These are the parts we'll deal with first. Extract them and break them down as shown. You will need the screw for the turret, the spring loaded indexer and the spring as well.
Let's cut up the turret's base first. Chop off the barrels, being sure not to damage the pivot point. Then we can begin chopping off the unneeded bits:
File the area the barrels will glue to flat. Note the "rib" that will sit between our barrels and the pivot point. Leave that a bit high for now. That "cross" of ribs needs to be the same diameter as the O.D. of our CPVC.
I drilled out the air holes to 5/16". I wish I had went with 3/8" now but sometimes it's better to leave a little extra material and do a little extra sanding later.
Now let's fit the barrels. I used 10" lengths. Square up the end that will meet the turret base carefully. Test fit it and check the alignment. My design has a small length of CPVC, close to the base of the turret, glued in place. We need to take that into account during test fitment.
Glue the barrels into place. I used superglue but epoxy is great too. Glue in the small barrel spacer CPVC at this point. It needs to be located forward enough to allow us to get a screwdriver in there. Don't glue a spacer on the end yet. Wait for the whole thing to cure.
Enlarge the holes in the back of the turret to meet the I.D. of the CPVC carefully. You may need to trim down that center post a bit later during the tweak phase.
After the glue cures we can fit a barrel spacer to the muzzle end. I used this as an opportunity to get it to point straighter. 2 of my barrels were very straight. I glued the spacer to the straightest one and let it dry. Then I glued the next straightest. Then I was able to glue the slightly out 3rd barrel to the now strong, straight 2 barrel assembly. After drying time I glued the "out" barrel to the other three using a piece of tape and bands to keep it in position.
Next let's work on the plunger tube section. The plunger tube is a damn fine match to the O.D. of 1/2" PVC. It fits snugly in a coupler. Cut it down to a depth that suits your blaster and coupler. You could replace the stock plunger tube section with 1/2" PVC. Take a small screwdriver and pry out the stock o-ring. Drill out the air hole to 3/8"
I am using an idea which princexbuster gave me for the seal. He suggested that craft foam would be great in an application like this to replace the stock O-ring. Sand the face of the plunger tube flat. I added 2 layers of craft foam, glued onto the face to act as a seal. Trim the excess foam along the sides.
Now we'll deal with indexing the turret. Sand the stock, spring loaded indexer flat as shown. Now we need something to glue to the face of this that'll index to the inside of our barrels. I used an orange plastic button. I sanded it pretty flat on one side and glued it to the indexer's face once it was the right dimensions. This is where your seal will be made or broken. The height of this indexer will determine the force applied to the seal. I test my seal by priming the blaster and then putting my finger over the end of the barrel, sealing it. Try not to add force to the barrel. Just hold your finger there. If the barrel holds air when you pull the trigger you are good to go. If all the air pressure leaks you need to keep adjusting the height of the indexer, or the tightness of the turret. You may even need to adjust the height of the craft foam depending on the thickness. One trick is to tighten the pivot screw quite tight the first time you assemble it with the craft foam seal. Leave it sit for a few hours. This will tend to compress the seal a bit giving you a more accurate idea of how to tweak the whole thing.
This is the final thickness that worked for me. Glue it up. I added an additional small spring to keep the turret level.
Add the screw to the center of the turret. It may be wise to add a drop of superglue to the screw hole here (after taking it apart) at some point to keep it tight during use. Mine is good so far.
In usage the rotation is quite smooth. The indexing works good. The seal is excellent. Surprisingly there is no wobble or play in it. The durability of the single fixing point and screw is not what I would like. It's not something I would want to drop hard on concrete. It's also not flimsy and will handle normal use. I will look into strengthening this.
Edited by iamthatcat, 21 February 2012 - 01:16 AM.