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Low temperature drying conditions of Pinus radiata wood for avoiding internal stain
1989 - IRG/WP 3507
It has been observed that, if in little sawmills, timber is dried with a low temperature schedule, it arrives at destination with internal sapstain besides of superficial mould. In this study, the lowest drying temperature at which wood should be exposed for sterilization, which results to be 52°C, is searched. It is not possible to avoid entrainment of pentachlorophenol, even though a waiting period of 72 hours after dipping the wood in a pentachlorophenate/borax solution before drying is considered. The residual content of pentachlorophenol in wood should be at least 400 µg/cm² or the moisture content less than 23% for avoiding the development of mould.
M C Rose


In-situ pressure injection for preservation of rubber wood (Hevea brasiliensis Muel Arg.)
1992 - IRG/WP 92-3688
Rubber wood is widely used for the manufacture of furniture, doors for housing and packing cases. However in an untreated condition it is highley susceptible to sapstain and decay fungi and borers. Its utility gets considerably reduced if the wood is not treated well in time. Preservative treatment has to be given within the period of felling and transport to prevent not only loss of structural properties and wood material. Although Boucherie, hot-cold bath diffusion, pressure impregnation, vacuum-pressure impregnation processes for treating timbers have been successfully employed for protection, but the process in cumbersome and difficult to adopt at the site of extraction. Hence, it was found necessary to evolve a simple and convenient method to treat trees in-Situ. A simple pressure injection technique was adopted to treat the standing tree using an instrument designed at the Institute (IWST). This instrument is easy to operate and inexpensive. It was observed that the movement of preservatives was satisfactory and effective. Samples of wood taken from treated stem of such trees were subjected to attack by brown and white rot fungi in the laboratory. It was observed that wood samples treated with Borax, boric acid and Bavistin (1:1:0.2); Borax, boric acid and Sodium pentachlorophenoxide (1:1.5:1) and Bavistin and Ekalux (0.5:0.5) showed higher resistance to fungi and insect attack compared to boric acid and Borax (1:1) in both laboratory and field conditions. Treated wood also retained natural colour and was free from fungal and insect attack for over 24 months in storage. Studies in this method of treatment of plantations species are in progress.
H S Ananthapadmanabha, V R Sivaramakrishnan


A comparative field test of the effectiveness of anti-sapstain treatments on radiata pine roundwood
1986 - IRG/WP 3376
Peeled radiata pine posts were sprayed with one of six antisapstain formulations, with and without a wax water-repellent additive, to evaluate the protection given by each treatment. After 3 months' outside storage the best treatments tested were 4% product Busan 30, 2% product Busan 1009, and 2% active sodium pentachlorophenoxide (NaPCP) with 1.5% borax. After 6 months' storage posts sprayed with Busan 30 were of sounder appearance than those sprayed with Busan 1009 or NaPCP plus borax. The effect of a water repellent on the moisture content of posts and on the severity of the fungal degrade was variable between treatments and requires further research.
J A Drysdale, R M Keirle


Diffusion treatment plants (Latin America - Africa)
1974 - IRG/WP 333
B N Prasad


Ten year field test with a copper-borate ground line treatment for poles
1993 - IRG/WP 93-30017
A wood preservative paste consisting of borax and copper naphthenate has been tested to determine its efficiency in protecting wood from decay fungi and insects. The paste was applied to polyethylene-backed wraps that were fastened to the below-ground portions of unseasoned southern pine pole stubs. After 4 years of exposure in Mississippi, the untreated control stubs were completely deteriorated. The below-grade portions of the treated stubs remained sound after nearly 6 years of exposure due to movement of copper and diffusion of the borate throughout the cross section. Borate and copper also moved vertically in the stubs and was present in sufficient amounts to protect sections of the stubs as high as 3 feet above grade. After 9 years of exposure, the below-grade portions of the treated stubs had limited areas of decay and no termite damage; the majority of the cross section remained sound. Wood analysis indicated that concentrations of borate in the sound areas were about 1/10 the estimated toxic threshold. A visual examination and push test indicated that the treated stubs continued to be protected at groundline after 10 years of exposure. It is hypothesized that the continued protection of the below-grade portions of the stubs against both decay fungi and subterranean termites is the result of copper-borate complexes that have formed in the wood.
T L Amburgey, M H Freeman


