Replies

1. 
   Sphere | Feb 05, 2004 07:23pm | #1

   mold..

   Go Stab yourself Ya Putz! Ya think I Parked here?
1. 
   forestgirl | Feb 05, 2004 07:39pm | #2

   The mold I've seen on wood and lumber has been black or white.  I've never seen green.forestgirl Another proud member of the  "I Rocked With ToolDoc Club" .... :>)  you can take the girl out of the forest, but you can't take the forest out of the girl ;-)

1. 
   Sphere | Feb 05, 2004 07:52pm | #4

   I have seen plenty too much..esp. on oak...it happens.

   Go Stab yourself Ya Putz! Ya think I Parked here?

2. 
   pghdan | Feb 05, 2004 08:02pm | #6

   It isn't mold I'm fairly confident.  Almost looks like a green stain or dye.  I'm sort of wondering if it could be an early version of treated lumber.  Similar green tint.

2. 
   forestgirl | Feb 05, 2004 07:42pm | #3

   I have no idea if it's a preservative or not.  Have you used a little sandpaper to see how deep it goes? 

   I wonder if something could have reacted with the tannin in these two woods to produce the green sheen.

   forestgirl Another proud member of the  "I Rocked With ToolDoc Club" .... :>)  you can take the girl out of the forest, but you can't take the forest out of the girl ;-)

1. 
   Sphere | Feb 05, 2004 07:52pm | #5

   lime from plaster too...while we are guessin..

   Go Stab yourself Ya Putz! Ya think I Parked here?

3. 
   Loach | Feb 05, 2004 08:54pm | #7

   My father-in law always primes or at least back-primes just about everything with a copper based preservative that leaves stuff slightly green.   He says that it helps prevent mold and bugs, and that it has been 'common practice' for as long as he can remember - at least since the 1930's!

   Loach

1. 
   pghdan | Feb 05, 2004 09:31pm | #8

   Thanks for the insight.  I was somewhat concerned it might be an arsenic based product (I have several kids around the house) and was wandering if I should handle it with more care.  After what you said and thinking about it I guess the green color of CCA treated lumber probably comes from the copper component and not the arsenic.  I wish I had a digital camera so I could post some pictures but I haven't gotten around to buying one yet.

2. 
   jonsherryl | Feb 05, 2004 10:28pm | #9

   Loach, I'm not sure we have this one solved yet. I suspect the old wood treatment you are referring to is copperas (AKA: green vitriol, ferrous sulfate.) It's a green crystalline substance and it's deadly poisonous.

   On the other hand, I've seen samples of both oak and chestnut that have been infected with a mold that turns these woods a vivid green color...so, I think the jury is still out on exactly what this is. If the green tint on the back of this trim is uniformly spread and rather superficial (barely penetrates the surface), then the odds are it's a coating on some sort. But if the green color appears to be patchy, penetrates the wood deeply in some spots, and if the wood seems to be weakened and powdery in the areas of the darkest coloration, then the odds would tip in favor of it being a decay fungus.

   Either way, I don't think it means that this old trim has to be scrapped. It probably wouldn't hurt, though, to coat the back side of the trim with shellac or varnish just to seal in whatever it is. If it's a fungus (mold) and the trim is used in an environment that keeps its moisture content below 20%, the mold will stay dormant...and there's not much chance of children getting to the back side of trim once it's nailed in place...so, the sealer coat should keep any of the stuff, whatever it is, from getting airborne. 

4. 
   Paul_Snyder | Feb 05, 2004 11:58pm | #10

   Sounds like stain or dye to me. When matching old finishes, the best clues to the original finish come from the backs of various pieces. I had to match some new work to pieces from the time period you're talking about and the fist step in the matching process was to use a gereenish/brown dye; the original had the same base color. I used a brown stain over the greenish dye. There's a post on matching the old finish here - http://forums.taunton.com/n/mb/message.asp?webtag=tp-knots&msg=15515.1

   Paul