Varnishing temperature...?

Captain Crisp

Captain Crisp

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I was really hoping to do some varnishing this Saturday, but it's only going to be 10-12°C.
Is that too cold? Or can I risk it?
Thanks!
Crisp
 
That depends. Do you want to risk it or do you want to know it's fine? Time of day will be important too because that max temp will not be for long. Inside or outside?
 
Outside... But I can put the cover back on... Which might make a wee bit of difference... Is there an obvious sign that it's too cold?
 
Captain Crisp said:
I was really hoping to do some varnishing this Saturday, but it's only going to be 10-12°C.
Is that too cold? Or can I risk it?
Thanks!
Crisp
Click to expand...

You've obviously got internet access - you should be able to find the manufacturer's data sheet. That will tell you the limits for temperature and humidity.
 
Leave the cover over for a while and if the sun is out, very quickly the temperature under the cover will rise (depending on material), both air and substrate. Always bests if you can varnish while still undere the cover; but some decent light will be important.
 
Pre warm your tin of varnish in a bowl of hot water. This ensures it goes on without need for any thinning due to low temperature. The test is do you get a nice even curtain of varnish running off your brush after dipping it in the pot.
 
I'm varnishing today. It's only 8C in the boatyard but I've stood the varnish tin in a saucepan of hot water. Also there's a bit of a sun which usually is a no-no but today should warm up the wood nicely. And for the first time in weeks there's no wind. Possibility of rain later. Frankly by this stage I'll take whatever I can get. To hell with perfect mirror finishes, I want to get sailing.
 
Check for a cold wind. That can really make it bloom.

It also depends on the varnish. Early and late season I use Eipifanes Rapid clear. Prep in the morning. Apply at noon and it’s dry before the heat of the day is lost.
In summer I use Epifanes gloss. Much nicer finish but need a good 12 hours of still, dry and low humidity weather. But it does make wood look beautifu.

The key is you can mix snd match the coats.
 
At lot depends on how much thinners are used in the varnish, and the mixed varnish warmed to 20°C.
That's info from 'The Big Book of Wooden Boat Restoration', written for the Swedish climate.
 
So just to summarise, it can't be too cold and it can't be too hot, nor too humid nor too dry and no sunshine. And you need these conditions for each coat, oh and the first coats should be thinned. Oh and you may have to sand between coats....oh and each coat has to be put on after the correct drying time.....and you need to keep this up every year ad infinitum.

GRP anyone?
 
Sea-Fever said:
So just to summarise, it can't be too cold and it can't be too hot, nor too humid nor too dry and no sunshine. And you need these conditions for each coat, oh and the first coats should be thinned. Oh and you may have to sand between coats....oh and each coat has to be put on after the correct drying time.....and you need to keep this up every year ad infinitum.

GRP anyone?
Click to expand...

Life's too short to varnish. Go for the natural look. Or avoid wood altogether.
 
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