Why do you object to sanding? You don't have to remove all of the original varnish, particularly if you are wanting a satin finish, just sand a little with about 80 grit to roughen up the surface and provide a tooth for the new coats. Wash it down probably with clear water on a wet rag to remove any dust before applying new finish.
There are now exterior grades of urethane which are very durable and even a water based one should stick to the previous finish. You will get cracking and blistering from the sun. Any moisture in the door will migrate toward the heat and cause the fibers of the door to swell and contract. The heat may also cause the finish to expand differentially to the underlying wood and ultimately the surfaces begin sliding over each other breaking the bond between them.An oil finish will not do this but it needs to be renewed more frequently, otherwise it wears away. I am guessing that your finish is variable because the underlying surface is not uniform. The varnish will allow some of that to show through. Hope this is helpful, I realize you preferred a solution which does not involve sand paper but the only other reasonable alternative is to strip the door all the way down with some or other chemical stripper and you will be sanding after that anyway. . . ----- Original Message ----- From: [EMAIL PROTECTED] To: [email protected] Sent: Wednesday, May 28, 2008 11:52 PM Subject: [BlindHandyMan] over varnish Howdy, A few years ago wow, many now, our front door was painted with spar varnish. It was said to be an indoor outdoor coating used on boats. I agreed, correctly or incorrectly. Over time it has roughened up on the side that gets the early sun. I've washed it down and resurfaced it. I used more spar varnish. i love what it did for a table I built two years ago, so figured same over same on the door. There are places that seem not to take this new stuff. i washed with a weak phosphate cleaner which has never failed me. (in it's high strength, it will pit enamel paint and almost doesn't need sanding). So I'm getting tired, as this will be the 4th light coating of spar varnish, I've put on the door. I'm wondering, is there anything else, i can use? Something that will take the sun as well as spar varnish (or better) will be compatable with what is on the door, and will not look splotchy coating the places that didn't coat with the spar? (satin finish) I didn't want to sand as it was kind of pitted enough for sure. i use that cleaner in it's weakened state to degrease. Any solutions short of sanding out there? ------------------------------------------------------------------------------ No virus found in this incoming message. Checked by AVG. Version: 7.5.524 / Virus Database: 269.24.1/1470 - Release Date: 5/28/2008 7:20 AM [Non-text portions of this message have been removed]
