Veneering glue

[GeoffS]

I know glue appears to be a well exhausted topic, however I have not been able to find an answer to:-
A readily available glue (Bunnys, Dahlsens or mail order) which is suitable for gluing Aust Hardwood (Tassy Oak) veneer to MDF.
It would also need to tolerate reasonable warmth from having electronic gear placed on it.
Cheers - and I hope I am not starting a verbal war!

[chris_hewett]

I too am researching this topic as I am building some speakers that are marine ply interior and MDF exterior. Reading an old Fine Woodworking magazine they had an article on veneering using yellow glue and a heat source to activate the glue. They recommended titebond II. I bought a couple of bottles from Carba tec, 500ml bottle for about $12. Have not started the veneering yet, so cannot tell you how it works yet...

Hope this is of some assistance.

Chris

[Rocker]

AV Syntec (http://www.avsyntec.com.au/) recommends one of their urea-formaldehyde glues for veneer on MDF. They have a distributor in Mildura.

[GeoffS]

No they don't - the local distributer stopped retailing anything as at 1st September. Don't believe everything you read on the WEB!!!
Have to do some more searching.
Found another problem - found the Selleys u/f glue and it is EXPENSIVE. If the other one is anything like as expensive it would be cheaper to forget veneering, just use solid timber!!

Cheers and thanks for the help even if it was a a bit of a miss.

[Rocker]

Carbatec feature urea formaldehyde glue in their catalogue. It is a bit pricey at $42 for a litre. In Brisbane they sell it with the summer hardener, which means that the pot life of the glue is 3 hours, even at 30 C. This is fine for bent lamininations, but maybe not for veneer. If you can get the winter hardener instead, the pot life and clamping time are much shorter.

Timbecon also have UF in their catalogue cheaper; what they do not tell you is that they are out of stock, so I waited 10 days for it in vain after ordering it online; I was not informed that they were out of stock until I rang to find out why my order had not arrived. This is Timbecon's 3rd strike as far as I am concerned, so they are out!

[GeoffS]

Thanks for that info Rocker - I might follow up on those although they are still rather expensive. I find 2 mix glues a bit wasteful. You have to mix up more than you think you will need, (so that it all goes off at the same time and you can't waste time mixing more) and I don't know how viscous these are but some are very viscous and that leads to waste also.
I might just try yellow glue for my first experiment. It works well for laminating and veneering isn't that different particularly as my veneers are rather thick.
Yes Timbecon are a bit eratic - when they are good they are very good but - you know the ditty!
Thank for your help
Cheers

[Rocker]

Geoff,
I am inclined to think yellow glue sets too quickly, except in cold conditions, to be useful for veneering, at least if you are dealing with large areas. I would also disagree with your statement that it is satisfactory for bent laminations. It is liable to creep under stress. It may be OK for thin laminations that have gentle curves, but thicker laminations with tight curves would be liable to fail.

[echnidna]

Most antique furniture was veneered using hide glue which may be a little difficult to find these days. But ordinary supermarket gelatine is exactly the same except it has been prepared under hygenic conditions as a foodstuff. The only thing is you must mix it stronger than a food jelly mix and I have forgotten the proportions as a glue but its cheap enough to experiment with.

I expect if you can find the mass to water volume ratio (online or in a library) for traditional hide glue that will be near enough

[echnidna]

Ordinary pva reactivates exactly the same as yellow glue does but it can cause black stains in some timbers.

[DarrylF]

GeoffS,

Slightly left field here, but I gather you're building an entertainment unit, and I gather you're using plain tassie oak veneer (or wanting to anyway) - why not just buy the MDF pre-veneered? Definitely easier, and quite possibly cheaper. I've used this stuff with a Jarrah veneer and it comes up nicely.

And yes, you can get it with genuine un-finished veneer on it - not talking about the plastic looking stuff.

[AlexS]

I've had success using 2 pack epoxy for veneering. but it needs to be vacuum bagged or clamped for a while.

At present, I'm trying Hardies Hydropoxy 501, which is really designed for hardboard, but was all I could get in small amounts in a hurry. It seems to work OK but has to be clamped for 24 hours +. I'm using Tassie oak on mdf. Don't know how it would stand up to heat, but other epoxies have given no problems.

When using epoxy for veneering, you need the thinnest possible layer on each surface.

Good luck.

[GeoffS]

Whew! suddenly a hole host of replies to this.
DarrylF - Not sure where I would now go for veneered MDF locally - the firm that used to retail the Syntec products is also where we used to buy veneered MDF - no more retail sales. Basically we only have Bunnies and Dahlsens here. Otherwise one can try the local 'cabinet makers' however they are so busy making kitchen cupboards for the housing boom that never lets up here most don't want to talk to you. Anyway - I have never tried veneering so I want to do my own - even to cutting my own veneer out of some hardwood - interesting exercise.
Echnidna - Hide glue - I threw out my last glue pot, it had developed a leak but I think I still have some pearl glue somewhere. A couple of firms advertise pearl glue, but my main worry there (apart from putting together a new glue pot) is that it can go off rather quickly and needing to work the two surfaces together until it starts to grab. The proportions to mix - 1 lb of glue to 1 1/4 to 1 1/2 pints of water. (with acknowledgment to 'The Australian Home Craftsman' by Alex Smith publishing date 1929) Yes, ordinary PVAs do stain and as it is likely to creep through the joins I would prefer not have a heap of parallel lines!! I am thinking of making an experiment with the Triton crosslinked PVA - it is not supposed to stain.
Rocker - I wasn't talking about bent laminations - under those stresses I think it would creep. And yes, it does go off a bit quickly, particularly if you apply only a thin layer. I got caught by that today assembling a frame - all fitted OK on a dry test then one corner gave me trouble in the final glued assembly, by the time I finished fiddling with it the glue was definately off - fortunately not very important, there are other bits to hold it together.

After putting all this on paper (screen) I am beginning to think that hide glue is worth a try - now where do I get a glue pot?

Cheers all

[echnidna]

2 alternatives to a conventional gluepot.
1. Some craft shops sell a small pot (about the size of an ashtray) for working with hotmelt glue sticks
2. Use an old electric frypan, fill with water. Put your glue in a large jam tin in the middle, works very well though its a bit cumbersome.

[Rocker]

Since my last post on this thread, I have tried out the urea formaldehyde glue that Carbatec sells (AV203 with a powder hardener). It is fine for bent laminations, but I doubt if it would be good for veneering, unless you can get the liquid hardener instead of the powder one. The powder hardener, which also contains filler, is a bit granular and makes the glue rather viscous. It would probably form too thick a film to be suitable for veneering
The UF glue that Timbecon sells, however, (when they have it in stock) has a liquid hardener and is less viscous.

[GeoffS]

Echnidna - I might look in the craft shops - if that doesn't work I'll try the 2nd hand shops for an old frypan - actually that sounds quite good, no need for a gas burner going.
Rocker - How long to did you get to work with the UF glue, assuming you didn't use too much hardener? I always thought they went off rather quickly - or certainly went very viscous quickly.
I am going to try the Triton glue for my first experiment - it is the bottom shelf of an entertainment unit and will be completely filled with LPs - the veneer will have no hope of coming off, and it will never be seen.
Thanks for the assistance and I will post my results.
Cheers

[Rocker]

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]

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]

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]

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

[chris_hewett]

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]

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]

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]

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]

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