15 replies to this topic

[Banshee]

I'm replacing all the internals of my nitefinder and I have all the parts except the plunger rod. I don't have any extra rods lying around to make an extra long one and frankly that sounds like a cheap way to go, so i want to build one. However I can't seem to find the materials ANYWHERE. I'd really rather not order something if I don't have to, so I'm wondering what to use that can be found at regular stores. I've looked for 3/8" square metal tubing in all sizes and the don't have the right size. They do have steel but its way to heavy. Wood is too fragile, and they don't sell acrylic or Plexiglas thick enough. I'd like some PVC square rods but I have no clue where I'd find that other than online? Is it used for something specific so I might be able to find it at a specialty store?

Any ideas?

Edited by Banshee, 26 January 2010 - 12:39 AM.

[cheesypiza001]

Go to a hobby store and you should find some plastic tubing/rods in different sizes and shapes.

[Zorns Lemma]

Take acrylic sheet and solvent-weld them together if you really don't want to order 3/8" thick sheet or rod.

[wingd man]

Take acrylic sheet and solvent-weld them together if you really don't want to order 3/8" thick sheet or rod.

Unless the solvent weld reinforces the rod, that will definitely break, Acrylic is terrible except for maybe some cosmetics. (Yes I realize I'm talking to one of the unholy 3, but I can say this from repeated personal experience.)

[Draconis]

Take acrylic sheet and solvent-weld them together if you really don't want to order 3/8" thick sheet or rod.

Unless the solvent weld reinforces the rod, that will definitely break, Acrylic is terrible except for maybe some cosmetics. (Yes I realize I'm talking to one of the unholy 3, but I can say this from repeated personal experience.)

Why wouldn't laminated sheets be stronger? It is a general engineering concept supported by various technological achievements such as plywood, automotive windshields, two-ply bath tissue, and the three stacked condoms I use to safely bang your mom.


I make replacement rods out of 3/8" square nylon. Nothing else has worked better.

[ggk]

3/8" square pvc rod works well too and it is not nearly as expensive as nylon.
I used it on my nf with a full length [k26] spring and it is holding well.

[Lucian]

3/8 X 3/8 plastic with a shim under it as its a little to small.

[Zorns Lemma]

Unless the solvent weld reinforces the rod, that will definitely break, Acrylic is terrible except for maybe some cosmetics.

Yes, acrylic has shit impact resistance when compared to materials such as polycarbonate, nylon, or polyethylene, but given the situation the OP suggests, it is the easiest material for him to obtain and work with.

As long as there is adequate plunger head padding and the gun isn't dry-fired constantly, I don't anticipate any problems with an acrylic plunger rod, unless the catch well is cut incredibly deep, in which case the rod might snap there after a lot of abuse.

[ggk]

lucian that material is not very strong and will most likely break at the catch. I tried it and that is what it did for me.

[Banshee]

Alright well it seems like a 3/8"x 3/8" would be the best route but where do I get it? Can it be found at a hobby shop as Cheesy suggested?

[Zorns Lemma]

Alright well it seems like a 3/8"x 3/8" would be the best route but where do I get it? Can it be found at a hobby shop as Cheesy suggested?

Maybe. Your best bet for buying something in a store is to look for a local plastic store.

[Draconis]

Sometimes, yes. Really just depends upon how awesome your hobby shop is. I buy mine from a local plastics manufacturing shop. They have sheets of 3/8" that they cut off at about 4' lengths, and will sell me two for about $20. Which is relatively inexpensive as far as that kind of stuff goes. Square shape bar is always expensive, I guess.

[CA13]

If you ever bought an expensive Lego Technics set you probably remember the extra long girder with the incredibly large amount of holes. Those girders are actually very useful if you have an N.F. without any major spring replacements, I.E. an N.F. with a razorback spring added.

[wingd man]

unless the catch well is cut incredibly deep, in which case the rod might snap there after a lot of abuse.

Okay, that may be possible, but I can say from personal experience that one cut a bit less than half way will break after less than 30 shots, no dry firing.

On topic: as long as it isn't wood or acrylic it should work fine.

Edited by wing'd man, 26 January 2010 - 09:01 PM.

[cheesypiza001]

Alright well it seems like a 3/8"x 3/8" would be the best route but where do I get it? Can it be found at a hobby shop as Cheesy suggested?

Likely to be - if they have a Plastruct display (usually a blocky red-brick-colored turntable thing)
If it's Plastruct, 3/8" by 3/8" and gray, then it's probably ABS, which is reasonably strong. If it's white, that's styrene, not very much strength in tension - don't bother buying it.

But a solid rod, such as the PVC or nylon from mcmaster, should be quite a bit stronger. Hobby shops might have something like that too, I would think especially one that deals with R/C flying, you could get carbon-fiber tube - expensive but quite strong especially in tension.

Lucian got that from a local hobby store. It's gray and hollow, probably ABS according to what Bob said. I can take some pictures tomorrow.

[ggk]

The little display that the light gray rod was in said it was nylon and for the price you could buy better stuff.
I am telling you that that light gray stuff from the hobby store is not good for being a plunger rod. I used the stuff and it broke. It also hard to get a plunger head attached to.If you need a pic cause you dont believe me then I will see what I can do.

If you need one made I have some extra pvc rod and I could make one or sell just as much as you need.