nasty glue line

[digger]

I've done a few projects that required edge joining timber to make wide panels. The Boards were planed and then glued with biscuits and sash cramps using selleys aquadere as the adhesive. Some weeks/months after finishing a fine line appeared where two boards joined. I've been using recyled australian hardwoods of various species salvaged from old building sites etc so they are well seasoned.

I've heard that its the pva glue tends to creep after time causing these glue lines. Is the glue the cause?

Does anyone know a good wood glue that is readily available for edge joining recyled australian hardwoods that won't produce a glue line after a couple of weeks/months.

Or is there a different method to stop or minimse this effect.

[Rocker]

Digger,
I have had the same problem with pva glue. I think the best solution is to use urea formaldehyde glue with a liquid hardener, obtainable from Timbecon. I find that the UF glue with a powder hardener that Carbatec sells tends to leave a more visible glue line, due to the filler that is added to the powder. You could also use Timbecon's full-strength epoxy, but that is twice as expensive as their UF glue. UF glue is the preferred glue for bent laminations also, since pva's tendency to creep makes it unsuitable for any application where it is under constant stress.

[DarrylF]

I think we've all had the same problem with PVA - in fact yesterday I noticed it has happened on a really nice box I made, just on the rear edge. It seems to only really happen on less than perfect joints - where I say edge join boards with edges that are a little rough and the glue line is wider it is worse.

Rocker is right - UF glue works well. I've done a bunch of cutting boards with it and the glue lines are perfect and don't move. You can buy a Selleys UF glue in a smallish red box at Bunnings etc. It is a little expensive though - about $30. I'm sure there are some other alternatives out there - maybe do a search for a site that outlines all the glue type options.

[Shane Watson]

Simple answer - dont use PVA.

Check out AV Syntec's Web Site (http://www.avsyntec.com.au) for detailed test reports etc.

There AV203 UF adhesive is exceptional in its performance and is specifically developed for edge joining of aust hardwoods.

[Sprog]

Originally posted by digger
Some weeks/months after finishing a fine line appeared where two boards joined. I've been using recyled australian hardwoods of various species salvaged from old building sites etc so they are well seasoned.

I've heard that its the pva glue tends to creep after time causing these glue lines. Is the glue the cause?

Does anyone know a good wood glue that is readily available for edge joining recyled australian hardwoods that won't produce a glue line after a couple of weeks/months.

Or is there a different method to stop or minimse this effect.

Although the wood is well seasoned the moisture content changes. Allow the wood to sit for a couple of weeks to allow all the pieces to equalise their moisture content.
Aliphatic resins are superior to PVA.
I use Titebond and Titebond II, never any creep with these glues.

Titebond literature (http://www.titebond.com/download/pdf/ww/4pageWoodGluesTB.pdf)