Screening results of fungicides for sapstain control on Pinus radiata
1983 - IRG/WP 3236
Thirty-two compounds were tested to determine their ability to contain the growth of stain, mould and rot organisms on fresh Pinus radiata D Don. A screening technique was employed using 35 to 50 mm diameter biscuits of Pinus radiata stemwood 10 mm thick. No compound was found to be cost effective when compared against the standard treatments of NaPCP (0.5% a.i.) plus borax (1.5%) and Captafol (0.2% a.i.). The best compound identified was a guanadine compound Guazatine which at 0.2% a.i. was slightly better than the standard treatments employed in New Zealand. From these results and previous published work it would appear that mixtures offer more hope of a low hazard, cost effective treatment to replace the presently used industrial standard.
P J Hayward, J Duff, W Rae


Steam/hold/APM boron treatment - Treatability trials with green gauged radiata pine
1987 - IRG/WP 3439
Freshly sawn 100 x 50 mm radiata pine was green gauged, steam conditioned and preservative treated with a mixture of borax and boric acid using a modified Alternating Pressure Method (APM) treatment schedule. A 12 hour holding period between steam conditioning and treatment resulted in the necessary moisture loss and moisture re-distribution to facilitate treatment to NZ Timber Preservation Authority preservative retention and distribution requirements.
P Vinden


Status of wood preservation industry in India
2005 - IRG/WP 05-30388
The paper traces the history of wood preservation industry in India, listing various mile stones for creation of treating capacity. The preservation industry developed with the development of rail road system on the line of most other developed countries. The most popular wood preservatives are CCA, CCB, ACC, Creosote and recently LOSP have also appeared in the market. The major users of CCA is the Cooling tower industry, which use more than 50% of the current CCA produced in the country. CCB and Boric acid :Borax rule the furniture industry. The use of LOSP is picking up as brush on applications and in the remedial treatments. The overall picture of preservative used (around 1350 tons CCA equivalent) is quite disappointing considering the volumes of non-durable woods used annually 22.5 million m3.
S Kumar


Removal of copper, chromium and arsenic from CCA treated wood using boron compounds
2005 - IRG/WP 05-50230
This study evaluates the copper (Cu), chromium (Cr) and arsenic (As) removal from CCA treated wood using boron compounds such as boric acid, borax (sodium tetraborate), and Timbor (DOT, disodium octaborate tetrahydrate) at varying (3 and 5%) concentrations. Remediation processes were taken at 1, 5 and 10 day intervals. Metals in remediated chips or sawdust were then analyzed using ICP and XRF. Results showed that, higher level of Cu was removed followed by As and Cr. The percentage removal of metals was higher in saw dust then chips. Borax at lower concentration (3%) removed 41.4%, 18.3% and 44.9% of Cu, Cr and As, respectively, in 10 days while at higher concentration (5%) 65.8%, 55% and 55.8% of Cu, Cr, As, respectively, were removed for the same period. Boric acid removed 39.7%, 15.5% and 35.6% at lower and 50.7%, 48.9% and 50.9% of Cu, Cr, and As at higher concentration, respectively, while DOT was not an effective extractant. Distilled water extraction removed 27.3%, 23.7% and 22.8% of Cu, Cr and As respectively. In case of chips, borax removed 30.3%, 19.7% and 24.9% of Cu, Cr, and As; boric acid removed 25.5%, 12.2% and 19.5%; DOT removed 22.8%, 10.8%, 14.2% and distilled water 17.7%, 11.1% and 10.2% of Cu, Cr, and As, respectively. Increasing the concentration of solution has greater effect on elements removal. Among the three compounds tested, borax removed higher levels of metals compared to boric acid and DOT.
B Tarakanadha, T Hata, S N Kartal, W J Hwang, Y Imamura


