SpudFiles

Hi,
Im new in all this business.
I want to build a tiny spud gun from copper.
The ignition i think to use is from a electric lighter.
All the connection going to weld exept the the combustion fill that i use a threading cap.
see the picture above and try to help me.

Um..hi?
You've given us no info really. You've told us you want to make a copper spudgun. I'm not sure if you're really actually asking a question..

So I'll weigh in. You need a threaded, airtight way to refuel and purge your chamber. Remember to clean out stale gasses after each firing. With copper on a small scale, a problem you will run into is the spark gap. Ideally, you would use a spark strip but I'm unsure if you're at that stage yet. Simply connect one of the sparker wires to the chamber (the earth, not the live!), and insulate the other, feed it into the chamber and position it close to the wall. It'll hurt spark efficiency by giving a blunt surface, but it's probably the best method.

An electric lighter. Do you push a button, it clicks and theres a spark? That's a piezoelectric ignitor. If it has a AAA battery or similar in it then it uses a capacitor similar to a camera flash. For a gun like this, especially with an uninsulated chamber go for the piezo. Much safer.

By the way, the "live" end is the end that won't shock you if you touch it.

Keep in mind your sentence structure and punctuation, saying things with more sense will get you better responses.

Welcome to spudfiles, and good luck.

this should probably be in the min, but whatever. there are threaded adapters available for the re-fueling end, as well as threaded caps. I would solder a regular end cap by the barrel, drill and tap a hole for 1/4 or 3/8" NPT, get a threaded 1/4 or 3/8" adapter to put on the barrel, and thread it in.

If you wanted, you could file off the lip on the 1/4" threaded adapter and push the barrel in further, so that it is about half way into the chamber when it is threaded in. This would give you more barrel length for the same overall length. You could also have the wire from the piezo spark to the barrel inside the chamber for better performance, as long as you didn't Teflon tape the barrel threaded adaption.