Typar For Controlled Drying of Wood

Discussion in 'Tutorials and Tips' started by Mark Levitski, Apr 13, 2013.

  1. Anyone experiment with films or fabrics such as Typar to control drying of roughouts or blanks? Instead of anchorseal coating or paper bags? Perhaps to make some bags out of this material that will last longer than grocery bags and will be slower to release moisture. Sometimes the paper bags are a little too quick, even with doubling them, and usually for me the anchorseal treatment is too slow.
     
  2. Bill Boehme

    Bill Boehme Administrator Staff Member

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  3. Richard Jones

    Richard Jones

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    Bill,

    Are you referring to the differences in the two products or an issue with the concept?

    Thanks.

    Rich (still on the first cup of coffee) in VA
     
  4. Ian Thorn

    Ian Thorn

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    So bill would you say Tyvek is the good one to try or would in your opinion do you think the vapour release is too great.I have use it on buidings but hadnt thought of it for this use

    Ian

    Ps I think Richard may have the information we seek
     
    Last edited: Apr 14, 2013
  5. Bill, yes, I have read a little about the differences. The main issue is what perm factor would be best for slow moisture release without mold and mildew. The Tyvek does seem to be too fast, as it compared to natural "unwrapped" drying in tests. It has perm of around 50 if I remember right, where the Typar has a perm of 13.

    I will do my own experiments, but meanwhile, I thought I'd test the waters. Keep the comments coming if you can share anything.
     
  6. odie

    odie

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    Mark......I've never used Tyvek so can't give input, but I believe there would be others, including myself, who would be interested in your test results. It's going to be awhile to fully season some roughed bowls, so be sure to come back and post your results when you have them.

    How do you determine that a rough bowl has stabilized? Do you do it by weight? If I were going to perform this experiment, I believe I'd take two identical roughed bowls taken from the same tree, and have the same MC......preferably above 20%. Anchorseal one, and Tyvek the other. From there, weigh monthly until the MC has stabilized.

    Any significant difference in time to stabilize would indicate the source method of preventing moisture escape. If there is no significant time difference to season a roughed bowl, then I guess you could conclude the Tyvek is at least as good an option as the anchorseal.

    Thanks for starting this thread.

    ooc
     
    Last edited: Apr 14, 2013
  7. Lloyd Butler

    Lloyd Butler

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    I guess in the end if the Tyvek or similar worked, then you now have an entirely new way to store the blanks as well. A tyvek "bag" with a handle sewn on could be hung on wall pegs rather than piled on the shelf.

    You could staple a tag with the wood type, source and date to the bag when you start the drying and swap it out for the next piece.

    I use anchor seal or a heavy coat of paste wax and toss them on the shelf in my shed to dry.

    Lloyd
     
  8. Bill Boehme

    Bill Boehme Administrator Staff Member

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    Several years ago there was an exotic wood importer in Peru that used shrink wrap plastic to retain moisture rather than Anchorseal. By the time that the local Rockler's Hardware received some pallets of the wood, it already was rather moldy. I see Typar as being very similar in that it essentially forms a moisture barrier and that is not good for very wet wood. I do not have good feel for how well Tyvek would work, but it might be just the right thing. Anchorseal slows down moisture loss, but it is not a total barrier by any means. The cost of Anchorseal is not too bad so I will stick with it for the time being or until my supply runs out.
     
  9. I get the point, Bill. Have a look at figure 8 in the article you linked above. It shows the drying curves of the various fabrics. Tyvek has a quick, steep drying within the first few days. Typar is slow and steady over time and after 20 days has not even quite reached the Tyvek results by then. I would tend to think that slow and steady would be better.

    Another thing is that is it not water that is transferred from the wood as it dries, it is water vapor. These fabrics are not like a plastic film or shrinkwrap that holds moisture in. They are designed to let it out while keeping out liquid water.

    I'm sure that a lot would depend on what climate/conditions exist where it is used.
     
  10. Bill Boehme

    Bill Boehme Administrator Staff Member

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    My thought is that even with no treatment to slow down drying, wood takes years to dry when stored in t he sme conditions as Anchorsealed wood would be stored -- out of the hot sun, etc. For example I had a large mesquite log about 32" in diameter stored for about five years -- outdoors some of the time. When I cut it up into smaller pieces the interior was still very wet. Given that the wood slowly loses its moisture naturally, then a wrapping of Tyvek -- maybe several layers, might be comparable to using the wax emulsion. Of course, I am just speculating and I am wondering what a minimum purchase of Tyvek would be -- enough to wrap a large house or several houses?
     
  11. Bill Boehme

    Bill Boehme Administrator Staff Member

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    I just checked Home Depot and a 9 ft. X 150 ft. roll is $159.00. I can coat a lot of wood with a one-gallon jug of Anchorseal at $12.
     
