Oven and Light box suggestions for stability test

Hi, I am looking for a reasonably priced oven and light box for cosmetic stability test. Any suggestions is truly appreciated.


  • To run a 4 week stability test on my creams way back in 2016 I did as is seen in the photo:

     I used a dehydrator as the BOX.

      A 40 Watt bulb provided the heat. The lamp with the 40 Watt bulb was put on a cookie sheet and NOTHING flammable was near the bulb(!).

         I had a digital thermometer that has a probe with which you can read the temperature at a location farther from the thermometer itself. You might be able to see that white cord leading from the thermometer INTO the box(?). I adjusted the height of the shelf inside until the area on the shelf was 40 Celsius.

        There is cardboard on the shelf so my jars of cream & lotion  did not fall through the shelf.

    I covered the entire set-up with a bed sheet so that it remained DARK INSIDE the box at all times.

     The temperature inside the make-shift box was monitored. I moved the temperature probe around on the shelf to see if the temp. was the consistent, and it was "close enough for rock & roll" all over the shelf surface. 

     I know this is NOT lab-grade equipment. However, it worked very well AND I did NOT have to buy anything since I already use the dehydrator for fruits and other stuff. 

     I JUST looked at a sample from Jan. 17/16  (same formula that I tested a few months later in the above set-up) and it is STILL nicely emulsified. It is now 6 years old and 8 days old. I can assume my formula is good 😁.
  • Thanks @Margaret! you are very creative :) It is admirable. How do you do your stability testing under various lighting? Do you have a light box or you put them next to the window? I am trying to find or make a light box to avoid temperature change. Not sure what kind of light bulb I need to get to replicate north facing sunlight.
  • I did NOT test under variable light conditions, it was just this "mechanic's light" with a 40 Watt bulb,  under the shelf. The samples were on the shelf above the "mechanic's light".  I just used my dehydrator, modified,  as seen in the photo. 

    The temp. inside was quite steady at 40 Celsius, as I recall. The lightbulb did a great job of putting out a consistent amount of heat for my needs.

      Could be I'm wrong, but since my cream sample is OVER 6 years old, I think my modified dehydrator did a pretty good job of estimating if the cream would still be emulsified after 1 year at room temp. 

      I only did this accelerated stability test when I was experimenting with a certain ingredient. I wanted to know if it was a good idea. I am no longer experimenting with new ingredients, so my dehydrator merely dehydrates food items now 😄.
  • edited May 16
    Hey! You can use a special lamp like an LED smart light desk lamp inside of a box to provide the same efficiency friend has this lamp for the same purposes, and I can say that this device works perfectly and has a wide range of color-changing options. If you are looking for a cheaper version, I can recommend you buy the smart bulb from the Vont brand. The two-pack of those will cost you only around 15$. Reach me in PM if you are interested. I will share with you the site where I usually buy them.
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