Expert: Jamie Yocono - 9/2/2006

Question
ihave a teakwood rocker that is kept outdoors. i applied linseed oil as directed after purchase. afer one seasone stored outside during spring/summer only it has developed black spots that i feel are mold. the porch that it was stored upon was a west facing, and developed green mold substance to the floor that the teak wood rocker has rested upon. i have p powered washed the green substance from the porch floor and removed the railing.
i cleaned this furniture with a mixture of bleach, laundry detergent and the most of the black spots are still remaining. i wish to apply linseed oil again if i can remove the black spots, but am unsure if this is adequate. please, help this ameture!

Answer
Hi Haley,

Well... I learn something new all the time! I swear, sometimes I learn as much new stuff answering these questions as people do reading my answers.

One of my favorite books on wood finishing is Understanding Wood Finishing by Bob Flexner. In fact, a friend just gave me the new, updated copy and it's great. So I looked up your problem, to see if his remedy was the same as mine- bleach. But I learned something really amazing, something I didn't know at all.

First off, you were on the right track with bleach, and in most cases, the black dots simply dissolve away. I think your problem is complicated because of this- and this is what I just learned in Bob's book- mildew FEEDS on linseed oil.  

So I suspect your mildew is a stubborn problem, and is going to need some 'persuasion' in order to eliminate it. His book mentions diluting regular household bleach with one part bleach to 3 parts water. Let it soak, and then I would scrub the black spots away with a 3M scotchbright pad. You probably want do this outside, with a garden hose rinsing away everything. That black mold can be dangerous, as can the bleach, so make sure you do this safely.

I think the reason the black dots didn't go away is because you needed to scrub them off. Since they were feasting on the linseed oil, they were probably well seated and not easily destroyed.

OK, after a good scrubbing with diluted bleach, you need to use the proper finish that will not allow that mold to reoccur. There are two things you need to do to protect the wood- block the UV rays, and seal the wood from contact with moisture that leads to mildew. If you don't do these two things, you're going to have the mold return, although the linseed oil was part of the problem, so...DO NOT USE LINSEED OIL!

There are some great finishes out there for your Teak. Watco actually makes a finish called Teak Oil, that is specially formulated to moisturize and revitalize Teak wood. But I am pretty sure it's not an exterior finish. But- Watco also makes an exterior oil finish. So here are a few suggestions-

You could buy a pint of Watch Teak Oil, and a pint of their exterior oil, too. Apply the teak first, probably two coats, and then another couple of coats of the exterior. I love Watco, it's the best. It will make your Teak look like new.

Another great finish is something called CWF, which stands for Clear Wood Finish. When I lived in Ohio, it was the finish of choice by professionals who treated wood decks, furniture, and playground equipment. It looks milky when you apply it, but it turns transparent and is wonderful on the wood. It comes in clear and with a honey colored tint.

Last resort would be Thompson's Water Seal. It will waterproof your chair, and that's mainly what you want to accomplish. I feel like Thompson's won't rejuvenate the color of the wood as well as the first two finishes will. Just my opinion.

All of these three finishes should be available at Lowes and Home Depot, so you shouldn't have any problem finding them.

Remember- you need to get rid of the mold- with a diluted bleach solution and some old fashioned elbow grease (scrubbing) and then put something on that will resist the mold growth. Linseed oil will promote mild growth, so DO NOT USE IT. Try to find one of the products I mentioned above and you should be fine.

OK, Good luck, I hope this helps. Please feel free to write back if you have any further questions after reading this.

Jamie Yocono
Wood It Is! Custom Cabinetry
Las Vegas, NV
www.wooditis.com