12 replies to this topic

[Aeromech]

Preface
As I have only recently began building homemade Nerf blasters, it is fitting that I share my first-time experiences with those in a similar position that may have less experience or know-how. This write-up marks the culmination of the lessons learned over two blasters before it, and represents an entry level Rainbow-pump blaster with a modified setup.

Additionally, this homemade guide does not necessitate the use of a drill press, hole saw, or mill. This write-up serves to prove that a new homemade builder can create a durable and reliable blaster using only hand tools. That being said, it is not easy, and those new to homemades should still proceed with caution. I have ample experience with crafting and tinkering, and I was able to figure this out pretty easily. Don't jump in headfirst. I try to point out my reasons behind doing things the way I do herein, and I can only recommend proceeding with a firm understanding of the system.

Credits to:
Ryan McNumbers for his Original Rainbowpump writeup

Stark and the Rainbow clan for the brilliant rainbow catch design

Daniel Beaver for hosting the catch templates.


Strap on those safety goggles and let’s begin. All descriptions shall be located BELOW their reference photo for this write-up.

Raw Materials
McMaster-Carr:
49035K86: Schedule 40 Clear PVC Pipe 1.25”
9562K46: Rotary Shaft Ring Seal, 0.95” to 1.07”
8541K18: Black Nylon Rod, 0.5”
9245K51: 2" OD Clear PETG
9637K26: [k26] Compression Spring, 11” Length
8574K28: Polycarbonate Sheet, 12”x12”x0.25”
96565K36: Catch Spring
4880K636: ½” PVC Wye

Ace Hardware:
1 Box Pan Head 6-32 Machine Screw, 3/4” Length
1 Box Flat Phillips 6-32 Machine Screws, ½” Length
1x Pan Head 8-32 Machine Screw, 1-½” Length
1x Pan Head 8-32 Machine Screw, 1-1/4” Length
1x #10 Washer
1 ft of 2” PVC Pipe
1x 1-1/4” PVC Tee Coupler
2 ft of ½” PVC Pipe
1x ½” PVC Ball Valve
2x 1” to ½” Bushing
1-1/2 ft ½” CPVC Pipe
1/2" of 1/2" CPVC foam insulator tubing
1x Tub of Silicone Grease
1x Tube Lithium Grease

Home Depot:
Plumber’s Goop (Couldn’t find it in Ace)

Walmart:
2 Cutting Boards
Packaging Tape
Craft Foam

Zumiez:
Skateboard Tape (optional, but it’s only $5 for a 4 ft sheet)

Tools
Safety Goggles
Safety Gloves; you’re laughing now but they’re damn helpful.
Hacksaw
Course File
Less-Course File
Rat-Tail File
Phillips Head Screwdriver
Tapping Wrench
6-32 Tap
8-32 Tap
Electric Drill
Set of Drill Bits
Countersink
Sandpaper
Gorilla Tape
Sharpie
Printer
Stick glue
Hot glue gun
Tiny bit of blu-tac
Table Vice


The Genesis of the Design


This is my first series of Homemade blasters, as the figure above illustrates. From bottom to top, the first, the second, and the third blaster in the series. This write-up focuses on the third, which takes the lesson learned from the previous two designs.


General Dimensions





Complex CAD drawings can be intimidating. Here are some simple drawings that outline the lengths of each large piece. Mechanically, I separated the Rainbow Pump into three sections: The “upper,” “lower,” and “pump,” and the plunger rod to reference later in the writeup. This design actually deviates from the original Rainbowpump design, but allows for new plunger tube assemblies, or “uppers” in this case, to be swapped out easily without having to fabricate a new handle.


Adhere the Bushing


Wrap both of the bushings in plumber’s tape until the bushings fit tightly in the 1-1/4” Clear PVC Pipe. Cut off the excess tape from each bushing. Set one aside.


Apply Plumber's Goop around the outer diameter of the Bushing and press it in there firmly. Be sure to perform this step outside. There's toluene in that shit.


