Mould on pine timber

[JoshNZ]

I have some fresh sawn slabs from an Oldman pine log I picked up and have this white spore like mould growing on it several days later.

It is wood I'd like to use at some stage, am I best to remove it or spray down with something or just ignore?

Thanks!

 

[Ianab]

You can spray the mold with dilute bleach to kill it. Then get some fans or more airflow happening. Once you can get at least the surface layer dry mold wont grow any more. And unlike some hardwoods, you can't really dry pine too fast. 

[moodnacreek]

Pine and warm weather don't mix. Any pine I cut from May to September has to be sprayed, to much extra work. A lot of members think blue stain is cute but my customers don't.

[slider]

i use  to spray ,now i sticker it and use fans.

[Ianab]

Pine and warm weather don't mix. Any pine I cut from May to September has to be sprayed, to much extra work. A lot of members think blue stain is cute but my customers don't.

Its winter here in NZ, but not cold enough to stop mold growing, and humidity is usually even higher. Summer seems easier here, if you can get the airflow, because it starts drying sooner. We have about 10C, rain and humidity ~90%. 

[moodnacreek]

The traditional pine cutting season in the northern U.S. is October to March. This seams to be changing as our winters are getting shorter. So those of us up north need to pay attention to the southern states and Australia and New Zealand as they would not have the cold weather to saw and dry pine and other stain prone species. When I was younger I thought once you learned that was it. I never thought things would change so much in my life time.

[JoshNZ]

I should've waited for a dry spell in the weather but we're having a bit of a crap winter as NZ usually produces, lots of rain these last couple of weeks.

I think I cut the logs on a grey day and was rushing to put them in the shed in the rain. I got sick after that and left them a week so it's not surprising. It was more a test for the mill after reassembly, I don't have much desire to keep pine I was cutting flitches to take thin boards from for a friend then decided to leave them as flitches. Got dreaming about some heavy slab bars.
How long should 150mm pine beams be left before using? Does anyone have any experience building with green timber? I'm planning huge mortise and tenon + peg joints, heavy enough that would prevent twisting anyway.

I scraped and sprayed them down with sodium hypochlorite today. Left a patch of mould to monitor it's efficacy.

[Ianab]

I scraped and sprayed them down with sodium hypochlorite today. Left a patch of mould to monitor it's efficacy

Bleach should knock back that mold, but you need to get it dry to stop it coming back. 

Very different climate here in NZ compared to most of the US. Mostly alternates between warm and humid, to cool and humid. :D

[JoshNZ]

I hadn't even really noticed the blue mold. The white stuff peels off, smells like mushrooms, seems harmless. How deep does the blue mould stain? It's quite covered on a couple of the slabs.

Might have to mix a stronger brew of bleach I don't think my first one did much

[Ianab]

Smells like mushrooms? Probably a sort of fungus then. Bleach might not kill it as easily as mold. The "blue stain" is another type of fungus which will grow all through the sapwood of pine and feed off the sugars it finds. It basically the first stage of the wood starting to rot, and it doesn't really affect the structure of the wood, just the colour. 

Once you get the wood dried down below about 20% none of those molds or fungus can grow any more. 

[Don P]

That's what I was wondering, I suspect the white is the fruiting body of white rot that was already present in the log, one of the decay fungi. Was this log dead or down for some time prior to sawing?

[GeneWengert-WoodDoc]

Technical review.  

Fungi need four environmental conditions to be active...
  *. Oxygen
  *. Warmth 50 F to 100 F, with 90 F being ideal
  *. Water , but too much water eliminates oxygen and fast drying really helps
  *. Food (Different fungi need different for.  Blue stain or sap stain fungi like the sugars in the sap; decay fungi like a component of the wood so weaken the wood; mold and mildew do not like wood, but use microorganisms, dirt, etc, on the surface of the wood for food.)

Eliminate one of the four to stop fungal activity.  If we cannot eliminate, then poison the food and use a commercial chemical that provides protection for a few weeks.  The chemical does not carry over to the ultimate consumer, but gives protection until enough water has been evaporated that the fungi can no longer be active.  The chemical provides a barrier to prevent entry of the fungi into the untreated inside wood.    Such chemicals are usually applied immediately after sawing by dipping the entire piece of lumber in the solution.  A few places dip the stacked lumber pile.  The chemicals are quite safe for this use, using common sense protections and drip pads.  In past decades, the solution was also sprayed, but with slight wind, the environment gets covered too.  Spray is no longer used safely.  Such chemicals do not always control mold and mildew, as the chemical does not poison their food.

Note that slight blue stain is not a grading defect for structural wood, but may be an issue for appearance lumber.  Most commercial sawmills use fast drying to control fungi.  They cannot afford to shut down when the weather is real warm, so then poisons are used.