[krazzz]

I am doing some varnishing on my boat. I checked the forecast and the overnight temp was supposed to be above the dew point so I thought I was in the clear. When I got back to the boat this morning I found that I had a lot of "blushing." It was 65 degrees when I started with an overnight low of 57 and a dew point of 51. Humidity was somewhere around 40-50%. My question is, how much time do I need before nightfall to prevent this? It is supposed to be similar conditions tonight.

Also, I have never varnished over blushing before. Do I have to remove all of the last coat or just give it a light sanding?

 

[Westsailforever]

I try to be done by lunch time .(when out side) I would sand off that last coat .

 

[MooGroc]

Unless you are trying to achieve close to perfection, I would just lightly sand it with 220 and put a new coat on. The blush will mostly disappear.

 

[MarkSF]

My suggestion would be to add a little thinner, that will make the coat a bit thinner, and dry a bit faster but not skin over. Worth a try.

 

[christian.hess]

blushing can also be causes by solvents still in the wood before applying your first coat...

remember first coats should be really thin so they penetrate, and progressively less thinned out till your last coat...

weather permiting

like someone else said, early morning till around 10-11am, never during midday sun or direct sunlight, shade prefferably and if you are in cooler weather at least 3 hours before sundown

so if your sundwon at 7pm your last coat should be applied around 4pm or so...to let it set before the humidity sets in at dusk.

 

[krazzz]

Thankfully the sun goes down here around 9:35 so I have plenty of time before dark. I went down last night, did a light sanding and had it varnished by 7:00. Just checked on it at lunch and it looks beautiful! (Well good enough for the girls I date anyway, hahah.) Two more coats and I will call it a wrap.

 

[christian.hess]

at least 5!!!!!!!!!!!! 7-8 is the golden amount!

 

[krazzz]

My next coat will be number 6 (the blushing happened on #4.) I have found that 6 coats is a pretty good amount. I may try an extra one or two though. Can't hurt, might as well finish the can. I also did a test where I sanded between every coat or just sanded before the last coat and there was no difference between the two.