I’d like to finish some boards using Minwax Polyshades. These boards will be on a covered porch and not get wet. The can says it’s for interior use.
Is it the temperature extremes that will cause failure or is humidity or will they be fine on a covered porch? Would a coat of exterior varnish help aleviate any problems? Or this just asking for trouble?
MERC
Replies
The biggest problem is that it is not UV resistant.
The second problem is that any surfacce filming finish will soon fail ion an exterior environemt and flake off.
The printed instructions are there for good reasons. Use it if you like, but in a year, you will have three times to work, trying to sand and prep for the right product
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I don't think it will see anymore UV light on a covered porch (north side of the house) than it would as interior finish in a south facing room. I'm using the color "bombay mahogany" which is the only stain I could find that really put a Mahogany type look onto SYP. I guess I could choke down and buy Mahogany and just put an exterior varnish on it.
MERC.
Avarnish is still a surface friulming finish that will check and fail soon. They do require a lot of maintainance so count the cost first.
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Yes, you are correct and I should have known better than saying that here. My original intention was to use a penetrating oil type finish on Mahogany (non-film forming finish), for the exact reasons you sight. Since this trim will be right up against screening, I'd like to be able to freshen it up occasionally and I think a penetrating oil will be my best bet.
Thanks for the advice, I'll try to do some more research and refine the approach.
MERC.
You might want to look into a UV resistant finish (yes it will get more UV outside than inside; no windows to block the UV light). Sherwin-Williams has some lacquers and there is always spar varnish. You can add TransTint colors to them.