8 replies to this topic

[T da B]

Sup guys,

I'm about halfway through my first homemade, a Ryan-style RainbowPump, and I've stumbled upon a startling realization. Upon studying the write-up, it seems like once the blaster is assembled there is no way to remove the plunger rod. Seeing as the front bushing/coupler will be solvent welded, the only way to remove the plunger rod is through the back. Unfortunately the internal coupler blocks the Rainbow Catch from sliding out the back, and the screws to remove the internal coupler are blocked by the plunger rod.

One of the design paradigms I swear by is modularity--all my blasters can be easily taken apart and maintained after they are built. I can't see any way to get the plunger rod out without drilling holes through the plunger rod, or drilling new holes in the plunger tube to hit the handle screws at an angle. Solution #1 might compromise the integrity of the plunger rod and solution #2 (aside from seeming impossible) would be a nightmare when putting the screws back in. Attaching the handle to the plunger tube with set screws would never hold up in the long term. Perhaps some of you guys with more experience than me can chime in--is it a design flaw or is there something I'm missing?

~T

[quertyman]

Why did you use a internal coupler? it is not necessary in any way. The reason ryan used it (I think) is because it would make it easy for him to use his mill to cut the slots out. Just read over a couple of times. It is most definitely a design flaw.

EDIT: I have found the solution! Unscrew the plunger rod from the front and pull it out. That is if you screwed on the plunger head. If you used the same technique ryan did on the plunger head you are not in good luck. Once the plunger rod is out you can just unscrew the coupler and disassemble. This whole deal seems like it came out of nobody using his exact design until now.

Edited by quertyman, 05 November 2013 - 08:22 PM.

[Exo]

Erm, you could also just use screws on the front bushing instead of solvent-welding it into place.

[quertyman]

Erm, you could also just use screws on the front bushing instead of solvent-welding it into place.

He was planning on doing that then solvent welding it in place to get 100% seal. I actually used liquid epoxy to make mine seal and only after I did that did it seal perfectly.

[T da B]

EDIT: I have found the solution! Unscrew the plunger rod from the front and pull it out. That is if you screwed on the plunger head. If you used the same technique ryan did on the plunger head you are not in good luck. Once the plunger rod is out you can just unscrew the coupler and disassemble. This whole deal seems like it came out of nobody using his exact design until now.

Good call! Fortunately I haven't built the plunger rod yet, so I think I'm all gravy.

~T

[Ryan201821]

Don't solvent weld it. I used a piece of the internal coupler to use as the bushing. It sealed perfectly inside the tube so I didn't need to glue it. The bushing does need to be removable to take out the plunger rod, handle, pump handle, etc. It'll be completely awful if it's stuck there forever. You'll have to do black magic to get your blaster to come apart unless you're planning on doing some variations.

If you aren't using internal couplers, you want these. They are 1 x 1/2" round reducing bushings. The lip on the front can be slightly hammered inside 1 1/4" to seal perfectly. You can optionally add tape to the outside diameter below the lip, and seal it that way as well.

I've been doing this for years and it works quite well, is cheap and easy. The trick is finding them. I've only known for them to exist at Home Depot. Their online store also shows a hex version, don't get that one. It also has a separate page for the round ones, so maybe it's a specific manufacturer that sells the round version.

[T da B]

Thanks for the info, Ryan. I suppose I'll hold off on using solvents and see how good my seal is--I'm using the same internal coupler specified in the writeup. Even if I do have a leak, I can probably just plug it with something that isn't permanent, like hot glue.

~T

[quertyman]

The bushing does need to be removable to take out the plunger rod, handle, pump handle, etc. It'll be completely awful if it's stuck there forever. You'll have to do black magic to get your blaster to come apart unless you're planning on doing some variations.

Their online store also shows a hex version, don't get that one. It also has a separate page for the round ones, so maybe it's a specific manufacturer that sells the round version.

But it doesn't if you just unscrew the plunger head. Why did you do what you did when making your plunger head ryan? It seems overly complicated and unnecessary, was there a reason for this?
And was I right in saying you used 2 separate body pieces so you could use your mill for the slots?

Also, hex bushings work just fine. You just have to dremel them a little to get them to work is all.

Edited by quertyman, 06 November 2013 - 06:30 PM.

[Ryan201821]

But it doesn't if you just unscrew the plunger head. Why did you do what you did when making your plunger head ryan? It seems overly complicated and unnecessary, was there a reason for this?
And was I right in saying you used 2 separate body pieces so you could use your mill for the slots?

Unscrewing the plunger head is a lot more work in my opinion. In my case specifically, it's not even possible to detach it inside the plunger tube. I'm not sure how you see how it's overly complicated. It's just three different sized tubes nested inside of each other. Much easier than cutting discs out on the scrollsaw. It literally takes two minutes to make the plunger head. I also think the attachment method is better having the screw perpendicular to the plunger rod instead of the threads holding the entire load of the spring, like when using the traditional three disc plunger head. This was one of the many flaws with +bows and eventually would strip and cause the plunger head to fall off over time.

You're right about why I have two pieces for the plunger tube and slotted piece. It's much easier to do on the mill. Having two tubes also makes installing the Rainbow catch a whole lot easier.

Also, hex bushings work just fine. You just have to dremel them a little to get them to work is all.

Sure, but you're missing the point entirely. The front lip on the round bushings fit and seal perfectly inside 1 1/4" without any dremeling.