Performance of Tuff Brite C™ and other formulations against blue-stain, mold and brown-stain in freshly-sawn rubberwood (Hevea brasiliensis) in the humid tropics of Peninsular Malaysia
1997 - IRG/WP 97-30163
The relative anti-sapstain and anti-mold efficacies, including brown-stain development in freshly-sawn rubberwood (Hevea brasiliensis) in the Malaysian tropics, between selected water-based product concentrations of formulations Tuff Brite CTM without/with added Borax (at 1.5/0, 1/1.5, 1.5/1.5 and 2%/1.5%), PQ8TM without/with added Borax (at 2.5/0, 1.5/1.5, 2/1.5 and 2.5%/1.5%) and NeXgenTM/NeX-BriteTM combination (at 1/0.25, 1.5/0.25 and 2%/0.25%) were assessed visually. Rubberwood boards, dipped in these concentrations for 1 min. were subjected to an 8 weeks sapstain trial in a FRIM sawmill shed. Sodium pentachlorophenate/Borax combination (at 2/1.5 and 2%/2%) was the reference anti-sapstain chemical. The rough-sawn boards were rated for blue-stain and mold weekly, while both the planed and the internal faces of the boards, sawn lengthwise into two-halves, were rated for blue-and brown-stain only after 8 weeks. Results for the rough-sawn boards, planed boards and the internal faces of the boards revealed a generally consistent excellent performance of Tuff Brite CTM without/with Borax against blue-stain and mold in rubberwood, protection being marginally better than that of NaPCP/Borax. Over a range of concentrations, performance by the remaining fomulations PQ8TM without/with Borax and NeXgenTM/NeX-BriteTM were variable: rated satisfactory (generally <10% surface infected) and/or poor (31-50% of surface infected) against sapstain and/or mold. Against brown-stain development (i.e. to conserve the natural cream/yellow hue in rubberwood), Tuff Brite CTM without/withBorax also appeared to be relatively better (generally yellow-to-light brown hue) than the other formulations, but perhaps only marginally so than NaPCP/Borax (light blue as well as yellow-to-light brown hue observed).
A H H Wong, T L Woods


Preservative treatment of rubber wood (Hevea brasiliensis) to increase its service life
2005 - IRG/WP 05-40320
Rubber wood (Hevea brasiliensis) possess excellent properties for interior designing, wood working and furniture making. But it is very much susceptible to sap stain and mould fungi which decreases the service life. For profitable uses , it is necessary to increase the service life of rubber wood. To protect the rubber wood from wood degrading agents, the sawn timber were treated with Borax – boric acid solution and Copper-chrome -boron solution by soaking process and Lowry empty cell pressure process following moderate treatment schedule. It was found that rubber wood can be treated satisfactorily by both the processes with acceptable penetration and retention.
K Akhter


Biological resistances of wood-metaborate composites using the borax solution system
2001 - IRG/WP 01-30259
Combinations of wood and metaborate composite were prepared from sapwood specimens of Japanese cedar (Cryptomeria japonica) and the borax and metallic salts system using the diffusion-penetrated process. Wood-metaborate composites were produced as follows: water-saturated specimens were first impregnated by a saturated borax solution and then diffuse-penetrated with Zn2+, Ca2+, or Pb2+ solution. Biological resistances of the composites as well as their leachabilities were evaluated. The precipitates of three kinds of metaborates in the wood proved to be insoluble in water by the leaching test. In the decay test using a brown-rot fungus (Fomitopsis palustris) and a white-rot fungus (Trametes versicolor) and in the termite test using a virulent subterranean termite (Coptotermes formosanus), the composites showed generally excellent decay and termite resistances with the negligible weight losses of specimens. Particularly, the lead metaborate formed in the wood provided a superb biological resistance against decay and termite attacks. In addition, the precipitates of these metaborates were found to be soluble in the acidic solution, suggesting a possible way of the easy removal of chemicals from the wood for disposing of wasted composites.
Liang Lin, T Furuno


