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Users of lumber are probably familiar with bluestain. Some may wonder if the amount and type of stain transmitted by the mountain pine beetle affects the wood in any way. Comprehensive testing recently confirmed that beetle-transmitted bluestain has no practical effect on strength properties or gluing characteristics. Neither does the bluestain affect the adhesion of furniture finishes. The stain causes some possibly beneficial changes to dimensional stability, checking and permeability.
Blue-stain lumber is harmless to one’s health, and does not affect the use of lumber in building construction.
Technical data provided by:
FPInnovations - Forintek Western Region
2665 East Mall
Vancouver, B.C.
Canada V6T 1W5
Telephone: 604 224-3221
Fax: 604 222-5690
Forintek Canada Corp. is Canada's national wood products research institute. Their role is to support the forest products industry in optimizing manufacturing processes, extracting higher value products from the available resource and meeting customer's expectations of performance, durability and affordability.
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Summary of tests carried out by Forintek on blue-stained wood |
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Test |
*Number of Test Specimens Blue Stained / Non-Stained |
Results |
Relative Density ASTM D2395-93 Method B |
220/220 |
No Statistical Difference (NSD) |
Bending modulus of elasticity ASTM D143 Section 8 |
220/220 |
NSD |
Bending modulus of rupture ASTM D143 Section 8 |
220/220 |
NSD |
Impact bending strength (Toughness) ASTM D143 Section 11 |
220/200 |
**Blue-stained wood 5% lower impact bending strength |
Truss plate tension splice test CSA S347 -99 (modified) |
60/60 |
** Blue-stained wood 6% higher grip capacity |
Dimensional stability/checking Forintek test method |
54 (3 Packages of 18)/54 |
NSD |
Absorption of preservatives Dip Treatment Pressure Treatment
Forintek test method |
60/60
60/60 |
Blue-stained wood absorbs significantly more wood preservative |
Gluing Block Shear Test ASTM D905-89
Delamination Test D1101-92 |
3 Replicates of 30 samples x 2 glue types x 2 wood types (stained/Non-Stained)
1 replicate x 30 samples x 2 glue types x 2 wood types |
NSD
NSD |
Finishing properties Visual assesment Forintek test method
Adhesive tape tests ASTM D33359-93 |
40 two-sided panels
80 |
Blue-satin can be disguised with dark finishes
NSD |
NSD - No Statistical Difference
* These are numbers planned. Actual sample replication was usually larger.
* Although these differences are statistically significant they are regarded to be of no difference from a practical point of view. |
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