Slow drying pine tar question

hi all,

I built a small shed myself, mainly out of wood and mainly with hand tools. It was a lot of fun!

Now I have also made the rain gutter out of wood myself. I coated it with pine tar. But because I did this late in the season during colder, wetter weather, it hardly dries.

Even when there is a lot of sun and heat the tar tries (penetrates the wood) slowly, but during these time of the year (autumn) even slower... I have therefore put it inside in a heated room (about 16 degrees C) in the hope that it will dry faster than outside, where temperature averages 6-8C.

Do you perhaps have any ideas, how I can promote the drying process? Or should I just be patient and keep waiting? The gutter has been drying for about 10 days now and the tar seems to be getting subtly drier now....

I've just started experimenting with pine tar not even two months ago, and I think about this issue a lot myself. Not sure about your environment, so I have a couple questions to consider.

- Is it relatively humid where you are? Although it's cold, high humidity may be retarding the drying process.

- What's the composition of your pine tar?

There may be a lot of resin vs. other components, which may keep it in a semi-liquid state. The recipe we used here very recently calls for two parts pine resin, one part organic matter, one part wood ash. I suspect you can fiddle with these ratios depending on your application, much like when working with cob/adobe. I suspect if you have more in terms of solid components, the pitch would dry quicker.

In any case: since the gutter seems to be drying, then I'd suggest you let it take its course and in due time it ought to be dry enough. Maybe it's proceeding "as scheduled," and everything in your process is nominal. For future projects, consider both the time of year and the different ratios of components. Make your observations, and keep them in mind as you continue to work with pitch for more construction projects.

Good luck to you...!

Have you considered using a steel gutter and capturing the water for domestic use?

@Stephen B. Thomas thanks for your response! I use a commercial product: https://www.auson.se/wp-content/uploads/2020/03/Black-Pine-Tar-ENG-200213-1.pdf

Unfortunately when applying the tar, I did it outdoors, and it was moist. I did that in order to prefent excessive fumes. After 4 days I moved the gutters indoors. After another 4 days I turned on the heating of the room, and right now, after almost 2 weeks, it seems the tar is slowly drying! It still feels sticky, but not as fluid as a few days ago. I think I have to be patient?

The only "problem" I have are concerns about the shed having no gutters at the moment, as rain water is spashing against the wooden walls. The wooden wall starts about 15 cm above ground level, as the measured foundation wall extends at least 15 cm above ground level. All wood is painted, so I guess it can handle some splash water for antother 1 or 2 weeks?

@John C Daley: yes! But I liked the idea of using wood as much as possible, as I had it in stock.

I plan to drop the water into a hole in ground,  so no downspout, and fill that hole with shells against splashing, and then I want to dig a trench to a wadi for drainage

Hi, finally I decided to dillute the tar that has been curing for two weeks using 100% ehtanol: I applied it with a paintbrush ans just "painted" (dilluted) it using ethanol in order to spread the wet areas and help it suck into the wood. Not sure if this helped the drying process, but last week I decided it was good enough, although some parts were still sticky.

I mounted the gutter and it looks beatiful! And it works perfectly. I dug two small canals and two wadis, so every gutter has its own wadi to let the rainwater soak into the ground. I mounted two bamboo sticks vertically touching the gutters, they both are just put into the ground where the canals start. I checked this during windy conditions: 6 Bft, and some moderate rain. There was almost no water movement to be seen at first glance, but when I put my finger against the bamboo stick, water was flowing over my finger. When I removed the stick, the water was dripping in a much bigger radius. So it seems this is working quite good!

Good that it worked! For future reference, though: When treating wooden boats with pine tar, it's traditionally mixed with linseed oil and turpentine, to make it more easily absorbed by the wood. One recipe I've seen calls for equal parts of the three ingredients.

My only experience with the application of pine tar was during my purest x-country ski phase where you would use pine tar on your wooden skis. Whatever formula was in the SWIX pine tar it usually was ready for scraping and applying the appropriate wax within 48 hrs.. I do remember watching ski techs use a heat gun sometimes.  Man a lot of memories, pine tar, kick wax, glide wax, different temp wax, ski skins, I like wax less skis now, a lot less work.