The efficacy of boron preparations
1987 - IRG/WP 3400
The toxicity threshold of boric acid for egg larvae of Hylotrupes bajulus Linné is approx. 0.4 kg/m³ of wood (71 g B/m³) over a 12-week test period, and approx. 0.3 kg/m³ of wood (53 g B/m³) over a 6-month test period. The corresponding values for borax are 0.5-0.6 kg/m³ of wood (56-68 g B/m³) and 0.3-0.4 kg/m³ of wood (34-45 g B/m³). The values are somewhat lower in the case of the egg larvae of Anobium punctatum Degeer. Boron compounds can only be used as stomach poisons. They have a very slow effect on the larvae of both the house longhorn beetle and the common furniture beetle. Boron compounds are very effective in preventive treatments, but less well suited to curative use. Boron compounds are particularly useful in the prevention of a wide range of woodrotting fungi. No fungus is known to offer serious resistance to boron. All of the fungi investigated are killed by the application of 632 g of boron per m³ of wood. Boric acid is more effective than borax against fungi because it contains a higher proportion of boron. True dry rot dies when 55 g of sodium polyborate is applied per m² of brick wall: this represents approx. 11 g of boron per m².
J T De Jonge


Analysis of the boron content of preservative treated oak and pitch pine heartwood before and after leaching
1992 - IRG/WP 92-3697
Studies to determine the effects, if any, of a variety of boron formulations on heartwood of English oak and American Pitch pine have been previously reported (King et al (1991)). Small wood blocks were treated, at 10°C or 45°C, with borax, polybor or Boracol 20 for periods of 1 month or 4 months then analysed or continuously leached with tap water for a period of 1 month. Reported results showed minor dimensional changes coupled with some weight loss in most test blocks. The boron contents of all blocks have been analysed by the spectrophotometric method of (Williams (1968)). Although an average of 92% boron was lost many of the treated blocks still retained a protective level of boron (>0.04% B). Boron concentrations left in the leached/treated blocks relate to wood species, block orientation, overall weight loss and type of formulation. The results presented in this paper provide further evidence for the applicability of boron formulations to historic timbers and indicate that even in situations of some moisture movement protection may still be afforded by boron treatments.
S McCutcheon, G M Smith, J W Palfreyman, B King


Diffusion treatment of gauged radiata pine timber using "Boracol 20"
1987 - IRG/WP 3437
Green gauged 100 x 50 mm radiata pine timber was preservative treated by brush application of "Boracol 20" followed by diffusion storage. Preservative retention analyses indicated that retention requirements in the core could be achieved within a six week diffusion period, thus representing a time saving of 25% over conventional boron treatment of rough-sawn radiata pine. Similar treatment of kiln dried radiata pine resulted in approximately 5 mm penetration. A longer diffusion period did not result in improved preservative penetration.
D R Page, P Vinden, S Retter


Water analysis in chemicals, wood or chemically treated wood using a new analytical method for selective water detection
2006 - IRG/WP 03-30391
Water or moisture content analysis can be a challenging task in many applications. However, knowing accurately the type of water which can be found in a given sample or product can provide important information about a chemical compound used for wood treatment and especially about the treated wood sample. Moisture content in wood plays an important role in fungal growth and it needs to be extensively monitored. In this study, a new method for the moisture content or trace water analysis will be reviewed. The principle of the method, the main components of the device, the advantages and disadvantages of the method called Selective Water Detection System (SWDE), will be reviewed and presented. Probe molecules and wood samples will be used to explain and examine the type of information one can get using this analytical method. The method can provide information about how water is bonded to a substrate and what type of interactions water has in a sample. This information can be used to evaluate the structure of a chemical used in wood preservation, monitor the water repellency, or determine the type of chemical compound present on the treated wood (e.g. hydration number, weakly or strongly bonded water molecules, etc.). Probe molecules based on boron, commonly used as wood preservative will be used to explain and describe the instrument capabilities and the type of scientific information which can be obtained.
R Craciun, D Taylor


