Sanding Teak Wood
Though I do not recommend regular sanding of your teak wood, there are situations that simply demand that you remove a little of the surface of the wood to remove the other stuff you want to remove or to reduce the checking in the wood caused by weathering of unprotected teak.
Just a note, if the checking is on decking or a swim platform or steps, do not remove it all! The checking provides escape paths for the water under your feet so you don’t hydroplane and slip.
Sanding teak or any oily hard wood is not likely to become “fun” but it can be considered to be a labor of love when the proper conditions exist. What are those conditions? Well, having a friend or partner is pretty high on the list, a good supply of cold drinks helps too, but having the right materials and equipment make the most difference.
In 2003 I decided that a teak refinishing business was a smart thing to do to make money, so I rented a 1200 sqft shop and put up a website and contacted all the lawn care people to get names of people who had nasty looking teak furniture. Though the business failed to meet expectations I learned plenty about finishing teak wood.
I got a contract with a local assisted living facility that had lots of teak yard furniture. After sanding a couple hundred teak benches that were really raunchy I found that the sand paper I usee was everything to reducing the pain to a minimum.
I used all sorts of sand “paper” and found all of them, including the so called waterproof ones to be totally useless. They loaded up and came apart in just a few minutes wet or dry!
Soooo, one Saturday when I was browsing through the local flee market and found some industrial grade belt sanding material ends (small rolls too short to use in the intended machine) in grits from 36 to 200. I bought the smallest rolls of each grit and went home smiling.
The next day I went down to the shop with my treasures and started testing each grit on the teak bench that was next in line to be finished. To my surprise, if the word “BONDED” showed up on the back the material, it was waterproof. If it didn’t it generally wasn’t waterproof. This is important because dry sanding teak with any kind of sanding material is useless. The wood and the sanding material load up in less than 1 minute and generally ruin the paper because you can’t get the wood dust and teak resin off the sand “paper”.
The next thing I discovered was that anything over 100 grit was just about useless for my purpose. Also, anything under 50 grit was just too course and caAused lots of little “C” scratches no matter how light I pressed on the sander.
Speaking of sander, a jitterbug air sander did the best job of the the sanders I tried. An electric “Palm Sander” worked pretty well too, but it will not stall like the air sander if you put too much pressure on it. And belt sanders are way too aggressive. A 2 second laps of attention is enough time for a belt sander to do considerable damage.
If you don’t have an jitterbug air sander and a 120 psi 6 cfm air supply you’re stuck with an electric sander. Even so, the possibility of getting an electric shock while wet sand with a double insulated palm sander is very low, provided you don’t dip the sander in a bucket of water while you’re standing in a puddle of water.
If you simply put enough pressure on the sander to position it, the sander and the belt sanding material will do all the work for you and not damage the wood.
Unfortunately power sanders don’t work for tight places like in between boards. There you need to be using one of the medium grit sanding sponges made by both 3M and Norton. For really tight spots there is a wedge shaped sponge that fits perfectly and does really well. The sanding sponges are water proof and need to be wet while sanding to prevent loading. The motion of these sanding block should be along the grain as much as possible. Cross grain sanding will leave scratches that are difficult to remove.
What I found to be acceptable for preparing any teak (both furniture and marine applications) with moderate to heavy checking was 60 to 80 grit bonded belt sanding material on a 4 by 7 inch Jitterbug air sander. You use no real pressure on the sander, but you need to keep the wood wet (not flooded) to keep the sanding dust and teak resin (wax) from loading up the wood and sanding material. Even wood that had the remains of varnish or urethane finishes was no problem, though using some MEK based stripper did make the process much faster.
Wet sanding does cause the grain to rise if the wood is left wet for an extended period of time. If the wood is rinsed and dried promptly very little grain rise occurs.
Sanding teak will smooth the finish and restore the beautiful color of the wood, but it does not prepare the wood for finishing. Anytime you remove wood from teak, you expose new teak resin which prevents finishes from bonding or adhering to the wood. Using sodium hydroxide (part A of most 2 part cleaners), sodium hypochlorite (bleach), hydrogen peroxide, and most acids attack the micro fibers that hold the big fibers of the wood together. Fortunately, teak does not breath so these products can’t soak in more that a few thousandths of an inch sparing the bulk of the wood from their damage. However, they do weaken the surface where whatever finish you apply attaches to the wood. When the surface wood separates from the rest of the board, the finish fall off too.
Just a note of sanding teak decks, steps and swim platforms. Checking is a good thing and should not be removed completely because it provides an escape for water and pond slime that is on your wet feet. This escape mechanism is critical to avoiding slips and falls due to hydroplaning on the wood.