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As I previously mentioned, I started using polyurethane just recently. I always assumed that it would cure in a day. Probably because of the catalyzer. So I buffed after one day. But I think I was wrong because I could see further shrinking in the following days. So I wish I did not buff so early. So the qeustion is: how is the curing time of polyurethane compared to nitrocellulose lacquer?

Most of what I use in the way of cat poly is buffable after 16 hrs. @ 70 F. Did you perhaps over/under catalyze? What brand material?

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Brian

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Curing depends entirely on how the system was designed to cure. It's far too generic a question to ask how long 'polyurethane' takes to cure. It could take as little as a few hours or as much as a few weeks. You have to get this information from the manufacturer. Use fresh material, and mix carefully.

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StuMusic

Sorry its an italian brand. Home made. 16 hours is a short time. I still can smell solvent after few days. I googled around and found that poly can be left to cure even 30 days. In this case, I don't see much advantage vs nitro. It displayed shrinking as well.

It's hard to say how long that brand of polyurethane needs to cure but the polyurethane made for guitar finishing such as Seagrave or Cardinal, the Seagrave being used on Bleedlove, Huss and Dalton and Goodall Guitars, need around two weeks to cure. This may be because they are cellulose. Auto polyurethanes can take less time but can be little less flexible. Many feel the main advantage would be that polyurethane is far less likely to cold check and it can be dry sanded without gumming up a ton of high grit sand paper. Best of luck, just give it some more dry time and see how it turns out.

Wow, so cool to see you here Addam! I've admired your work (from afar up north in Canada, over the net) over the years.

Welcome to the OLF, hope you'll stick around and offer us your expertise from time to time!

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