This is how I allow the Goop to cure. I let it rest vertically for about 12 to 24 hours, to ensure that the goop doesn't drip out of one side. Maybe superstitious, but in any case keep the tube outside until the goop is fully cured.


The Rainbow Catch

Here are the templates for the rainbow catch, hosted by Daniel Beaver. Print out 2 copies. Make sure you click "actual size" and not "fit to page" when you print, otherwise your templates will be too small.


Cut out the templates, and a few squares of polycarbonate...


and glue them onto each piece using super sticky stick glue.


Stick it in your vice, and use your course file to trim each side right up the the black line of the outer circle on the template, but do not file away any of the black line itself, this actually represents material that is supposed to remain intact.


Now file down each corner to form an octagon, again trimming right up to the black line.


Use your file to blend together two of the adjacent sides.


The knife is pointing to the blended side. Repeat this blending on all corners to create a circular part.


Repeat this process of filing flats, then blending them together to all rainbow catch parts.


To create the hole in the catch plate, first drill out a 1/2 inch hole in the center of the plate. If the drill torques the part out of the vice, drill the largest diameter you can, and then ream out the hole to 1/2 inch diameter with your rat tail file. The bottom corners should be square. To create this effect, drill a small diameter hole, maybe 1/16 or 3/32 just inside of those corners. Then, use a knife to carve out the flats on the two walls and the floor of the catch plate.


Now you have the desired shape. Drill out the outer two catch plates, using a 7/32" drill bit for the outer holes. The center hole should also be 1/2 inch in diameter. Drill through and ream out if necessary.


Use a section of 1/2" Nylon rod to keep the outer holes of the outer two catch plates in alignment while drilling.


Drill and tap the bottom of the inner catch plate, first with a 7/32" drill bit, then a 6-32 tap.

TO TAP: Place a bit of lithium grease on the end of the tapping tool. Once the teeth of the tap have gripped the material, screw one turn forward, then one half turn back. One turn forward, half turn back. Repeat until the desired thread depth is achieved. The grease acts as a means of heat dissipation and ensures smooth entry. The backing out after each turn allows the built-up material inside the hole to clear out. I've broken a tap before by not following these rules.


After drilling both holes, leave the bit in one of the holes, and tap with the entire assembly in a vice. This will ensure the threads line up once the catch assembly is put together post-fabrication. Tap using the 6-32 tapping bit.


Screw together the two outer catches. Test fit in a piece of 1-1/4" PVC. That's the catch.


Plunger Assembly, Part 1

There are many plunger head designs out there, but I could not find just a "skirt seal" plunger head. Alas, I found it necessary to improvise. This plunger head yields a perfect or damn-near perfect air seal.


Take the second Rainbow catch template, and set up the two outer catch plates onto two pieces of polycarbonate. We are only using these templates for the outer circles this time. For the third piece of polycarbonate, trace around the inside of the rubber ring seal with your sharpie.


This time, file slightly inside of the lines, using the same technique as the catch to file flats, then blend. Repeat for the other outer catch template. The smaller traced template should fit snuggly inside the ring seal.


Drill and tap using a 1/8" drill bit followed by the 8-32 tapping bit through each polycarbonate disc. Use the template to center the hole on the larger two disks, and eyeball the center of the small one; the best way to do this, I've found, is to center a water bottle cap underneath this piece, and make a center mark based on the central divet of the bottle cap.


Screw on a large disk then the small disk onto the longer 8-32 screw. This larger diameter screw is used due to higher stresses that the plunger head encounters.


Slip on the ring seal, and then screw on the final large disk locking everything in place. There should be a firm force pressing the seal together from the outer two disks. The interior disk is used to keep the seal centered.


Cut the Nylon rod down to 11-1/16". File off both ends with the fine file, ensuring a flat surface on each end of the rod.


