Festool Owners Group

GENERAL DISCUSSIONS => Finishing and Painting => Topic started by: walleye guy on April 17, 2020, 03:25 PM

Title: Tannin bleed
Post by: walleye guy on April 17, 2020, 03:25 PM
I finished my basement a few years ago and have noticed on some of my casings that I have tannin bleed through.  I plan on repriming with BIN and topcoating with SW Proclassic.  Originally the boards I used were the pre-primed, so like a  dummy I thought that was good enough and just put on a couple of coats of Proclassic.  Lesson learned.

So my question is this: can I simply scuff sand and then apply the BIN, or do I have to sand more intensely?

Thanks!
Title: Re: Tannin bleed
Post by: Woozal on May 18, 2020, 11:52 PM
Shellac?
Title: Re: Tannin bleed
Post by: walleye guy on May 19, 2020, 12:27 AM
Yeah, BIN is shellac.
Title: Re: Tannin bleed
Post by: tjbnwi on May 19, 2020, 12:30 AM
Unless it is oak casing, I'd be suprised if it is tannin.

Scuffing and coating with BIN will work.

Tom
Title: Re: Tannin bleed
Post by: walleye guy on May 19, 2020, 01:06 AM
Fairly certain it is pine.  What I'm seeing is orange spots/streaks showing through the paint.
Title: Re: Tannin bleed
Post by: Slippycog on May 19, 2020, 03:08 AM
The BIN ( AKA white shellac) will stick to anything, no need to sand, but I’d advise cleaning with a detergent or TSP solution to remove any dirt, and scuff-sanding to remove any defects in the existing paint. BIN dries fast, so flow a lite coat on with a china bristle brush and watch for runs/drips. Avoid going back and re-brushing after about a minute has elapsed; doing so will drag the partially dry BIN and put brush marks in the coat. BIN is available in aerosol cans, so if you are only doing a door jamb or two, that may save time and create a smooth foundation for the topcoat. I’ve found the aerosol cans put out a strong spray, so it’s easy to flow too much on, causing runs, so do light dusting passes until you get the hang of it. After it dries in 30 minutes go back and lightly sand out any defects; go easy, this stuff clogs sandpaper easily; I like to use the soft sanding sponges and suck out the debris with a vacuum after a few strokes. Your brushes and tools clean up fast with a dunk in denatured alcohol to get out the bulk of the stuff in the brush, then dunk in janatorial strength ammonia (I pour some in a pint size mixing cup, then swish the brush around in there) then rinse in soapy water, and finally rinse with water. If done carefully, the final paint coats come out glass smooth. Good luck!
Title: Re: Tannin bleed
Post by: tjbnwi on May 19, 2020, 08:39 AM
Fairly certain it is pine.  What I'm seeing is orange spots/streaks showing through the paint.

To me, this describes sap more than tannin.

Tom
Title: Re: Tannin bleed
Post by: Cheese on May 19, 2020, 10:03 AM
Like Tom said, tannin bleed is usually associated with cedar or redwood. Pine is not one of the common offenders.

Here's some info from SW.

https://www.sherwin-williams.com/homeowners/how-to/problem-solver/dirt-stain-discoloration/SW-ARTICLE-DIR-TANNINSTAINING
Title: Re: Tannin bleed
Post by: walleye guy on May 19, 2020, 12:03 PM
Would BIN help with the sap bleed?
Title: Re: Tannin bleed
Post by: Slippycog on May 19, 2020, 10:03 PM
The BIN should block tannin or sap just fine...