Performance evaluation of Borax: Boric Acid treated Green bamboo through new VAC-FRI and conventional processes
2006 - IRG/WP 06-40327
Amongst giant arborescent grass bamboo is the only versatile member containing lignocellulosic materials like wood. Therefore it offers almost parallel uses where wood is traditionally an established material. The wood scarcity, environmental role of our natural forests, longer rotation cycle of plantation species, ban in felling, the ever growing utilization demands of wood to the tune of 3.2 million tones and its abundant use even as fuel and complex R&D technologies related problems like growth stresses, drying stresses, refractoriness in treatments are several interacting factors in the field of wood utilization. However, bamboo is a relatively simplified material in comparison to wood. Therefore, developmental work in bamboo processing is much easier and simpler in comparison to wood. The treatment of bamboo is much simpler than the treatment of wood in the form of poles provided appropriate technologies are developed. Bamboo species are perishable regardless of prevailing beliefs, regarding its durability amongst traditional societies. More so one rainy season any where in the country or round the year high humidity zones in costal areas and Northeast are suitable grounds of severe sapstains or borer attacks in its products in case adequate treatments are not done. The present paper highlights this aspect and describes the developmental work at FRI. Boucherie process of treating green bamboo is well known. Further progressive work was done at FRI and a number of processes were developed for treating bamboo in green/dry, split and round form. However the latest breakthrough is achieved in treatment of bamboo and this new approach is much faster and more efficient while maintaining the economics of the treatment well within the reach to entrepreneurs one such a process VAC-FRI. D. strictus, B. nutans, B. arundinacea, B. balcooa and B. gigantius, species, known for structural and other uses were treated with 4% Borax: Boric acid by Boucherie, VAC-FRI, wick and diffusion processes. Natural durability and performance after treatment was evaluated under shade and ground contact. Results revealed that new process VAC-FRI is comparable to all other known conventional process.
S Tripathi, S N Nautiyal


Effect of fire retardants (monoammonium phosphate and diammonium phosphate, mixture of monoammonium phosphate and borax and ammonium sulphate) on beech wood with dipping and Lowry methods
2006 - IRG/WP 06-40350
In this study, the possibilities of using four kinds of chemicals as fire retardants with 12% concentration for beechwood (Fagus orientalis Lipsky) was surveyed. Providing testing samples that are related to the measurement of fire resistance properties according to JIS A-1321-1975 standard were evaluated. Wood samples were impregnated with Lowry and dipping methods. In this study, samples impregnated with diammonium phosphate by Lowry method had the best fire resistance properties. Wood samples impregnated with diammonium phosphate had the highest compression parallel to grain and highest resistance of hardness and samples impregnated by ammonium sulphate had the least total shrinking.
M Akhtari, D Parsapajouh, M Arefkhani


Effect of fire retardants (monoammonium phosphate and diammonium phosphate, mixture of monoammonium phosphate and borax and ammonium sulphate) on beech wood with dipping and Lowry methods
2006 - IRG/WP 06-40350
In this study, the possibilities of using four kinds of chemicals as fire retardants with 12% concentration for beechwood (Fagus orientalis Lipsky) was surveyed. Providing testing samples that are related to the measurement of fire resistance properties according to JIS A-1321-1975 standard were evaluated. Wood samples were impregnated with Lowry and dipping methods. In this study, samples impregnated with diammonium phosphate by Lowry method had the best fire resistance properties. Wood samples impregnated with diammonium phosphate had the highest compression parallel to grain and highest resistance of hardness and samples impregnated by ammonium sulphate had the least total shrinking.
M Akhtari, D Parsapajouh, M Arefkhani