This is the catch notch in the fully assembled blaster. The front is sloped at 45 degrees, and the rear wall is vertical. When the blaster is primed, the spring exerts a force forward on the plunger assembly. the catch is "caught" in that little notch, and basically gets in the way of the plunger rod, stopping it from moving forward. When the trigger is pressed, the catch is pushed upwards and out of the way of the plunger notch, allowing the plunger assembly to slam forward with the force of a thousand laser beams. The notch itself should be about 1/3 of the diameter of the rod.


Drill one end about 1 inch deep with a 1/8" drill bit, then tap with the 8-32 tap.


Screw your plunger head onto your plunger rod.


Blueprinting the Body Tube


At this point, your goop is likely dry. Trim off any extra goop that protrudes outside of the diameter of the clear PVC. No need to trim the rest.


Measure out 11-1/2" from the front of the clear PVC and make a mark on the PVC. Using your gorilla tape, wrap around the tube at the mark, and trace around the tape.


When the tape is removed, a circumference of distance 11-1/2" from the front of the PVC remains. This allows for clean placement of screws in the blaster.


Make four marks around the front of the blaster. These marks can be accurately placed using the hexagonal bushing to locate the marks; one on each of two opposite corners of the hexagon, and one on each of two opposite sides of the hexagon.


Using gorilla tape again, stretch the tape from the mark to the opposite end of the tube. Ensure it's straight, then draw a line from front to back on each of the four marks.


Mark a circumference about 1/4" from the rear of the PVC bushing. There are now four points of intersection between this ring and the four straight lines. Drill 7/32" holes on each of these points.


Countersink these 4 holes so the opening is the same size as the head of the flat headed 6-32 screws. Screw them into place. Tapping here is optional, only because the PVC is so soft. If you are having difficulty in securing the screws, by all means tap the holes with the 6-32 tap. The heads of the screws should be approximately flush with the PVC tube.


This is where the catch shall go inside the PVC tube. On the left hand side is the circumference where the forward-most catch plate will rest. Make a mark between each of the straight lines on this circumference. This is where screws will eventually anchor the catch to the PVC tube.

The mark on the right is made 1/2" to the rear of the catch circumference. This marks the extrema of the slots.


Slots


Start by drilling many small holes down the 2 lines on the sides of the blaster, beginning from the previous mark just behind the catch circumference. These slots will eventually extend all the way to the rear end of the blaster, but this method seems to make for straighter slots, as opposed to simply hack-sawing from the rear of the blaster to cut out the channels.


Widen the holes to about 7/16 wide. If this diameter is not achieved, there is no need to worry....


The slots will be widened using the file. The gorilla tape initially protects the rest of the PVC tube.


When finishing the slots, draw a line using this gorilla tape on each side of the holes. CAREFULLY file up to these lines.

Edited by Aeromech, 23 November 2015 - 01:32 AM.

[Aeromech]

Ensure that these tape lines extend all the way to the rear of the PVC tube...


And cut out the remaining material with a hacksaw. File smooth the edges of the slot.


Plunger Assembly, Part 2


Cut out about 1/4 inch of the insulation foam.


Use hot glue to unite the seam


This is one more piece that requires the fabrication techniques described in the catch section, however this piece does not require any sort of precision. It simply serves as a guide for the pump (which will be created shortly.)


The only requirements for this piece are that it fit inside the Clear PVC and plunger rod, and that the "wings" that protrude out of the slots fit snuggly inside the PETG that will make up the pump, as shown.


Drill for 7/32", then tap for 6-32 screws at the center of each of the wings.


Focusing on the back of the plunger tube, drill and tap for the remaining 1-1/4" 8-32 screw.


Drill a small through-hole on the side of the plunger rod, about 3 inches from the end. A 3/32 bit will be sufficient. Save this drill bit.


Cut out a polycarbonate rectangle, 1/2" tall and about 2-1/2" wide. This will be the priming rod that the pump will push back.


Drill and tap for the 8-32 1-1/4" screw. Put the #10 washer over the screw before screwing it into place.


