Tired of waiting for someone to massage my back, I decided to build this massage device .

This PVC Back Massage Device simulates the massage as if it were done with the thumbs. It also moves up and down.

This device consists of several parts, so I will treat each part separately and at the end I will put all the parts together.

The English language is not my first language, so I will try to be as clear as possible ...

I hope you enjoy it as much as I do ....

Step 1: TOOLS & MATERIALS

MATERIAL:

PPR CONNECTORS:

PPR ELBOW 45 - 25mm (2 pieces)

PPR ELBOW 90 - 25mm (4 pieces)

PPR TEE REDUCED 25-20-25 (2 pieces)

PPR COUPLE 25 - (2 pieces)

PPR TUBE: 20 & 25 mm

PVC CONNECTORS:

TEE 3/4" SCH 40 - (26 pieces)

ELBOW 3/4" SCH 40 - (16 pieces)

CROSS 3/4" SCH 40 - (4 pieces)

COUPLE 3/4" SCH 40 - (4 pieces)

END CAP 1" SCH 40 - (3 pieces)

BUSHING 1" - 3/4" SCH 40 - (7 pieces)

TEE 1" SCH 40 - (4 pieces)

COUPLE 1 1/2" SCH 40 (1 piece)

BUSHING 1 1/2" - 1" SCH 40 - (1 piece)

PVC PIPE SCH 40: 3/4" & 1"

PVC Cement

PVC Cleaner

BOLTS & NUTS:

THREADED ROD 3/8" x 920mm

BICYCLE CHAINWHEEL 18 TH - (3 pieces)

HEX NUTS & WASHERS 3/8"

3/8" LP GAS FLEX HOSE (20 cm)

ELECTRIC MATERIAL:

Servo Tower Pro MG995 - (2 pieces)

Arduino ONE or NodeMCU or Raspberry Pi as Controller with Motor Control

Shield Battery Drill

TOOLS:

PPR SOCKET FUSION WELDING MACHINE

DREMEL

PVC CUTTER:

Step 2: "THE FINGERS"

"The fingers" are made of Polypropylene Random Copolymer (PP-R) pipe and fittings.

Pipes made from PP-R are lightweight, do not corrode, rust, or scale and they are joined via heat fusion for permanent, leak-free joints. It is more soft than PVC pipe and it is for this reason that this material was used to make "The Thumb", these pieces are designed to simulate the movement of the thumb when giving massage and are driven by a servomotor.

PP-R WELDING AND PROCESSING TECHNIQUES

Welding device and tool

1. Only welding devices and tools may be used for welding pipes.

2. Tighten up the threaded inserts for holding the tools in cold condition firmly with the Allen wrench and clean with a fibre free cloth or paper if necessary. Screw on the tools hand tight. They may not extend beyond the edge of the tongue!

3. Switch on the device. The thermostat lamp and control lamp must now light up. Set the thermostat to 260°C. The heating up process has been completed when the thermostat lamp goes out.

4. Tighten up the tools once again with the Allen key. Never tighten up a tool with pliers or other tools since this would damage the coating and could make the tool unusable.

5. The welding tools have to be mounted according to the diameters thus the edges do not loom over the heating device. Tools from diameter 40 on are always to be installed at the back hole.

6. Plug in welding device and control whether green operating lamp is switched on. The warm-up phase takes between 5 and 20 minutes depending on the outside temperature. The welding device is operational as soon as the orange lamp is switched on.

7. After the device has been switched off, wait until it has cooled down. Never cool down the device with water! Danger of injury! In addition electronic parts such as the thermostat could be damaged. Remove contamination with a fibre-free cloth or paper as well as alcohol if necessary.

8. The device may only be used when it is in a dry state. It must be stored in dry and dust-free conditions.

9. Proper functioning of the device can only be guaranteed when the tongue and tools are in perfect condition. Defective or contaminated parts must always be replaced. Defective or contaminated parts must always be replaced.

Preparations and operation
Before starting assembly, the welding tools have to be checked for impurities. If necessary, the welding tool needs to be cleaned by a non-fibrous cotton cloth or rough paper cloth and possibly also with spirit. While doing so, the Teflon coating of the tools must not be mechanically damaged.

