Thread: What is 'FJ' Pine?

FJ stands for finger jointed.

This is when they connect smaller pieces of wood together with joints that look like interlacing fingers (hence the name of finger jointed). This means that small sections can be joined to form a longer section. It is usually much cheaper than normal pieces of timber but each section can differ markedly in terms of colour / grain / look etc.

Hope this helps. Gavin

Woodwould

I think you may mean VJ pine which is a board with tongue and groove and about 140mm minus the t&g wide 10mm thick often used for lining of a house. A lot of the much older houses sport this timber. Its now used for feature walls in form of pannelling, and used in quite a lot of furniture. It usually has a v shaped groove along the outer side about 2 to 3 mm deep. its not too bad for a cheaper timber for lots of jobs.

I have used the timber Gavin mentions and called FJ pine. A lot of boards used for facia are this type of board, usually finger jointed to prevent twisting and curling up.

Regards Mike

Thanks chaps! Finger-jointed makes sense for the stuff I was looking at. I thought initially it might have been F****** Joke!

As time goes by, the sections used to make up FJ pine products are getting smaller and smaller.....

When the pieces get REALLY small we'll just call it chipboard

I'd love to see the machinery that joins all this stuff together in operation. I imagine it would be highly automated. Has anybody got a link to a video of this process?

ajw

I agree - it would have to be highly automated to make it worth using knot-free lengths as short as 3" (which I've seen in some 75 x 75 FJ pine posts I bought recently) !!

I'm thinking a really BIG machine...lots of levers...flashing lights....maybe Wallace & Grommit's Pine-o-matic??

Originally Posted by Mr Brush

I agree - it would have to be highly automated to make it worth using knot-free lengths as short as 3" (which I've seen in some 75 x 75 FJ pine posts I bought recently) !!

I'm thinking a really BIG machine...lots of levers...flashing lights....maybe Wallace & Grommit's Pine-o-matic??

Reminds me of the Chicken Run movie. Mrs Tweety's machine: Chickens go in, pies come out.

ajw

LOL - I was thinking of the Knit-o-Matic, I'd forgotten about the chickens....

Originally Posted by ajw

I'd love to see the machinery that joins all this stuff together in operation. I imagine it would be highly automated. Has anybody got a link to a video of this process?

ajw

No video, but I toured a glu-lam plant many years ago, and the finger joints were made at each location by jogging one of the timbers sideways by half a finger's width. Then a single rotary cutter with multiple fingers passed vertically through the gap, cutting both sets of fingers. At the next station, a glue-coated brush passed through the gap (with the offset now un-done), and the timbers were pressed together for clamping. There might have been a heating station to accelerate curing of the glue. Essentially, the timbers were made into a single quasi-infinite length, but cut to the required lengths at another station along the line, and stacked for assembly. Probably a similar process for stock lengths of moulding, etc.

The principal reason for such finger jointing is to increase yield of material, from pieces too short otherwise, and/or to exclude knots. Finger-jointed moulding is best painted, for appearance, although I've seen clear finishes in cheaper construction. For glu-lam beams, specifications usually limit finger-jointed parts to the interior layers, or to near the ends of the beams on the tension layers. Selective assembly accomplishes this.

Cheers,
Joe

I was back in Boston, USA earlier this year where eastern white pine is ubiquitous and everything seemed to have been finger jointed. Individual sections from 400 to 1500 mm long.

And thicker timbers were actually laminated from thinner pieces. eg 4x2 was laminated from 4x1's. Guess this is because thinner wood spends less time in the drying kiln, and it is thus cheaper to laminate than cut to 4x2.

Also was impressed by the overall quality of the product. White pine is at the bottom of the desirability table and is the cheapest timber. Aus radiata processers have a lot to learn!

Cheers

Graeme

Northtech Semi Automatic Finger Joint System from Hermance Machine Company

It stands for Fu#$in Junk!

Originally Posted by ajw

I'd love to see the machinery that joins all this stuff together in operation. I imagine it would be highly automated. Has anybody got a link to a video of this process?

ajw

Both yes and no.

The automated machinary are worth millions of dollars, then you still have to buy the computers and software to run it and pay yearly licensing fees on the software... and built the framework for it to run on and then build the conveyor system and maintain it...

I have worked in the mills in NZ years ago...

Some are automated, some semi-automated, partially automated, or just plain old manual operated using man/woman eye... (if you get the chance have a tour of a modern working timber mill it is fascinating)

The biggest and best use scanning, infrared and ultrasound to check for imperfections, gum pockets, foreingbodies (nails, hooks,, pegs, etc), they also use those methods to grade the timber according to what is needed... it is immensly complicated and starts at log level...

I'll try and explain without letting trade secrets out:
When the log is loaded into the plant, the timber is moved about by a operator sitting in a closed room with a pc and camera's scanning the log to see the best way to cut the log, dress it etc...

The bits are then sent to various sections of the mill by this operator according to grade/colour/sap/etc.

At the next step the timber is then graded using the above mentioned scanners/eyes/ultrasound, hammers further for imperfections, gum pockets, foreign-bodies (nails, hooks,, pegs, etc), Here the timber is pre-graded to application (i.e. clears, FJ moulding, structural, framing, or simply for gluts and fire only, etc)

The timber is then cut to size and dressed according to the above...

Then the timber is shoved in a kiln to dry (they use moisture meters, etc here)

Then the timber is FJ'ed (Finger Jointed)

Here the timber is also assigned or reassigned according to what orders the mill has, i.e. if they have a glut of orders for FJ mouldings and have plenty of structural grade FJ, they will use the structural FJ and cut it up into mouldings...

Here the timber will be further sorted into quality and LOSP grades (H1.5 to H6) and or CCA... They timber is then flashed off (LOSP) or Kiln dried (CCA)...

The timber is then shipped to wholesaler...

Disclaimer: Some steps and crucial bits are left out on purpose...