Flash don’t melt – Choosing and preparing cache containers

When it comes to choosing a container for a geocache the possibilities are endless. You can get as creative as you like and use almost anything that you have to hand as long as you consider a few basic rules. First it needs to resist the weather. Second it needs to be durable so that it will stand the test of time and the countless fumblings and fiddlings of those that come to find it. Thirdly it needs to be able to blend in with its surroundings. Either the container should be of a shape and colour that is easy to hide or additional camouflage should be employed to ensure that it is not discovered by anyone other than the geocachers trying to find it.

As I am new to this I am opting to keep it simple for the moment. The most common types of containers you will come across are plastic 35mm film canisters, tubes of various sizes or small Tupperware style food containers. Obviously a whole industry has sprung up around the sport and you can buy containers that are designed to be geocaches from the ground up but you can also find cheap and effective alternatives all over the place in your local supermarket or from many online sources.

A clear plastic container with clip tabs on the lid to seal itMy first hides will be using plastic food boxes that have clips on the side to seal them from the weather. These come in all sorts of shapes and sizes and can be bought for just a few pence if you shop around right. We found some in a charity shop and for the sum of £2 we got two small rectangular containers and two smaller round containers. ASDA are also a good source of these types of box and we bought a 3 pack of ever decreasing in size round ones for a pound.

Now these fit the bill in terms of being reasonably water tight and also of a decent enough size so that people can swap swag and trackables which was also a requirement of mine when placing caches. But it doesn’t really do much for the blending in part of the equation. A clear plastic container is going to stand out like a pork chop at a Jewish wedding when it is stashed in the bushes. After doing some research I have decided that the boxes needed to be painted. I settled on black as this can generally look inconspicuous in a lot of different surroundings. Doing a bit of reading I noticed quite a few comments about paint peeling off plastic containers and I didn’t want that. No point in me going to all the trouble of painting it if in a few months all the paint will have peeled off. This thing has to last at least a couple of years out there in the wild. More research… the internet is a wonderful thing and I came across two possible solutions. The first was to use a paint thinner on the plastic first to destroy the smooth shiny finish to allow the paint to adhere better. The stuff is called xylene and you only need to wipe the boxes over with a cloth moistened with a bit of this stuff for it too work. It is rather fierce though and can burn if it comes into contact with the skin so gloves are a must. I thought this might be an option but then I came across an alternative which appealed to me greatly. Upon reading a thread on a discussion group about a guy trying to paint his model helicopter I discovered a technique called Flashing. In a nutshell by applying a flame to the surface of the plastic briefly the resin layer that gives the plastic its shiny finish is broken down and the result is that the paint now has something to adhere to. At first it sounded a bit daunting but on closer inspection I realized that the process looked quite simple and did not require anything more than a gas blow lamp or even just a gas hob. Now I am not going to take the flack if you try this and set fire to your house, eyebrows or dog or whatever but if I can do it as a blind person without the aid of a safety net and the fire brigade on standby then I am sure it is within the capabilities of most adults.

Holding the small plastic container with long Tongs I pass it through the flame on the hob to flash it


Using the biggest ring on the cooker I hold the container with some big BBQ tongs and pass it through the flame. Don’t hold it in the flame but instead keep it moving. You are trying to subtly affect the molecules of the top layer of coating on the plastic not melt the thing! Keep it moving, keep turning it around, keep taking it out and repositioning the tongs so that the entire surface of the container and lid spends a little time in the flame. The whole process only takes a couple of minutes to do a container and lid. You may notice the surface of the plastic going a slight cloudy finish although this depends on the actual type of plastic your container is made of. Once you have finished allow the plastic to completely cool before then spraying with your chosen paint. I have used just your bog standard matt black spray paint that you can get from Halfords but other colours and paints and indeed suppliers are available. You may need to apply more than one coat, the more coats you apply the better the chance of the paint staying intact for longer but bear in mind that the more layers you apply the more expensive it will be.

There are other options for camouflaging your containers such as camo tape or camo bags or using natural camouflage to cover your boxes but so far this is my first hide and this is the option I have chosen this time. I will be interested to see how the container fairs once it has been out in the world for a few months.

The small container is now painted a matt black

Container after flashing and painting

This entry was posted in Geocaching, Hiding Geocaches and tagged , , , , , , , , , . Bookmark the permalink.

4 Responses to Flash don’t melt – Choosing and preparing cache containers

  1. Pingback: You get out what you put in! – What to put in a geocache | Washknight

  2. I didn’t know about flashing. May try that myself next time.


  3. Pingback: Creating the cache listing and submitting for review | Washknight

  4. Pingback: Creating the cache listing and submitting for review | Washknight

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