Processing times, welding depths

1. Cut the pipe at right angles to the axis of the pipe (Use only Wefatherm by REDI pipe cutters or other suitable pipecutting wrenches!)

2. Remove any cutting chips and deburr the pipe.

3. Mark the welding depth with a gauge and suitable marker

4. Align the position of the fitting with the aid of the auxiliary marking on the fitting and the continuous line on the pipe

5. Insert the end of the pipe into the heating sleeve up to the marked welding depth without turning it and at the same time slide the fitting without turning it on to the heating mandrel up to the stop. Observe the heatingup time given:

25 mm : 7 seconds

20 mm : 6 seconds

IMPORTANT: Timing for the heating-up time should not be commenced until the welding depth on the heating sleeve or the stop on the heating mandrel have been reached!

6. At the end of the heating-up time, draw the pipe rapidly from the sleeve and the fitting rapidly from the mandrel and push them together immediately up to the point at which the mark indicates the welding depth, being covered by the bead that will have formed. During this process do not rotate pipe and fitting relative to one another.

IMPORTANT: In order to prevent the internal diameter of the pipe being reduced or in an extreme case to prevent the pipe being closed, do not insert the pipe too far into the fitting!

7. During the processing time keep the pipe and fitting in constant position relative to one another. (The parts which have been welded can still be aligned relative to one another during this phase but may not be twisted relative to one another!) The welded item can be fully loaded immediately with completion of the cooling time. This welding technique produces an inseparable union. The material of the fitting and of the pipe will have melted together with one another.

Step 3: "THE WRIST"

This piece is the support of "the fingers" and being supported by four rails, it allows to raise and lower the trajectory of the fingers.

This piece it is made of PVC pipe Schedule 40.

CUTTING PVC PIPE

CAUTION: Be sure to take breaks between frequent cutting to avoid hand fatigue.

STEP 1

Using a tape measure and a marking tool such as a pencil, mark the point at which you want to cut the pipe.

STEP 2

As you open the handles of the ratchet-style pipe, cutter, the blade will also lift. Open the pipe cutter handles completely, so that you can fit your pipe in between the blade and the jaw of the pipe cutter.

STEP 3

Hold the pipe one hand with the mark you made facing up, and slide the pipe between the blade and lower jaw. Place the blade of the pipe cutter on the mark and squeeze the handles until they come into contact.

STEP 4

Grasp the handle with pressure until it the blade meets the mark, then release the handle and repeat to use the ratcheting action. Continue ratcheting down onto the pipe until you are completely through the pipe and it separates into two segments.

CLEANING PVC PIPE

CAUTION: Be sure to use hand, eye and breathing protection when handling Acetone. While, unlikely, should you feel dizzy for any reason, leave the room and seek fresh air immediately.

STEP 1

Perform the cuts necessary for the PVC pipe segments. It is easier to work with smaller sizes and cut first, rather than working with large segments. You will want to work with each small section at a time, as you will need to act quickly before the acetone evaporates.

STEP 2

As mentioned before, work outdoors or in an open garage. Acetone emits vapors which are harmful and can cause dizziness or headaches. It may be best to use a respirator when working with Acetone, just as a precaution.

STEP 3

Before you begin, be sure to use gloves when handling acetone. You will want to use the heavy, yellow kitchen gloves, as the acetone will break down thin latex or nitrite (blue) gloves.

STEP 4

Apply an extremely small amount of acetone onto steel wool by tipping the acetone can into the steel wool pad. Do not use large amounts as it will carry it down the pipe and cause the ink to streak.

STEP 5

Rapidly work the surface of the PVC pipe in a circular motion. Concentrate on the areas of lettering and bar codes first, as the acetone will evaporate quickly. Act very fast as the acetone begins to evaporate when it meets with air.

STEP 6

Working quickly, immediately wipe away the ink and smears with a clean cloth rag until they disappear.

ASSEMBLING PVC

CAUTION: Be sure to perform all activity with PVC cement in a well ventilated area.

WARNING: The PVC cement method is permanent, and the PVC pipe cannot be removed from the fitting after 30 seconds. Be sure to perform a dry fit to ensure all pipes are cut correctly. Check to make sure your items are square immediately after seating, if required. PVC Cement Assembly Steps

STEP 1 (OPTIONAL)

An optional step is to clean the areas of the fitting and PVC pipe with a PVC cleaner or primer. This will guarantee a secure bond, and is recommended. Run the primer or cleaner dauber around the outside of the PVC pipe and the inside of the fitting.

