Moisture Meters

I am interested in opinions/experience with moisture meters. I am in the market for one and understand that the newer ones are more accurate. I have seen a number of misreadings by older models that have been costly on a number of levels.
Specifically, I have a balsa cored deck with the usual trouble spots - cleats, fills, etc. Obviously these areas were not properly isolated from the core. We have an older meter that I do not trust and after taking core samples - I trust it even less. I have heard that the newer models are more accurate. That being said, I thought that I would see what opinions were here or suggestions regarding makes and models. TIA.

 

No real experience with this, but can't you re-calibrate your old moisture meter. Could be a lot cheaper.

 

Dutch Peter,

Thanks foryour reply. We called one of the surveyors that we use and borrowed a GE Protimeter. It gave better readings and this week we will proceed. Between the two, I have a better idea on how to proceed.
I didn't think anyone was going to reply - suprised me - given what I have seen on this site.
Thanks again.

 

always use two meters, you may have the top of the line one thats reading wrong, i always carry two meters,

 

Diag.
I have used both the protimeter and a lignomat probe.
For my purpose, (testing strip planking with no sheathing) I found the
probe better as I did not get inaccurate readings from the embedded edge nails.
Obviously for your application a non-invasive meter is the way to go.
The Tramex "skipper" seems to be widely accepted as a good radio frequency meter for GRP.
I use both,probe and non-invasive, in the building industry and compare.

BtW, I have built an balsa/epoxy deck for my boat and will be installing deck
fittings soon. Wake up call on the necessity of epoxy annuli! Thanks.
Epoxy annuli = 2 X bolt diameter.(Elements of boat strength)
http://share.shutterfly.com/action/welcome?sid=3AcuGzRozZOWg&emid=sharshar&linkid=link4

 

"Annuli" - good word - I like that. Thanks for the reply(s). This boat is strip planked and both meters like the moisture content in the topsides.
I've seen this with balsa decks since the early '80s - that's when I started doing this type of work. We had nightmares. Still, people resist isloating the core. I've been out of this for a few years but picked up this job for a friend this winter and all my memories of balsa came cascading back. I think we've got it, though.
Roly, I would not hesitate to make your 'annuli' larger - what will you use - high density? micro fibers? Personally, I like to get some ply or solid stock in there. Problem is the time element.
Jack, yes two meters is good - gives me a much better sense of what to repair. The one meter is too sensitive, which intiated my post - areas we knew where good and varified with core samples.
Balsa - great stuff if it is done correctly.
Thanks again.

 

Yeah . i wasn't too sure about the spelling on that. Not a word I use often.
No time for spell check!
My wife made me pull the boat to "fix it good".
Supposed to be a 3 month job.
A complete rebuild and 3+ years later; sheesh, if only I knew then
what I know now.......
Yeah I guess that 2 X is a minimum, but we will be putting SS backing plates on the inside.
What is the best way to remove the balsa? Bent nail in a drill?
We have 2400gms of triax in the hardware areas on the inside.
I guess we will use 403. What is high density?

 

A common tale - it's a sorry addiction..... and Murphy's Law is always at work.

Removing Balsa:
It depends..... bent nail would work. An Allen wrench in your drill will work, too. The triax is nice just make sure your "annuli" is big enough to prevent any compression in the deck from cleats, for example. You want to displace the load as best as possible. Also, with just epoxy and filler, make sure you fill the void you create, completely. It may be quicker to cut in either ply or solid stock in high load areas. Would be stronger but, it depends on specific application. I think either would work well.
404 is High Density. Look on the West System site for details. I went to one of their workshops on their products way back when and they had us bond a steel threaded eye in a piece of wood and then break it by clamping the block and hooking a cable to the eye and some type of winch. There was a load cell on the cable side that puled it apart. We came in second with a combination of micro fibers and high density. 1st used all high density. It was convincing although I don't remember what the load cell read. I like it and it works well. Like I said their site has more tech data so it's worth a look.
I get a little 'anal' with the repairs because I don't want to see them again and it's good business. It often cost a little more - depends what you or your customer want to spend. Always a little exercise in compromise with these issues.
The SS backing plates are nice - .25" aluminum works well, too. .125" on smaller apps. With .25" SS I have tapped it and bypassed the nuts - again it depends on specific job - often faster just to use a lock nut and be done with it.
What you have learned with this boat is good preparation for the next one - that's how it works..... GL!