Humidity During Build

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AsaBlanchard
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Joined: Mon Mar 29, 2010 10:10 pm
Location: Lexington, KY

Post by AsaBlanchard »

Jim,
My email is res03jgw@verizon.net . If you send me your email, I will send you the Microsoft Excel file that Terry Conners provided. If you don't have MSExcel, I can send it in .jpg format.
Asa Blanchard
BearLeeAlive
Posts: 196
Joined: Tue Aug 18, 2009 7:00 pm

Post by BearLeeAlive »

Email sent, thanks.
-JIM-
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Glen Smith
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Joined: Sat May 08, 2004 9:08 am
Location: Baie-St-Paul, Quebec, Canada

Post by Glen Smith »

These are the two charts concerned.

Image

Image
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Redbird Bernie
Posts: 28
Joined: Sun Oct 17, 2010 3:14 pm
Location: Illinois, USA

Post by Redbird Bernie »

Please anyone correct me if I am wrong, but under ordinary conditions you do not need to worry much about relative humidity or the moisture content of your wood especially if kiln dried.

I don't recall whether relative humidity or moisture in the wood is much of a factor in the application of epoxy, but it should not matter when stripping as long as the wood was dried to begin with and relative humidity doesn't fluctuate wildly to the extreme for a prolonged period of time. Whatever moisture is in the wood at the time of epoxying will be sealed in and make no difference whatsoever.

If you are concerned about shrinkage or buckling during hull construction, you probably should not be. While expansion and contraction does occur, under ordinary conditions it is doubtful that you will even notice it.

Bernie
BearLeeAlive
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Joined: Tue Aug 18, 2009 7:00 pm

Post by BearLeeAlive »

Bernie, I do lots of other woodworking and consideration for expansion and contraction of wood cross grain is a major consideration, to ensure that there are no joints opening up, or wood cracking if held too tight on the sides. I see the joints in our hardwood floors open and close if the humidity is not maintained evenly throughout the year. I have also read a few times where people stripping a canoe had the hull expand a bit, and pull away from the moulds. This is what my major concern is at this time.

I just did a major reno and last winter was the first time we used our attached garage, and I bought some machines and set up the woodshop this past summer. I have mostly done woodworking in a dedicated shop, not in a shared garage.

I am not sure of the effect of high humidity on epoxy, but regardless will ensure it is only moderate, but I do know that it will affect the finish, and finish times of some finishes like varnish, especially if solvent based.
-JIM-
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Redbird Bernie
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Location: Illinois, USA

Post by Redbird Bernie »

I totally agree with you that the effects of humidity on wood and wood construction should never be ignored. Like your floor, my living room floor made of stranded bamboo visibly expands and contracts from one season to the next. However, unlike fine furniture and flooring which must be designed to accommodate expansion and contraction due to humidity, a canoe hull once epoxied is effectively sealed from moisture and will not move.

While you should definitely be mindful of the effects of humidity, my point was that you are worrying too much. As long as you are not going to build your canoe over a long period of time spanning several seasons, and there aren't any long term extreme changes in temperature and humidity levels, it is unlikely that you will encounter any problems with moisture. Lots of builders work in unheated, unconditioned sheds, building over long periods ranging from weeks to years and they seem to manage just fine.

As to the hull lifting off the moulds from expansion, I am thinking that it is more often related to poor holdown techniques then humidity... not that it can't happen.

Eventually you'll find a way to closely control your working space environment. In the mean time, don't let it stop you from starting to build.

Bernie
BearLeeAlive
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Joined: Tue Aug 18, 2009 7:00 pm

Post by BearLeeAlive »

Bernie, I don't doubt for a minute I am worrying too much. I just would not want to have there become and issue, and have been monitoring it.

I have also laid down the law with my wife and daughter about driving in and out of the garage. Once per day is what I allowed, and if they are going to come and go, the car must stay out. There has been at the most an equivalent of 1 gallon of water a day land on the floor, and we have a mop handy to wipe up the excess.

I have been monitoring the RH in the garage in the last few weeks, and that has stayed between 30 and 55, usually around 40. I have also been monitoring a piece of cedar for moisture content, and that has risen from under 6% to somewhere between 6-7%. My meter only reads in 1% increments. So, that is still quite dry, and I don't fear a problem. I will keep up the vigil of metering though.

No slowing down, only gearing up for the build. I picked some 16' cherry for the trim, ordered some cane. All I have to do now is to figure out what glass and epoxy I want to use, and get them ordered. The station moulds will likely be set tonight, I will then build the stems, and add the bead and cove to the strips. Then full bore to the end.
-JIM-
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Redbird Bernie
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Joined: Sun Oct 17, 2010 3:14 pm
Location: Illinois, USA

Post by Redbird Bernie »

Hi Jim,

Looks like your readings are in keeping with what Asa Blanchard said. Are you still thinking of installing an HRV? If you do get one, let us know how much of an improvement you get.

My shop is in a small area of our basement so I don't have the moisture issues you do, just dust and dirt all over the place. My Black & Decker dust collector does a fairly good job to 10 microns but that's just not enough. Recently we installed a new and more efficient furnace so I kept the old one which I am now modifying into an air filtration system. I'll be using a Honeywell 16X25X4 Merv 13 media filter with a 1" electrostatic air filter in front of it. The blower has 4 speeds and even at the lower speed puts out like a jet engine. Obviously I'll have to scrounge up a timer to cycle it on and off according to need.

Bernie
BearLeeAlive
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Joined: Tue Aug 18, 2009 7:00 pm

Post by BearLeeAlive »

Bernie, I am going to just keep monitoring the levels in the garage for now.

If I feel the humidity is getting too high, I am now thinking of just going with a small dehumidifier. I think the HRV is a better idea, but the dehumidifier is cheaper, easier and I can take it with me when I sell.

I have seen a couple filters made with stacking furnace filters and using a furnace fan. The seem to work very well and at a decent cost.

I have a 3hp dust collector that I open all the ducts to, an use an air gun to blow the dust off everything. In minutes the shop air is all clear again. It would be nicer to collect the dust as it is made, maybe I will build an air filter some day too.
-JIM-
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