Latest base coat mixtures aren't quite the same


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jameslawson
jameslawson
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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.
Warren (Staff)
Warren (Staff)
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The resin formulations are different but ultimately it is still epoxy based chemicals hence why it cured okish.  Its hard to say for sure how it will perform long term.  Certainly heat will help the resin cure as well as it can and then see how it goes after that.  It might be beneficial to do a "post cure" as well to see if that is a failing point now rather than later on -especially if its something going in the sun and could benefit from a post cure anyway.  Its a large project so best take precautions now before you go too much further. 

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant
GO

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