Does Sanding Sealer go off

[Stephen Jones]

Hi,

I have a tin of HMG Model Sanding Sealer, i have no idea how old it is and it has been opened but is sealed well . The tin is 250mls and the price on the lid from the Hobby & Model Centre Bolton, is priced at £5.26, but no date.

I also have clear shrinking dope again no date.

Will i still be able to use them.

Cheers Steve

[jrman]

Probably. They may have turned a bit brown and thickened but should become workable if thinned and stirred well with cellulose thinners.

[brokenenglish]

Steve, if it's still liquid you'll be able to use it OK. Dopes and similar nitro-cellulose liquids don't "go off", they solidify.

Anecdote: When film coverings became the norm, in the early seventies, I was a bit afraid of no longer being able to obtain dope, so I purchased quite a large quantity (around 20 litres of Humbrol). I used this perfectly normally over the years. It stays "as is" as long as it's left unopened, even up to 20 years or more. When you start opening the can and using it regularly, it will gradually thicken, but it just needs a bit more thinners than normal, and preferably a few drops of castor oil, and it will be perfect. Sanding sealer will be the same, except that it will probably need stirring well to distribute all the sediment.
The only obvious advice is to properly close the tin each time. I use a small hammer to lightly tap the cover into the tin.

Proof. The plane below was doped in 2012, using dope purchased between 1972 and 1975.

[Stephen Jones]

Thank`s Brokenenglish,

It is still very runny but does look a little orangey.

Cheers Steve

[Scott Edwards 2]

I recently reverted to nylon and dope covering for a project, and had half a rusty tin of Humbrol stuff. A bit treacly, but a slosh of thinners, a good stir and it was fine. The date ? 1984. Thirty five years. Do I win a prize ?

[Martin Harris - Moderator]

Dunno - but I still have a tube of tissue paste bought in the late 70s, some Joyplane sanding sealer that I suspect I bought back then and a tin of veneer adhesive from around '76. It's prompted me to check and the sanding sealer is jet black but still liquid and the contact adhesive is still vaguely white with a bluish tinge that I don't recall from the nearly 45 years since I veneered my knock-off Gangster 42 wings!

I was always told to invert tins briefly after replacing the lids to ensure they were sealed against air ingress.