Make a plunger-kebob. The order of said kebob is, from the front, [k26] Spring, Rainbow catch, Foam Insulation, Winged Pump Part.

Several things to note: The 3/32 drill bit is holding the [k26] spring forward. The heads of the screws on the catch are facing rearward. If they were facing forward, the screw heads would interfere with the spring.

The foam insulation tube we cut out earlier serves to soften the impact of the pump when the finished blaster is being pumped. The winged pump piece will hit this foam and not more polycarbonate or the screws sticking out of the catch.


Screw on the priming bar, ensuring that the bar is parallel with the floor of the catch notch on the plunger rod. The purpose of this priming bar is not just to prime the blaster, but also to keep the catch notch level with the catch itself. If the plunger rod was not guided by the priming rod, the plunger rod, being cylindrical, would rotate, and fail to engage the catch. The plunger would not lock back.

The plunger internals are now captive.


To add some padding to the plunger head, apply some stick glue to the head face.


Cut out a disk of craft foam and press it against the plunger head. No padding means that two harder materials will slam together every time the blaster is fired. The padding helps preserve the life of the blaster.


Securing the Internals


Remove the drill bit from the plunger rod and slide the plunger-kebob into the PVC tube.


Push the catch forward so the forward catch disk is aligned with the marked circumference. Drill a 7/32" hole through the PVC and into the Polycarbonate disk being careful not to drill into the nylon rod. Temporarily secure the catch with a 6-32 screw. Drill and tap the hole opposite the temporary screw for a 6-32 screw. Repeat for the two remaining marked areas. The screws should form an "X" in the catch disk, that is, the screws should be diagonal not vertical or horizontal.


One at a time, remove one screw from the catch, countersink, and then replace the temporary screw with a flat headed 1/2" 6-32 screw. Repeat for so all four points are secured with flat screws, flush with the PVC tube.


On the bottom of the catch, the hole drilled in the central catch disk should be visible. Drill a 9/64 hole through this region, making sure this new hole in the PVC is in line with the previously drilled hole in the catch. Do not drill into the catch.


Screw a 6-32 screw into this hole with a small piece of catch spring over the screw. The catch spring should rest on the head of the screw and the body of the PVC tube. When screwed into the catch, the spring is constantly pulling down on the catch, so when the notch on the plunger rod interfaces with the catch, it is secured in place by the force of this small spring. When this screw is pressed up, the catch releases the plunger rod and the plunger flies forward.


Trim off the excess material on the priming bar... the bar should fit inside the 2" PVC without any collision. Also note the secured screw and spring at the top of the photo.


Remember that extra taped bushing from earlier? This will be the piece that maintains the shape of the PVC now that the slots have been completely cut through. Secure this part using the same technique as the catch plate: 4 flat headed screws in a diagonal fashion, all countersunk to be flush with the PVC.


The ring of screws securing the catch mechanism is 9-1/4" away from the rear end of the PVC tube. 9-3/8" would also work. This measurement is important only in the final assembly: when the "upper" and "lower" assemblies are connected, this dimension is necessary for the trigger to properly interface with the catch screw. More on that later...


Here, the screws securing the rear bushing are evident. If you trim your PVC tube a bit too short, (as I did in this case,) simply file away at a bit of the PVC tee, as marked on the tee.


When the rear of the tube is eventually secured in the PVC Tee, this bushing will not interfere with the connection, as seen above.


These are "speed holes." Ignore the weird design, basically just drill three holes 3/16-5/16" wide IN FRONT of the catch mechanism, to stop the formation of a vacuum behind the plunger head. Without these holes, a vacuum can form behind the plunger, drastically slowing down the plunger.


The Pump


"Blueprint" four straight lines down the length of the PETG/Polyester tube to mark the quadrants of the pump.


Mark the slot on the bottom rear of the pump tube, IT should be about an inch wide.


