Veneering glue

**Rocker** · 29th October 2003, 08:35 PM

Geoff,
I had just enough time, using AV203 UF glue with the summer powder hardener (SN) in the recommended ratio (1:3) to glue up six laminations a metre long, which took about 25 minutes. But I was working in very hot conditions (about 35C). In cooler conditions, the glue takes much longer to go off. However, as I mentioned before, I think the powder hardener makes the glue unsuitable for veneering because the granular filler makes the glue film rather thick, and the glue is fairly viscous even immediately after mixing.

**alf t** · 29th October 2003, 10:22 PM

Geoff,
All you need is a good PVA such as AVSyntec and a good vacuum press or the like. You could thin the PVA with water if it is too thick but don't get too wrapped up with technology if simple answers suffice.
Alf

**GeoffS** · 29th October 2003, 10:41 PM

Rocker -
I took your point about the powder but it sounds like it might be worth trying with the liquid - likewise heat can be a problem and my shed would be just as hot as your locality later in the year - if not hotter. I'll try the Triton glue first as explained below.
Alf T -
I have been hoping somebody would say that. That is why I am going to try the Triton PVA - it may not be as good as Syntec but it is certainly better than the common or garden varieties - it is supposed to be non-staining. I can buy it locally, the AVSyntec I would have to order from AVSyntec which would add postage etc to the cost plus I would have to wait!!
Thanks again

**alf t** · 29th October 2003, 10:44 PM

Geoff, The Triton is possibly Syntec anyway!!!!
Alf

**chris_hewett** · 31st October 2003, 09:06 PM

Geoff,

Talking about using yellow glue, and the comment that it goes off too quickly, I think some might be a little confused as to the technique used with PVA glues and veneer. My understanding is that you apply the glue to the pieces and ALLOW IT TO DRY. You then mate the two pieces, move to the position you want and then RE-ACTIVATE the glue with heat. That is you use the heat from an iron to MELT THE DRY GLUE. White PVA glues have a low melt point and will melt at around 82 degrees C and you can re-activate the glue indefinately, yellow PVA melts at around 121 degrees (between wool and delicate setting on iron) and can be reactivated up to several weeks after application and waterproof cross linking PVAs require around 177 degrees (cotton-linen on iron) and must be reactivated within about 72 hours.

The above info is taken from Fine Woodworking issue 108 from October 1994. I have not used this method yet, but plan to in a few weeks when I get to that stage in my loudspeaker project (For those interested, I am building a pair of 'Ariels' a complex transmission line design, picture attached)

Chris

**GeoffS** · 31st October 2003, 10:40 PM

Thank you Chris - I have been wondering about this because I thought(?) I had read something about using heat on PVA glues, but as nobody else had mentioned it I was thinking I must be mistaken.
Not sure how well it would work because my 'veneer' is my own cutting and about 1.5 mm thick - might have trouble heating through it. I will make some experiments.
I presume the picture above is a speaker box and not a maze for testing rat intelligence. What is it? Woofer, mid-range (it ain't no tweater) and is it just a single folded horn or is it applying front and back loading? Just curious as it looks so complex. Looked again - 2 seperate speakers each with their own port? Still don't see how it works at the bottom end.
Cheers and thanks for info.

**chris_hewett** · 31st October 2003, 11:43 PM

View from the side, front of speaker box is to the left (speaker holes not cut out yet). It is a midrange-tweeter-midrange design, the two mids have a tuned transmission line each and exit the labarynth out out of those eight holes you can see at the bottom of the side... The open bottom and top to be completed after the sides are mated. If you are interested I can start a new thread, dont want to hijack this one...

**GeoffS** · 1st November 2003, 07:23 AM

Certainly interested Chris but that is all. My own speaker boxes are far more modest and quite OK for our ears. You could comment though, what size speakers and what is the power rating. I get the impression the power rating is high (the material thickness) but judging by the mallet the speakers are not very big. Little boxes making big noises!
If I may I would like to forward the pic to a friend who still does make new boxes for his own use and can afford to make loud noises (no near neighbours)
Cheers

**chris_hewett** · 2nd November 2003, 12:27 PM

No problem with the picture Geoff. Speakers are 48" tall, 13.5" deep, 8" wide. Actually very efficient and were designed for very low power tube amps. As I am getting to the stage where I need to think about the veneering side of the project, does anybody have a good source for veneers in the Sydney area ( I live in Southern Highlands). I am more interested in the range/service/advice offered than price.

Thanks,

Chris

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