# Removing Sap on big-ass Pine Beams



## ecopainter2 (Jul 27, 2010)

Hey everyone, you may know me as Ecopainter. I had to start a new account because I forgot my password. Just wanted to say hello and let you know who I am.
Currently I am doing a project with some huge pine beams. (12x12) and I am trying to finish them for the interior of the home. I have a belt sander on them now to get them smooth which is fairly easy. The only problem is the sap!!! No matter how much I sand, the sap clogs the sand paper and then still won't come out completely; so when I apply the stain you can still see the modeling from where the sap is. Any suggestions? Any cleaners to remove this stuff? I wouldnt be too concerned if we were applying a clear stain, but it is pretty dark and doesn't look good with hundreds of white spots! Also do you think I should use a conversion varnish or just a standard lacquer? Thanks so much guys! Hope all is well!
Eric


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## H2O Paint Chemist (Jan 7, 2010)

The best overall tar/greasy gunk remover I've ever used is Citra-Solv. It's a concentrated extract of orange peel oil and is organic and biodegradable and it smells like oranges. It cuts all kinds of grease and crud fast. Try it full strength, and if that works, 50% cut with water to save money. I've never seen it outside of health food stores.


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## Retired (Jul 27, 2010)

ecopainter2 said:


> Hey everyone, you may know me as Ecopainter. I had to start a new account because I forgot my password. Just wanted to say hello and let you know who I am.
> Currently I am doing a project with some huge pine beams. (12x12) and I am trying to finish them for the interior of the home. I have a belt sander on them now to get them smooth which is fairly easy. The only problem is the sap!!! No matter how much I sand, the sap clogs the sand paper and then still won't come out completely; so when I apply the stain you can still see the modeling from where the sap is. Any suggestions? Any cleaners to remove this stuff? I wouldnt be too concerned if we were applying a clear stain, but it is pretty dark and doesn't look good with hundreds of white spots! Also do you think I should use a conversion varnish or just a standard lacquer? Thanks so much guys! Hope all is well!
> Eric


The belt sander is generating heat. Best IMO to switch to even hand sanding if the wood is smooth enough. 

That sap is what is used to make real turpentine. The sap is soluble in half a dozen hydrocarbon base solvents from acetone to plain paint thinner (Stoddard solvent)

After a thorough wash job to partially remove the the surface sap, maybe try one of the universal wood dyes or more specifically a "spirit" soluble analine dye. A trick to using this type dye is to wet your wood with the appropriate solvent. In this case, paint grade alcohol. 

The beams are going to continue to weep. After staining, If I was calling the shots, I'd apply 3-4 coats of Zinsser SealCoat as a barrier to the topcoat. SealCoat is compatible with alkyd poly, nitrocellulose and non steareated lacquers and conversion varnish.


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## MNpainter (Jul 17, 2008)

I deal w this all the time here in the northwoods, its not the sander its the sap. Laquer thinner is your friend here. No special sealer is needed varnish or whatever you normally do. If the sap is going to continue to bleed it will do it no matter the sealer.
steve


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## PressurePros (May 6, 2007)

Steve nailed it. It will come back. Only effective long-term technique is R.O. & R.


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## Retired (Jul 27, 2010)

Lacquer thinner is great, being a mix of several hydrocarbon base solvents. The sap or resin is also soluble in turpentine and alcohol as well as naptha and kerosene. Wash type lacquer thinner can contain oil in small amounts and may also contain retarders. Best bet IMO is acetone. Acetone is what it is, evaporates almost instantly and leaves no residue. 


The Zinsser SealCoat is essentially a de-waxed blonde shellac at about a three pound cut. The chemists at Zinsser have figured out a way to extend the shelf life of de-waxed, bleached shellacs. Shellac is biochemical and in some areas especially in UK, knots are treated with a relatively uncut version of shellac called knotting fluid. The SealCoat can be cut 100% with paint grade alcohol. This will promote fast dry times. Generally unless it's very cold, about half an hour between coats dry time is plenty. 

