This page describes how to make your own Sea Diver bell similar to the 1970's Parker Brother toy
"Sea Diver". The Sea Diver toy includes a clear plastic bottle full of water with some gravel,
small plastic items and a yellow diving bell with claws on the bottom. When you squeeze the
plastic bottle, the diving bell lowers and the claws open. Release pressure on the bottle and
the claws close as the diver raises - hopefully with one of the items you were trying to bring
to the top.
The original toy
How it works
The diving bell contains a pocket of air. When the bottle is squeezed, the pressure within increases
and compresses the air in the diving bell allowing water to enter. When enough water enters, the
bouyancy decreases and the diving bell sinks. Release pressure and the air pushes the water out causing
the diving bell to rise.
The claw mechanism works by way of a small float within the bell that raises as the water enters
thereby pulling the claws open. Water exits, claw closes.
Considerations in construction:
When constructing the diving bell, there are several points to keep in mind.
Everything should be a little loose and the float should not be tight within the housing.
Too tight and the water entering the diving bell will stick the float to the sides.
The pivot points on the claw arms should be as close together as possible so that the connections to
to the float can also be as close to center as possible. Too wide and the float slips off
the claw. For that reason, the pivot axle for the claws is mounted on the outside of the
bend rather than the inside. This matters a lot so make sure to pay attention to this point.
The float should be as low as possible within the diving bell.
The diving bell requires a balance between the bouyancy and weight. You can either use
brass screws with washers or a copper ring. Getting the weight right with the copper ring
can be tedious while the screw and washer setup allows for easy adjustment of the weight.
Length of 3/4" clear acrylic tubing.
Length of 1/2" clear acrylic tubing.
1/16" sheet styrene.
Thinnest sheet styrene from Plastruct. Not sure what the thickness is but you can probably
get away with using the 1/16" and just file it down or maybe leave it at 1/16". This is for
the float and the goal is to keep it as low as possible.
Liquid glue for styrene. The kind that you brush on.
Length of 20 guage copper wire.
Weight. Either two 6-32 x 3/16" brass screws and #6 brass washers or a piece of 3/4" copper pipe.
The tubing is sold in 1' lengths at Tap Plastics and the 1/16" sheet styrene can be found there too
in the scrap bin. You barely need any. Tap also has the glue. They may also have some thinner styrene
but if not, a hobby store should have a Plastruct display with the sheet styrene and some other pieces
you can use to dress up the diving bell.
Wide flat file. Wide enough to file ends of 3/4" tubing.
Small file set. I used the flat, square and round files.
Hack saw. This is to cut the tubing.
Needle nose pliers.
6-32 tap if using screws for weights or tubing cutter if using copper pipe. If you don't
have a set, you may be able to just screw into the plastic directly. The styrene is fairly
Helpful if you have them:
Helping hands to hold wires while soldering.
Dremel with cutting wheel and sanding wheel to cut screws and flash on plastic caps.
Small digital scale for getting weight just right (mostly if using the ring weight).
Layout the base of the diving bell. First cut a small piece of the 1/16" styrene
that's about 2" sqaure. Make sure there is at least one corner with a true right
angle. Use your square to draw a crosshairs. Center two circles over the crosshairs.
These should be the inner and outer sizes of the 3/4" tubing. Mark ends of what will be a
centered 3/8" slot for the claws. If you are using the screws for weights, draw another couple
3/8" centered marks on the other line for the screw holes.
Drill the holes in the base. To make the slot for the claws, use the point of your small
rat tail file to make a series of set points between the two end points of the slot.
Make sure that these are not too close together since the drill will wander. Drill the
holes with a 1/16" drill bit. Use the hobby knife to remove some of the material
between the holes then use the small flat file to finish the slot. If you are using the
screws as weights, set the points and drill with a #31 bit then use your 6-32 tap
if you have one. If not, try the screws without the tap. Maybe drill a slightly bigger
hole if needed.
Cut the tubing. Cut a 1" length of the 3/4" tubing and file the ends as flat as possible
with the large file. Cut a 3/8" length of the 1/2" tubing and file as flat as possible.
Make the claws. Strip some of the 20 guage copper wire and make 2 1" lengths and 2 1 1/2"
lengths. Using your best method - I used the helping hands - align one long and one short
piece into a cross shape leaving about 1/2" at the top of the 1 1/2" piece. Every end will
later be trimmed so the exact placement isn't critical - just try to make it as square as
possible. Now, solder at the joint then file the excess solder from the shorter pieces as
this will be the pivot point. Use the edge of the needle nose pliers to bend a right angle
on the long end for the claw and on the other end for the lever.
IMPORTANT: Make sure that the pivot point is on the inside edge of the bend.
If you use the exact length
of the pliers, for the claw end, you will have the same length when you do the other arm.
Using two pieces of 1/16" styrene glued together, make a small thickness jig to cut the
pivot points of the claw arms and the claw hooks to approximately 1/8". Trim the lever
end of the claw to roughly 1/4". This will be trimmed later once installed. Repeat this
entire process for the other claw arm.