Drill holes at the corners of the slot. Round corners distribute stress far better than sharp corners. This drilling ensures that the pump will not fail under stresses at this point.


Cut out the slot with a hacksaw.


Repeat this corner drilling technique for the front of the pump, and hacksaw away the top half of the forward part of the pump.


Here is the pump with the aforementioned cuts, view from the bottom-side.


Drill and 6-32 holes that align with the hole in the pump piece in the plunger assembly. Leave about 1/8" of space between the pump plate in the plunger assembly and the rear face of the pump. We want the pump itself to push back the priming bar, not the pump plate in the plunger assembly. Countersink these holes.


Test fit into place with the flat headed screws.


The winged "pump plate" serves only to guide the pump. The big hole in the center of the pump plate is to allow the plate to glide over the plunger rod without any resistance. Because the wings fit into the slots on the body tube, the pump cannot rotate, being affixed to the winged plate with screws. Additionally, your pump can now only move forwards and backwards the distance that the slots will allow.


Cut out a piece of the skateboard tape to match the front of the pump...


And secure it to the pump. The skateboard tape already has adhesive, so just press it into place. When everything looks good, secure the pump to the pump plate, locking the pump in place with the rest of the "upper."


Constructing the Lower


Secure the 2" PVC over the PVC tee with gorilla tape.


Drill, tap and countersink the top and bottom of the tube-tee assembly. Remove the gorilla tape.


Cut out this small notch on the bottom front of the 2" PVC tube. This is where the spring-screw from the plunger tube will stick out.

Edited by Aeromech, 09 May 2014 - 11:06 AM.

[Aeromech]

Just like this.


Back out both the top and bottom screws on the lower, and slide the "upper" 1-1/4" PVC tube all the way into the PVC tee. Remove the top screw and drill through this hole through the 1-1/4" PVC lower. Screw the top screw all the way into the tube, securing the upper to the lower. Repeat this process with the bottom screw.


The Barrel Assembly


Take a 2" segment of 1/2" PVC and hammer it into your wye. Drill a 7/32" hole into the rear of the wye, securing the PVC segmentm with one of your 6-32 screws.


This screw prevents darts from being sucked into the plunger tube. When the plunger is pulled back, a vacuum is created, pulling darts into the tube. This screw gets in the way of that, so no darts will be lost in the blaster's insides.


This is a 16" piece of 1/2" CPVC hammered into a 3" segment of 1/2"PVC. This is your actual barrel.


Using a knife, bevel out the inside edge of the PVC-CPVC barrel, allowing darts to more easily be pushed out of the barrel.


Here's the final assembly. Load the darts in through the top ball valve. The "magazine" is just the diagonal 1/2" PVC tube; the darts fit loosely in here. This one is actually a bit longer than I like it; the longer your hopper magazine, the lower your ranges will be. When firing the blaster, air pressure forces a dart forward and out through the barrel.


The Handle

Here is the technique I use to make handles. Everyone's hand is different, but below is the general shape I used, that changed over the course of the trimming. The handle consists of three plates of cutting board, screwed together to increase thickness.


Start by tracing out a basic shape onto your cutting board.


For hard to reach posts, use your drill with a large diameter bit to make sharper corners.

Saw out the general shape, then use your files to trim the part down to your desired shape.


Trace around the completed section twice. The handle will consist of 3 sheets of cutting board screwed together.


Modify your two "outer" plates to include the extensions on the top. These will hold the trigger in place. Roughly cut these shapes out.

Screw together the three pieces with 3/4" long 6-32 screws, your can make a faux-countersink using a 5/16" drill bit and drilling in only 1/8 to 3/16 of an inch. This sinks the screw heads in so it doesn't hit your hand, and this technique save you from buying a whole new set of screws.


File down the edges of the handle to be flat...


Then bevel the corners. From here, blend together the edges to round them out with the course file. The final shape is largely determined by feel.


File out the top plane with the round part of the course file. This creates a plane that is concave-up and will better interface with the body of the "lower;" two round surfaces will connect at opposed to one round and one flat.