Preservative treatment of strips of Bambusa balcooa by soaking process using Borax-Boric acid
2008 - IRG/WP 08-30478
Bamboo strips made from Borak bamboo (Bambusa balcooa) were treated with 10% borax-boric acid aqueous solution by soaking process. The moisture contents of the bamboo strips were 12%, 20% and 30%. The strips were soaked for one, two, three, four and five days. The penetration of the solution was investigated by colour test after soaking and drying. Full penetration was observed after three days of soaking in case of strips containing 12% and 20% M.C and the strips containing 30% M.C showed scattered penetration after five days. The retention of the preservative chemicals through the strips was calculated from the absorbed solution after treatment. Retention of 25.5 kg/m3 and 21.5 Kg/m3 was found through the strips of 12% and 20% M.C respectively after three days. The strips containing 30% M.C attained 20.5 Kg/m3 retention after five days. The strips containing 12% and 20% M.C were used for making composite products for the preparation of chair and table and kept for service test.
K Akhter, M W Sheikh, M M Rahman, T A Chowdhury, M H Chowdhury


Fungal decay resistance and durability of wood products made from borax-impregnated wood and bonded with corn starch and tannin adhesive
2009 - IRG/WP 09-30494
At present, the production of wood composites mainly relies on the petrochemical-based and formaldehyde-based adhesives such as phenol formaldehyde (PF) resins and urea formaldehyde (UF) resins, which are non-renewable and therefore ultimately limited in supply. This paper concerns the decay resistance of wood products bonded with a new, environment-friendly adhesive derived from abundant and renewable cornstarch and tannin.To improve the total resistance of the composite against both Coriolus versicolor and Coniophora puteana rots fungi, borax (di-sodium tetraborate) was added in proportions of 0.5%, 1% and 2% (w/w) to the cornstarch-tannin adhesives. The results showed that increasing the concentration of borax in the adhesive decreased the mechanical properties of the composite. The best way to avoid this problem was to use wood impregnated with borax. Biodegradation studies were conduced on new composites, first without any treatment, followed by borax at 0.5 % aqueous solution treatment. The results show that wood impregnated with borax, in presence of tannin and sodium hydroxide in the adhesive improves the total resistance of the wood composite against both Coriolus versicolor and Coniophora puteana rot fungi.
A Moubarik, A Pizzi, A Allal, F Charrier, B Charrier


Effect of borax-boric acid Treatment of simul (Bombax ceiba) Veneers on Glue-Bond Quality of Plywood
2010 - IRG/WP 10-40525
The glue-bond quality of plywood made of treated simul (Bombax ceiba) veneers was investigated. The veneers were treated with cold and hot water solution of borax-boric acid (BB) of different concentrations and treatment durations. The plywoods were made at three different pressures in hot press using urea formaldehyde glue. The glue-bond strength of untreated plywood in dry shear-test was found to be 2.17 and 2.29 N/mm2 made at 1.05 and 1.40 N/mm2 pressure respectively. It was observed that the values of load at failure of treated plywood in dry shear-test gradually decreased with the increasing treatment duration and concentration of solution. Comparison of the bond strength of untreated plywood with the treated ones made with urea formaldehyde glue showed that all the treatment combinations lowered the bond quality. It was also found that 10% BB solution and highest treatment duration (3 for cold water days and 60 minutes for hot water) lowered the bond strength of the plywood which met ‘B-grading’ requirement. However, the values of glue bond strength in all other BB treated plywood met ‘A-grading’ requirement for gluing. It may be due to the highest percentage of chemical deposition within the cell wall structure lowered the bond quality. For all the treatments, low values of shear strength were observed in plywood made of hot water-treated veneer compared to that of cold water.
K Akhter, Md Abul Hashem, S Akhter


