Thread: Best glue to join Jarrah Edge

Hi David and welcome to the forums. I would think that something like Titebond II or III would be more than adequate for the job. You can get this at Masters or Carbatec. I have used these glues on Jarrah tables of varying length and depth with loose tenon joinery and have had no problems. I would think the dowels would be 10mm diameter (at least) I guess it would be best to allow the dowels to set in one half of the top before glueing the two pieces together. It would probably also be a good idea to give the faces to be joined a light go-over with fine sandpaper, just to remove any oxidation of the surfaces. You will also need to clamp the table quite securely for several hours I would think.

Regards,

Rob

Having made a few Jarrah tables I use Selly Aquahere and more recently Parafix PVA wood glue to which both will work fine in addition to as above with the titebond. Also as said above all the old glue must be removed back to new/bare timber.

I did research into this years ago.

The PVA types of glue do work in Jarrah, BUT after time (a few years) the acid in the sap in the Jarrah attacks the PVA. The vinyl expands and you get a ridge under the varnish of rubbery vinyl that rises up and looks feels crap.

In essence all soils in WA where Jarrah grows are slightly acidic side of neutral so the sap that remains after the wood is dry - is still acidic.

So I went thru the CALM library at the office and found a research report that destruction tested various glues on WA Eucalyptus timbers including Jarrah. They butt jointed boards them put them out in the weather near Narrogin at Dryandra - and monitored them for some years.

The consensus of the researchers basically seemed to be that Urea Formadehyde was best followed closely by Epoxy resin.

So we went all UF62 glues, for a few years, UNTIL - we had glue joint failures, start to appear. Whether the catalyst failed or what I don't know - but the glue crystallized and went brittle and joints were starting to come apart on furniture.

After that we went to Epoxy resins only. (Epiglass / EpiGlue and later megapoxy as it was cheaper).

We never looked back after that... still have furniture now made from Jarrah 20 years later with epoxy resin that have joints holding up well.

Others mileage may vary.

Cheers

Thanks for sharing the findings of your research. Did you look into whether the age and/or moisture content of the Jarrah had any effect on the longevity of the PVA glue joint? If so, what did you find?

I did study timber technology course once at tafe as part of forestry studies.

When I left CALM - I built our own seasoning kiln.

I had one of those Tramex brand non invasive impedance type moisture meters.

I dried Jarrah down to about 11%EMC - then let it recondition up to 12% emc before working it.

I didn't really get a chance to do anything much with green / improperly seasoned timber... and glue.. I was (still am) a fastidious batsurd about using kiln dried wood.

I've made some lengthy posts in the past about the intricacies of kiln drying, running a drying schedule, and removing sap (free moisture) inter cellular moisture and intra cellular moisture... if your really interested.

All I could imagine is that if you have more of the mopisture in any of those 3 forms within the wood - that you have the presence of even more acid - to attack the glue. Epoxy is impervious to acid - which is why it's a great glue for our timbers.

You can get away with using air dried wood for joinery - but there not much glue in Joinery work - the whole point of the joinery trade is to make mechanically strong joints after all. So you can get away with a little more movement in joinery than you can in cabinetry for e.g.

Green / unseasoned wood has has higher tangential radial and longitudinal shrinkage rates, that dry wood - and Jarrah's a reasonably high shrinkage rate compared to some other more stable timbers (sheoak for e.g.)

If you do glue these less stable forms of green / unseasoned Jarrah then your putting those joints under even more strain due to the higher shrinkage rates over time that using kiln dried wood.

Again I've posted before about the 3 different shrinkage rates of WA Hardwoods.

Its a big topic...

Short answer tho is lots do it (use wood thats not dry enough) - we are all human you use what you have at times.

Dry Jarrah has a "ring" to it... it has a different feel (weight wise) and even slapping a 6 x 2 length with the palm of your hand - you can tell if it really is dry or not, with enough experience.

I hate to think the volumes of 6 x 2 Jarrah that I dressed straightened over the jointer for joinery.... house lots at a time - and not just entry door - but every frame and jamb in the whole house - one house i did for one of the managers at the local Bunnings mill - was all the jambs and frames for his whole house (2 story) plus solid Jarrah doors to fit ever frame and jamb.

If you handle enough of it off the log green and into the kiln and then out of the kiln dry into storage racks and then out of storage racks and across the docking bench and then the jointer thicknesser etc - you get to be able to tell the difference without a moisture meter eventually.

A lot of what I milled and dried that was surplus to my needs - I used to sell to Ausdens Joinery.

Good days hard days - thank God they are over.

So green / air dried Jarrah and any glue basically doesn't mix.

Kiln dry it to about 12%EMC for the swan coastal plain & use epoxy resin you won't go far wrong.

Cheers

Thanks for the additional info