Fine Points of End Coating

      Advice on applying Anchorseal or roofing tar to log ends immediately after felling. October 19, 2013

Question (WOODWEB Member) :
What is the best way to do end coating, before sawing as logs, or after milling? The logs that I receive are 6'' longer than the lumber length so I have to cut them down to length.

Forum Responses(Sawing and Drying Forum)
From Contributor A:
Coating the logs is much easier than doing a lot of boards. I leave the 6" trim on the lumber until it is dried then cut to length if desired. I use Anchorseal which is a good product.

From Gene Wengert, forum technical advisor:
My suggestion is two coats of Anchorseal or similar on the logs. If applied soon after felling, you can shorten your logs by 4", which saves time sawing (maybe 3%), reduces log weight, reduces waste, and makes the next log a little bit large in diameter. In tests that we did in Wisconsin in the summer with oak and maple and two coats (not brushed out too thin), we eliminated drying end checks, but not stress cracks, on virtually 100% of the logs, as well as log stain, for 12 weeks. In case you did not get the message, thin coats or one coat is not too effective.

From the original questioner:
One more question, a guy offered me butt white oak logs for $70/ton delivered to my place. He told me to go and choose whatever I want and cut to my specs before being weighed. All logs are from north east GA region. Is it worth it or not?

From Gene Wengert, forum technical advisor:
At $70/ton, you are paying about $450 to $500 per MBF, a great price for a high quality log. However, if there is decay, warp, etc., then the price looks worse. If it is knotty (a field tree), then it is likely poor grade and likely to have bacterial infections, etc.

From the original questioner:
It will be a good price if it will be a good percent of FAS and 1c grade, because 2A and under grades are much less than 450/mbf/, 500/mbf. I can buy FAS 4/4 for $1100 and 1c for $625 delivered.

From Contributor A:
I respectfully disagree with Dr. Wengert's assertion that cutting 4" off of the logs and leaving only 2" of trim will be somewhat beneficial. In my experience, Anchorseal penetrates up to 1", maybe slightly more, into the ends of the logs. This could leave some of the product in the ends of the lumber.

From Gene Wengert, forum technical advisor:
You may get penetration of an inch or more if the log ends have dried somewhat, but not with freshly cut ends.

From contributor C:
Our business involves thick, wide slabs for table tops. We have them custom sawn and then air dried and have them custom kiln dried. Our end coating is roofing tar. Absolutely no moisture gets through. We get zero end checking. We also use it on susceptible areas like knots, crotches, etc. There is also virtually no penetration into the wood of the tar, even on maple sapwood. Need I mention that roofing tar is a lot cheaper than Anchorseal?

From Contributor A:
I think I'll try the tar after I use up my current supply of Anchorseal. Thanks for the tip.

From Gene Wengert, forum technical advisor:
In the kiln drying classes I taught and in on-site training, we always suggested asphalt roofing cement as end coating for kiln samples. It worked on wet wood very well, but it was troweled on and had to be thick. It did make a mess when it got on my clothes. After drying, it was still a bit tarry, so it had to be removed so it would not gum up the planer feed rolls.

However, due to the time to apply, this material was not suggested for lumber end coating (it might take an hour to apply to 1 MBF) except for very thick walnut gunstocks and specialized tabletops like Allan S. mentions. The high value justifies the expense of application and the removal afterwards.

Application when cold is difficult, at best. I have seen small pieces of wood, like short squares, using hand dipping of the ends in a tray of melted paraffin. Fire hazard, but very effective.

It would take quite a lot of material to coat log ends, so I am not sure about the overall cost compared to a sprayer using Anchorseal or similar. I have not seen the penetration of oils on fresh log ends from Anchorseal in hard maple. Fresh ends would mean coating within a few days after harvesting, when the logs get to the mill. Anchorseal has the advantage of evaporating when the kiln is over 130 F, so there is no carry-over into the manufacturing plant.

From contributor C:
As usual, Dr. Gene is spot on. My wife has not been happy with what the tar does to my clothes!

Also, if Anchorseal is cheap enough in large quantities (i.e. 55 gal drums), I don't doubt that it would be more effective spraying it on logs. We cut our slabs very soon after the tree is felled, so gumming up a saw blade isn't an issue. I don't doubt that tar will soften up in a kiln, but we are far enough north (Minnesota) that tar usually resets fairly quickly. When it's cold, we use a hot plate to soften the tar, which really makes a mess. For high end material, tar is definitely a very good way to go, just wear very old clothes.

From Contributor A:
I guess for the limited amount of hardwood I saw I'll stick with Anchorseal as I only saw hardwoods when I get a sick tree in my 65 acre woodlot. A 5 gallon pail lasts me about 2 years.

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