Thread: How long should PU glue last

Hi Bob,

Their tech sheet says minimum shelf life 1 year - presumably that is if stored according to recommendation:

http://www.targetsupply.com/pdf/data...e_techdata.PDF

Regards,

Brian

Originally Posted by homey

Hi Bob,

Their tech sheet says minimum shelf life 1 year - presumably that is if stored according to recommendation:

http://www.targetsupply.com/pdf/data...e_techdata.PDF

Regards,

Brian

Thanks Brian, that probably explains it, 3 years in a hot shed is not going to be too good. Interesting that the Titebond PU lasted for longer although it did crust up a long more - of course there was a lot more air space above the glue level;.

I think if you look after it, it will last forever. Everybody knows that PU cures by moisture, what I found was that, just before PU cures, evaporation of solvent takes place. So as long as your glue has a reasonable amount of solvent in it, you can rejuvenate your glue with added solvent. I have a Gorilla PU glue that I bought from Masters all those years ago, sitting in the garage while I was in NZ. When I came back, it has sort of gone quite thick. Not wanting to throw it away. I thinned the glue with a solvent, gave it a good shake and it was just as good as new. After I finish, I place a kid's balloon over the tip to try to keep the evaporation down. I'm still using it.

Polyurethane glue catalyses with the moisture in the air, if you could store it in a vacuum it would keep forever, but once it’s exposed to air, and therefore moisture, the process starts. I have lost track of how many half full bottles of that foaming poly wood glue I’ve thrown out, It’s bloody annoying, and it’s good glue too. There’s a sika one with a Superman on the label which comes in a cartridge for a caulking gun which I’ve found lasts the longest, most likely because there’s no air in the container it’s in.

Thanks everyone for the responses .

The gorilla PU has an odour of strong acetic acid so wondering is that is the solvent but I am reluctant to add vinegar because most of what is commonly called vinegar is 96% water.
Pure acetic acid is a surprisingly good solvent and is available but it costs more than a replacement bottle of the glue.

The instructions say is if thickens (which it has), to thoroughly remix the contents of the bottle. I have done that but it doesn't seem to have unthickened that much.

Meanwhile I have parked the glued up pieces in the sun and the glue does seems to be hardening albeit slowly The pieces are nothing special and I have plenty of replacements so if it fails I can easily remake them.

There’s a very good little chart in an article by UK woodworking guru Marc Fish (Furniture & Cabinetry, issue 167)

https://marcfish.co.uk/wp-content/up...ort-cutsah.pdf

Regards,

Brian

Well its definitely hardening now. Today was really humid so that might have something to do with it.

Originally Posted by BobL

Well its definitely hardening now. Today was really humid so that might have something to do with it.

If you thin it with a solvent, like acetone or paint solvent, not acetic acid, it will make it easier to harden.