How Long Does it Take

[banjo1]

The question is :
How long does it take oil based varnish to completely cure?

How long does it take for spirit varnish to completely cure?

In looking up varnish info. on the net, I have read of some taking longer than others.

[sunburst]

Well, you've already answered you own question.
Some take longer than others. It also depends on weather, humidity, etc.
Basically, to completely cure, spirit varnish takes a long time, and oil varnish takes longer.

[banjo1]

Thats about a straight a answer that I could hope for.???
Thanks John http://www.mandolincafe.net/iB_html/non-cgi/emoticons/biggrin.gif

[Chris Baird]

I actually get my oil varnish to cure faster than shellac. And, yes it all depends on what type of varnish you are using. Collings has done away with the shellac top coat on their varnish mandos, I think there may be some good wisdom in that.

[Michael Lewis]

Some makers are using Behlen's Rock Hard Tabletop Varnish. It is a phenolic resin/oil blend I believe, and dries quicker and harder than any other I have heard of.

I am using the oil varnish from Int'l. Violin. It takes it's time to dry but is a fairly tough and very thin finish the way I apply it. I know this because twice had to scrape and sand it off a mandolin. Apply very thin coats and make sure it is dry before applying the next coat. It feels and looks "right".

[amowry]

I usually let my spirit varnish cure for about two weeks at 70 degrees before I do the final rubout. I believe it's similar in composition to Behlens.

[oldwave maker]

Ultraviolet light helps cure oil varnishes.
Without it my fulton style colophony varnish made with local pinyon pine sap and linseed oil would take a decade or more to dry, in the sunshine it takes a few hours.
a well aged bottle of behlens violin varnish (spirit)
takes months, I think there must be a shelf life on the shellac in it.
that old can of IV nicoseco I bought at the gal auction several years ago was the same way.
Rockhard needs the UV also unless you like fruitflies layered in, it seems almost as hard as nitro after a few months
Chris- you're maling your own?

[amowry]

The Behlen's spirit does indeed lose its ability to harden-- I mix up my own every time I need some for that reason.

[Chris Baird]

I have a pretty powerful UV booth that zaps most oil varnishes pretty fast. Many modern varnishes have some UV "inhibitors". These "inhibitors" are actually mild UV initiators which provide addtional crosslinking upon exposure. They don't act as UV block.
I also mix my own shellac. It is easy and the fresher the shellac the faster the cure time.
My personal mandolin was finished with pinion sap. It has lots of crazing.
I buy my oil varnish and add a few things. http://www.mandolincafe.net/iB_html/non-cgi/emoticons/wink.gif

[RJinRI]

So, for oil varnish to completely cure, say at a temp of 65 F and 45% RH, would 2-3 weeks seem about right? I've used the oil varnish from Int'l Violin on an IV kit ( some coats were thin, others, maybe not so thin, and its finally looking rather nice) & i'd sure hate to slap the bridge & strings on too soon.

[banjo1]

Does the varnish blend into one coat like nitro does?

[RJinRI]

Banjo1...I suppose it does blend, if applied correctly..mine could be a whole lot better, but then again, this is my 1st attempt.

[amowry]

Oil varnishes won't amalgamate like lacquer and shellac do, which means that you can get witness lines if you buff through the topmost coat. That's one reason a lot of builders "finish" oil varnish by French polishing it with shellac. Spirit varnish (mostly shellac) typically amalgamates into a single layer.