moist air composite construction?

[sigurd]

How dry must the building space air be?
Materials are corecell, carbon, spectra, epoxy, glass.
Vacuum bagging mostly, I hope.

[marshmat]

Hi Sigurd,

None of the materials you mention should be particularly sensitive to humidity during layup. Make sure they're dry in storage- no liquid water- but I've never run into, nor heard of, humidity-related layup problems in vac-bagged construction when the ambient RH is less than 80 percent or so. Some of the epoxies can be rather temperature-finicky, but as long as you don't have condensation I don't think you're likely to encounter humidity-related problems with them.

If the RH of the air is near saturation, you could get some condensation if you're storing your materials frozen. But I don't think it's much of a concern in any kind of normal air conditions. Norway doesn't have a monsoon season, to my knowledge

Now, liquid water is another matter- if you have a roof leak dripping onto your core storage racks, that could be a problem.

[sigurd]

oh that is good to know. Thanks.

[TeddyDiver]

Originally Posted by marshmat

Norway doesn't have a monsoon season, to my knowledge .

Allmost
http://www.bbc.co.uk/weather/world/c...ml?tt=TT004060

[TeddyDiver]

here's the stat..

[sigurd]

yes there is no seasonal rain, it rains the whole time.

[AndrewK]

Sigurd, I would follow the guidelines from your resin manufacturer, all epoxy data sheets that I have seen say 70% RH max. This has been my biggest problem as for most of the year this means I can only laminate between 10:00 - 16:00.
I tried to get an indication by what amount would the laminate be degraded when RH is above 70% from my resin manufacturer, all I got is the repeat of the 70% RH but they acknowledge that not all builders abide by this.
So if anyone has any test data I would love to see this, is it a 2% or 20% degradation?

If you are going to be using vacuum then consider infusion because this process allows you to pull out all of the moisture from the dry laminate before you introduce the resin. Provided you have very high vacuum.

Cheers
Andrew