Quick PVA questions

[No skills]

Hi all,

I've been laminating some thin timber onto a plywood box (cladding/veneering sort of) but I've had to stop before the job is finished, theres been plenty of squeeze out of pva glue over the remaining unclad bits of box (which I have wiped off with damp rag).
Question is will I need to key the plywood with some sandpaper before I restart the job tomorrow? I was wondering if the squeezed out glue would of sealed the surface preventing good adhesion next time? The ply is slightly curved so I need a good bond to help with the addition of the less curved timber.

Second question is about pva's lifespan in the bottle, I have been offered a couple of unopened bottles which are a year or more past their 'use by' date on the bottle. I'm not so much bothered by the date (been using some from the same batch) but more the fact that they have been kept in an uninsulated storage space since they were purchased, will the cold have ruined the glue somehow?

Novice questions I know but I don't normally do this sort of thing

Thanks for any help!

 

[jim_hanna]

Hi all,

I'm not so much bothered by the date (been using some from the same batch) but more the fact that they have been kept in an uninsulated storage space since they were purchased, will the cold have ruined the glue somehow?

PVA is ruined if it freezes.

Regards
Jim

 

[marcros]

it can be damaged by frosting, although some glues can stand it. Titebond dont recommend freezing it, but say that it can stand freezing and thawing up to 5 times. Sometimes it has a cottage cheese like consistency, or dries powdery. Best solution would be to open it and try some on some scrap.

 

[Paul Chapman]

I would give that old PVA a miss. PVA is water-based and if it's kept in a cold place, below about 5 degrees C, the constituent parts will separate and it's then useless.

In the overall scheme of things, adhesive is quite cheap, so buy some new stuff and keep it indoors in the winter.

Cheers :wink:

Paul

 

[ericholl1]

I would give that old PVA a miss. PVA is water-based and if it's kept in a cold place, below about 5 degrees C, the constituent parts will separate and it's then useless.

In the overall scheme of things, adhesive is quite cheap, so buy some new stuff and keep it indoors in the winter.

Cheers :wink:

Paul

Is there much difference between quality of PVA available? or is it mostly standard? could I use the PVA I get in 5lt tubs to use when plastering or is a different type of PVA?

 

[Paul Chapman]

I would give that old PVA a miss. PVA is water-based and if it's kept in a cold place, below about 5 degrees C, the constituent parts will separate and it's then useless.

In the overall scheme of things, adhesive is quite cheap, so buy some new stuff and keep it indoors in the winter.

Cheers :wink:

Paul

Is there much difference between quality of PVA available? or is it mostly standard? could I use the PVA I get in 5lt tubs to use when plastering or is a different type of PVA?

I am aware of the PVA you are referring to but I've not used it so can't really comment. I use EvoStik Resin W, either the standard one in green containers or the water-resistant one in blue containers.

Cheers :wink:

Paul

 

[Phil Pascoe]

If you do any turning you could use up your old stuff sealing the end grain of sawn down timber. For a general purpose PVA, I find Everbuild D4 as good as anything. It's 100% waterproof, and compared to Titebond it's cheap.

 

[andersonec]

The PVA bought in tubs for sealing is just that 'for sealing' although called 'PVA bond' it is for sealing plasterboard and other porous materials. PVA adhesive is for gluing wood and can be obtained in various grades, D2 is for internal work only, not water resistant. D3 is for general joinery work and is water resistant. D4 is suitable for outdoor work doors windows etc. some kitchen worktop manufacturers use it, I suppose it could be classed as waterproof. This is only information I have gleaned over time but I am sure there will be more knowledgeable users on here.

Andy

 

[Phil Pascoe]

, "I suppose it could be classed as waterproof."
The manufacturers state on the bottle that it is 100% waterproof. That's a bold statement if it's not.