  12. You're right, Bill. For the smaller applications, buying a whole roll would not work. But maybe it can be done on a club or group basis, where the roll could be split up and shared, just like buying a 5 or 55 gal. container of Anchorseal.

    I don't use Anchorseal for my roughouts. I use paper bags, either single or doubled. However, we do go through at least 5 gal of Anchorseal a year for endsealing our log, branch, and misc. other stock. My wife and I both use a lot of bags for isolating various small slabs and my roughouts from drying too fast. I would not get to decrease the amount of Anchorseal, but would rather get a better control of drying, as well as have a more durable (paper grocery bags don't get but more than 1 1/2 cycles of use here) sack.

    Don't throw out the baby with the bath water.

    P.S.- Depending on the size you need, you could get anywhere from 80 to over 300 bags from a roll that costs about the same as 9 gallons of Anchorseal. Straight from the company, A.S. is now
    $85/5gal ($17/gal).
     
    Last edited: Apr 15, 2013
  13. odie

    odie

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    I wonder how well some freezer paper would work? This paper has a plastic-like coating on one side and bare paper on the other. It seems like this paper would slow moisture loss down further than what plain paper bags might do. This would be easy to test, because it can be purchased at the grocery store in small quantities.

    I do tend to agree with Bill on this, because I've been using anchorseal (actually a wax emulsion sealant similar to anchorseal, available from CSUSA) with great results. It would be hard to make me switch methods, that is, unless there is some great value in any benefit the alternative may have.

    Because I don't discount the possibility there is some extra benefit to Typar, I am definitely interested in hearing about your test results, Mark.

    Very interested in what your findings are.......

    ooc
     
  14. Dean Center

    Dean Center

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    Useable sized pieces of tyvek/typar can be obtained at no cost from the trash piles of homes under construction. I'd like someone to try this out and report back.
     
  15. Bill Boehme

    Bill Boehme Administrator Staff Member

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    Our club members get it for $12/gal because we buy it in 55 gallon drums. Freight has been the biggest cause of price increases.
     
  16. john lucas

    john lucas

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    Just my own thoughts on this. I find stretch wrap stops drying and can promote mold. I should say I live in Tennessee because all of this varies with locale. Stretch wrap is great for saving pieces of a few months until you can get to them to rough turn them. Plastic garbage bags work just about as well but are harder to stack and you can't see through them to see what wood it is.
    Waxing with parafin is next. It does let the blank dry out but it will take quite a while. I have saved cherry blanks for 2 years when completely covered with wax. They aren't totally dry but dry enough not to move much when turned. I turned an Urn our of Maple that was 10" around after 2 years and it didn't move at all. If you just seal the end grain portions the wood dries faster but I have had some minor cracks on larger blanks.
    Anchorseal is third in the how fast things dry in my tests. If I put 2 coats on is seems to really slow down the cracking and the wood seems to dry faster than the wax or plastic. If I seal only the end grain portions they dry quite a bit faster of course.
    Paper sacks speed up the drying the most of these 4 methods. I have had some hollow forms crack when roughed with fairly thick walls. Most of my bowls don't. I have occasionally had mold but it hasn't gone very deep so when re-turning it's gone. I use the paper sacks a lot for finish turned pieces. I'll put the piece in the sack for the first week. It seems to greatly reduce the chances of checking but it does take an extra few days to a week or more to dry a bowl about 3/8" thick.
    None of this is even remotely scientific. I've been doing this experimenting for about 7 years now and have greatly reduced my losses. I don't have ideal places to store the blanks so I had to go to these extremes to reduce my losses.
    Damn it's windy. It just blew an Oak rocking chair off my front porch. Hope my new roof holds up to this.
     
  17. One good reason I am looking for options is that I do mostly natural edge or bark inclusion pieces. Not the best to coat these with AS.
     
  18. John Nicholas

    John Nicholas

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    Housewrap

    Housewrap, Tyvek or similar might work.

    Look for the 'PERM" Rating. <.1 PERM is a class I vapor retarder. This is considered as a vapor barrier.

    Class II rate from .1 PERM to 1 PERM is classified as a impermeable vapor retarder.

    Class III rate from 1 PERM to 10 PERMs and are classified as a permeable vapor retarder.

    I think you would want some material with a PERM rating in the 1 - 10 range, Class III. This should include all brands of house wrap.

    Don't get too involved in the Dow Sales Pitch for their product. You are not using this to wrap a house. You are using it to retard the drying of a turning blank.
     
  19. Bill Boehme

    Bill Boehme Administrator Staff Member

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    That's one way of stating it although it seems somewhat confusing since paper sacks retard drying the least of the four methods. None of the methods speed up drying -- they are all ways of slowing down the process.

    However, my wife is from Tennessee and she says things like, "_______ (fill in blank) turned up missing" so I am able to understand Tennglish although I don't speak it.
     

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