Painting Guru's - Automotive Hardner for clear coats lifespan

[redcoupe86]

Once opened, how long is Automotive Hardner (the catalyst) good for. I need to respray my H-4 euro trim ring (sanded thru the damn clear like an idiot). I opened it last thursday. Want to tackle this over the Thanksgiving Weekend.

Its a half pint can of OMNI AU mh168.

[JEM]

If the container is sealed tightly it can last several weeks,if air gets in it can harden quickly. Wipe the threads where the cap screws on so the cap dose not bond to the can.

Jerry

[Matt-Man]

Moisture is a real killer for hardners also. As long as the lid is sealed and wasn't left open for a long time on a high humidity day, it will be fine for months. One sign of a contaminated hardner is the clearcoat will be "seedy", meaning the clear will look like is has fine little particles in it after sprayed that appear to be dirt or dust, but are really little chunks of clear.

Matt

[redcoupe86]

It was only open for like 20 seconds. Just enough to pour the amount I needed then I sealed it tight and kept it inside the house.

[JFairman]

I'm wondering the same thing. I have a half quart of Omni clear, and 1 unopened small can of slow hardener that is for that half quart of clear.
I used all the basecoat color, except for what was left in the bottom of the spraygun. I saved that for touchup paint, and have most of a gallon of reducer left to keep it liqued in the future...

Is the shelf life of the remaining clear a few weeks or a few months?
The small can of hardener should be good for longer seeing as it is unopened

Would freezing it be good to make it last longer or bad?

[dean]

I painted an MB about 12 years with BC/CC. I just refinished my finished Fuchs and I sprayed them with the 12 year old CC. Seemed to work fine.

I wouldn't freeze it.

[Matt-Man]

Just keep it sealed (not frozen) and it will be fine for months. If it has been around for a year, you might want to toss it. Sometimes if it is bad, the results may show up as poor flow qualitys (bad orange peel) or die back (fine wrinkling) or other quality problems that might not be apparent until sprayed. In other words, the stuff might pour out of the can fine, and mix fine, but not give quality results.

Matt

[the]

A week or 2 is fine, as long as the bottle was reasonably sealed.

In my experience, for most hardeners, if the bottle is sealed well (wiped down before sealing), hardner stays good for many months. I'd agree with matt's post above. If it starts pushing a year, I'd start getting concerned, for most hardeners/catalysts.

dean, 12 year old paint and hardener that had previously been opened?!? WOW! I have bottles of hardner sitting on my shelf that are maybe 5 years old . . . they are solid as a rock!

[redcoupe86]

thanks for the input guys. I used it and all turned out fine. Didn't rub throught the clear this time color sanding!!!!!