Varnishing struggles

Builder's Forum
1

Good afternoon,

I began my CH 17LT on March 17 with some plans, epoxy and a few 4x8 sheets of Okoume.  It's been a lot of fun and a lot of satisfying work up to this point where I have a few coats of varnish on and can see the light at the end of the tunnel.  This leads me to my question about varnish application.

Based on what I read, I made what might be an unfortunate decision and used Schooner Gold varnish, thinning it with 333.  The first coat of varnish when on very nicely on top of the epoxy with barely a streak.  I had not varnished anything before and I was quite impressed with the first coat.  After wet sanding with 400 grit and applying a second coat to the bottom and sides, I had more streaks than I would have liked.  After wet sanding again and applying a 3rd coat,  even more streaks to the point where it looked crappy.  Last night I wet sanded again and had a very smooth surface before applying the 4th coat.  Again, lot's of brush marks but not as many as the previous coat.   

As of now, I have 4 coats on the bottom and sides and only one coat on the deck.  The deck looks awsome in terms of streaks but it only has 1 coat of varnish on top of the epoxy.

Why would the first coat on top of the epoxy go on so nicely yet the subsequent coats do not?  The temperature is 75 in my shop and I've been thinning the Gold 4:1 to make it flow.  I am using good quality 2" foam brushes from the local paint shop.  I only want to put one more coat on the bottom and sides but want to get it looking more like the first coat did on top of the epoxy.

Thinking out loud...
Do I need to thin the Gold even more?  Did I accidentally thin my first coats more and that's why it went on so nice on top of the epoxy?  Was the epoxy cured more verses previous varnish coats? Should I let the varnish cure for a couple of days before wet sanding again and applying the 5th coat?

Any advice would be greatly appreciated. 

Thanks.

2

Dogan,

Ditch the 333 and get some mineral spirits to thin with. 333's evaporation rate is too fast in my opinion. Here is a excerpt from a post I made a few weeks ago about applying varnish. 

 

"Keep doing what you are doing as far as wet sanding. Use 400 grit and add a drop of dish washing detergent to the water. Use a scrap of closed cell foam as a sanding block. When you think you have leveled the surface, take the foam, turn it on edge and use it as a squeege. This will highlight all the low spots in the previous coat and allow you to truly level the surface.

If I may, I would like to share my "Secret recipe" for making varnish a rewarding experience. First, thin it 10% like you have been doing. Get some Penetrol at your local home store or paint store. Penetrol is a flow agent, that makes the varnish less tacky to brush and will help it flow. I add 10% penetrol to thinned varnish. If your varnish is cold, put the can in some warm water to bring the temperature up. 

Now, to apply it, use a foam roller and a brush of your choice. work in small sections on your hull, one panel at a time. Roll out about 12-18" sections and tip from dry to wet. It helps to have the brush you are using moistened with varnish. Do the bottom and sides first, that way you can perfect the technique before you start on the deck."

If you have any more questions, feel free to contact me. 

Joey

 

 

 

 

3

Thanks for the advice Joey. 

I wet sanded the deck last night and put a second coat on it which I thinned to 3:1 with 333.  That went much better so I think you're right on about the thinning.  With that much 333 in there I probably accounted for more loss due to evaporation and still had a mixture that flowed well.  I have mineral spirits and will also try to track down the Penetrol here in Canada.