Varnish not sticking

Hi folks,

I just put on my second coat of Interlux schooner varnish and am having some problems. This is the first time I'm doing this so everything is a learning experience.

The first coat seemed to go on just fine. There were a few small areas where the varnish seemed to bead instead of sticking but I figured this would take care of itself on the next coat.  I wet sanded with 400 grit and carefully wiped off the crud, waited for everything to dry and then starting doing the second coat.

The varnish was a bit thicker than yesterday but it still seemed to spread okay. After a bit I noticed that some areas were just not being convered. I re-applied some varnish in the larger of these areas but retouching didn't seem like a good idea.

I used MAS expoxy and wiped the boat done with denatured alcahol after finishing the sanding. I'm wondering if I haven't sanded enough or if I should wipe everything down again with denatured alcahol or with varnish thinner.

Any ideas would be appreciated .

Thanks

 Elliot


9 replies:

« Previous Post       List of Posts       Next Post »

RE: Varnish not sticking

Beading sounds like a contaminated surface, maybe blush. How long has it been since you applied the epoxy?

Laszlo 

RE: Varnish not sticking

Hi Lazlo

Glad you're up so early.

It's been close to three weeks since I finished the epoxy, but I thought blush wasn't suppososed to be a problem with MAS. I also hand sanded the whole thing with 300 grit sand paper and I wonder if it's too smooth.

The wierd thing is that the first coat covered better than the second. It feels like some kind of chemical contaminant but I've only used denatured alchahol after sanding the epoxy and then water when wet sanding the varnish. Do you think I should rub it down with paint thinner or something else?

Thanks a bunch for the help.

Elliot 

RE: Varnish not sticking

 

From your description it seems like you've done everything right.  Were you wiping down with a rag?  Fabric softener in the rag will do it every time.  So will exhaust from from a nearby clothes dryer.  Another source of trouble we found was fallout from an overhead roll-up garage door:  specks of lubricant trickle down.

RE: Varnish not sticking

Hi John

So happy you're checking this on a Sunday which is definetly a boat building day for me but not for you guys. 

I did use rags made from an old tee shirt. Go figure ... However my wife doesn't use fabric softner and she hangs things to dry. If there is some contaminant from this rag what can I do about it?

Thanks

Elliot 

RE: Varnish not sticking

 Well, solvents are your friend---do the usual wet-sanding procedure to flatten out what's there.  Then swab the thing with solvent to remove any impurities and let it dry for an hour or so.

Letting the solvent dry is important.  On a humid day, THAT can cause adhesion trouble because it penetrates the cured varnish surface and only evaporates slowly.

RE: Varnish not sticking

Hi everyone,

It just occurred to me that the water here in the country is softened to get rid of the iron. In the shower after washing it seems that my skin is covered with what feels like an oily film. Could this have something to do with it since my using the same water for the wet sanding?

Thanks

Elliot 

RE: Varnish not sticking

No. That oily film after bathing with softened water is your own natural skin oils which the softened water did not remove. If there really was oil in your water, you'd see it all over your dishes, floating on top of cooking water, etc. Softened water is actually better for most chemistry so it shouldn't be a problem.

Here's a thought - did you touch the problem surfaces with your bare hands?

Laszlo

 

RE: Varnish not sticking

Lazlo,

I've been wearing gloves whenever I work on the boat.

I put the thrid coat on this afternoon after sanding and wiping everything down with denatured alcahol I'm not sure that the alcahol did anything. Maybe varnish thinner would've have been stronger. I also added just the smallest amount of thinner to my varnish which was feeling too thick and also to help things stick better.

I applied the varnish very carefully using only a foam brush and checked and double checked everything as I went. Whenever there was a problem area I immediately did it again going pretty slowly and pressing down quite a bit. Anyway it came out really nice compared with the previous coat. 

Not sure exactly what made it go better, but better it is and that's the important thing.

Thanks for all the help and I will send pictures in a week or two. The boat has to be ready for my birthday party and official boat launch on June 14 .

Elliot 

« Previous Post     List of Posts     Next Post »


Please login or register to post a reply.