STEP 2

Using the PVC cement dauber, found inside the can, apply a small amount of PVC cement to both the PVC pipe and the inside of the fitting. Apply the cement only to where the two will come into contact.

STEP 3

Quickly insert the pipe into the fitting, being sure that it is seated properly, to the point of impacting the detent. Check for squareness, if required and hold the pipe and fitting together firmly for 30 seconds.

STEP 4

Allow the pipe and fitting connection to set for at least 2 minutes before putting weight or additional pressure onto it. This will allow the chemical weld to cure. You can join other fittings within the structure while waiting for the cure time to complete.

CONSTRUCTION:

THE WRIST is formed by two symmetrically coupled parts.

Each part is composed by a PVC cross, on which the FINGER is inserted.

The PPR pipe of 20 mm fits inside the 3/4 "PVC pipe, so 3/4" PVC pipe rings are placed inside the ends of the cross, over which the 20 mm PPR pipe of THE FINGER will pass.

At the end of the Cross a structure formed by three TEE is placed.

The central TEE contains inside it a nut on which the threaded rod passes, converting the rotation movement of the bar in an upward and downward movement.

To the ends of this TEE is placed perpendicularly a TEE, on which the rail will pass.

Step 4: THE MOTOR

The Motor is responsible for transmitting the movement by means of a chain, to the cogwheels of the rails, allowing raise and lower the fingers.

The motor and the gearbox of a BLACK AND DECKER battery drill were used. The gear is of a bicycle gear wheel.

CONSTRUCTION:

Use an old electric screwdriver without the battery section. The motor body was fixed with epoxy to a 1 1/2" COUPLE.

Use a 2" OMEGA PIPE CLAMP to attach the motor to the support arm.

Step 5: THE RAILS

The rails are responsible for supporting and transmitting the movement from the motor to the wrist, allowing the movement of up and down the fingers.

CONSTRUCTION:

Step 1 (THE GEAR):
A gear is construed using the bicycle sprocket and a PVC 1" END CAP and 1" to 3/4" PVC reduction.

The bicycle sprocket is adjusted over the reduction by making three notches on which the sprocket fits.

At the end, epoxy glue is applied and the PVC END CAP is placed.

The center of the PVC END CAP is marked and a 3/8 "drill is made on which the threaded rod is fastened.

A small section of gas pipe is placed on the end of the threaded rod and on this a small section of PPR pipe of 20 mm is placed, which in turn is inserted on a small section of PVC pipe of 3/4" and all this assembly is placed inside the reduction.

The threaded rod is fastened with nuts to the assembly.

Step 2 (THE RAILS):

The structures of the upper and lower ends that support the rails and the threaded rod must be assembled.

The upper structure consists of a cross and two PVC TEE.

The PVC cross is placed at the center and a TEE is placed at each end.

On the PVC cross passes the threaded rod which has placed on its end the gear built in the previous step.

On the TEE are placed the rails that are formed by 20 mm PPR pipe.

The lower structure is made up of three PVC TEE, the one in the center holds the end of the threaded rod and the ones in the ends hold the rails.

On the ends of these structures is placed a TEE whose function is to fasten the rails to the rest of THE STRUCTURE(See Step 6).

The length of the rails is determined by the length of the threaded rod used. In this case, use a single threaded rod of 920 mm and cut it in half. When assembling the set gave me a pipe distance of PPR of 41 cm for each rail.

At the end a bit of PVC grease is placed on the rails and inside the TEE of the wrist.

Step 6: THE STRUCTURE

The structure is formed by PVC elements that join the various parts of the device. It is responsible for giving support and rigidity to the device.

I used an old tubular chair to assemble the structure.

CONSTRUCTION:

STEP 1:

A section of 1" PVC pipe is placed over the chair tube, and a TEE with a 3/4" reduction in the central part is placed at the ends of this pipe. On these reductions the pieces in a "C" form are coupled.

STEP 2:

Two 90 degree elbows are placed to form a "C" shaped piece and with this piece the structure is adjusted to the 1" PVC tubes that were placed on the chair tubes.