Preservative Treatment of simul (Bombax ceiba) Veneers with Hot and Cold Water Solution of borax-boric acid by Soaking Process
2010 - IRG/WP 10-40528
Veneers of simul (Bombax ceiba) were treated with different concentrations of water- borne preservatives borax-boric acid (BB) by soaking process for different time periods. In the case of hot water treatment, it was found that the average retention of preservative chemicals increased gradually with the increasing treatment period from 20 minutes to 60 minutes. Similar trend was observed in the case of cold water treatment when treatment period was increased from 1 day to 3 days. The maximum retention (20.37 kg/m3) was observed from the samples treated with 10% BB solution for 60 minutes and in 2.5% BB treated samples, the average retention gradually increased from 5.35 kg/m3 to 7.16 kg/m3 when treatment duration was varied from 20 to 60 minutes. In the case of cold water treatment, maximum retention (22.97kg/m3) was observed from the veneers treated with 10% BB solution for 3 days and 7.35 kg/m3 retention was obtained when treated with 2.5% Borax-boric acid solution for 1 day. According to the Indian Standard (IS-1902), the retention of 4 kg/m3 boron compounds are sufficient to offer protection for non-structural purposes.
K Akhter, Md Abul Hashem, S Akhter


Effect of preservative treatment on dimensional stability of plywood made of treated simul (Bombax ceiba) veneer
2012 - IRG/WP 12-40575
The dimensional stability such as thickness swelling and water absorption of plywood made of treated simul (Bombax ceiba) veneers were investigated after 2 hours and 24 hours soaking under water. The veneers were treated with hot water and cold water solution of borax-boric acid (1:1), neem leaves and mahogany seeds of different concentration (1:10, 1:20, and 1:40) at different treatment duration. It was observed that the values of swelling were increased with the increase of soaking time from 2 hours to 24 hours. In the case of plywood made of borax-boric acid treated veneers, the percentage of swelling were increased with the increase of borax-boric acid concentration. The values of thickness swelling were also increased with the increase of treatment duration from 20 minutes to 60 minutes and 1 to 3 days. The values of swelling obtained in plywood made of neem leaves and mahogany seeds treated veneers were higher than that of borax-boric acid treated veneers and near to the untreated samples. The mean values of percentage of water absorption in plywood after 2hrs and 24 hours water soaking were determined. It was found that after 24 hours soaking, plywood made of mahogany seeds treated veneers absorbed more water than that of neem leaves treated veneers. All the values obtained from treated samples after 2 hours and 24 hours soaking were lower than the control samples. But it was observed that higher amount of water was absorbed in neem leaves and mahogany seeds treated board in comparison with borax-boric acid treated board. It was also noted that the values of water absorption in leaves and seeds treated board were near the values of untreated samples.
K Akhter, M Mahabubur Rahaman, A Ara


Development of composite furniture using bamboo strips, bamboo mat and rubber wood veneer
2014 - IRG/WP 14-40679
Bamboo offers cost-effective component in panel form is well suited to wood substitute can be used as furniture components. In the present study, borak (Bambusa balcooa ) bamboo were used for manufacturing bamboo panel. Mitinga (B. tulda) bamboo were used for making mat and rubber wood veneers were used for manufacturing mat overlaid veneer board. Borax-boric acid (BB) treatments were given to enhance the durability of mat, strips and veneer. The treatments were carried out using borax-boric acid (1:1) aqueous solution of different concentrations at different time schedule by soaking process. The optimum retention of preservative chemicals through mat, strips and veneer were determined. Using 5% BB solution, the average retention was found 21.90 kg/m3 in A (1.22 m X 0.91m) size mat and 24.39 kg/m3 in the B (0.61 m X 0.91m) size mat after 3 days soaking. Using 7% solution, retention of 25.17 kg/m3 A size mat and 28.44 kg/m3 were obtained in B size mat after 3 days treatment. In the case of bamboo strips, highest retention of 26.22 Kg/m3 was found when treated with 7% solution for 3 days. Highest retention 24.53 kg/m3 was obtained in 7% BB treated rubber wood veneers after 3 days soaking. Average retention of 22.07 kg/m3 was found when veneers were treated with 5% BB solution for 3 days. It was observed that, veneers were treated with 7% BB solution attained average retention of 19.20 to 24.53 kg/m3 after 1 to 3 days treatment. It was found that the retention were gradually increased with increasing concentration and time period. After preservative treatment, the materials were used in making composite products for chair.
K Akhter, M Mahabubur Rahaman, M H Chowdhury, M Zahirul Alam


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