Inspired by Leo V's website, I've spent the last couple of days doing roughing mostly. Still have a long way to go before I match Leo's three zillion blanks drying on the shelf, but it's a start.
Got me thinking about drying though. Usually I rough turn to 10% of diameter, slather on end grain sealer inside and out (on the end grain - I ignore the side grain) then toss them in a paper bag w/shavings. Wondering what everybody else does. Leo seems to coat them and toss them on the shelf w/o any bagging. I presume he coats the inside and out. Is the whole thing coated?
So what's everybody else do after roughing? Seal and bag? Seal only? Seal inside and out? Various permutations of the above? Yeah, I know about finish turning wet bowls and letting them warp. But I'm not asking about that.
I turn bowls only out of "free" wood, harvested (or stolen, depending on the source) from storm-damaged or serviced trees in my immediate area (having a
110 year-old golf course 2 blocks away helps a lot). I rough to 10% and then paper bag. If I have a blank that needs to dry extra slowly (cherry or beech come to mind), then I'll spray the outside of the bag with water daily for a week or so. No shavings, no coatings. In my experience, wet shavings grow mold and don't do much to retard drying. Coatings of any kind would cost money, not in the spirit of my "free" wood or of the advertising I do to sell the bowls (from "reclaimed" wood!). I lose only a few to checking.
Got tons of cracked bowls and went to turning thin and letting them warp ...
Bottom line of failure of bags, etc. ? I live in Central California... hot, dry summers make everything crack..
Add to that the fact that lots of folks use their basements for bowl drying because the temperature is more even.... basements are pretty much non-existant in California..
Now, if I had a giant wine cellar with temp & humidity control... *g*
Here in Central Texas, the humidity in the summer is tricky for drying bowls. I have a shop that I leave open to the weather, except for storms. and have found the denatured alcohol soaking method, wrapping the outside and tape at the edge to give more success than failure. I am in the middle of a large run of elm that was storm damaged and very wet when cut. Weekly weight tests labeled on the day of the comparison, is my only gauge as to when to start finish turning these blanks that are 14" down to 8". I might add that 12" to 14" deep hollow forms are included in this run. I turn a lot of mesquite as well that I try to cut only in the winter. If cut in the summer, when the sap is high, I soak in denatured alcohol. EMC is usually achieved within 8 weeks. I hope this comment helps you.
I've got a basement, so I put them where the air doesn't exchange much and stays at ~75% RH after the first day or two. When I get around to it, I move them to dryer places to store for use. 65% or less.
First day or two wants to see the surface moisture I've ejected centrifugally dissipate, otherwise they mildew on me. Which is why I don't coat. Played that and suffered the consequences, though places where it's really dry would benefit, I suppose. Makes no sense to coat the inside, that's under compressive stress, so no cracks get a chance. Slowing loss on the outside which _wants_ to pull apart is yet another matter.
If you've got a humidity gage, test various locations and you can play a real shell game, even to the point of pushing drying if you're impatient. First stage there is to turn thinner than 10%. Most domestic stuff can take a 5-7.5 % over desired wall thickness without a problem. Look your varieties up in the FPL literature to help out.
My RH is usually around 65% I think. They're just out in my garage, which is semi heated. Guess I could bring them inside after a while; how long do you wait before you move them? It's usually a bit warmer in the house so it would speed drying up a bit.
Since most of my wood is somewhat spalted anyway, a little bit more doesn't usually hurt. The really nasty looking stuff turns off in 1/16" or so. I always *mean* to turn it sooner, but somehow it usually sits on the wood pile for a year or so before I get to it! Oh well.
I'm not sure I understand you here George. The wood warps and cracks radially. On a 1" thick wall, I can't imagine that there's much difference in stresses on the inside of the bowl and the outside. I'm not talking about coating the bottom or sides - just the end grain. Since it's just an inch thick, it can dry pretty fast, hence coating both sides of the wall. But maybe that's overkill? An old Scotsman like myself doesn't mind not wasting the extra Anchorseal!
