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Make a PVC Pipe Evidence Container


PVC pipes are devices that are easily made by you or your Public Works Department.  They provide sturdy, waterproof protection for items such as guns and knives and, due to their watertight capability, can also be used in place of a bucket to hold other physical evidence.  I like having a number of pre-made PVC pipe evidence containers on hand to give me a selection of sizes to choose from one that would fit a rifle, another that would protect a handgun, and so on.  When you use one of your PVC pipes in a criminal case, be prepared for the possibility of never getting it back.  The pipe becomes the recovered item's package and could stay with the case until the case is closed.  For this reason, I prefer to have the police investigator I am assisting furnish the container.  I explain to him what size it should be and where the police can usually get one made (Public Works).  If the investigator cannot furnish a container, I provide one of my own, knowing I might not see it again.


There are three main parts of a PVC pipe evidence container:


1. The pipe - The pipe comes in many diameter sizes.  The most popular and most used is the 6 inch pipe.


2. The end cap - It's important to get a true end cap to ensure you have a watertight container.  I have tried screw-on caps as an end cap, only to discover that these caps leaked all the water out.


3. The sealing cap - There are two main types of sealing caps used, the screw on cap and the pressure-fitting cap. 


I personally prefer the pressure cap because it is much more convenient to use underwater, the large wing nut making it very easy, even with a gloved hand, to get the large O-ring to create a watertight seal.  The screw-on cap can certainly be used and is much cheaper, especially if you are paying for it.  Due to silt, sand, mud and other substances on the threads, you might be able to get only a couple of turns on the cap when attempting to seal it underwater, making it difficult to get a good seal.  To overcome this, you simply bring the container to shallow water, unscrew the cap, rinse off the threads and screw the cap down tight.  Of course you want to do this while being careful not to expose what's inside the container.


Whatever cap you use it's important not to lay the filled pipe in an investigators trunk or back seat. For safety, always stand the pipe up on a back -seat floorboard or some other similar location because water has a way of getting out and can do some damage to radios and other equipment it might be around.


Making a PVC Pipe Evidence Container


I have PVC pipe evidence containers that can hold all types of weapons such as knives, revolvers, rifles and shotguns.  The popular 6-inch pipe can be used for any of the weapons mentioned.  The length of the pipe is the only thing that changes.  For most knives and handguns, I cut a section of pipe approximately 1 foot long and for a container that can hold most average size rifles and shotguns, I cut a section of pipe about 4 feet long.  I will give the instructions for making an evidence container for a long gun.  When you get around to making an evidence container for a knife or handgun, just cut it down to the right length.


The parts you will need are:

  • One 4 foot, 6 inch pipe

  • One PVC 6 inch end cap

  • One PVC 6 inch screw-on cap

  • One can of PVC primer or cleaner (optional)

  • One can of PVC cement


To put the container together, follow these steps:


1. Cut the pipe to the proper length.  You can use a fine-tooth saw.  Try to cut the pipe square (perpendicular to and at a right angle to the length of the pipe).


2. Smooth the edges and burrs by filing.  Remove all burrs on both the inside and outside edges of the pipe.  You can also bevel the outside end of the pipe to ensure easy insertion in the cap.


3. Dry fit the pipe and fittings prior to actually putting on primer/cleaner or cement.


4. Make sure surfaces of both the pipe and the end cap (you will attach the end cap before attaching the sealing cap, i.e., the screw-on cap) are clean.


5. Apply primer or cleaner to the outside of the pipe and the inside of the end-cap fitting.


6. Apply a thick layer of cement to outside of the pipe.


7. Apply a thin layer of cement to the inside of the end-cap fitting.


8. Quickly assemble the joint with a twisting motion (¼ turn) while pushing the pipe into the cap as far as it will go.  This guarantees an even distribution of the cement onto the cap and pipe.


9. Wipe off excess cement.


10. Hold the joint together for about 30 to 40 seconds.


11. Repeat the process for the screw-on cap.


12. Let both joints stand undisturbed for about 15 minutes.


There you have it.  You just made your own PVC pipe evidence container.

I sometimes use a pressure cap and not the screw-on-cap for my evidence containers.  If this is the case, once you attach the end-cap on your pipe, you are done.  A pressure cap seals onto the pipe by itself and does not need to be attached beforehand.


Special Note: It's important that you never leave a PVC pipe container filled with water laying down. Water has a way of working its way out through the cap. Many land investigators have placed a filled pipe in their trunk or back seat and have found their trunk or seat filled with water. I educate them on this possibility and have them place it standing up on the floor board of their back seat supported in that position. That way it gets to the lab or police department the way it was intended.

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