Hi all!
I am new here but a friend told me about this forum and it looks great! I am new to sawmilling. I bought a Woodland Mills HM126 earlier this spring. I have had a lot of fun with it and learning more each day I cut with it. One thing I am wanting to learn more about/handle better is my drying process. Ultimately I think the answer is building a solar kiln but until then I just have my barn to stack my cut lumber in to dry.
My current issue that I would welcome some input on is in regards to mold on my large timbers. I have stacked a bunch of 2x6x9' for fencing and put 1.25" stickers in between and no mold. Same with some 2z6's and 2x10's etc. However, I am getting ready to build a "timber framed style" pavilion on my property 12x16 in size. For that I have milled 8x8x10' posts, 8x10x12' and 6x10x12' for my frame and 4x10 for rafters. I cut the 8x10's first and they have been stacked for a couple of months. The 8x8 posts I stacked on top of the 8x10's and all of it using 1.25" stickers. I pulled the timber out of the barn today to get ready to start actual building. There is a good bit of mold on the pieces I first cut. Some of it appears to just be surface, some looks to be what I think is called "blue stain." I took it all out and sprayed with a bleach solution and scrubbed with a brush. As you can see in the pics, the discoloration didn't go away and it is still splotchy in places. So here are my questions:
- What did I fail to do that I should do in the future to prevent this? Should I spray the larger timbers with a bleach solution the moment I stack them so that mold doesn't start to grow? I thought airflow would be pretty good @ my barn as they were stacked near the opening and even got a little bit of afternoon sun.
- The bleach solution didn't make it go away completely. I don't mind this so much as I think I am going to put a natural finish on it and kind of like that darker look it seems to create with the blue stain if that is what it is? If I wanted to get it to go 100% away what is the method used to do that?
I'm thinking in the future I should spray with a bleach solution right as I stack them and also use 4" stickers to improve airflow for these bigger pieces. Thoughts?
And lastly....what finish would you all recommend to keep it a natural look but darken up that pine just a hair? Seems a finish that still allows the wood to breathe is 100% necessary. I'd like something that weathers pretty good and upkeep is just putting another coat on maybe every other year or so. I've heard linseed oil isn't preferred and can encourage mold growth but have heard that heritage products has some stuff that is good for larger timbers that are still drying.
I have photos but it doesn't seem to want to let me upload them here or I haven't yet figured that out :) I've tried to upload them so maybe they will show up ha! if I uploaded them correctly the first few pics show the mold or fungus as I found it and then the last few where the timber pieces just look grey, etc. is after I sprayed with a bleach solution and scrubbed them with a brush.
(https://forestryforum.com/gallery/albums/userpics/74119/1.jpg?easyrotate_cache=1698537232)
(https://forestryforum.com/gallery/albums/userpics/74119/2.jpg?easyrotate_cache=1698537234)
(https://forestryforum.com/gallery/albums/userpics/74119/3.jpg?easyrotate_cache=1698537239)
(https://forestryforum.com/gallery/albums/userpics/74119/4.jpg?easyrotate_cache=1698537244)
(https://forestryforum.com/gallery/albums/userpics/74119/5.jpg?easyrotate_cache=1698537246)
(https://forestryforum.com/gallery/albums/userpics/74119/6.jpg?easyrotate_cache=1698537254)
(https://forestryforum.com/gallery/albums/userpics/74119/7.jpg?easyrotate_cache=1698537257)
I've had similar issues especially with pine.
I think the number one factor is when it is sawed. If I saw it in the summer when it is hot and humid, Ive had it stain and mold within a day. If I saw it when it's cooler/cold, it's much less of an issue.
I have also tried bleach and found that the results aren't immediate. Spray it a number of times over a few days and you will see it gets better however you may not get rid of it completely.
Welcome to the forum. There is lots of reading to be had here on this subject because it happens to a lot of folks. Use the search tool to find that reading material.
The short answer is that you need lots of airflow over and through summer milled pine to get that surface moisture before the mold sets in. Once it is in, it is in and getting it to go away, as FPP said above, is tough and limited. If you have to mill it in the summer, think about investing in some fans to blow through your stickered pile.
Just a question, but are you sure there was no discoloration in that wood when you sawed it? Also, when were the logs cut, winter is the best time for pine.
Here are a couple ideas:
Saw in the winter.
Much larger sticker and bigger gap between timbers on the same row.
Start the stack high off the ground.
Keep grass and weeds short around the pile.
Put them under a good cover with LARGE overhangs.
Put the stacks in a place that gets lots of wind.
Use a fan/s to blow air through the stack the first couple weeks or months.
Narrower stacks.
Welcome to the forum. Lots of air flow, fans of necessary.
You need to leave them stacked outside with good air flow long enough to dry the surface and near the surface. When I stack timbers I use 3.5" stickers (two 4ft 2x4's screwed together). I only mill hardwood, but a few days outside is usually good for hardwood. Pine is a different story. More food for the mold there, so the exterior moisture needs to be brough down enough that it cannot grow. Fans if inside would be good. I'm not sure how oxalic acid would work on the mold stain, I have not tried it myself, but I want to.
Also if you choose to sand your timbers with say a 4x24 belt sander, that may remove some of it as well besides giving you a smooth finish. I usually oversize my timbers by 1/2"(12mm), because I plane and sometimes sand them after they've been air drying in the barn for a few years.
By the way, you don NEED to dry timbers. You cannot kiln Dry timbers as you'd end up with dryness on the exterior, and wet on the interior. Not a good thing to do. If you just leave them air dry for a year or a few, most of the movement will happen and you'll have more stable timbers and they won't shrink so much in the frame. This is more an issue with hardwood than pine, but is by no means required. Lots of frame are cut and raised green.
The finish that probably most timber frames use is Heritage Natural finishes. It's a mix of tung oil, pine resin, beeswax, citrus solvent, and can have UV or pest control additives if specified. It can also be dyed using pigments they supply. We mixed a dark chocolate colored opaque dye in the Heritage oil we used on the outside timbers of our barn. This will help protect them from the sun/fading.
Welcome to the Forum Tony Sawmill!
You will get some really great advice here!
Thanks for the insight everyone and hello Troy! :)
sounds like fans would have been optimal...may need to get the power set up to my barn lol.
next time will be raising them up off the ground more than just 4" and will be using larger stickers between pieces.
I guess I will try a 2nd bleach spray today....
my slab is poured and I hope to start erecting the frame here in the next week or two!