Alder warps quite a bit - going much less than 10% doesn't leave much room for error or subsequent design. Other woods can be much better behaved, but around here if you're talking free you pretty much have your choice of alder, mountain ash, spruce or hemlock. Kinda slim pickings. I have placed a board inside the bowl perpendicular to the grain which helps, but that's a pain if you're doing a bunch of bowls...
Good point Dan. Much different here than in the Southwest, or even most places down in the lower 48. So for comparison's sake, I'll mention that I usually turn alder and that the RH is around 65% on average I think. My garage is semi-heated - a bit warmer than outside when it's rainy and a bit cooler when it's sunny...
At the risk of offending our resident expert on 'little known or cared about facts," you know who he is. the guy who does not write in sentences and offers dubious web references to prove his points. I rough turn to about 10% of the final thickness, then soak in Denatured Alcohol for about 24 hours. After soaking, the outside of the blank is wrapped in brown paper leaving the inside of the bowl open.
I weigh the bowl every day and record the weight to a tenth of an ounce. Typically, the weight of the bowl has stabilized within two weeks and is ready for final turning. My criteria for stabilized weight is when the weight of the blank is constant for three consecutive days.
Is this a prefect system? Is it the fastest way to dry? I don't know the answer to these questions. What I know is that after thirty or more bowls dried this way, only one cracked. The remainder warped but not enough that they couldn't be trued with a second turning.
I usually rough turn to a nominal 10%, although for small bowls it may be a bit more as I rarely go below 5/8 inch wall thickness. I paper bag the rough out, put and keep in a basement checking and changing bags daily. (You can air dry and re use the bags) If any small cracks start, I will hit with thick CA. Usuallly I do not use any sealer but have on some occasions where multiple small cracks appeared.
After a few weeks, I leave the bowl out, at first on the floor, later on a shelf: how long depends on species, how wet the wood was at the start and how urgent my need for finished pieces is. Nothing scientific, just intuition and experience.
With mesquite, I just turn to finish thickness and allow to air dry, then sand. The stuff is wonderfully stable and well behaved. Partially seasoned maple burl can usually be handled the same as mesquite
Hey Harry, ye is not offended. ;) Lately, Florida air has more water than it can hold and brown bagging these rainy days means carrying alcohol out of the store in a brown paper bag.
Being a rule breaking dummy, I chop the bark & twigs off NIP logs, cut to blank length and rough turn to round. Then I paint the entire blank liberally with any cheap 50% LDD, store under open cover and get around to turning them when I please. Works for me, but I don't recommend this secret to anyone else since scientists on Norfolk Island have shown that it only works for me.
I got a log about a month ago that was supposed to be Birch. Cut it into four blanks and was looking forward to turning some nice green wood. The bark or the layer just under the bark was so abrasive that the edge on the gouge lasted less than a minute. One pass on the blank and there were streams of wood going over my shoulder and on the next pass...nothing. Once the layer was gone, it turned like butter. In fact I set a new, personal, indoor record for the length of shaving. This was at least six feet long but since it was full of curls, it must have been longer. That' fun!
