Use a quality brush to apply marine varnish.
When you need a tough surface that will resist moisture and bright sunshine, consider adding a top coat of marine varnish to your project. Used by boat owners and contractors, marine varnish adds a level of protection that far surpasses most finishes. It’s not for every project, however, and when you're applying it over latex paint, follow some special techniques.
Instructions
1. Prepare the surface of your object before varnishing. In this case, you will be applying the varnish over latex paint. If you have not painted the object yet, choose a flat latex paint. The less gloss on the final paint coat, the better the marine varnish will adhere.
2. Use a liquid sanding solution on pre-painted objects. Since marine varnish is clear, you will easily see the color of the object beneath. For this reason, don’t use sandpaper as it can scratch and remove some of the colored finish. Apply the solution with a clean rag. Rub it thoroughly over the surface and dry it off with another rag. This will remove the gloss so the varnish will stick.
3. Prepare a well-ventilated varnishing area where wind is not a factor. Marine varnish is tough to remove if it drips on concrete or a floor. Use drop cloths liberally under and around your object.
4. Put on your respirator and get started. Fumes from marine varnish are very strong and you could quickly develop a headache if you breathe them. Choose a respirator that filters out fine mists. Marine varnish vapor is toxic.
5. Open your varnish without shaking it. A common mistake made by many is to shake a can of marine varnish. Unlike paint, the varnish will develop tiny bubbles if shaken and you will have to wait a day or two until they subside. If you varnish when bubbles are present, they will be in your finished project and make the surface bumpy and unattractive.
6. Brush on a light coat of varnish in one direction. If you develop a run, you’re using too much varnish. Dip no more than 1/3 of the brush into the varnish and allow it to drip off before applying. Resist rubbing your brush against the rim of the can because it will create tiny bubbles that drain back into your varnish.
7. Apply an entire coat once you get started, then let it dry thoroughly before applying a second light coat in the same manner. It’s important to finish one entire coat because the object may show lap marks otherwise.
