iDRY Vacuum Kilns

Sponsors:

Best way to Determine M/C?

Started by luke, September 03, 2003, 09:15:07 PM

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

luke

I seen a moisture meter that scans the board, but someone said that's not as a accurate reading as a moisture meter that "sticks" in the board. Is this a true or false statement?
Checking into grade sawing, building a dry kiln and moulding machines.

BBTom

I have been told that the studies that have been conducted have shown that the two are very comparable between 5 and 15% moisture.  Keep in mind that none of them are accurate over 30% moisture.  The best way to determine moisure content is to cut a sample and oven dry it.  But, if you need a nondestructive reading, and are reading between 5 and 30% then go with a known manufactuerer such as Wagner or Delmorst, and you should be happy.  Best meter to use is the type your customer uses!!!!
2001 LT40HDD42RA with lubemizer, debarker, laser, accuset. Retired, but building a new shop and home in Missouri.

Don P

I agree with that, the customers meter is gonna be the judge  :D. I've got a report somewhere on several types and they were all accurate according to the test.
 A pinless lets you "sweep" an entire board, a pin type is a spot check. A pinless is limited to about 1/2" depth of reading. I do alot of thick timber and so opted for a pin type with 3" insulated pins that only read at the tips.

Den Socling

Stick meters are more accurate at the point where they are stuck but MC can vary in a board. Good meters (like Wagner's L601-3) will penetrate 1" without making holes in your wood but beware of the "sweeping" mentioned earlier. Dry conditions can build up a static charge if you slide them along a board and that can blow them up. Wagner might fix it once but, I know from experience, that, if you blow them with static a second time, you need to get out your wallet.

Don P

Den,
I spoke beyond my personal experience, dumb. The source of my statement is supposedly well informed.
 
The word scanning is used by Wagner in their info...I would be hard pressed to pay for that repair , this is advertised as a "quick scanning meter"
QuoteThe rugged L601-3 is specifically designed for the demanding environment of the sawmill or wood products manufacturing plant where quick-scanning of lumber is a must.
Even large boards can be scanned from end to end in seconds....
:-/ http://www.wwwagner.com/index.cgi?sec=secondary&page=l601-3_quick_scanning_moisture_meter

Does the user's manual warn of this?
What mc's were you running when the static happened?
How do you avoid static build up? Lift and place?
How do inline meters avoid this problem, seems like it would be rampant in that application?

I am in no way doubting your experiences just wanting to learn about something I had not heard about.

Den Socling

Don,
When one of our customers was refused a warranty repair by Wagner, I started investigating. I found that similar failures had happened before with this and other customers. After talking to Wagner, they decided that the problem was caused when people slid the meter over a layer of wood while unloading our vac kilns.
I don't remember where I got it but I found in my file a sheet from Wagner titled "checking the moisture content of veneer". It mentions the L601-3. It says "static needs to be addressed, as Wagner's warranty doesn't cover static damage". One suggestion on this sheet is the same as they offered to me. "wear a Velcro wristband with a tethered strap which is grounded." When I told the guy at Wagner that this was crazy, as everybody slides Wagners around on dry wood to make sure it's dry, he said don't do that. Lift the meter and set it down on a new spot.
I guess I have a problem with my definition of "scanning a board".
I would think that "scanning" was sliding the meter along the board.
Den

Den Socling

PS In-line meters are not touched by the wood. The conveyor carries the wood through the meter and doesn't slide it across the meter.

Jason_WI

I have a L609 and slide the meter along the board to check for wet spots. I never had an issue with ESD (electro static discharge for those non engineer types) but I suppose in the winter when the RH is low it wouldn't take nuch to generate a static charge.

I have taken my L609 apart to see what makes it tick. Not much for electronics in there. I looked real hard to find $275 worth of parts and figgured I will have to move the decimal point over two places to $2.75 cause that's all that's in there.
Those sneaky engineers sanded off the part numbers on top of all of the IC's. Probably because the design is trivial and any rat shack store could supply the parts.

Basically there is an oscillator circuit (probably LM555) and a comparitor circuit. The black square piece stuck on the back of the enclosure is basically just an inductor etched on a circuit board. Ain't a a whole lot. I suppose the specific gravity for speicies cheat sheet is worth some bux for the research....

Jason


Norwood LM2000, 20HP Honda, 3 bed extentions. Norwood Edgemate edger. Gehl 4835SXT

luke

It sounds like either one will work, but the moisture meter that sticks may be more accurate for thicker lumber. The scan type moisture meter I was referring to is, one that woodmizer makes, it sells for $300  U.S.,  I may want to check into the stick type, because I'm going to need to check some structural framing lumber, that will be 1.5" to 2.0" in thickness.
Checking into grade sawing, building a dry kiln and moulding machines.

Don P

Thanks Den,
I think I see an opportunity here, can't decide whether to call it the hovermeter or the foosmeter  :-/ Wagner thinks they got quick scanning now, just wait  :D.

Luke,
If you get into much depth the meter will require a slide hammer, I think push in pins go about 1/2", then they go to the hammer. Pins can be insulated or uninsulated...course after awhile the insulation wears off and they all end up uninsulated. The insulated read just at the tips for a true reading at whatever depth they are driven to.

pappy

Luke,
I have used the Delmorst moisture meter for 14 years (with the same 9 volt battery) in my custom woodworking business and when the meter reads between 6 - 8 percent I used the wood without any  problems.

We live in a very dry climate in the winter it'll go below 40 percent moisture in the house and we have to be really sure of what the content is in the wood.

I have seen furniture manufactured from away that literally falls apart when it gets down to minus 40 for a week or so when we're kickin' the wood stove real hard.

termite
"And if we live, we shall go again, for the enchantment which falls upon those who have gone into the woodland is never broken."

"Down the Allagash."  by; Henry Withee

Don P

Termite's post reminded me I had put up a pic of my meter this past winter showing just what he is talking about.


Thank You Sponsors!