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I like to measure mix ratios by weight instead of by volume, when I can. Royal Lac Post Catalyzed shows a mix ratio of 7 to 1 by volume, so I contacted Vijay to find out what mix ratio by weight he recommends. This is his response, which goes a bit further and provides some recommendations on thinning and a spray schedule:

Hi Don,

Volume or weight, the ratio of 7:1 remains same. I usually make a mixture of
21 gm of finish and 3 gm of catalyst. Next I add 21-25 gm of denatured
alcohol and mix well. This consistency is good for brushing, padding or
spraying. If you are spraying or brushing, no more than 4 coats in a day
with 2 hours in between coats. Padding is different because it is dependent
on how much alcohol is added to the pad. Watch my videos for more
information.

After first day of application wait for 24 hours before deciding to apply
more coats. Each day of application is followed by a day of rest before
application resumption.

If you are padding, make a new pad for each day of application.

Regards,
Vijay

Great information. I haver been spraying non diluted. I am about ready to start spraying a ukulele tomorrow and we will see how it sprays diluted.

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Don. I have been French polishing with regular Royal Lac but am interested in spraying with the post cat product. Please let us know how it goes.

_________________
Steve Smith
"Music is what feelings sound like"

Don, I don't know the shelf life on this stuff, but I bought Royal-Lac Post Catalyzed ( Shade: Clear Super Blonde, Size: Quart ), back in January of 2017. It's never been opened. I also have Seal-Lac ( Shade: Super Blonde, Size: Quart ).

If it will still be good and is useful for you I will ship it to you.

Brad

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That’s a generous offer, Brad, but I think that would be beyond the shelf life, so let’s not. I appreciate it, though. I think I remember that you didn’t have a good experience with Royal Lac. Any details you can share? I French polished a guitar with the original formula a few years ago, and I liked it. Now that I can spray, I’m looking forward to experimenting a bit.

What is the shelf life post catalyzation? Do you mix a fresh batch for each spray session or can you mix up enough at once for one days spraying or the entire spray schedule spread over many days?

One day at a time.

No worries, just thought I would check. It will make it to the trash on the next shop purge.

I wouldn't put too much stock in my experience with Royal Lac. I was definitely not diluting the product, so that could be it. I was also spraying with an Earlex unit at that time and I had a hard time getting anything to work back then. I'm looking forward to hearing your feedback on it.

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Chris--

I figured I would give a little more detail than I did before. It is a catalyzed finish with a 10 hour pot life. Vijay recommends only spraying a maximum of 4 coats in a day, 2 hours apart, so that gets you to a little over 6 hours that are needed for 4 coats, then you stop for the day. So, it makes sense to mix enough for 4 coats in a single day. But, I see no reason why you couldn't mix it fresh for each coat, if you wanted to.