Are all pva's the same ?

[Streeter]

My friend always insists on using evostik wood glue. I on the other hand tend to slum it with cheaper brands . I'm not aware of any adhesive failures to date. As evostik can cost up to 3 x the price of ,say, everbond or no-nonsense I do wonder if there is more to the differential than a pretty green container. So, is there actually any appreciable difference ?

 

[Hudson Carpentry]

Strength, different batch mix tolerance, open/drying times.

 

[Streeter]

I have no idea what batch mix tolerance is !
Drying time seems broadly similar to me , I don't think I've ever come across a glue that cures too quickly to clamp unless it's a roasting summer day so ,yes , that could be an issue. But I guess I'm really most interested in final strength. I can't find any test data on this .

 

[Lowlife]

PVAs can be very different, some of the cheaper brands in particular can dry to a rubbery consistency which is hard to sand, there's one that I used to use for modelmaking that sanded better than any other, I forget the name now but it's important on very soft woods that it's easy to sand. I can't say I've ever noticed any great difference in strength, but then I've never actually done any controlled tests on PVA as I have done with PUs for instance.

 

[Hudson Carpentry]

I have no idea what batch mix tolerance is !
Drying time seems broadly similar to me , I don't think I've ever come across a glue that cures too quickly to clamp unless it's a roasting summer day so ,yes , that could be an issue. But I guess I'm really most interested in final strength. I can't find any test data on this .

When they mix the ingredients they will not be as strict with the mix ratio's.

How clear they dry is another.

 

[Steve Maskery]

My chemistry degree didn't cover PVAs, unfortunately, but I can say from personal experience that, no, they are not all the same. Definitely not.

My general reach-for PVA is Wudcare. It sets quite quickly; glue, clamp, make a cuppa and you are good to go on.

OTOH, for complex glue-ups I use one with a longer open time, like Everbuild or Evostick.

I've never had a PVA bond failure, but they certainly do not all behave in the same way.
S

 

[woodbloke]

OTOH, for complex glue-ups I use one with a longer open time, like Everbuild or Evostick.

S

I used to use Titebond III, which is a great, if expensive glue. I now use the D4 Everbuild glue which is equally as good, but as I can buy it locally for less than a fiver (for a litre of glue) the TBIII isn't used any more - Rob

 

[Dodge]

I'm with woodbloke - I only use Titebond 1 or 11 which is actually an aliphatic resin glue and far superior to PVA.

One thing I do not like is PU glues that foam on curing as I have had experience of excess glue swelling in the back of a mortice hole during curing and when the sash cramp is removed the pressure is sufficient to actually push the tenon out again. :shock:

 

[andersonec]

D3 is the usual type sold by builders merchants and the sheds, D4 is an industrial type and used a lot by kitchen worktop manufacturers, personally I use Cascamite, shelf life is longer as it's a powder, only mix what you need, it can be used for exterior work and is stronger than the usual D3 PVA.

Andy

 

[Hudson Carpentry]

I used to use EverStik's D4 glue (blue), it's a PVR not PVA and seems stronger to me but after using titebond I now only use TB1 and 3

 

[yetloh]

personally I use Cascamite, shelf life is longer as it's a powder, only mix what you need, it can be used for exterior work and is stronger than the usual D3 PVA.

Andy

Me too. I particularly value the long open time, although I use Resinmite which is the same stuff but cheaper from AG Woodcare than Cascamit and is available in a 750g tub which I find the ideal size for me.

Jim

 

[Jimbob101]

Titebond glues are the only way to go. All of their glues are vastly superior to any PVA on the market and resist creep for laminated curved work. They are also wood coloured instead of opaque white and do not show up as much if you miss cleaning up a bit. You can also sand them as they are hard and not rubbery.

 

[Jake]

All of their glues are vastly superior to any PVA on the market

The so-called aliphatic resin ones are a PVA - well, the actual glue bit in them is. The aliphatic resins are a modifier added to PVAs and other glues to increase the initial grabbiness - tackifiers - hence the gloopy texture. They do seem to add a lot of them, but the tackifiers do nothing to increase ultimate strength (in fact, all things being equal increased amounts tend to decrease it). What they do do is change the experience of using it in a way which is very cleverly calculated IMHO.

Which is not to say they aren't good glues, but they are totally overhyped.

I'd rather have a high quality euro-produced D4 cross-linking PVA at a un-hyped (but not bargain basement) price. I find the enhanced glorpiness of TB an irritant, given the increased difficulty of spreading it to the thinness which is actually required for a good bond.

 

[woodbloke]

D3 is the usual type sold by builders merchants and the sheds, D4 is an industrial type and used a lot by kitchen worktop manufacturers, personally I use Cascamite, shelf life is longer as it's a powder, only mix what you need, it can be used for exterior work and is stronger than the usual D3 PVA.

Andy

Well...I do wonder about urea formaldehydes . 'Cascacmite' was the glue of choice when I started out years ago but I found even then that shelf life was limited...after a short while in the tin it became unusable as the powder never seemed to mix properly. Then there was the wastage if you mixed too much...a bit difficult to 'unmix' it and put it back in the tin. That said it's great for things like veneering and laminating, but the sheer 'user friendliness' of modern PVA's and their derivatives mean that for me at least, urea formaldehydes glues (and similar) are left on the back burner for every day usage in the 'shop. There's also the slightly worrying aspect that uf's go off glass hard, which makes them unsuitable where some flexiblility is needed, as in chair joints...one of the reasons why the late Alan Peters never used them, sticking to PVA's instead - Rob

 

[Aled Dafis]

I actually need some glue this week, so you guys reckon that D4 is superior to D3, and that the titebond stuff is overhyped. I tried TB3 and didn't get on with it as it was too runny, I found that it would drop beads of glue all over the bench/work/me...

