To glue or not to glue

[Gretch Flo]

That is the question. On this forum it has been stated that some cracks close up by them selves and that CA will impeded their closure. Some say "slap" on the glue when you first see it.
Is there a difference between real wet wood and quite drier wood in these 2 conflicting statements? A friend gave me some split "firewood" which was fairly dried sassafras. I scribed a circle and cut with band saw (saw no splits in the blank -altho there were some splits in end of the half log). Put on lathe and finished the outside with one layer of cellulose sanding sealer, and one or 2 coats of Deft Danish oil finish used with 600 sand paper and wiped off. No splits on this natural edged bowl, but the next day when I returned to the shop there were 6-7 splits traversing the annular rings (i.e. not a ring shake) . I had not put a plastic bag over it thinking that it was quite dry-My moisture meter this am says 11% and there is no conversion for sassafras in the chart that comes with the wagner-but this is fairly dry, and I am guessing over a few days it will go the 7-8%. I superglued and resanded with danish oil finish and proceeded to turn the inside and finished. . This am everything looks the same as I left it and is in a room since yesterday afternoon where there is a wood stove-i.e. very dry. Any thoughts???? Gretch

 

[Dale Jablonski]

Gretch, I've had some of the same experiences and am trying to get a feel for this myself. Could you provide more information on size (diameter) of the the sassafras and where it was stored i.e. outside exposed to weather then brought inside to heated shop? thanks.

 

[MichaelMouse]

Checks in dry wood may close when the piece is rehydrated. They will still be points of weakness, regardless. In the case of firewood, a dry summer followed by a damp fall will make a lot of things look better when they really aren't. The only way I know of discovering what's there is to give a wipe with some mineral spirits and watch for wicking where the checks are not fully closed. Excellent habit to get into when determining how to cut a log up the middle as well. Heart checks will reveal themselves and help you chose a path for the saw. Checks caused by heat from sanding can be closed by topical application of water, or if you have patience, waiting for the RH to take over.

If your friend had that firewood on his covered outdoor stack, it was probably around 15% moisture content in Lansing area. If it had been rained, or if, as is true of most of my firewood now, snowed upon recently and then cooled, it could be quite a bit wetter on the outside. Moisture meters aren't much use on curved surfaces, less accurate still on finished surfaces, so you want to know what the RH humidity in the shop was. Mine's a fairly good 36% at the moment, which means wood at EMC should read 7% MC. Bet you are a bit lower, especially if the weather has been cold and the stove lit. It would take an extremely favorable shape to avoid new checks, much less the revealing of old ones with that differential, even if you had not made the mistake of leaving it unhollowed.

You have now turned the inside which will relieve a lot of the drying stress on the outside, and you have bulked things up with your glue and hidden them with oil. About as much as you can do. You might get a favorable visual, but next time either leave the firewood in a warmer place for a few days prior to turning, or turn the inside out same day so it can't put all the drying stress you subjected this piece to on the outside. Either bag it or bowl it.

If the inside tries to shrink as it dries, it'll get smaller, so no problem. The outside can't get much smaller without checking, because it's held back by expanded wood inside. Has to crack. That's why we seal the outside end grain or wrap the outside, but can leave the inside alone. It's under compression.

 

[Ron Sardo]

That is the question. On this forum it has been stated that some cracks close up by them selves and that CA will impeded their closure.

Yes, some cracks may close, but the wood doesn't mend itself. Those cracks are still there waiting to open up again.

 

[Bernie Weishapl]

Most times even if the crack closes I will hit it with thin CA. They can still open if left alone.

 

[odie]

Hi Gretch......

Moisture meters give an indication of moisture content at a given point in time and space.......but, what they don't tell you is whether the moisture content has stabilized. A moisture content that has stabilized is what you want to know......

You can determine MC stabilization by using your moisture meter over a given time frame, but you probably know that moving the probes a few inches can give you different readings on the same block of wood.......so, it is very prone to failures. What works with a little more consistency, is observing the weight of the wood, also over a time element.

I use my Mini-Ligno E on every block of wood I aquire, to get an initial indication of moisture content. Somewhere about 10-12percent MC is the point where a decision has to be made........turn it?, or season it? In this range, there is some amount of gamble, if the decision was to turn it.

Under 10percent and it's a good bet that it's safe to turn. Over 12percent, and it always gets seasoned.

If the decision was to season the block, it gets roughed and anchorsealed. Roughed bowls get weighed monthly, and when 3 consecutive months of unchanged weights are recorded, the MC has stabilized.

ooc

 

[Gretch Flo]

Jake:"Could you provide more information on size (diameter) of the the sassafras and where it was stored i.e. outside exposed to weather then brought inside to heated shop? thanks."
Jake-the bowl is 8"x4". About 1'2" thick (would have gone thinner but with the cracks and all.....The wood was already split for firewood. Not sure when she did that, but her firewood is stored in a shed . I'll try to remember to ask her details. She brought 4 pieces over to my deck( 3 sassafras and one beech limb crotch ) and left them there where they sat for 3-4 weeks as I just had arthroscopic hip surg 2 weeks ago, and work got in the way of my addiction. I think the trees were dead when she cut them up. (sassafras dies and uproots easily-I have several on my boundary line.) So they were uncovered while in my possession. (sink or swim attitude!!)I brought them into the unheated 3 seasons room for a week, and then got to turning the one in question 2 days ago, after being in the heated basement for a couple of days..
Odie:
"Moisture meters give an indication of moisture content at a given point in time and space.......but, what they don't tell you is whether the moisture content has stabilized. A moisture content that has stabilized is what you want to know."..
I am using the danish oil as a wet and dry application and maybe to slow down drying. In this case it obviously didn't work I think Michael is correct in that the cracks were there, I just didn't see them. The moisture meter reading this am on the bowl was 11% and now reads 7%. It is my experience that dead wood dries very quickly, and I wait to have the readings stabilized before applying final finish. Sometimes depending on thickness of bowls and the wood, takes 5-30 days. Wagner meter info says can read thru finish. I really trust the thing. Yes Michael, the wood can take on moisture in humid days and I can "see" it happen with the meter.

Michael "You have now turned the inside which will relieve a lot of the drying stress on the outside, and you have bulked things up with your glue and hidden them with oil. About as much as you can do. You might get a favorable visual, but next time either leave the firewood in a warmer place for a few days prior to turning, or turn the inside out same day so it can't put all the drying stress you subjected this piece to on the outside. Either bag it or bowl it.".
Good advice-actually it was in the heated basement a couple of days before I turned it. Tomorrow I'll find the scrap end and pass min spirits over it. I saw it today and don't think there were any cracks in the concave scrap. The bowl cracks are on both end grain ends-the insides are fine-so far. One reason besides running out of time is that sassafras doesn't move much during the drying period if I remember correctly.
Michael-would covering with a plastic bag over night have prevented the cracks IF they weren't there already???????

Lyle Jamieson , Traverse City, Mi, (where I have attended his turning group demos several times) says there is too much good wood out there than to turn wood with cracks. I agree it is really a pain to do all the repair and looks crappy, but some of the wood is so darned pretty....... Guess you have to know when to hold em, and when to fold em. I have been feeding my wood stove lately at times with "folding em" :mad:Gretch

 

[Charlie Knighton]

Gretch, for cracks appearing while/after turning. i have in the past done both, that is glue em and leave them alone


lately if cracks no more than an inch i usually just leave it alone especially if crack near some figure in the wood