I had a 250ml tin of Septone contact adhesive in the cupboard that I used a couple of years ago to glue on some footpads. I only used about half the tin at the time. Got it out of the cupboard yesterday to glue on some other footpads and when I opened the tin it was goo and unuseable. The lid appeared to be on tight. Is this about right?

This arvo I bought a new tin and smallest size they had was 500ml so I'm wondering if there is some way to help increase the shelf life after opening and what maximum shelf life you could expect?

the local hardware man gave me a tip when I complained about contact shelf life, he said, "put it in a sealed plastic bag and store it upside down". Since then that's what I've been doing, and it's probably more than tripled shelf life.

But yes, even when the lid appears to be on tight, it can still soon loose it's solvents and turn into unusable goo.

That's a great tip
Agree number of times you think I have just the product for that job and go and get it and its useless.

Yes it has a shelf life and its not very long. Yes you can improve shelf life by storing cans upside down (glues paints spray cans resins all benefit) better still is what's called a nitrogen blanket, a spray can full of a nitrogen rich gas mixture sprayed into storage bottles & cans before sealing them up, it pushes out water vapour oxygen etc and leaves a heavier than air layer of inert gas. It's essential when storing two part epoxy or polyurethane casting resins which will bubble and cloud if they absorb any water. However.....there is always a however, contact glue works by having a fast degassing compound (amines as far as I know) which is what lets them dry so fast, this makes them inherently unstable and so they don't like being stored for any length of time. They tend to thicken, separate, dry out or loose their consistency. This makes old glue un reliable and a bad attempt to save money.

Ive been shopping with these guys for years who sell one brand along with other interesting casting and moulding products.
www.barnes.com.au/release-agents/dry-air-f720-spray-1239

Select to expand quote

peterowensbabs said..
... better still is what's called a nitrogen blanket, a spray can full of a nitrogen rich gas mixture sprayed into storage bottles & cans before sealing them up, it pushes out water vapour oxygen etc and leaves a heavier than air layer of inert gas.

You'd have to use xenon or argon gas to get a layer heavier than air. Oxygen is slightly heavier than nitrogen. The nitrogen "blanket" is not really much of a blanket since air is about 80% nitrogen.

Select to expand quote

boardsurfr said..

peterowensbabs said..
... better still is what's called a nitrogen blanket, a spray can full of a nitrogen rich gas mixture sprayed into storage bottles & cans before sealing them up, it pushes out water vapour oxygen etc and leaves a heavier than air layer of inert gas.

You'd have to use xenon or argon gas to get a layer heavier than air. Oxygen is slightly heavier than nitrogen. The nitrogen "blanket" is not really much of a blanket since air is about 80% nitrogen.

Yes its is 70% N but it is not pure nor dry. I can only vouch for the fact that it works. I don't know the exact chemical make up of the stuff but it is heavier than air as you can see the vapours pushing out condensation etc.

Have put opened seam sealant in freezer in it's metal tube - bagged with a clear label due sharing food storage. Pretty amazing to find it good to use after a couple of years - and still can repair a wetsuit or tent-hole.

peterowensbabs thanks for that!! I've been looking for dry air blanket since ERA stopped making it and many places told me you just can't buy pressure packs of any brand of dry air. Now at least I know of a brand to look for resellers

Select to expand quote

peterowensbabs said..
I can only vouch for the fact that it works. I don't know the exact chemical make up of the stuff but it is heavier than air as you can see the vapours pushing out condensation etc.

The Safety Data Sheet shows that F720 consists of 30-60% "hydrocarbon propellant", which is stuff like propane or butane. Both gases are much heavier than air, and should form a nice protective barrier. So it's more a blanket to keep air (and nitrogen) out than actual "dry-air".

Select to expand quote

Mark _australia said..
peterowensbabs thanks for that!! I've been looking for dry air blanket since ERA stopped making it and many places told me you just can't buy pressure packs of any brand of dry air. Now at least I know of a brand to look for resellers

I get it through Barns Products but they are expensive (I work in film so they pay for fast reliable delivery). ERA became very unreliable both in terms of stock and delivery dates! Im sure you can find the supplier/,manufacturer of this brand.

Select to expand quote

boardsurfr said..

peterowensbabs said..
I can only vouch for the fact that it works. I don't know the exact chemical make up of the stuff but it is heavier than air as you can see the vapours pushing out condensation etc.

The Safety Data Sheet shows that F720 consists of 30-60% "hydrocarbon propellant", which is stuff like propane or butane. Both gases are much heavier than air, and should form a nice protective barrier. So it's more a blanket to keep air (and nitrogen) out than actual "dry-air".

I buy the large tubes of no name Contact adhesive from the local 'Cheap hardware' store for a couple of bucks a tube. It seems to work every bit as well as the 'name' brands.

Flipping the can upside down seems a great idea .
Its the fumes that makes the glue.
A new glue will stink more than an old glue.
The use by date is printed large on these glue tins.
I pick the back tin with the newest dates