There have been many posts about the discoloration on the front of our house and my desire to address that by painting over it. The last we left this subject in October, I painted a test patch with linseed oil paint to see how it withstood the winter.
At Tim's suggestion, I took a wire brush and cleaned off a section of the wood before painting. My plan was to paint over both brushed and non-brushed sections to see if the paint took differently.
I was surprised at how relatively easily a lot of the black discoloration came off, pretty much as a powder. This makes sense as the jarn vitrol is an iron-based product, and I'm sure what I was removing was a form of iron oxide.
The more I ponder it, though, I think I need to brush the face of the house before painting. Paint must adhere better to the wood without the iron in-between; that's just common sense to me.
Of course it is easy to sit at a desk in Texas and say, "sure it's simple to hand-brush 20 square meters of the house!" I am sure I will curse my decision, once up on a ladder this summer. But I think it's the best thing to do.
Our friends at Amazon have a ridiculous array of wire brushes available. I plan to pick out a couple of types and see how they work out during our April visit. I'll do the brushing deed in July, and have the house painted in September. That's the plan, anyways. There has been a lot of discussion about this over the years, and things always seem to change. But that's the plan for now.