Moisture meter musings

[oldbilbo]

I've acquired a cheap moisture meter ( from Toolstore, as recommended by another forumeer ) with a pair of small spikes, and am all britched up to go make some productive use of it.

There's a GRP boat sitting outside, where it's been now for some months, and I'm wondering if I have any 'damp patches'.

Do I calibrate this thing - and how? Should I simply map 'relative' readings along the hull? How do I interpret something meaningful from the device?

 

[Deleted member 36384]

The only advice I can offer is what I have read in books about yacht surveying. Some of the meters require calibrating against sections of known dryness. One book used a 10mm section of dry GRP for this purpose, used as a confirmation test as well. In another they use relative readings i.e. above the water line, where the hull is known to be dry, say on the hull outside a galley cupboard. Beware any area that puddles fresh or bilge water as that may give a reading.

Note I have never used a meter, so this information is just recollection, to put it in perspective.

 

[Poignard]

The meters with spikes on are for use with wood. The ones for grp have pads.

 

[robmcg]

Careful, nothing worse than an 'uninformed' wielding a moisture meter. Was selling a boat once and a punter with a moisture meter told me that the boat had wet hull readings and would require peeling, drying and epoxying. I pointed out that this was strange as I had just spent thousands having the boat treated under independent surveyor supervision - and the boat had only been in the water for a day since it was done. No arguing with him though - he was convinced!!. Mind you, gave me a bit off a laugh.

 

[nimbusgb]

Relative readings are the way to go, aabove and below the waterline.

Wouldn't want a spiked version though.

 

[VicS]

There is a guide, written by Nigel Clegg, On the use of the Sovereign Moisture Meter on GRP here http://www.passionforpaint.co.uk/downloads/sovguide.pdf although that meter is now obsolete I beleive

And One on using the Tramex Skipper moisture meter http://www.passionforpaint.co.uk/downloads/skipperguide.pdf

More info generally about osmosis etc on the website http://www.passionforpaint.co.uk/index.htm

 

[pappaecho]

Beware copper based antifouling,it will give false readings