making epoxy pistons

[Counterstriker]

o0o0o0o! I undterstand!! I think.. Bit do I drill the holes through the whole piston but not no hitting the rubber disk?

[STHORNE]

o0o0o0o! I undterstand!! I think.. Bit do I drill the holes through the whole piston but not no hitting the rubber disk?

Correct!!! Finally he turned his brain on lol.

[bigbob12345]

no you dont drill any holes in the piston at all unless you have orings which you dont.

sthorne he almost got it but he isnt there yet.

[Counterstriker]

no you dont drill any holes in the piston at all unless you have orings which you dont.

sthorne he almost got it but he isnt there yet.

Dude.. I know I never said I wasn't gonna not use a o-ring.. I never even started to make it.

[bigbob12345]

okay sorry Im like half awake right now so yeah...
Well may I recommend that you dont use an oring

[jackssmirkingrevenge]

but you dont usually have air leak all around the piston

Yes, you do. Adding equalisation holes if your piston isn't completely airtight (not just a very tight fit) is a waste of effort and leads to a less efficient launcher. The only time when an equalisation hole or two filling valves are needed is if your piston is 100% leak-proof, and most of them aren't.

[Counterstriker]

oh. how do you usualy atatch your small diameter sealing faces? a screw would not fit in a bb barrel.

for smaller diameters (and i´ve done this with 3/4" cal launchers too, like theo ne in the showcase) I prefer to attach the sealing component to the barrel and simple have a solid piston.

Can I make an epoxy plug for the barrel then drill a hole to fit the barrel the just put neoprene on the barrel seal and skip adding it to the piston?

Like this:

[keep_it_real]

ya that would work too. But depending on how wide the rubber is (skinnier is better) everything (neoprene, and piston) has to be very flat to make a seal. If it wasn't flat, it would make a seal at high pressures but when you're filling it with a bike pump, at the start it might leak. On 3/4" cal barrel, I would just attach the neoprene to the piston. It's just easier.

[jackssmirkingrevenge]

You need a secure way to attach the rubber to the barrel though. I find that automotive rubber hose is excellent for this application and comes in a variety of sizes.

[Counterstriker]

ya that would work too. But depending on how wide the rubber is (skinnier is better) everything (neoprene, and piston) has to be very flat to make a seal. If it wasn't flat, it would make a seal at high pressures but when you're filling it with a bike pump, at the start it might leak. On 3/4" cal barrel, I would just attach the neoprene to the piston. It's just easier.

I am not using a 3/4" barrel.. The chamber will be either an 1" or 3/4, the barrel will be more like 6-10 mm. I don't believe I could find a washer for that size.. I may bring the barrel to 1/2.. I am not sure. I will go to home depot this weekend and see what they have. And the lighter gray layer in my picture is an epoxy cylinder that will have the neoprene, So my question still stands, Would I have to add neoprene on the piston if I go by my diagram.

[jackssmirkingrevenge]

If you have neoprene on the end of the barrel then you don't need it on the piston.

[Counterstriker]

niglch the low viscosity epoxy he used is called marine epoxy they should have it at your local home depot if they dont ace and lowes have them to.
and about it sticking to the wall things white lithium grease and other similar greases are better cooking oil just doesnt cut it with epoxy.

I don't think they have low viscosity epoxy at any of the stores you named.. its all that thick junk.. I can't buy it of the internet cause its way overpriced shipping (16$). I wanted to keep the job cheap.. Can I just use wood dowel wrapped in electrical tape with neoprene head?

[jackssmirkingrevenge]

Can I just use wood dowel wrapped in electrical tape with neoprene head?

You could, in the same way you can use a coathanger as an aerial for your car...

[Counterstriker]

Can I just use wood dowel wrapped in electrical tape with neoprene head?

You could, in the same way you can use a coathanger as an aerial for your car...

So I am guessing it wouldn't be that effiecent? Well I will go to another home depot.. If they don't have low vicosity epoxy I will just get the thick stuff or a dowel.

[jackssmirkingrevenge]

How thick is "the thick stuff"? It doesn't have to be like water, just runny enough to flow. As long as it's not a paste it should be adequate.