Is D4 better for laminating also?

Cheers
Aled

 

[Phil Pascoe]

"Resin W" interior is good for glue chucks- you can wash off what's left easily. There are hardly any left now that aren't water resistant.
If open time is really critical, you can always damp the joint down first.
Can anyone tell me why so many glues are supposed to be applied to one surface only? It doesn't seem to make much sense?

 

[yetloh]

Well...I do wonder about urea formaldehydes . 'Cascacmite' was the glue of choice when I started out years ago but I found even then that shelf life was limited...after a short while in the tin it became unusable as the powder never seemed to mix properly. Then there was the wastage if you mixed too much...a bit difficult to 'unmix' it and put it back in the tin. That said it's great for things like veneering and laminating, but the sheer 'user friendliness' of modern PVA's and their derivatives mean that for me at least, urea formaldehydes glues (and similar) are left on the back burner for every day usage in the 'shop. There's also the slightly worrying aspect that uf's go off glass hard, which makes them unsuitable where some flexiblility is needed, as in chair joints...one of the reasons why the late Alan Peters never used them, sticking to PVA's instead - Rob

There is undoubtedly a lot of personal preference in glue choice, and rightly so because just about any quality glue that is suitable for furniture is more than strong enough. I have not found a problem with the shelf life of UF glues provided that some basic precautions are taken. The most important of these is to buy from a supplier who sells plenty of it so that you can be sure it hasn't been sitting on shelf for a couple of years. The second is to reseal the air tight plastic tub that it comes in these days as soon as you have decanted what you need. I also transfer it into a smaller tub when there is not much left in the original, to reduce the amount of moisture laden air above the powder, which probably helps.

Coming back to the comparative properties of UF v PVA I do think the much greater open time of UF is of great value. When people say that the open time of PVA is a non-issue i do wonder what sort of glue ups they are doing. Perhaps they use the glue up in stages approach but I think this is a poor second best compared with doing it in one hit. For me, the big advantage of this is that it eanbles the cumulative effects of minute squareness errors that can sometimes occur in a complex structure up to be counteracted by selective clamping without placing excessive strain on any particluar joint.

As for Titebond, I do use it for some things but I don't like it. Despite its gloopiness I find it still has a real tendency to slide around where UF gives useful tack. Where it does score is in speed of curing which makes it particularly useful for jigs and small items.

Now, if someone can come up with a glue with the open time and tack of UF plus the cure time and flexibility of glue bond of PVA, then that would be a winner.

Jim

 

[woodbloke]

I think I was probably buying the uf stuff in large tins and not using it quickly enough, or not decanting it into smaller pots when the big tin started to get say a third, or half-way down.
Interesting and valid point about complex glue-ups Jim, which are a bit of a 'mare at the best of times. My solution of late has been to always try and break a complicated gluing situation into a series of much smaller ones. Even so, the rate that PVA's and similar glues go off and grab :evil: in the hot weather mean that I've got to be really organised and get the cramps on within 10 mins, after that it's a bit of a no-hoper. I may well give uf's another shot later on - Rob

 

[jimi43]

I'm 100% with Dodge....Titebond I for non-waterproof needs is the one I use simply because it has never failed me...even on guitar neck breaks which has to be one of the ultimate tests of strength. It resists drag with superior tack and as mentioned above is aliphatic resin...pva with modifiers which are important.

I think the hype is due respect for something that works better than most, a respect from me from experience...which means I choose it and pay more.

For waterproof PVA type uses I use the waterproof Evostick in the blue tub.

I absolutely cannot get on with UF glues at all. I have tried all suggestions from those who love it and it is still not working for me...but I like the colour of the tub from Titebond....lovely purple colour... :mrgreen:

Cascamite (and variants) can go off quite easily and then it is useless but for clean new wood with a fresh batch works well...particularly on butt joints

One tip I got from a model maker for rapid hard fixes and repairs is mixing PVA with CA glue...a good quality one. It works!

Jim

 

[Sgian Dubh]

My solution of late has been to always try and break a complicated gluing situation into a series of much smaller ones. Even so, the rate that PVA's and similar glues go off and grab ... in the hot weather mean that I've got to be really organised and get the cramps on within 10 mins, after that it's a bit of a no-hoper. I may well give uf's another shot later on - Rob

Rob, liquid hide glue has a useful extended open time of about twenty minutes, and that might be an alternative to UF adhesives. When I lived and worked in Texas-- brutally hot and humid mostly, at one point I just about gave up entirely on PVA and aliphatic adhesive formulations and switched over to liquid hide glue for most standard assembly jobs: even in Texas in July or August I got about 15 minutes to do a glue up with this stuff. As is the case with all adhesives liquid hide glue has its plus and minus points that I'll not elaborate on here. On a side note, you can extend the open time of PVA or aliphatic resins with up to ~5% additional water mixed in, which is sometimes useful. Slainte.