Newbie Advice for Wood Refinishing

[alofns]

I want to refinish the exterior woodwork on my Redwing. It's varnished but some spots where the finish has worn off have turned grey. Do I have to sand all the woodwork down to the bare wood, or is there a way to clean up the spots and layer on the varnish?

[CharlieCobra]

Oxalic acid mixed with hot water, brushed in vigorously and left overnight. Flush several times with clean fresh water until no crystal residue remains after drying. Sand lightly and varnish with the rest of the wood.

[CalebD]

I would also offer that since the wood you are describing sounds like teak that teak oil (similar to Tung oil) will significantly enhance the look and color of the wood once you mitigate the gray areas.
If you do use teak oil on it then you merely need to wipe the wood down with Acetone prior to applying a finish.
As for finishes, varnish looks great but is a constant maintenance headache, been there done that. With varnished exterior wood you can expect to have nearly constant maintenance and nearly 9 coats. Cetol Natural Teak looks pretty close to varnish and lasts longer in the elements in my experience. Cetol Marine looks like crap (IMHO) but also stands up for about 1 year before needing re-coating. Bristol Finish is supposed to hold up exceptionally well to the elements but can be a bit difficult to work with (or so I hear) and is not especially cheap.
I suggest you keep your cabin wood varnished (if it is) and use a more robust finish for your exterior wood like Cetol Natural Teak.

[alofns]

Originally Posted by CalebD

I suggest you keep your cabin wood varnished (if it is) and use a more robust finish for your exterior wood like Cetol Natural Teak.

Can I apply Cetol over top of the varnished wood?

[alofns]

Originally Posted by CharlieCobra

Oxalic acid mixed with hot water, brushed in vigorously and left overnight. Flush several times with clean fresh water until no crystal residue remains after drying. Sand lightly and varnish with the rest of the wood.

Is there a product name for Oxalic Acid? or where would I buy this?

[DwayneSpeer]

Originally Posted by alofns

Is there a product name for Oxalic Acid? or where would I buy this?

Google oxalic acid and choose from the few hundred hits you get.

Also this cleaner will just clean up your wood, you will still need to sand it to get the ridges down. I use a heat gun and scraper to remove old varnish, it's much, much faster and I have a lot of bright work on deck.

Good luck.

[sailingdog]

Originally Posted by alofns

Is there a product name for Oxalic Acid? or where would I buy this?

Any hardware or paint store...

[CharlieCobra]

If it is in fact Teak. You'll have to get Teaka A and B for it. You can get it at Jamestown Distributors online.

[T37SOLARE]

I want to refinish the exterior woodwork on my Redwing. It's varnished but some spots where the finish has worn off have turned grey.

You sure it's varnish? As bad varnish will go yellow before it fails and then peels to reveal the gray wood. I've found that Cetol is much softer and can chafe down to the wood and then turn gray with out the peeling.


If your sure it's varnish, I would wood the bad areas by either sanding or heat gun stripping & sanding. Once the bad areas are sanded smooth, I'd patch them with varnish thinned 50% for 2 coats, then 25% for another coat or two and then refinish everything with as many coats of full strength varnish until the the varnish has filled to not notice them.

But most likely, you''ll be better off stripping everything to bare wood and building up to 6-12+ coats of varnish.

[PorFin]

OK, just a few things to add to the other good info above:

1. Oxalic acid is also known as wood bleach -- that may be an easier starting poiint when you talk to the fine folks at the hardware store.

2. I've found two-part wood bleaches to be a little easier to use than oxalic acid crystals. You mix the two parts together and then apply them to the wood and let them do their thing. Sometimes it takes more than one application to get the results you want. You may (or may not, depending on the product's instructions) need to neutralize the acid after it dries with a solution of water/white vinegar.

3. Any time you apply water to bare wood you will raise the grain, and should sand it back down smooth before you apply your finish.

4. If you want to see what color the surface will be once the finish starts going on, wipe it with a rag dampened with mineral spirits. This will darken the wood, but won't raise the grain like water will.

5. Before you lay that first coat of finish, make sure you thoroughly brush off -- or better yet , vacuum -- any dust on the surface of the wood.

====

For ease of application, you can't beat Cetol Natural Teak. Four coats, with 24 hrs dry time between, and you're good to go. The downside is that you've got to take ALL of the existing finish off (unless it's already Cetol.)

If you want to go the traditional route and use varnish, Epifanes Wood Gloss has served us well. As long as you apply a follow-up coat after 24 hrs but before 72 hrs, you don't need to sand and dust the surface between coats.

Hope it all comes out well for you.