They told me all my paint supplies was expired. Is there a shelf life?

[oldcarnut]

About 4-5 years ago I bought a paint kit of Limco 800K 2K primer w/LH810 hardner, Limco LC4000 clear w/LHM Hardner, and Limco Supreme basecoat w/LBR1380 reducer.  I had started back then to use it painting my firewall and engine bay areas before installing the motor and now today getting ready to finally work on the body.  Went the store to get more paint to match just in case I got short and they told me all that stuff I had was no good anymore and I needed to rebuy more.   Something about sitting in the can so long.  Its never been mixed and its at least 80% still full.  The paint formula isn't made anymore as its now Limco Supreme Plus formula and it uses a different hardner so I understand that and so $300 later I have another gall of paint  2qts of LR12 reducer and a new qt of LHM hardner without new primer or clear bought yet. Dang, the whole kit wasn't but $250 for all of back then. Is this true or what can happen if I use it?  Was thinking of trying it under my hood and fenders to see but I'd like your opinions from the painters here. 

[68 RT]

Depends on how it was stored. I have had a pint of some PPG paint for touch ups for 20 years and the most I do is mix it and it seems fine. I would say if it is unopened just mix it really good and try it.   

[oldcarnut]

I only opened it very briefly to mix enough for the engine bay.   I just called the tech support and they said unopened 5 years.  If I opened it up then it's no guarantee but they couldn't say one thing or another would happen or it wouldn't.  I'm going to try the clear under the hood and see what happens.  Too expensive to toss almost a full gallon

[Troy]

I don't know about opened paint and clear but I also recently learned that the hardeners actually harden - opened or not! So do body fillers. I think I lost about $600 in materials.

Troy