with additional follow-up modifications. This report presents results of the performance tests of wood samples that, besides the modification by means of acetylation, were additionally protected with seven commercially available coatings. Natural weathering was conducted in Northern Italy for 15 months. Samples were characterized with numerous instruments by measuring samples collected from the stand every three months. Superior performance was observed on samples that merged both treatments. It is due to the combined effect of the wood acetylation and surface coating. Limited shrinkage/swelling of the bulk substrate due to chemical treatment substantially reduced stresses of the coating film. Hybrid process, compared to sole acetylation of wood, assured superior visual performance of the wood surface by preserving its original appearance.

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