This is my interpretation of a ray gun that I made with some parts found at Delaney's Surplus a few years ago.
Step 1: Parts Needed
You will need something with a handle. I found this Type-2E Metco Metallizing Gun.
Then you need something that matches up well at looks like it could shoot some cosmic rays and kill some bad guys. Vacuum tubes always work great for this part. I am using a 5868 United Electron vacuum tube. It is fairly big. Measures in at about 6" tall and 4.5" diameter.
I also have this old screwdriver thingy that could work as a handle but did not have a smaller vacuum tube at the moment. I will save that for another project.
Step 2: Test Fit
Check to make sure the parts fit together and if any sanding or other items will be needed to put together. These fit together perfectly and didn't need any other prep work.
Step 3: Clean the Parts Up, or Not.
The vacuum tube had some information wrote in marker on it. The date it was put in to use and serial number. Using an alcohol pad wipe I was able to remove that stuff.
I like the grungy look of the metallizing gun. So we will leave that alone.
Step 4: Final Assembly
I put a bit of hot glue on the glass nub of the vacuum tube to hold it together.
The total cost for this was around $25 I think. As always your cost may vary depending on how you find the parts and if they are originally in working condition or not. I lucked out on finding these this cheap. Looking at ebay for these items the price could be up to $200 or more.