Make a mark on the "lower" the location of the trigger screw.


Take a scrap piece of polycarbonate and trace out the shape of the internal section of the trigger, it should be roughly semicircular.


Just like that.


Drill though the rotation point with a 7/32" drill bit.


Insert a small screw into the trigger as shown, then ream out the rotation hole with a 9/64" drill bit. This allows the trigger to rotate freely.


Drill a hole, perhaps 5/16" diameter, into one of the sides of the handle.


This, with the small trigger screw we just inserted, will create a captive trigger; it has a limited degree of rotational motion, and cannot spin all the way around.


Drill all the way through the rotation holes on the assembled handle with a 7/32" drill bit, so a 6-32 screw will fit in there.

Next we need to spring-load the trigger so you can be like all the cool kids.


Drill one of your small screws into the base of the center plate of the handle.


Drill your last small screw into the trigger.


Inserting a small piece of catch spring, held captive by the two small screws, will yield in a spring-loaded, captive trigger.


Drill and tap a hole at the rear end of the trigger, and insert a flat-head 6-32 screw in there.


Mark on the handle the location where the catch screw and the trigger screw will connect. The flat-top screw we previously added to the trigger allows the trigger to hit the catch screw with a little more surface area, and also prevents the metal of the catch screw from wearing down the polymer polycarbonate of the trigger.


Attaching the Handle


Back out the two "lower" screws, and remove the "upper" assembly from the "lower."


Line up these marks on your "upper" and handle.


Mark at least two places on the bottom of the lower assembly where you want to screw in the handle.


Drill only one of the holes into the top of the handle. Make sure you drill deep enough to secure a 1-1/4" 6-32 screw, so use a 7/32" drill bit. Here, I used a tiny piece of blue-tac to hold the screw into place on the head of the screwdriver.


Screw in the screw partway into the handle. To reach the screw, you will have to drill two holes at the top of the upper tube to align with the holes you wish to use to screw in your handle. A 5/16" drill bit should do the job. The location of these holes are not critical, they just need to be over the handle attachment screws and be large enough that the screw head can fit in there.


Screw in the bottom screw just until a mark is formed.


Tough to see here but the screwing action you just did creates a small dent in the soft polymer of the cutting board. This gives you an exact location for your next drilling action. Once this is done, screw the handle completely onto the lower assembly.


Mine's a little crooked but who's counting?


Bam.

Results
->Now you have a cool blaster that can absolutely compete with the big guys.
->The separable upper and lower assemblies allow for a near universal use with every blaster of this type: you can mix and match any upper to any lower so long as the trigger screw and catch screw line up, and the two rear screws are in alignment.
->This plunger yields a perfect air seal. This is the second time I have achieved such results on a blaster.
->No ranges but the thing hits hard. From 20 feet I cracked the clear cover plate of a plastic clock I was aiming at using slugs.


Killin' Time.

Additional Notes
Damn this thing requires some elbow grease. Fabricating Polycarbonate with man-power is absolutely possible, but it is not easy. This method is meant for newer builders or those without machines to get their feet wet in the hobby.


Threw on a sub-optimal paint job. Will definitely be warring with this blaster, I am totally in love with her.

Now go make a gazillion slug darts.

Post away! I look forward to questions, comments, etc.

Edited by Aeromech, 09 May 2014 - 01:25 PM.

[Thorn]

Nice writeup! I'm sure it will be helpful for newer builders to have a writeup of a rainbow pump that only requires a drill and various hand tools. However, I'm sure there are more exact ways of finding the center of the polycarbonate disk on the plunger head then eyeballing it. There are many rules for finding the center of a circle, and if you trace the outside of the circle on a piece of paper, then find the center on the paper, you can then mark the center of the disk because the polycarbonate is clear. Also, I might of missed something, but it seems to me that you are relying solely on the force of the screw from the priming bar to keep the plunger rod in place. As the screw begins to loosen, the plunger rod will rotate, making the blaster not catch. Other than that, the pictures and instructions are clear, and it is overall a great write up. Good luck in the contest.

