I ran low on XCR base coat the other night so I mixed up a batch using an old bottle that I found.

I noticed immediately that it was much darker and was covering the bright aluminium silver much much better, previously I had found the base coat only gave a very transparent brown colour. Another thing I noticed is it was no longer separating / pooling, it laid flat just like it used years ago when I first got into composites.

However.. tonight when clearing the bottles out I noticed my mistake, that ''old bottle'' was of the 100:33 mixture. The hardener will most definitely have been of the new 100:41 batch as I was sharing it with the standard clear XCR epoxy, I definitely mixed it to a 100:41 ratio too.

If I'm totally honest it's cured pretty well, it appears to sand with only some tiny areas being a little stubborn. The overall finish doesn't feel waxy or gummy like a incorrectly mixed batch of epoxy would.

Can anyone confirm if this mistake is going to cost me hours of sanding, or can I stick it out in the sun to make sure it's really cured and then continue?

The project I'm attempting is a huge aluminium bonnet so sanding it back down can take hours.

I do believe I've found the reason why I fail to get super dark base coat applications though, including the pooling issue even after wiping with acetone and rubbing alcohol (I tried both individually). Since the 100:41 batch replaced the 100:33 mixtures it acts very differently for me.