Drying times

Greenheart

Greenheart

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I expect "Drying Times" is the name of a column in a yachting periodical, but I'm thinking about varnish.

I'm accustomed to epoxy drying quickly, but I want to protect the epoxy from UV, so I've put on a layer of Epifanes.

The label says "dustdry/tackfree after 3 hours, recoatable after 24 hours", at 18° Celsius, which must have been the temperature in my garage since yesterday. What it doesn't say, is when the finish will stop resembling treacle toffee, to the touch.

Have I done something wrong? How much longer till I can handle it comfortably and subject it to weather?

Thanks!
 
dancrane said:
I
The label says "dustdry/tackfree after 3 hours, recoatable after 24 hours", at 18° Celsius, which must have been the temperature in my garage since yesterday. What it doesn't say, is when the finish will stop resembling treacle toffee, to the touch.
Click to expand...

I think 'reassembling treacle toffee to the touch' is what it means by 'dust dry/tack free'. Why yours isn't so after 3 hours others will be better able to suggest.
 
Perhaps I can put another layer of nice quick-drying epoxy over the top of the varnish, to seal in the stickiness. :rolleyes: :hopeless:
 
I have been using Epiphanes for some time. At first, I used to do the varnishing indoors (one tiller and occasionally a jackstaff) and it seemed to take about three days for the varnish to dry. It took me a long while to work out that my dry, centrally-heated house was the problem and that humidity is necessary for cure. I now do it in the garage, in the winter, and it dries much quicker.
 
Thank you sir, I don't understand it, but I believe you.

Maybe it'd dry instantly, if I put the item back on the boat in an English midsummer...there is a suggestion of humidity out there.
 
I'm hoping that someone who actually knows can answer, but as I understand it, varnishes are not like they used to be, when drying depended on the solvent evaporating, but now depend on reacting with moisture in the air to cure them. It has been pretty humid today, great varnishing weather perhaps.
 
Apparently the solvents in epoxy require at least a fortnight's drying after application, to cure fully, and varnishing over epoxy sooner than that risks entrapping the solvents resulting in a permanently squishy layer. I left mine about a week...less than two, anyway.

Please don't quote me, I may only have inferred it from Epifanes' description, but I seem to have hurried unwisely or ill-informedly.

And I certainly applied a thicker layer than is prudent. I really wasn't using it to make the wood look nice, just to protect the epoxy...

...so it is happy but merely incidental that the wood now looks glorious, and the smell of the tung oil is wonderful...

...and it'll be a pity if it needs a coat of paint to stop my passengers' skin sticking to it. :rolleyes:
 
I think it goes like this:

If the stuff underneath isn't a hundred million squillion percent dried, hardened and gone off then the stuff on top stays sticky.

Try using ordinary varnish over week old Sikaflex and it returns to the consistency of left over French mustard (if brown I could have chosen another simile)

Don't ask me why it goes wrong it just does. I too would like to know why.
 
Varnish over epoxy - it'll dry, eventually. Probably. Takes a long time though.

Did you wash the epoxy before varnish?

Do not put epoxy over the top!

Well worth doing, in certain circumstances, IMO.
 
Pye_End said:
...it'll dry, eventually. Probably.
Click to expand...

Thanks for that. :biggrin-new:

It certainly hadn't occurred to me to wash the epoxy before varnishing. I was thinking the solvent-base of both products wouldn't welcome the introduction of water. Please don't tell me epoxy doesn't have solvents in...in what I call my mind, it is firmly in the non-water-based product category!

Actually, the outer face of the first item I varnished, does now seem almost entirely dry. It occurs to me that since application, the still-tacky side has been on the under-side...is it possible that makes a difference? Anyway, once the piece is back on the boat, it won't capture dust and crud with the tacky side concealed.

There are other items that I haven't even checked on yet, hanging up in the garage. I hope they're dry, but I won't epoxy over. :encouragement:
 
Interesting thread. I find that something varnished (with conventional varnishes) in my garage takes a lot longer to dry than it does outside, especially if there is a breeze. Putting an electric heater in the garage seems to make no difference.

Using Epifanes RapidCoat on my coachroof I find I can get 3 coats on in a day if the weather is warm and breezy, but inside I have never been able to get more than on coat a day on.
 
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