Edited by Thorn, 07 May 2014 - 11:36 AM.

[Daniel Beaver]

Looks really good.

[Bchamp22795]

Strong write up! Very easy to follow.

The blaster itself looks excellent for being made with hand tools and a power drill. I also like some of the variances you made on the original design. I think I'll have to get a few nice files now. Keep up the good work.

[Exo]

That must have taken a while with no power tools.

[Meaker VI]

Good work showing what can be done *without* many power tools. One thing though; if you've got a drill, how hard is it to get a couple of hole saws for disc cutting? I think I got my set at sears for like $15, and I'd gladly pay that for not needing to do all the work you do to get discs.

[Aeromech]

I'm sure there are more exact ways of finding the center of the polycarbonate disk on the plunger head then eyeballing it.

...it seems to me that you are relying solely on the force of the screw from the priming bar to keep the plunger rod in place.

Thanks! Edited the write up to reflect this. And you are correct. If it does loosen up, all it takes to re-tighten it is a screwdriver to the plunger head and rotating it couple of degrees. I would rather not use adhesives and be able to change my design in the future if I see fit than lock the thing down permanently. After all, I'm still learning and I want to try out some ideas in the future.

That must have taken a while with no power tools.

You betcha. Took me three days to complete.

Good work showing what can be done *without* many power tools. One thing though; if you've got a drill, how hard is it to get a couple of hole saws for disc cutting? I think I got my set at sears for like $15, and I'd gladly pay that for not needing to do all the work you do to get discs.

I got the correct diameter hole saw from Ace hardware, and was super excited to use it, knifed through the packaging and discovered my beautiful hole saw shank was too large to fit in my wimpy 3/8" drill chuck. So I adopted this method instead of searching for such a device.

Edited by Aeromech, 07 May 2014 - 07:10 PM.

[Thorn]

Have you considered making an omnidirectional catch notch to create even wear and avoid having to worry about the plunger rod turning out of place? Ryan's omnidirectional plunger rod from his Rainbowpump rev. 2 and Daniel Beaver's omnidirectional catch notch (he posted it in the original rainbow thread) are both good options that can be built easily with your tooling.

[Langley]

Nice! Hand-made rainbow pump is not an angle I anticipated, but it's a cool idea.

Couple of notes about the write-up:
The diagram is the last time many of the measurements are brought up, particularly the distance of the catch from the plunger head. Might be worth duplicating the diagram where appropriate or throwing in an extra photo or two.
The purpose of the winged piece is a little unclear, mainly because I think you skipped the steps where you drill the pump sleeve and screw it into the winged piece.

[Aeromech]

Have you considered making an omnidirectional catch notch to create even wear and avoid having to worry about the plunger rod turning out of place? Ryan's omnidirectional plunger rod from his Rainbowpump rev. 2 and Daniel Beaver's omnidirectional catch notch (he posted it in the original rainbow thread) are both good options that can be built easily with your tooling.

This design doesn't really require an omni-plunger rod. Should the need arise to meet some future design requirement, then I will absolutely make use of one. But such plunger rods for this type of blaster just add an extra unnecessary step.

Nice! Hand-made rainbow pump is not an angle I anticipated, but it's a cool idea.

Couple of notes about the write-up:
The diagram is the last time many of the measurements are brought up, particularly the distance of the catch from the plunger head. Might be worth duplicating the diagram where appropriate or throwing in an extra photo or two.
The purpose of the winged piece is a little unclear, mainly because I think you skipped the steps where you drill the pump sleeve and screw it into the winged piece.

Thanks! I will update the writeup when I get home tonight, the thing's super easy to disassemble. Looking forward to using it next weekend.

[Brad]

Thanks for the write up this will be my first homemade blaster and I might have some help from a friend that makes very nice homemades