Drying bowls how, you ask??? There are some basics, but there are many BUTs, and IT DEPENDS, so what works for me should also work for you, yes, IF your conditions are like mine, your wood the same, thickness etc etc etc. Give up yet ?? So what do I do. Normally turn to 8-10% at the rim, than thinner as I go to the bottom. Make sure I start with wood that does not have splits already, it I don't want splits in my finished work I date and I.D. the rough out, and go over the turning very carefully to see if there are any signs of checking, ( if there is any, it is almost always because they were there already, and normally get caught while turning the outside, and I turn them away) also are there knots or the rim very close to the pith, knots are CA'd with thin CA soaking in, the pith area gets CA often if I expect the wood to check. Some woods I will paper bag, or newspaper if to big for a bag, which wood you ask, well in my case not many but Cherry and Mulberry are often bagged, and also the ones with the very small checks, and I do not CA the small checks, I used to do that, but the glue lines will stay, and now I will just let the roughout dry, I do check them regularly in the beginning less so after the initial week or so. I found that often the small hairline cracks are totally gone when the wood has dried, if not and I am not able to turn them away, then I might soak in 50/50 glue /water for a few hours and give them another drying tour, the water/glue soak will swell the wood and the glue will keep the wood from opening up again, works for me and you won't see the glue lines like the CA lines in my experience. I do anchor seal bowl blanks, but not roughouts. Now my cabin that I build to dry my roughouts is almost airtight and fully insulated, the seams were caulked and the small windows double paned with lexan, the interior walls floor and ceiling and doors are unpainted wood, (1 infrared 150 watt light bulb will keep the interior above freezing if I find the humidity going to high) the reasoning for this is that the wood from the building and the roughouts and also the air work like a absorber, slowing down the humidity swings and also the insulation slows down the temperature swings, it still gets hot or cold but it takes longer, the humidity will get higher or lower but it takes longer, the wood will dry but it takes longer. I have used this for well over 10 years now and it works for me. I did get unexpected splitting but they are very few and far between, 1 or 2 cases I got by leaving the doors open one sunny day and a big Elm that was in there for only a few weeks got a large split, and also one day I had a larger black walnut sitting on my mower where the sun shone onto it, I got checks on the inside and outside where the sun shone in and against it, so yes I do screw up sometimes, but other than that hardly any unexpected splitting. Then there are those times when I turn something with a large knot or reaction wood and/or bark inclusions, I do know that some might split on me, for instance I do have one black walnut crotch wood turning right now that has some bark inclusions and also a knot inline with that, bark and natural edge also left on it, I did know that it was going to split on me so I made a stainless steel staple from wire and put that across the bark inclusion, yes the knot split but the bowl is still together, BUT SOMETIMES YOU CAN"T WIN. The best way to keep wood from splitting is to give it time, give it time to move while the water leaves the wood, give it time to keep the stresses low in the wood while drying. If there is TOO much of a difference between the amount of water on the edge of the wood and deeper inside the wood than the wood WILL split, however some wood splits not as quickly as other wood Elm, Catalpa, Willow etc. are some woods that I know not to split easily, Arbutes, Lilac, Tartarian Honey Suckle are some that I know want to split just looking at it. Boiling these does help, in my experience, (boil 1 hour per inch of thickness and keep and leave under the water till it has cooled off) Well this should cover most of your question I hope.
yesterday was 103 with about 20% humidity... today and tomorrow are supposed to be 104 to 109 with about 15%... My shop averages about 10 degrees above outside temp, so it's not a good bowl drying place.. *g*
Day before yesterday the humidity was 100% temp 28 celsius(about 82F) today 30 Celsius and 60% humidity, nighttime temps run 60 to 70F.
My shop starts 10 degrees cooler (by the time I get going ;-)) ) than outside and stays that for a while, if I keep the door closed but goes up with the lathe and lights on, and I have the door open a few hours later, my wife says it's to warm, I say it's just nice, I love the summer weather here, but come December-January and I could stand some of your weather at that time.
Here's a question, have you ever tried to put a rough turned piece in a box and fill it up with dry or just barely damp sand ??? than set aside and have look after a few days, I wonder if in your environment that would work to slow the drying without getting a fungus or mildew going.
He Mac That'll improve only the temperature Mac, not the humidity, still you'd be able to work in relative comfort, and you'll work around the drying problem. Over here I (we) hate AC, we had it in our house and we never used it, about 10 years ago we did some extensive renovation and put in a high efficiency furnace and threw out the AC, I guess we need the furnace and you the AC.
Wish I had it here... I've probably spent 8 hours in the shop in the last 2 weeks because it's usually 92 - 95 degrees in there by 11 am.. I went out at 6:30 this morning to sand a bowl and it was 78 F outside and 85 in the shop..
Though I'd be inclined to store the stock which is drying outdoors and bring it in for a week before final turning. Keep it out so it won't frost your A/C coils too rapidly. Control the humidity by container. Most of your stuff is going to find a home in air conditioned circumstances anyway.
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