Black spots on locust?

[Neil_Asheville 114]

What is this stuff? This is a cut end from an exposed locust deck that has been down 3 weeks. Locust is grown and milled here in NC. This was pulled from the cut pile, however this spotting is all over the laid deck. No pattern to the spotting. 3% then 12% didn't really touch it. 120 grit sanding neither. First photo shows board wet with water with lighter end from 3% and then the sanding. From the second photo, you can see citralic with long dwell lifted (or pushed back in) 90% of it.

First look it appeared as surface mildew. Bleach and 120grit did nothing. Tannin was my next thought. Perhaps a mineral staining from something iron-like in the air/rain/dew? Is it coming up from within the wood to the surface? I have experience with finishing cypress and black spots coming up soon after stain, but those were almost powdery whereas these appear to be stains. With a percarb clean and acid step and finished with WoodTux my tests tell me it will look good. What I don't want to happen is they come back in a month after finishing.

Thanks!

/neil

[James 624]

Neil, there are different types of fungus and sap stains in wood. I've come up against very bad mold this year ( worst ever). If you don't get the mold out it will come back through the finish.

[PressurePros 248]

Neil and Jim. I am convinced there are new strains floating around. I have had Restore-A-Deck customers reporting and sending pictures of mold that looks just like your pics, Neil with the same bleach resistance. This is a complete long stretch and only my theory. I think the importation of all these hardwoods have introduced new mold strains into the US. I hve heard reports from every stain manufacturer (including Ready Seal) that have had strange stuff growing on them. Very bizzare.

[Adrian 155]

I took picture of one today that I stained in April with Bakers that has the "black bumps" on several planks and has pushed through the stain.

Deck is 5 years old, so it would not have been recently imported. But, that does not mean that it is limited to new wood. Or could it be more airborne after the fact from imported wood.

Back to the labs.

[PressurePros 248]

Adrian, I think it came in with imported lumber. Everything in a rain forest is nastier, stings you worse, kills you faster and thrives under varying conditions. It probably isn't a stretch to think it lies dormant until it gets back into rain. I have had reports of it showing up on over half of an ipe deck two days after a rain. That's not random spores finding some pollen and colonizing.

[Neil_Asheville 114]

What mold doesn't succumb to 12%??? Citralic removes tannic acid extractive. Citralic worked for the most part at removing these spots. To the contrary, bleach removes tannins / tannic acid from leaf staining on concrete, but had no effect here. I am confused:thinking:

[PressurePros 248]

Neil what you have could very well be some type of extractive bleeding. (as evidenced by acid removing most of it). The mold I am speaking of laughs at straight 5.5% and returns with a vengeance. I have never sugested nor tried 12%. I imagine that would be a death zone for even the most hardy strains or spores.

[Tmrrptr 164]

I really think the Pressure Pros are on to something here.

We've got killer bees, zebra mussels, star thistles, and a really long list of invaders including the english sparrow.

US Customs quickly admits they only inspect something like 5% of incoming containers, and they are looking for something they already know about.

Probably drugs or counterfeit nikes.

If immigration can't stop holes in our borders, cdc let aids into the country, who inspects lumber? Dept of agriculture???? I'm sure they all want more funding.

Forestry could not stop pine pitch canker here in CA..

And now we have lead in toys.

Who's to say an imported mold on pretty deckwood is well under control in it's own environment, but grows like wildfire when it gets to our climate zone.

Point being, no one knows what it is, until someone like Ken who deals with specialty wood frequently, raises the hue & cry.

I've read of microscopic bugs that seem to live happily in straight bleach used

to clean petri dishes... and no one thought that could happen.

We all know penicillin resistant bacteria exist.

I recall a few years back when scares of contagion traveled around the country... I was quite happy living in a 2 horse town, with little outside contact, known historically as the "protected valley."

So ...The guy I worked for says, "My ex-wife is flying in from Ramstein tomorrow, you go pick her up at LAX in the morning."

I think it was about the time Bruce and Brad came out with that 12 monkeys movie...

I sure hope Ken keeps up the good work !

r

[James 624]

Mold and sap stains on new wood have to do with controling moisture, storage before and after the milling process.

[plainpainter 217]

Those stains aren't extractive bleeding - I know what tannin stains look like - you can kill mildew with oxalic acid - I've seen mildew on fiberglass boat hulls come off with a Flood's deckswood, which is an oxalic based wood cleaner. That stuff is nasty mildew - I found some on a painted surface as well, it took 2 hrs of brushing with a TSP/bleach/surfactant mix to finally remove it.

I'd look into 2 stepping, first with a strong layer of oxalic/surfactant - then apply a strong bleach - with no caustics added. The combination at the very least will create a hypoclorous acid - let dwell. Then rinse - then come back with a killer TSP/bleach combo to remove the stain - if it's still there.

[plainpainter 217]

Bump....any new reports on odd mildew growths? Or did these mysterious strains just disappear?

[Beth n Rod 1,279]

Humor me. Post a picture of the end grain of the board.

Beth

[James 624]

Dan, I see this mold quite frequently now. Strong bleach is the only remedy.