Replies

1. 
   SteveSchoene | Mar 03, 2011 05:32am | #1

   Finishes can't make the underlying wood meaningfully harder.  Redwood is pretty soft, so you can expect dents and dings.  A good tough finish would be Waterlox Sealer/Finish.  This is a medium sheen wiping varnish, toward the semi-gloss end.  I'd brush on the first coat almost like an oil/varnish finish, with an initial wet application that I would add enough varnish to keep fully wet for about 10 minutes.  After about 5 minutes more, I'd lightly wipe off excess varnish.  The purpose is to let the early wood absorb what it will on the first coat.   Let this cure for 24 hours, sand lightly with 320 grit, and then wipe on very thin coats until you achieve an even sheen.  You can do the wipe on coats with with unembossed paper towels just dampening the surface on each coat.  These coats can be applied about 3 coats in a day, applying the next coat as soon as the preceeding is no longer tacky.  After three coats you should let the "set" cure for overnight before applying more coats.  After varnnish has cured for overnight or longer it is desirable to sand with 320 grit befor applying more coats.    

2. 
   AutumnWoods | Mar 03, 2011 10:18am | #2

   Soft Wood

   The only type of finish I know of that can help mitigate the soft wood problem is a two part poured on epoxy.  It builds quickly to a very thick film of an 1/8" to 1/4" and dries to an incredibly hard and durable layer.  This type of finish, along with some types of catalyzed polyester finishes represent the ultimate in durability, but the epoxy finish - unlike polyester - can be easily applied with a minimum of tools.  Now having said that, it can also be a royal pain in the butt, messy, sticky, dripping, smelly, etc.  Don't expect to get a perfect finish out of it just by pouring even though the manufactuer will claim as much, and make sure you finish both sides with the epoxy or wood movement will blow it up.  Also, be careful if you're planning on staining it, as some kinds of stain can cause serious problems with it.  Contact the manufacturer for advice.

   This is about how it goes in my experience:  Apply thin seal coat to both sides, finish sinks in to any crack or dimple, leaving an imperfect surface, let dry for a few hours as per instructions.  Pour on first heavy coat to back and front (one after the other seperated by a day), allowing to drip off edges onto floor (hopefully covered).  Keep brushing edges as long as you can, but it will still have runs and drip marks.  The top will look perfect for the first 15 minutes, then some areas will start to dimple or fisheye.  You will brush it out as long as possible, and in the end the area will be ripply.  Warm CO2 from a propane torch or your breath will pop most of the little bubbles that start to form as the finish catalyzes.  Be very diligent about getting them all.  Then a bunch of crap will start to land in the finish, such as dust and debris.  Also, every flying insect for a 2 mile radius will immediatly be attracted to your shop and land in the finish so have tweezers ready.  It's a good idea to fabricate some kind of cover to put over the drying top to keep junk out of it.  If the first coat looks like crap you can apply a second coat after sanding thoroughly.  When you're satisfied with the thickness, let it dry a week and proceed to sand out all the imperfections, ripples, runs, and drips and level the surface with sandpaper and a cork block, much like with other finishes.  Then, using wet-dry sandpaper and plenty of water for lubrication sand up through progressively finer grits until you're at 1500.  Then use automotive rubbing compounds of different grades depending on your desired sheen.  I've taken it all the way back to a mirror polish using this method.  Be very careful around the corners and edges where it's often pretty thin not to burn through.  You can also apply extra coats on just this area  to build it up. 

   As you've probably deduced, this is the kind of finish you thoroughly test on a piece of scrap from start to finish to make sure it will work for you.  Once you start, you're pretty much committed to it, and don't cut corners.  Follow the mixing directions exactly.  A good source for this product is Woodcraft.com who sells mirrorcoat.  Good luck with whatever kind of finish you end up doing.  Sorry for the long post, but I wanted to give you an honest idea of what's involved if you go this rout.