BRIT NERF Forum Index
Join! (free) SearchFAQMemberlistUsergroupsLog in
Questions about plunger seals on homemade blasters

 
Reply to topic    BRIT NERF Forum Index » Modifications -> Homemade Blasters View previous topic
View next topic
Questions about plunger seals on homemade blasters
Author Message
Please Register and Login to this forum to stop seeing this advertising.







m4rsmensch
Junior Member


Joined: 22 Jul 2013
Posts: 21
Location: Ruhrgebiet, Germany



Post Questions about plunger seals on homemade blasters  Reply with quote
Hi I plan to built myself my first homemade blaster in the near future.
It shall be a snap carbine. But there are some problems with the general composition of plunger seals. First of, I live in Germany so no imperial scale stuff over here. I will be using a 40mm PVC pipe as the plunger which provides me a 34mm ID. The piston will be 32mm AD PVC pipe.

First problem I encountered was the absence of O-rings thats would fit into this setup. Maybe I can find some in the near future in a bigger hardware store. But lets forget about that.

There is the other method which sandwiches washers and gaskets/rubber washer to create a seal. And I have some basic questions about those seals. Some of these seals are built, that the rubber washer is formed like a skirtseal. On others they remain straight.
My particular question is: What diameter should the rubber washer have to create a good seal? Should it be a tiny bit larger than the 34mm ID from the pipe? Or better like 35mm or 36mm?

You see I have absolutley no clue. I cant really figure out what the rubber washer sizes you guys use will do in the pvc pipe you have.

Hope you can help me out here. Oh and there might be other dumb questions to come Very Happy
Thanks in advance
Sun Sep 22, 2013 6:32 am View user's profile Send private message
OldNoob
Foam Data Collector


Joined: 07 May 2013
Posts: 4823
Fav. Blaster: Xtreme 180 Rapidstrike
Location: In the Boonies



Post Reply with quote
BlackBoarderV makes plunger heads on the lathe, he can supply you with one machined to fit your tube and probably spare Orings. His plunger heads are a thing of beauty compared to the crude homemade ones seen on some NIC blasters.

_________________
Big_Poppa_Nerf wrote:

Boff whats the damage? I have spent over 3 times my Nerf budget this month already. Part of me is trying to be a responsible parent/husband/house owner. The other half is just says 'Ahhhh, Screw it!'.
Sun Sep 22, 2013 8:36 am View user's profile Send private message Send e-mail
m4rsmensch
Junior Member


Joined: 22 Jul 2013
Posts: 21
Location: Ruhrgebiet, Germany



Post Reply with quote
Thing is I need them fast and by fast I mean yesterday....na ok maybe I mean Thursday and I dont think he will be so fast Wink

But I guess BlackBoarderV is a forum member here?
Sun Sep 22, 2013 5:09 pm View user's profile Send private message
SSGT
Nerf Addict


Joined: 12 Jan 2013
Posts: 1265
Fav. Blaster: 'Rave-N' CS-18, Elite Alpha Trooper (EAT) CS-12
Location: Durham



Post Reply with quote
Yeah, he's got a trading thread with his plunger heads among other nice homemade bits. Delivery before Thursday may be a problem though.

The benefit of the skirt seal is, as the plunger moves forward and pressure in the plunger tube builds, the skirt is forced to expand a bit and seals better. That means you should only need it to be the same (or only slightly larger) diameter as the inside of the plunger tube. The faster the plunger moves the better the seal. A flat washer seal needs to be supported from behind (usually with a metal washer) to stop it bending backwards and leaking.

You could always make either the plunger head or seal removable so you can change it later, but still have something that will work in time for Thursday.  Smile

_________________
Trust me, I'm an engineer! Very Happy

Antonius wrote:
Compoooter bits make shiny Nerf blaster go whoosh!
Sun Sep 22, 2013 5:25 pm View user's profile Send private message
m4rsmensch
Junior Member


Joined: 22 Jul 2013
Posts: 21
Location: Ruhrgebiet, Germany



Post Reply with quote
Quote:
A flat washer seal needs to be supported from behind (usually with a metal washer) to stop it bending backwards and leaking.

I knew that, but Iam unsure how large the washer should be to be a sufficent support. The metal washers I have are only 30mm in diameter. The gasket material is rather thick though, so the missing 2mm on each side wont be a problem.

Seems I have to do some "R&D". But thanks anyways Smile
I also contacted BlackBoarderV.


Sun Sep 22, 2013 7:22 pm View user's profile Send private message
Display posts from previous:    
Reply to topic    BRIT NERF Forum Index » Modifications -> Homemade Blasters All times are GMT
Page 1 of 1

 
Jump to: 
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum

Card File  Gallery  Forum Archive
Powered by phpBB © 2001, 2005 phpBB Group
Design by Freestyle XL / Flowers Online.
Create your own free forum | Buy a domain to use with your forum