"old" antifouling paint

[richarda]

Is it likely that antifouling can be past its use by date. I recently bought a tin of Altex No5 from a chandler that seems to be dated 2005. It seems a bit thinner than usual but the tin was sealed and I can't see how the usual solids could have dissipated.

 

[ukmctc]

once you mix it up, it shold be ok. I've mixed loads of old antifoul together of varied ages and it all seemed to work when applied to the boat. Infact I know of several yards who do this and charge for fresh antifoul every time!

 

[FirstAway]

Past shelf life

Yes, providing you can get it properly mixed. it shoulbe fine. Usually it will just "soft settle" where the heavier pigments drop to the bottom of the tin; ocassionally it will "hard settle" where the pigments begin to aglomerate and dry out but even this can be recovered if you have a powered mixer.

 

[savageseadog]

Not a problem but use one of those spiral mixers on a decent drill, you'll never mix it with a stick.

 

[BruceDanforth]

Stir it for 20 mins or so with a big stick

 

[richarda]

Thanks, I will work on the mixing, perhaps adding in some of last years heavier mix

 

[tompyn]

Nick the Wifes kitchen hand blender(electric) works a treat,job done!!!

 

[Bodach na mara]

Thanks, I will work on the mixing, perhaps adding in some of last years heavier mix

I would not do that without trying it with small quantities. I once added the remnants of the one year's International Hard Racing Copper to an almost full can of the next year's (after I had painted a bit of the bottom to get the level down a bit) and the whole lot turned to a gel in minutes. I have been very hesitant about mixing different batches of paint ever since.

 

[richarda]

Thanks Wight Dawn, it had crossed my mind that things could go wrong and I do have a plan B. The local chandlery has the antifoul I use (but at $10/litre more than I paid for the "old" batch last week) so that if it turns out badly I can start again. This morning however I am off to the slipway to use their paint shaker on both old and new and to try the mixing approach.

Now, what about varnish. Will an "old" (unopened) tin still be good after five or so years?

 

[Bodach na mara]

I never thought of using a hand blender (see post #7) as I usually use a stirring attachment in an electric drill. Hand blenders can be bought fairly cheaply and may be less expensive than the domestic discord resulting from the use of the one from home.

I have used old varnish on occasion. If it is still liquid when opened it is OK. I have had problems with previously-opened cans however. Sometimes, even though I had been carreful to replace the lid and seal it by inverting the can briefly. when it has been opened the next year the contents have gelled and are useless. Not that I have not used it on bits of wood that will not be obvious.

Finally a sad comment on the quality of shop assistants. I could not find my favourite paint stirring attachment in my tool shed a few years ago and went to buy another. I could not find one in the hardware store, so asked an assistant if they sold "paint stirring attachments for electric drills". The assistant asked "what is if for?" I suppose the only reply possible was "stirring paint!"