how do I get a smooth varnish finish coat

I'm having a very hard time getting a smooth finish coat of varnish. The underlying epoxy layer was sanded completely smooth. I applied Interlux Schooner varnish cut with 10% lacquer thinner and wet sanded with 400 grit between each coat until I got to 5 coats. Each coat had a rough texture when dried that sanded off easily but left a dull finish. I want a high gloss finish so I need to continue. This is on a restored canoe paddle so it would be easy to control the environment. The first 4 coats I hung the paddle in the shower and closed the curtain and turned off any air sources. The last coat I made a curtain that goes completely around the paddle and is closed at the top and bottom except for a small ventilation hole at the top. Also I shook the can but let it sit overnight before using it. I am using a new foam brush and following the technique described in Tips for Boatbuilders. Still bumpy. Any ideas or is the finish I want simply a wet sand and finish wax type of deal?  

Thanks for any help. 

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RE: how do I get a smooth varnish finish coat

for the best results spray it.



RE: how do I get a smooth varnish finish coat

Shaking the varnish was a big mistake.  Let the can sit for days, then stir very gently without entraining any air bubbles to mix before use.  If you see even the tiniest, most minute air bubbles, it will screw up your surface.  You may be able to vacuum de-gas the varnish in the can by taking a rubber glove (Playtex type, not nitrile), stretching it over the open can of varnish with the fingers sticking up, then burp as much air out of the glove as possible, even slipping a piece of aquarium tubing or similar between the can and the wrist of the glove to suck out as much air as possible.  After you have the glove deflated, put a few rubber bands around to hold that sucker tight to the can, the pull up hard on the fingers of the glove, stretching it to draw a vacuum in the can.  The further you stretch it, the greater the vacuum created.  Hold that stretch for several minutes at least.  The reduced air pressure in the can will cause bubbles in the varnish to enlarge, coalesce, and rise to the surface.  If you have a vacuum pump and a bell jar, that would work better!


You can sand with finer and finer wet paper to 1000 grit or higher to get a glossy surface. 

RE: how do I get a smooth varnish finish coat

The thing that really helped me was to add about 10% penetrol (thanks Joey) as a flow agent. Along with the thinner this made it flow on much smoother. I also wet sanded with 400 grit between the last few coats with a drop of dish soap in the water. This was a trick told me by a cabinet maker friend. The final finish was not glass smooth, but pretty darn good.


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