Dry box question, how to determine it's too dry.


Status
Not open for further replies.

BlindSpot

New Member
May 1, 2008
42
0
0
40
#1
Currently, I got myself a DIY dry box. Got a hydrometer, got a lock&lock box and some silicon gel beads. Assembled everything together and store my S5IS in it.

Now I been hearing that the humidity need to keep between 30% - 40%. Wonder what is the technic to control the humidity using DIY drybox setup. My current read is 18%.

I am worried cos keep reading about rubber melting or dissolving if the humidity get too low. Or other things I hear that internal motor lubricant will dry up.

Any one who is experienced can advice on this.

If you are really encounter real problem for storing stuff in too dry environment. Please share your experience and story also.

Thanks.
 

estel

New Member
Jul 17, 2006
344
0
0
#2
30-40% is a bit too dry i guess. Most people seem to recommend 45%-55% or something like that for cameras and lenses. 18% must be way too dry under any condition.
 

rvxing

New Member
Nov 7, 2004
538
0
0
Somewhere in little red dot
#3
18% is too low, when it is too low, your worry will be true. For optics, it is recommended at 45% to 55% RH. I normally keep it close to 45%RH. See Psychrometric Chart link and you will know how dry is 18%RH compare to 45%RH, abt >3 times in absolute humidity. S'pore indoor temperature should be around 27 to 32 degC.

Psychrometric Chart
 

Fotophilic

Senior Member
Jun 18, 2006
2,388
0
36
big tree town
#4
Currently, I got myself a DIY dry box. Got a hydrometer, got a lock&lock box and some silicon gel beads. Assembled everything together and store my S5IS in it.

Now I been hearing that the humidity need to keep between 30% - 40%. Wonder what is the technic to control the humidity using DIY drybox setup. My current read is 18%.

I am worried cos keep reading about rubber melting or dissolving if the humidity get too low. Or other things I hear that internal motor lubricant will dry up.

Any one who is experienced can advice on this.

If you are really encounter real problem for storing stuff in too dry environment. Please share your experience and story also.

Thanks.
Use less silica beads. Vary the amount and note down the diff. Adjust the amount of beads accordingly. The amount of dessicant will reach an equilibirum with the air inside. After few tries, u should be able to get the hang of it. Another way is to use a small plastic box to hold the beads. Limit the amount of holes u poke (or rather burn with a sharp object). I did these last time and it worked, but with thirsty hippo. Hope this helps.
 

ringoping

New Member
Dec 2, 2007
52
0
0
#5
Use less silica beads. Vary the amount and note down the diff. Adjust the amount of beads accordingly. The amount of dessicant will reach an equilibirum with the air inside. After few tries, u should be able to get the hang of it. Another way is to use a small plastic box to hold the beads. Limit the amount of holes u poke (or rather burn with a sharp object). I did these last time and it worked, but with thirsty hippo. Hope this helps.
use a small container (those used to pack chill when u 'ta bao' food) to fill the beads to half full, cover it with the cover (to prevent spills) and poke holes across the cover.

i managed to get 50% RH on the 1st attempt.
 

Jan 23, 2005
1,095
0
0
Singapore
#6
I am worried cos keep reading about rubber melting or dissolving if the humidity get too low.
I'm not aware how rubber would "dissolve" or "melt" due to a low humidity environment. Polymers DO become sticky or disintegrate for environmental factors like solvent vapors and plasticizers originating from furniture or other plastic items.

Or other things I hear that internal motor lubricant will dry up.
Is the lubricant water based? If not, how would the ambient water content affect it?

Until I see clear evidence to the contrary, I would relegate the "too dry for cameras/optics" scare to the realm of urban legends.
 

#7
I'm not aware how rubber would "dissolve" or "melt" due to a low humidity environment. Polymers DO become sticky or disintegrate for environmental factors like solvent vapors and plasticizers originating from furniture or other plastic items.



Is the lubricant water based? If not, how would the ambient water content affect it?

Until I see clear evidence to the contrary, I would relegate the "too dry for cameras/optics" scare to the realm of urban legends.
On some levels I would have to agree with you there. Many things that I own that have rubberised seals or componentry have disintegrated while sitting in normal drawers without any dessicant or aircon (ie. they are in ambient singaporean humidity, well over 50%).

That being said, lubricants can, and will, evapourate and all of this is based on basic physical principals dictating how much saturation volume is remaining in the air. This principal applies to anything that exhibits some vapour pressure whether that be oils or water. I have no doubt that in absolute dryness the air would be able to dry out the lubricant in your lenses/camera, but since (as it says in all the manuals) you should be taking your camera and lenses in for a service every two years or so I don't see how this will really become a big problem.
 

Jan 23, 2005
1,095
0
0
Singapore
#8
That being said, lubricants can, and will, evapourate and all of this is based on basic physical principals dictating how much saturation volume is remaining in the air. This principal applies to anything that exhibits some vapour pressure whether that be oils or water.
True - but a non-aqueous lubricant doesn't care about the partial pressure of water. It cares about the partial pressure of its own kind.
 

