Humidity and Your Camera: Making a Dry Box in the Tropics

We read an article a while back about how mold and fungus can start growing inside the lens or body of a camera, especially in high humidity environments like Costa Rica. The result was a frenzy of Google searches and, similar to when you look up some weird skin rash, the results were horrifying. To sum it all up, mold and fungus can ruin your equipment if you’re not careful. Worst of all, upon closer examination, we realized our zoom lens already had wisps of mold growing right under the front glass. Luckily, with the help of some miniature screw drivers and lens cleaner, we addressed the problem before it got worse. But the question still remained: How to keep a camera mold free in the tropics?


Camera Costa Rica

For those just traveling to Costa Rica for a week or two, a few silica packets (like the ones you find in a shoe box) placed in your camera bag and an air conditioned hotel room will probably suffice. But for longer stays, a dry box is the way to go. There are many commercially available dry boxes specifically designed for cameras and other electronics, but you can also easily make one yourself. We got most of the materials for ours from the local Maxi Pali (Walmart-owned store chain).

Here’s what you’ll need:

  • Plastic container with good sealing lid. It helps to put some weather stripping or something around the edge if it is loose.
  • Something to absorb humidity. Silica packets work and can be re-dried at low temps in the oven, but we couldn’t find any in Costa Rica. Instead we used a system of Calcium Chloride (similar to Damp Rid) which is more readily available here. Update: We have tried both methods and prefer the Calcium Chloride one. The Silica Packets worked great but were saturated within a month or so. We also found drying them to be a major hassle as opposed to just adding a little more Calcium Chloride powder to the Damp Rid container every few months.  
  • Humidity gauge. Again, we couldn’t find one here so we bought this one on Amazon and had a friend bring it down for us.
  • Rubber place-mat or something else to keep your equipment from sliding around in the box.


Homemade Camera Dry Box Photo
Completed Camera Dry Box


Our dry box setup has been a lifesaver. We keep the humidity level around 40-50%, adding more Calcium Chloride or Silica packets when needed, and store our camera away whenever we aren’t using it. Since our initial fungus discovery five months ago, we haven’t had any problems since. Hopefully this post will help keep your camera and lenses safe too.

If you have any other techniques that you use to keep your equipment fungus free, please let us know below.

Post by: Matthew Houde and Jennifer Turnbull-Houde



  1. Hi Jenn & Mat, we recently moved to a town 10 min north of San Isidro (Perez) and are dealing with some major mold issues. Yay dry season is almost here! Of course we are most worried about our camera and other electronics. I found one little spot of mold on my camera cap yesterday and remembered this article.

    We are still very new to finding things here and wonder where you get the Calcium Chloride? We found a plastic container and a dam rid container and just need weather stripping and Calcium Chloride.

    Thank you!

    1. Hi Kim, Yes, rainy season seems to have turned the corner so we will be in better shape soon! We have found Calcium Chloride at various BM grocery stores (there is one on Highway 2 south of town). We think there might be some at Lufer’s grocery store in Perez too so definitely check there. That is right in downtown. Usually they keep it with the cleaning products near the air fresheners. Otherwise, the big Walmart in San Jose has it reliably. Good luck with your search. We know how it is to try to find that oddball thing in Costa Rica.

  2. Hi Jenn and Matt,

    Thanks for the tip about Calcium Chloride. I was looking for some ideas for storing vegetable seeds and came across your article. Very handy! We live near San Raphael de Heredia and are also glad to see some drier days ahead.


  3. Hello, I do not have a camera but found you article very informative. I just moved to Costa Rica 3 months ago and knew I would be experiencing mold, but not to this degree. Mold on the couches, rubber shoes, leather hat…. I have not been able to find damp rid, but from your comment above I will be going to Walmart in Escazu very soon. I have also put clothes that won’t be used for a while in vacuum sealed bags. I too am learning where to buy things and what to buy, but I am still clueless on how to make this all work in the tropics.
    Storing spices and herbs
    Keeping lettuce fresh
    Keeping bananas fresh
    Storing food. (I have bought so many gallon zip lock bags that I think I should buy stock in zip lock)
    Any advice you can provide will be greatly appreciated. With the cost of electricity I do not want to run the AC’s all the time.
    Do I keep all the doors and windows open?
    Do I keep all the doors and windows closed?
    I love Costa Rica and will not leave.
    Another option is to grow mushrooms in my house, considering the cost of mushrooms I should be able to sell them then I can afford to run the AC!

    1. Hi Susan, Yes, it can be challenging to adjust to life in the tropics. It will get better, don’t worry! Mold will probably always be a problem unless you resort to A/C, unfortunately. We live on the South Pacific Coast where it’s very humid so we can relate. We do leave our windows and doors open almost all the time to maximize air flow. Ceiling fans are on 24/7- this is especially important in rainy season. If your house doesn’t have good air flow, you will still have some mold. We try to rotate through our clothing so that everything gets washed regularly, and put away things that we don’t use. Space Bags are great for that.

      For spices, the small bags are best so you go through them faster. For keeping ants, etc. off food, we have a few plastic storage containers. We’ve seen some quality ones that seal well at PriceSmart before, but they don’t always have them. You can find them elsewhere in San Jose, though.

      Some other tips- make sure your clothes are bone dry before you put them away. We store extra nuts like almonds in the fridge when we buy in bulk so that they don’t go rancid. Superglue is best stored in the fridge. We learned that from our Tica nanny 🙂 We don’t have one due to the configuration of our house, but if you can have a sealed bodega where you can use a dehumidifier, this is a great way to store things and not to have to worry about moisture and mold. Hope that helps. Hang in there!

  4. have you observed a humidity difference between using silica vs calcium chloride. I have bins like yours but with lids more like a Rubbermaid Tupperware I’m very happy with them and I have the same calcium chloride product as the dryer. But I’m still worried that I’m getting rust on high carbon steal blades like razer blades. I have paper die cutting dies if you wanted to know. I have some silica gel but I save it for small things like pill bottles. So have you seen that silica gel keeps it dryer then calcium chloride even if its a pain in the butt. I sprinkled some moisture evident silica gel in the dry box, its not a definitive test or anything but I’m curious to see how fast they change from blue (dry) to pink (saturated).

    1. Hi Mandrew, we felt as though the silica packets got saturated and stopped working too quickly so we only use the calcium chloride. However, we have some zip lock bags inside the dry box with smaller things like SD cards and USB drives. And inside the zip lock we usually put a silica packet or two. You could try that with the razor blades as well. Double humidity protection!

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