# stage condensation



## mmmcheechy (Aug 6, 2013)

Im on the tech team doing an outdoor concert series. I have a dance show coming up this weekend and Im having a hard time keeping the stage dry. Its a nice big black stage radiating its heat away at night and around 9 pm it starts to get a bit wet and slippery (very no bueno for dancers) I can't use gas or propane heaters because of the fire hazard. I can't use any electric heaters as we have limited power and every last amp is being used for sound and lights. half of our lights are running off 104 volts due to the lengths of the runs): I painted the top of the stage with black latex paint and it helps a little by I think both filling in the textured surface a bit and reducing the surface area slightly, and the paint itself has a higher coefficient of friction then the stage has unpainted and is less slippery when wet. but on the colder evenings its still a problem and it gets quite wet. the stage is about 4 feet off the ground and I have been thinking about putting stainless steel barrels or aluminum kegs filled with water under the stage to act as heat sinks and passively help regulate the temperature. any suggestions would be appreciated


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## josh88 (Aug 6, 2013)

I know of one ballet group in my area who had a similar issue and they got by with having three guys with large push squeegees hit the stage between each number. Three or four of them would them would come on right as the dancers left, and in a line just pushed condensation off in one direction. Alternating directions each number, one pass without stopping only took a few seconds. Not awesome but it worked for them and kept up with any moisture.


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## mmmcheechy (Aug 7, 2013)

not a bad idea. we have thought about using dry mops or push brooms with towels to dry off the stage. the stage is modular in 4x4 sections. the squeegees may have trouble with the gaps and unevenness in between the sections. but we may be able to push the water from each section into the seams.


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## josh88 (Aug 7, 2013)

In that case either pushbrooms with towels wrapped around them or the large dust mops. Both should work about the same


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## mmmcheechy (Aug 8, 2013)

I put a barrel with water under a section of the stage yesterday but it didnt keep that section dry. I'm really disappointed about that. this morning I found an anti slip paint additive made from crushed walnut shell at a local paint store. I'm going to mix that in with the outdoor latex paint I'm using (Id guess its around 100-120 grit if it were sandblasting media) I hope it gives enough grip to keep them from slipping but still let them turn without too much trouble.
Im not sure why but it seems to be the thermal properties of the textured plastic or mica veiner of the stage sections that allows or encourages the condensation. Ive made some plywood risers that Ive placed on the stage and have had no condensation on them at all.


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## techieman33 (Aug 8, 2013)

mmmcheechy said:


> I put a barrel with water under a section of the stage yesterday but it didnt keep that section dry. I'm really disappointed about that. this morning I found an anti slip paint additive made from crushed walnut shell at a local paint store. I'm going to mix that in with the outdoor latex paint I'm using (Id guess its around 100-120 grit if it were sandblasting media) I hope it gives enough grip to keep them from slipping but still let them turn without too much trouble.
> Im not sure why but it seems to be the thermal properties of the textured plastic or mica veiner of the stage sections that allows or encourages the condensation. Ive made some plywood risers that Ive placed on the stage and have had no condensation on them at all.



What kind of dance? Most dancers are going to hate dancing on a non slip floor like that, especially if they're wearing ballet shoes, pointe shoes, or any other shoe with a soft sole.


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## FMEng (Aug 8, 2013)

mmmcheechy said:


> Ive made some plywood risers that Ive placed on the stage and have had no condensation on them at all.



Was the plywood painted black? If not, there is the difference.


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## MarshallPope (Aug 9, 2013)

Is there any chance of covering the stage with a light-colored tarp during the day, or is it in use?


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## venuetech (Aug 9, 2013)

any surface that is cooler will attract condensation. Is your stage skirted around the edges or can air flow under the stage? Is it cool under the stage during the day?

my thought is that the shaded earth under the stage is cooler and this speeds your evening dew-point. there could be many solutions but the quickest one to try may be just a visqueen vapor barrier on top of the ground under the stage.


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## FatherMurphy (Aug 14, 2013)

Strange physics here as described... usually, something that is radiating heat is warmer than the surrounding things, and is unlikely to become covered in condensation. Also, if your stage was cooler than the surrounding air and being condensed upon, then the underside would show as much moisture as the top. If you're only getting moisture on top, I'd be suspicious that it's actually dew falling from the atmosphere above, in which case the permanent fix would be a roof of some sort. Plywood risers next to the stage not becoming wet sounds odd, unless their surface is more porous than the stage panels, and the dew is getting absorbed into the wood, or the plywood is hotter than the stage panels, and better evaporating the dew as it lands.

If it is dew, and a roof is not an option, switching to older metal-reflectored lights and turning them all on full in between numbers might help warm the stage surface up a bit, and help dry it back off, along with the above squeegee/towel suggestions.


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