help changing a flopper

i dont know but keep me posted im lookin at possibly makin my own spears all together

One side of the pin should be hallow. If you have access to a ball point hammer these are ideal. Place the pin throught the flopper and shaft and carefully flare out the other side until its flat. You dont want to work on it too much as it will weaken the pin.

be sure to have something solid behind your shaft when you start hitting the pin (i.e. steal plate, flate part of a bench vise, or smooth cement)

On your existing flopper you might try opening it up a little with pliers before you take it off.

Definitely try and adjust the existing one first. You can open it up with a screwdriver or tighten it with pliers (on the bridge of the flopper).

If you do replace it do the peining very gently so it rounds over the pin but doesn't bend it. A bent pin will bugger the whole thing up and never work.

I agree with Pastor,
try adjusting the original one first with some slight prying on either side. The rivet is most likely a monel rivet, which will be somewhat hard. They are typically installed placing a "bucking bar" on the smaller diameter end and a rivet gun shoots a "rivet set" against the factory head.
the bucking bar against the small end gives resistance against the rivet gun and causes that end to swell, forming a "shop head". On spear shafts the shop head is then ground or belt sanded to smooth it out.

[ame=http://en.wikipedia.org/wiki/Rive]Rive - Wikipedia, the free encyclopedia[/ame]

Dan Checkoway's RV-7 Project - Tools

These two sites can give a good overview of bucking rivets, probably way more than you need to know in order to install a flopper.

A quick and easy way to do it as an alternative would be to cut the shank of the rivet so that it is only about 1/16" longer than the shaft and floppers combined width. Install the rivet, hold the factory head down onto a steel plate or the flat portion of a bench vice (have someone else hold the spear shaft). You then take a center punch and hit a punch mark with a ball peen hammer into the center of the rivet shaft. Hit it a few times to flare the end of the rivet. Smooth or blend with a file.

Or just follow Pastors advice and pry out your existing flopper. I'd probably just do that if I was doing it at home.
I'm a machinist and aircraft sheetmetal mechanic, so I'd just take the shaft and flopper to work and hit it with a rivet gun.
If I couldn't do that, I'd just tweak the one you have on there.
Sorry for the long winded response.. I just wanted to contribute something. I had to log on to deeperblue before I went spearfishing. I leave in an hour.

Take care,
Mitch

Oh, to remove the old rivet, if you decide to go that route. Drill the factory head with a drill that's slightly smaller than the rivet shank diameter. Once the head is removed, use a pin punch and ball peen hammer to drive out the old pin.

please look here, i will post a "how to" tonight. small and badly adjusted floppers are the worst.. ask me how I know

http://forums.deeperblue.net/spearguns-accessories/77850-flopper-size-new-post.html

So.... after participating in this post one might think that I would go and check the floppers on my gun right? Well I didnt. It just kinda slipped my mind, or maybe I thought I was imune to the "bad flopper." Turns out im not!

Went diving yesterday in some of the most spectacular grounds I have seen here on maui. Swam out about a quarter of a mile, and we stumbled upon these huge underwater pinnicles. There was about 8 of them, all in the area of about 2 american football fields. These pinnacles rose from the bottom (between 70 and 80ft) to around 6-10ft from the surface. There were bait fish everywere. The diving was a little slow but exciting enough. Towards the end of the dive I found a school of Bigeye Emperor snapper (one of the hardest fish to get close to in Hawaii). Took a drop, and to my astonishment they came right in. Lined up a shot on what would be my biggest to date (10-12lbs) and click. Perfect shot right through the gill plate. As I began to swim towards him he "woke up" and started fighting, he swam right off the end of my spear.... my flopper never oppened!:head Upon closer inspection of my flopper back at the truck I noticed that it was getting stuck in the closed position. Come to find out my dive partner had noticed it earlier and neglected to tell me:vangry

Moral of the story? CHECK YOUR FLOPPERS! and adjust accordingly.

Another tune up you can do on your flopper is to get a sanding block and sand it smooth in a back and forth movement in line with the point of the shaft. This will reduce the resistance caused by steps at it travels through the fish

I use an ordinary hammer. Once I have the spear, flopper and pin resting on my vise I just start banging away lightly on the pin but constantly changing the angle of the hammer, burring it over into a dome shape. This also helps to avoid bending the pin. Had to make one from a bike spoke once.