Putting on RA rubbers

When you say "rigged" do you mean that you made loop with the wishbone completing the loop? If so, you should be able thread the wishbone through the small gap in the front muzzle hole.

Either way, from there, I guess you have to thread the rubber through one of the holes. 20mm rubbers are really thick. Silicone sounds like a good idea. If you don't have any, soapy water or glycerol should also work. If you are having a problem getting it started, I notice some spearos trim the ends of their rubbers to a cone shape (with a grinder or clippers), perhaps that would help.

[Any ideas Miles?]

Putting a new 20mm rubber band on a Rob Allen (or Rabitech) railgun

Was commenting on how well my 16mm rubbers were last last week & then noticed yesterday that they looked badly stretch & perished at both ends & at the muzzle. After removing them, it looks like mainly surface wear but it seemed like it was time to switch to the new 20mm band.

I almost had heartattack when I first saw the 20mm rubber (was expecting 16mm rubber) -- thinking how the heck is that thick thing going fit through the holes in the muzzle. Well it was pretty awkward. Here's what I did [WARNING: stretching thick, lubed rubber bands is dangerous:martial]:

0. Remove the spear & unclip the spearline.

1. Cut to the correct length (I left a little bit extra, just in case; all 3 charts that I checked recommended 64cm of 20mm rubber for 90cm railgun).

2. Fit the Dyneema wishbone (couldn't get any purchase without it -- but the end toggles do make the band even thicker at the ends).

3. Carefully trim the rubber ends to a crude, shallow, cone shape with super-scissors to make it easier to thread & guide.

4. Lots of v. slippery lube is essential - I used glycerine (I can never find that silicon/silicone lube everybody recommends for lubing & protecting rubber).

5. Key point: you need a good way to brace the gun while you apply considerable BRUTE FORCE. What finally did the trick for me was the outside garden table. I led the full length of the gun across the table with just the muzzle over the end. This allowed me to brace the gun without risking bending or breaking the barrel. Thread the wishbone through the muzzle gap, then pull the coned rubber end into the muzzle hole and then pull down hard on the other end using both hands. Plop - in it goes. Now pull the band through until its centre is at the muzzle - normal firing position.

6. To get the rubber into the guides on either side of the muzzle:
a. lube the rubber next to the guide
b. brace the gun vertically agains a table leg or the seat of a solid chair
c. pull down hard with both hands, with as much sideward pull towards the split in the guide as you can manage. Plop - in it goes.

7. Repeat 6 on the other side.

8. You will probably need to even the band out now -- good luck, I'm still working on that! (Not too worried, while loading the gun in the water, it is usually possible to adjust this).

There is probably a better way - but this at least worked. (Probably best not to attempt this immediately after a long, tiring dive).

Excellent, I thought there must be an easier way! 140cm RA -- you're obviously up for a challenge! I tried threading without the wishbone without success but (as you may have guessed) I started regretting putting the wishbone in almost as soon as I had done it. Pliers - interesting idea - I had to use a lot of force - not sure if I could grip that hard with pliers without cutting through the rubber (or causing untold damage in other ways!).

Leaving it long and trimming afterwards sounds like a good idea too -- a bit trickier to measure I dare say.

BTW I use a soldering iron to smear the constrictor knot & the end of cords - works well.