We stained a new white pine log cabin. First we used borate and let dry, then brushed on a heavy coat of stain and let dry, then brushed on a sealer. It was beautiful, however several months later it began to develop streaks and blotchs. We were told the logs were unevenly dried. Anyone else have this problem?
Hi, Syl. This is actually somewhat typical on new log homes. (In fact, it's so typical that Sashco actually mentions it in the maintenance instructions for our stains.) As the logs get used to their new environment, the porosity can change and will show up as blotchy areas. In addition, brushing doesn't generally get as much stain on there as spraying on stain, so the blotchy look can be a bit more pronounced.
The good news: with most stains, it simply means applying another heavy coat to even out the blotches. You should contact the stain manufacturer to make sure this is OK with their product, since some sealers need to be scuffed and/or removed before putting on more stain. But others can simply be applied one on top of the other, so check to make sure.
Hope that helps some! Have a great day!
Back brushing, when done properly, in my experience will always allow better penetration of stain then simply spraying it on. Most likely you have mill glaze on the logs from the hot milling blades when the logs are milled to size. Unless you remove the mill glaze by sanding or some solutions will remove it, you get blotching. When I was testing stains I observed that a number of the water based or water borne stains seemed to be more blotchy then oil based semi transparent penetrating stains.
Also, if you used water based stain, why would moisture levels be that much of a factor. Some stains are coatings and only lay on the surface adding to this potential blotching problem. Ask if the stain is a coating or does it actually penetrate the wood fibers.
Another question ! Did the stain you use have a top clear coat ? Some of these trap moisture and do not let the logs dry or breadth.
Did you start staining from the bottom going up with the staining? You cannot allow the stain to drip or run on lower logs that will not get stained for several minutes or hours later. Thats why you always stain from the bottom log and go up. If your streaks are from over-runs when staining top down this too will account for streaks.
Post the name of the stain you used on this site to alert others of this potential problem and explain how you stained it. ( brushed vs spray, oil vs water based, did you back brush, did you measure the moisture level before staining, did the stain require a Top coat, etc ).
I am thinking that the water based stain you used is a 'coating' stain that does NOT penetrate and that the sealer you were told to put on is trapping the moisture. It appears you did everything correctly up to the point of staining and then putting the sealer over the stain.
I used TWP, an oil based semi transparent penetrating oil stain and NO seal coat of any kind. No one in this industry to my knowledge is measuring moisture beyond what a moisture meter would measure on kiln dried logs when chosing to stain with a water based stain.
Call the maker of the water based stain you used. I think you will find that the stain is a coating ( more like a paint ) and dries mostly or all on the surface. The seal coat likely did not allow moisture exiting from the interior of the log to escape and what you are seeing is the results of trapped moisture. I would put the stain maker on notice and the company who milled the logs and claimed they were adequately kiln dried. Let them 'duke it out'. They cannot both be right. Also, even if there was some moisture in the logs when staining the log maker will take the position that had the seal coat not been applied, any residual moisture would have escaped into atmosphere w/o any blotching/streaking.
Regarding water based stains, try staining bare pine boards with water based stain w/o any pre-staining products applied. Often you will get uneven absorbtion of the stain on the pine, whereas, when staining the same boards with oil based you frequently do not see such unevenness.
The problem you now have with appling a second coat of stain is the seal coat you applied. If this is a clear coat, all you are doing is laying a new coat of stain on the seal coat and not into the fibers of the wood. I personally and just not sold on clear coats over any stain. If the stain has the proper water repelling characteristics and UV protectors why should any good stain on exterior logs then need a clear coat for a final coat ??????
We used Perma Chink stain which also directions said we need a seal coat. Another professional said he had used Perma Chink for 15 years, but their exterior stain left something to be desired. He didn't elaborate on his reasoning for that. The stain looked too nice for 5 to 6 months that I don't think this had anything to do with the stain. We have always used Wood Guard oil based stain for soft wood like pine and never had a problem
To the best of my knowledge, unless the surface moisture content is above 20%, you should not be having any problems in that area. Especially streaks and blotches. If surface moisture content was a problem, the finish would be peeling off due to water vapor pressure.
I do however wonder, was the logs cleaned with a bleach and/or tsp solution? If it was, how throughly was it rinsed? You see, bleach can leave a film on the wall if not properly rinsed. I would suggest checking the PH of the logs and go from there.
Sorry to hear of your frustrations...if I can be of any more assistance, please do not hesitate to contact me.
Inside Sales/Perma-Chink Systems/Colorado Branch
(800) 433-8781 ext.2033 - firstname.lastname@example.org