SpudFiles

I would like to make my own pneumatic pen gun. What do I need, and how much will it cost me. I am looking for pressure up to around 400psi, but thats just my safety limit. I will be firing it at about 80-100 psi. Any tips on a start? I would like it to shoot airsoft bb's, but I can cut some nail heads up or something and use that as ammo. I have schraders and pens already, just need to know what else I need to get.

Ok, first look at JSR's penguns, that should give you the basic idea.
1) We don't know how much it will cost, it depends what you have and how much the parts to make it are.
2) 80-100psi isn't enough for a pengun, 400 is better.
3)If you want it the size of a pen how will you shoot BBs? You will find that shooting pencil lead and small nails will be much better.
4)Normal pens won't be strong enough, something like a 6mm ID and 8mm OD aluminium or brass tube would be much safer.

No offence, but you have been making alot of threads like this asking simple questions that you could find the answer with simple search. I know sometimes it can be quite confusing but you gotta use your common sense

Just for a comparison, any barrel you could find to fire 6mm airsoft BB's would normally be used for the chamber of a pen gun.

I have $10 to spend on it, and thats really the amount I want. I can try and get some shock pump from a friend or something, but I really dont want to deal with high pressure till I get an air compressor (which will be awhile...) and an actual work shop. The size of the pen gun doesnt work, but BB's were the first thing that came to mind, and the safest thing. Alot of people think I am a saftey freak, well theres nothing wrong with that, no one has had as many close shaves to death as I have in 1 day. Back on topic, where would I find a 2.5mm brass or copper tube anyways? Also, what other parts would I need for a basic pen gun. I am a visual type of builder, I learn from watching someone else make it, and I need some sort of step by step process for it. And yes, I know I start multiple threads for different questions, but really, why is it so bad if someone is trying to learn?

I have $10 to spend on it, and thats really the amount I want. I can try and get some shock pump from a friend or something, but I really dont want to deal with high pressure till I get an air compressor (which will be awhile...) and an actual work shop. The size of the pen gun doesnt work, but BB's were the first thing that came to mind, and the safest thing. Alot of people think I am a saftey freak, well theres nothing wrong with that, no one has had as many close shaves to death as I have in 1 day. Back on topic, where would I find a 2.5mm brass or copper tube anyways? Also, what other parts would I need for a basic pen gun. I am a visual type of builder, I learn from watching someone else make it, and I need some sort of step by step process for it. And yes, I know I start multiple threads for different questions, but really, why is it so bad if someone is trying to learn?

Ok, you better start with something a bit bigger as you will be very disapointed with the power. Something like a 1 inch copper coax would be easier to make and would be more powerful. Home Depot or Lowes will supply everything you need. If you are a visual learner, read JSR's thread, it's full of pictures and drawings that pretty much explain it all.
Why is it so bad if your just trying to learn? Well as i said above, it takes about 10 seconds to do a search but you still expect us to spoonfeed you? It takes quite a while to learn all of this, i think you're rushing it abit, just take things at a slow and steady pace and the outcome will be much better. Find a design that you like and just copy it, you will learn so much more. Anyway, have fun and keep trying

We can't tell you what to use because it varies between each design. Meet the four criteria below with materials you find and you can build a pen gun.

1) Chamber: Some sort of brass, aluminium or other metal tube around 6mm in diameter.
2) Barrel: Same as above but about 3mm in diameter.
3: Piston: Can be made from ANYTHING. Use your imagination or look at JSR's and others pengun threads.
4) Fill/pilot valve: Schrader/presta valve

It's that easy. If you can't build a pengun from looking at JSR's threads and meeting the criteria above, we're not going to spoonfeed you through each step..."now epoxy the schrader valve in to the end of the chamber..."

but I really dont want to deal with high pressure till I get an air compressor

Why does that have anything to do with it? Assuming you're not wasting your money on a shitty $20 car tire air compressor, shop compressors only go up to about 145PSI max, more commonly 125PSI.

Back on topic, where would I find a 2.5mm brass or copper tube anyways?

Hobby store. Aside from that, don't go to a store looking specifically for 2.5mm brass tube by itself, look for something that may use 2.5mm brass tube that you can take apart and steal the tube from. I've got 6mm aluminium tube from weedsprayers before, you just have to use your head about these things. Aside from finding 2.5mm brass tube sold by itself, we can't tell you where you might find it. I find most of my sh|t in the garage.

Like the others have said, if you're making a real sized pengun like JSR and co, don't even bother if you're only using 100PSI. The ammo would go further, and faster, if you threw it. Unless you're shooting at a minimum of 300PSI, there's no point building one.