Thread: Question re "F" rating

Originally Posted by Zed

Any of you guys know about this "F" rating thing or can answer any of my questions ???

F rating is simply a measure of strength (as you have suspected). The higher the 'F' number, the stronger the wood.

No idea about food safe - I would guess that structural timber would have been treated. I suppose you could get a piece analysed if you have worries.

Originally Posted by Zed

1) would there be any pesticide treatment in the timber ?
2) would the existing glue be food safe ?
3) Can I use PVA as a bonding agent on a chopping board ?

Zed,
This one for the boyz from Grafton!!

1) unlikely, in fact almost certainly no, except for the spider and roach spray your mate may have used over the years

2) Probably, but maybe not! A beam of that age almost certainly does not have waterproof glue in the laminations. That almost certainly means that water and tomato juice will eventually dissolve it, whether or not it becomes a food contaminant ..... well I think I would rather not go there. Having said that, lots of lam-beams have been used for the same purpose without being listed on a World Health Organisation list!

3) I wouldn't - too dodgy round water and will eventually fail. I'd use epoxy, which is inert once it has cured.

As for "F" grading you are correct in that it is a measure of Stress capability, go HERE for a brief but informative overview of the stress grading system, although it doesn't appear to mention "E" as a measure of stiffness.

Cheers,

P

Oh well, I suppose I'll take it up to "my workshop" and get them to delaminate it a bit and use it as a frame for a work bench or some such non eating purpose.

Perhaps a end grain table top might look cute. coupla bits of inserted white wood (Ash or tassie oak) to break up the dull ironbark and bewwwwwwdiful mate!

Originally Posted by Zed

Hi,

1. would there be any pesticide treatment in the timber ?
2. would the existing glue be food safe ?
3. Can I use PVA as a bonding agent on a chopping board ?
4. Any of you guys know about this "F" rating thing or can answer any of my questions ???
Zed

G'day Zed.

If is as old as you say, it may be treated with either CCA or Creasote.
Have a good look at it and see if the is any sapwood on any of the lamellas.
You will know the sapwood from the true wood by a noticable colour difference in the one piece. If the sapwood is a greeny,bluey grey, then is is CCA treated. If the sapwood is a grey/black colour then it is Creasote treated. If the sapwood is cream/white/ grey, it is untreated.

The original glue may well be a formaldahyde bases adhevise...(BAD)

PVA... doesn't like water? I wouldn't use it

F is a strength rating.
Hooroo.
Regards, Trevor
Grafton

very unilkey to be pesticide treated.
If the glueline is dark the glue contains formaladahyde - a health hazard.
If the gluline is invisible the glue is probably urea based - health hazard unknown try a google search.
Crosslinked PVA would be ok - according to theory normal pva isn't.
But I made some hardwood laminates for a desk about 10 years ago with ordinary pva. A friend grabbed my offcuts and has used them as everyday cutting boards since without any problems at all. So much for the theory that ordinary pva is no good for cutting boards.

Originally Posted by Zed

:

would there be any pesticide treatment in the timber ?
would the existing glue be food safe ?
Can I use PVA as a bonding agent on a chopping board ?

Any of you guys know about this "F" rating thing or can answer any of my questions ???

Gidday Fellas,
*Being IBK the chances of CCA or Creo in the timber is low, however I wouldn't use it for food prep surfaces for my family just in case, I like to know the complete history if that is to be its fate.

*See Above answer

*Yep you sure can I did (15-20 yrs ago)and dumb luck has seen it last so far, mind you it doesn't see much moisture, just a wipe down. Now I know better I wouldn't do it again.

Any of you guys know about this "F" rating thing ?
Yep, where do you want me to start? If you really want to learn about Visual Stress Grading, send me a PM. But as has been stated previously by some of the many wise members that abound "F" stands for fracture and the higher the following number the better the timber will respond in a load bearing position. FYI the common ironbarks (RED, Narrow & Broad leaved) can reach the dizzy heights of F-34, which is the second strongest grade there is under the ISO's

Sorry forgot to say, the "F" rating can be applied to treated or untreated timber, this standard doesn't recognise if the timber is or isn't treated. "H" ratings are whats applied for treatment levels, completely separate animal is our "H" ratings.

Bruce......Mate.......Want to buy some hand planes??????

Went garage saleing on saturday.
Picked up a falcon
and a little stanley round top thingie all for $5.
Hooroo

Gents,

A wealth of infomation. thank you. I had a look at the timber and black sludge has come out one of the ends, I think it may be creosote, thus I cannot in good concience use it for chopping boards, either for your family or mine. discussed it with SWMBO and we have (read she) decided that it will make a perfect outdoor bench. it will even stand the weight of my fat **** if it is F34!

thanks lads.

Glad to be of assistance Zed, garden seating sounds like a wise idea, F-34 will stand your weight, my mass, and a couple mack trucks thrown in for measure.

Trev, will be in attendance in the morning, bring them.