Epoxy questions (aka JSR's field day)

[sandman]

right now im designing a bb gun for a friend cause he asked
but i will get his battery powered airsoft gun as payment

anyway i think i can meet most of the requirements he gave me:
600 fps: GGDT says i can with some rough numbers i used
semi auto: see below
CO2 powered: Easy enough
250+ feet range: Range Calc says maybe

So far ive come up with a coaxial design (i can make models if you require visual aids), but i am having trouble thinking of how i will make it semi auto.

But, before i post my idea i need to know if you can dremel part of a piston cast with epoxy out. Or will it crack and crumble?

[PVC Arsenal 17]

I don't see why you couldn't dremel epoxy. What were you planning on doing? O-ring grooves?

[Ragnarok]

I've dremelled epoxy before, but it has a nasty way of clogging tools. And I needn't remind you to wait until it's hardened...

And semi-auto sounds like it could be a challenge. Did you have any plans for the feed mechanism?

[Zen///]

Mon canard est en feu!!!
"My duck is on fire!!!"
Lol I go to french immersion school.

On topic: Maybe make a high powered vortex gun? And make the vortex block out of epoxy and drill various sized holes?

edit: http://www.spudfiles.com/forums/unregul ... 11684.html

or like that

[Ragnarok]

Why exactly would a lathe be needed for a vortex BBMG?

You brought it up - How many people can recognise the source of "Mon canard est en feu!" WITHOUT googling it?

[MrCrowley]

Full metal BBMG? Maybe some awesome lathe aluminium vortext block which you didn't want to blunt all your drill pieces on?



I learn German, not French. German is way better, just ask JSR

[ShowNoMercy]

But a lathe could turn out a vortex block, you would need a mill.

[Ragnarok]

Well, the original quote was in French (although from an English source). It's not my choice which language the author used.

[jackssmirkingrevenge]

So far ive come up with a coaxial design (i can make models if you require visual aids), but i am having trouble thinking of how i will make it semi auto.

The blow-forward breech is a good idea and relatively simple to make.

But, before i post my idea i need to know if you can dremel part of a piston cast with epoxy out. Or will it crack and crumble?

Depends on the epoxy you're using - the marine epoxy I use can be cut, drilled, sanded and polished easily, butfor example you cannot do that with araldite.

Lol I go to french immersion school.

sounds hairy

[f.c]

yes you can do this with epoxy. when epoxy dries its just like a plastic such as acrylic and can be treated accordingly.

[sandman]

well, i will not be showing my idea cause jacks gun puts it to shame so ill be using the blow-forward breech design, i was afraid at first of using it cause of the small size of the gun but JSR proved u can do it so i shall try it.

btw,i didnt read the whole topic but i thing that if you decrease the filling fitting diameter you could get closer to fully auto with the design

[DYI]

I understood the "Mon canard est en feu" bit, but I'm Canadian in Grade 10 French, so I probably should.

[mark.f]

The blow-forward design is definitely your best bet. I have tried the paddle design for automatic fire, and it plagued me with feeding troubles never fully resolved.

[sandman]

JSR can you tell me what the part of the valve that slides into the barrel is made of? Like if it is a common household object.

[jackssmirkingrevenge]

Here's a breakdown of the parts. All the tubing was purchased in one metre lengths from a hobby store, but you can find it online too.