Make the bushing for the claw arms. For these two pieces, you want to create two parts
with holes at the edge just large enough to hold the claw arms but allow them to pivot freely.
The holes should be 1/8" apart. First choose a piece of 1/16" sheet styrene and file the
edge of the sheet to be nice and square. This edge will be glued to the base. For now,
keep this piece fairly large and don't bother trimming it just yet as it's easier to
handle the larger piece. Mark off two sets of 1/8" wide marks and either drill each hole or
slot with a file. I don't have the exact size drill bit so I drilled with a smaller bit then
filed to size. Check the holes by butting the piece up against a flat piece with the claw pivot
in the hole. Once it can spin freely in each hole, that hole is big enough. Once all holes
are the right size, trim the pieces closely on all sides.
Install the claw arms. Place the claw arms in the slot then position one of the bushing over
them, center and glue. As quickly as possible, insert the other once and adjust so that the
claws open relatively evenly. Keep pressure on the pieces while drying and move the claws
while drying in case the glue has melted the plastic at the pivot points. Using the inner
circle as a guide, trim the lever side of the claw arms. Test by positioning the 3/4" tube
over the base. The claws should open and close freely. If not, trim as necessary.
Create the float. Cut 2 1/2" square pieces of the thinnest material you have and glue
them to either side of the 1/2" piece of tube cut in the above step. Once dry, trim the two
pieces close to the edges of the tube with either an Exacto knife, wire cutters or my favorite,
the cutoff wheel on the Dremel. Then file the flat pieces flush to the tube with the large
flat file. Next, cut 4 1/8" x 3/8" strips and glue them upright on the rouded sides of the
float you just made. Once dry, round them off with a file enough so the float fits inside the
3/4" tube. The fit should be pretty loose to avoid binding once water enters the tube.
Mount the float. The float mounts loosely to the claw arms with two small pieces
of plastic with a notch to allow the claw arm to slide through. Make these pieces much like
you made the bushings for the claw arms just with one hole each. Space them just wide enough
to fix around the pivot arm bushings. Not too tight so that they bind up but not too loose so
that they allow the claw arms to slip out. Glue the first one to the float then carefully
position the float onto the claw arms and the other piece. Adjust the float and the other piece
then glue the piece in place. Double-check the positioning as it dries and adjust as needed.
Close up the diving bell. Cut a 7/8" square piece of the 1/16" styrene and glue it to one
side of the 3/4" tube. Trim with a knife, wire cutters, Dremel, etc. then file flush with the
large flat file. Place the tube over the float and claw assembly and position it on center.
Holding the top of the housing tight to the float and claw assembly and turn it upside down back
and forth to make sure the claws and float easily open and close. Re-position if the edges of the
claw arms are hitting the sides of the tube. Once satisfied with the positioning, glue the housing
to the float and claw assembly. Once dry, trim and file the base of the float assembly.
Weight the diving bell. The weight needs to be just right. Too little weight and you can't
squeeze hard enough to get the bell to lower. Too much weight and it won't be able to pick anything
up. You can either use two brass screws and some washers or a ring of copper pipe. The easiest way
to get the weight right is to use the screws and weight because you can just add and remove the
washers. The copper ring looks a little better though. The brass screws will probably need to be
cut unless you can get some really short ones. Do this with a vice and a hacksaw or the Dremel
and cutoff wheel. What I like to do is thread the screw onto a nut and hold the nut with the vice
for cutting. The copper ring is made out of 3/4" copper pipe used for house plumbing. First cut
a ring about 1/4" with a tubing cutter. Then you will need to cut about 1/8" out of the ring so
that you can make the diameter a little smaller so that it eventually clips to the diving bell.
Attach the weight and test the bell. Adjust the weight as needed by either changing the number of
washers or filing down the copper ring.
Finishing touches. One thing you may also want to do is fashion a small loop at the top
of the bell like the original has. Occasionally the bell gets water-logged and stuck on the
bottom. It's much eaiser to get out if there is a loop at the top to hook on to with a bent
piece of wire like the original Parker Brothers toy came with. Of course you can also dress
the bell up with some other plastic detail and paint it as well.
Selecting a bottle. You can use large (2 liter) or small plastic bottles and most have
the same sized cap. The small ones are easier for kid sized hands. One thing I learned though
is that some bottles are not shaped correctly. I thought I'd found the perfect bottle with a
simple design but it turned out that since the bottom of the bottle turned up and into the bottle,
it plumped back out as you squeezed the bottle which didn't allow the pressure to be transfered to
Dress up the aquarium. Use some fish tank gravel or sand to dress up the kit and add some
items to pickup with the bell. I used some Lego pieces from my kid's vast collection. You can
buy Lego pieces bit by bit with their
Pick-a-Brick if you want.
For general use, you can follow the instructions for the original toy providede here.