Fingerjointing
Hi Folks, and Richard.
Richard had a query about finger jointed boards yesterday -- I thought at
first that these couldn't be very strong, but remembered exchanging emails
with John Welsford in New Zealand about the "zigzag" scarf described in his
boatbuilding book. (for anyone who hasn't heard of him, go to
http://www.woodenboat.net.nz/Designers/Johnandboats.htmlHe also has his
own site with his designs listed, but I couldn't find the link and I've got
to get to work soon.) Fingerjoints are similar (at least in my mind, to the
zigzag scarf.
Anyway, John has had a career in selling mill machinery, as well as
boatbuilding and designing, so I thought he would be fairly knowledgeable
about fingerjoints. Here is what he had to say about the subject.
Hello Jamie, thanks for the email. Coincidentally I have just shepherded a
fingerjointer installation though its certification process so your interest
is timely. The 4mm joint is stronger than the surrounding timber when glued
with Phenol Formaldehyde ( Resorcinol is the usual domestic market name for
"red Glue")
and I know that the European style mini fingerjoint is noticeably stronger
than the larger fingers with blunt tips that you will see used in non
structural product made in the USA.
Yes you can use FJ Softwoods for structural purposes as long as they are
glued with the red( waterproof) glue, but do bear in mind that they seldom
bend evenly because of the variation in grain and wood density from one
piece
to the next.
Hope this helps.
Jamie
Richard had a query about finger jointed boards yesterday -- I thought at
first that these couldn't be very strong, but remembered exchanging emails
with John Welsford in New Zealand about the "zigzag" scarf described in his
boatbuilding book. (for anyone who hasn't heard of him, go to
http://www.woodenboat.net.nz/Designers/Johnandboats.htmlHe also has his
own site with his designs listed, but I couldn't find the link and I've got
to get to work soon.) Fingerjoints are similar (at least in my mind, to the
zigzag scarf.
Anyway, John has had a career in selling mill machinery, as well as
boatbuilding and designing, so I thought he would be fairly knowledgeable
about fingerjoints. Here is what he had to say about the subject.
Hello Jamie, thanks for the email. Coincidentally I have just shepherded a
fingerjointer installation though its certification process so your interest
is timely. The 4mm joint is stronger than the surrounding timber when glued
with Phenol Formaldehyde ( Resorcinol is the usual domestic market name for
"red Glue")
and I know that the European style mini fingerjoint is noticeably stronger
than the larger fingers with blunt tips that you will see used in non
structural product made in the USA.
Yes you can use FJ Softwoods for structural purposes as long as they are
glued with the red( waterproof) glue, but do bear in mind that they seldom
bend evenly because of the variation in grain and wood density from one
piece
to the next.
Hope this helps.
Jamie