The shellac/SealCoat will stave off a topcoat degradation IMO, much longer that applying a "varnish" which in reality is likely not a true varnish but an alkyd polyeurethane. This is the reasoning for utilization of the SealCoat or a de-waxed, bleached shellac product. "Standard" shellacs are waxy and there is little or no bonding or adhesion of alkyd polyeurethanes to "regular' shellac. If the topcoat were true varnish, regular shellac is fine.

Hopefully these beams are being worked on, on the bench. Pretty easy to slap or rag on a couple of coats of shellac to stave off something that will cause almost any type paint or coating to degrade or fail. 

If more belt sanding is necessary for prep, maybe a switch to an open coat belt after a solvent wash would decrease the loading up of the belt. 

We had the same problems in the Pacific Northwest in both Washington, Oregon and Idaho. The major culprits being pine and cedar. The newer the growth the greater the sap content.

Another trick to reduction of sap bleed if paint is the topcoat is a coat or better yet two of one of the aluminum paints by Benny Moore or SW, followed by shellac. This can be done as fullcoat or spot prime. Again the SealCoat is the better product if the paint choosen is to be an acrylic. The wax in regular shellac inhibits the bonding.

The aluminum paint is also great for sealing in tar joints prior to finish painting.


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## ecopainter2 (Jul 27, 2010)

*Many Thanks*

The beams are going to be stain grade, so would you suggest lacquer thinner and then sanding? Or a mix of both? How long after cleaning with L.T can I stain the beams? And as far as an interior clear coat? Will the sap crack the seal of the clear and push its way out? Should I not apply a clear?
Thanks to all for your answers!
Paint talk is a savior for sure!


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## Delta Painting (Apr 27, 2010)

Retired nailed it! that is how I always do the type of sap removal and sealing.


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## ecopainter2 (Jul 27, 2010)

Retired said:


> Lacquer thinner is great, being a mix of several hydrocarbon base solvents. The sap or resin is also soluble in turpentine and alcohol as well as naptha and kerosene. Wash type lacquer thinner can contain oil in small amounts and may also contain retarders. Best bet IMO is acetone. Acetone is what it is, evaporates almost instantly and leaves no residue.
> 
> The Zinsser SealCoat is essentially a de-waxed blonde shellac at about a three pound cut. The chemists at Zinsser have figured out a way to extend the shelf life of de-waxed, bleached shellacs. Shellac is biochemical and in some areas especially in UK, knots are treated with a relatively uncut version of shellac called knotting fluid. The SealCoat can be cut 100% with paint grade alcohol. This will promote fast dry times. Generally unless it's very cold, about half an hour between coats dry time is plenty.
> 
> ...



Retired:
You are my HERO!!! I want to have the knowledge you do! You rock! Thank you sooooo much


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## Retired (Jul 27, 2010)

ecopainter2 said:


> Retired:
> You are my HERO!!! I want to have the knowledge you do! You rock! Thank you sooooo much


Not much heroic about painting for way too long. Many thanks..

You are probably done with what you needed to do by now. A wash with a hot solvent will take away some of that sap. When the solvent evaporates you shouldn't be able to smell it. I really prefer acetone to lacquer thinner. Acetone is pure and lacquer thinner is a mix of several hot solvents. ie acetone leaves no residue and evaporates really fast. There are solvent evaporative scales on the net somewhere that begin with ether at the top and end with kerosene at the bottom. 

Stain is sort of a generic term. To be on the safe side any stain or dye should be applied to wood that is dry with the exception of some of the dyes that are best used IMO, when the wood is damp with the specific solvent used to dilute the dyes as in water for the water solubles and alcohol for the "spirit" solubles.

I wish I could tell you that any or all of these methods to keep that sap from screwing up your paintwork are going to work 100%. The guy who figures that out will be my hero. Ain't found him yet..LOL


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