BlindSpot

New Member
May 1, 2008
42
0
0
40
#9
I'm not aware how rubber would "dissolve" or "melt" due to a low humidity environment. Polymers DO become sticky or disintegrate for environmental factors like solvent vapors and plasticizers originating from furniture or other plastic items.



Is the lubricant water based? If not, how would the ambient water content affect it?

Until I see clear evidence to the contrary, I would relegate the "too dry for cameras/optics" scare to the realm of urban legends.
Sorry, should be rubber or plastic, I am not sure which. But there are post always say they "melt" due to over dryness of the dry box/cabi.

Now my humidity in the box is kept at 33%rh. So is this alright now? Or should I let in more fresh air to up the humidity in the DIY dry box of mine?
 

Jan 23, 2005
1,095
0
0
Singapore
#10
Sorry, should be rubber or plastic, I am not sure which. But there are post always say they "melt" due to over dryness of the dry box/cabi.
There are also plenty of posts that discuss ghosts in haunted houses, for that matter. It is probably safe to assume that >95% of the people repeating these stories are only regurgitating what they read elsewhere, without any insight of their own. Not to say that "common wisdom" is always unfounded, but "everyone says" or "everyone knows" isn't a good criterion for assessing credibility.

Now my humidity in the box is kept at 33%rh. So is this alright now? Or should I let in more fresh air to up the humidity in the DIY dry box of mine?
I doubt anyone can guarantee you that anything is "all right". I would suggest though that the many discussions whether one should maintain 40%, 45%, 35%, or 42.7385% RH blow a minor matter completely out of perspective.

Another thing to consider is that RH isn't uniform throughout the dry box in the first place. All the folks getting sleepness nights on how to adjust their Digicabi or similar cabinet don't seem to realize that highly nonuniform RH distribution is the very principle on which these devices work.
 

BlindSpot

New Member
May 1, 2008
42
0
0
40
#11
Bad news, I tried to give my DIY a breath of fresh air today. I realised that my Hoya ND4 lens is cloudy. I suspect that's the fungus. OMG.

Could it be that it is due to the air trapped between the lens cap and the filter? I forgot to check which side it is, the cap side or the side exposed to the air.

How come they are growing? The rh% inside the box is maintained at 20 - 40%, temp is at 28 degrees +/-5.

Well, seems like nothing will stop them from growing.
 

#12
Bad news, I tried to give my DIY a breath of fresh air today. I realised that my Hoya ND4 lens is cloudy. I suspect that's the fungus. OMG.

Could it be that it is due to the air trapped between the lens cap and the filter? I forgot to check which side it is, the cap side or the side exposed to the air.

How come they are growing? The rh% inside the box is maintained at 20 - 40%, temp is at 28 degrees +/-5.

Well, seems like nothing will stop them from growing.
Just relax for a second mate before you panic. Just make sure that it is what you think. Fungus, in dry conditions, will not usually exhibit such "explosive" growth. It could be a number of other things.

1) Fog. Rapid changes in humidity and temp can make a lens fog up for several minutes. I know it sounds obvious, but just check.
2) Residue. If you have been shooting in salty air, or any air containing moisture that is carrying many impurities, then these can deposit on the lens glass. In fact, you can see this on glass that has been left sitting for a long time in areas with not-so-clean airflow. you can try cleaning this off by just gently breathing on your lens and cleaning it with a lens cloth.

Don't dispair right away. It might not be fungus! Good luck!
 

BlindSpot

New Member
May 1, 2008
42
0
0
40
#13
Just relax for a second mate before you panic. Just make sure that it is what you think. Fungus, in dry conditions, will not usually exhibit such "explosive" growth. It could be a number of other things.

1) Fog. Rapid changes in humidity and temp can make a lens fog up for several minutes. I know it sounds obvious, but just check.
2) Residue. If you have been shooting in salty air, or any air containing moisture that is carrying many impurities, then these can deposit on the lens glass. In fact, you can see this on glass that has been left sitting for a long time in areas with not-so-clean airflow. you can try cleaning this off by just gently breathing on your lens and cleaning it with a lens cloth.

Don't dispair right away. It might not be fungus! Good luck!
1) Well, it does not seem like fog to me, after I wipe it down and stored it. When I took it out today the ND4 filter turn cloudy again. The strange thing is again, the CPL filter that was store together with it remains clear.

2) This might be the case, because my home is near the sea, about 1km - 2km away just from the sea. But still, why is the CPL lens not affected.

This is so frustrating. Is it just residue in the air or fungus?? Or is it the material of the ND4 lens prone to have things growing on it?
 

lsisaxon

Senior Member
Nov 29, 2004
11,941
0
0
#14
I'm not aware how rubber would "dissolve" or "melt" due to a low humidity environment. Polymers DO become sticky or disintegrate for environmental factors like solvent vapors and plasticizers originating from furniture or other plastic items.



Is the lubricant water based? If not, how would the ambient water content affect it?

Until I see clear evidence to the contrary, I would relegate the "too dry for cameras/optics" scare to the realm of urban legends.
There are already several reports of SWM of lenses jamming when kept below 50%RH.
 

Status
Not open for further replies.
Top Bottom