Homemade Diving Apparatus

This is essentially a small diving bell that fits over the user's head and allows him to descend to moderate depths. It does not protect the user from pressure, but could be easily modified to do so. It should be noted that I am not responsible for any injuries sustained while using this device; If, however, you take the proper precautions, the possibility of this is small, even in the event of a pressure failure. This helmet can be made from simple, inexpensive materials. It can be operated by two people, and with some design modifications, could be made self - contained. I have made sustained dives of over two minutes without a problem, at depths of approximately ten feet.

Step 1 Design

This apparatus consists of a watertight helmet which partially encloses the diver's head, and is connected to a topside air supply by a hose. It is chained or otherwise affixed to a ballast weight to counter the positive buoyancy of the air trapped inside the helmet. It is very similar to diving apparatus used in the early days of ocean exploration.

Comments

[Dreistein]

i have got a air compressor,so what im going to do is make this but instead of a bike pump i will use the air compressor.

[9w2xyz]

Either one is not a good idea. Use Bellows. THe problem with pistons is that they tend to use oil as a lubricant. When it heats up under pressure...... it gets into the air. YOu ant to breathe that?

[SeaPanther]

Please don't do this. Unless it is for human use it can lead to mineral oils being absorbed through the lungs into the blood stream, damaging the lung lining and blood poisoning.

[Deutschmann]

That should work fine, as long as the manufacturer of the compressor didn't use any strange, toxic lubricants, but that seems exceedingly unlikely.

[xTOGx]

Builders, I am happy to see everyone interested in diving. I am a Salvage Diver by trade. Unfortunately, after reading this instructable I have identified some dangers. I DO NOT INTEND TO INSULT ANYONE...HOWEVER, I ALSO WANT YOU TO STAY ALIVE AND HEALTHY. I wrote everything, essentially, straight and to the point.

Hypercapnia - excess breathing of carbon dioxide that commonly gets caught in "dead space" of helmet. Note the difference in the Mark V dive helmet and KM-37. Over time, engineers reduce the dead space to reduce this danger. I suggest designing a lower profile helmet.

Asphyxia - simply put, lack of air to breath (in case compressor shuts off or leak in hose or what not)

Carbon monoxide poisoning - By using a regular compressor and not a diver's are compressor, which specifically uses lubricants and has an intake far far from the exhaust, you increase your probability of death. Consider it like breathing air from the exhaust of a car...not good. I suggest researching proper lubricants and different diver air compressors. Also, learn more about High pressure vs Low pressure compressors.

Decompression sickness - using the compressor will allow you to have more "bottom time." depending on depth and bottom time you may need to decompress, this allows nitrogen gases to be removed from your body. If you surface without decompression you may find yourself immobile. This is because a nitrogen bubble is trapped in the nerves that allow you to operate your legs, arms, or whatever it is that can't move. You then need to find a recompression chamber to shrink the bubble immediately. When treated hopefully the immobile body part will be able to move (expect loss of sensation). Aside from that, you can also die from Decompression sickness, depending if the bubble is trapped in your head or heart.

Pulmonary Over Inflation Syndrome - Air can get trapped between the lungs and chest cavity. This is more painful than anything else, see a doctor. If you do not regulate the air from the compressor with respect to minimum manifold pressure you may also over inflate your lungs. Think of the cartoon breathing in a balloon and over inflating. This also happens when you go from a deeper depth to a shallower depth with too much air already in your lungs.

Arterial Gas Embolism - Those going up and down 20 ft of water may find themselves within the cold grasp of AGE. Though different from Decompression Sickness it is treated the same as has many of the same dangers.

I made this list as short as possible. If you research each danger you will find greater detail. I encourage everyone to take a class in diving to learn how ti mitigate the dangers. I wish you all safe diving and good luck.

[bear7670]

what kind of safety and/or danger(s) should one consider if he/she had an air pump for in and one for out and has thinking of shallow dives (10 feet or less) for a time longer than a single breath?

-Bear

[ddzh]

Long time ago one seaman decided to dive using cast-iron kettle as a helmet and stones as a weight. When he reached the bottom he dropped stones and came to surface. He managed to cry 'help' and lost his consciousness. Soon he died.

His mistake was that he held his breathe while surfacing. 3-5 feet and one breathe may be enought to seriously damage your lungs and die.

[techno guy]

I made my own equation for finding the weight in ponds of the ballast.

ballast (lbs)=(capacity in gallons of inner helmet * 8) + (-weight of helmet+5lbs)

[snowluck2345]

just wanted to point out its not realy "your equation", many people have probably created it before you.

[techno guy]

Since the helmet has like 5 galons capacity, I calculated that the weight would have to be 44.5 lbs.

[SeaPanther]

If you use it at any depth you must be aware that the air in your lungs will be at a greater pressure than atmospheric. If you return to the surface with the pressurised air in your lungs multiple forms of damage can result.

WHEN RETURNING TO THE SURFACE YOU MUST EXHALE!!!

[Kryptonite]

I really ought to try this one!

[Doctor What]

 What a fantastically dangerous idea!  

[Deutschmann]

Opens up a whole world of unsafe possibilities, doesn't it?

[SirNoodlehe]

Exactly how I like it

[Goodhart]

Would a filter of some sort be useful?   I mean, pumping any particulates in the hose, etc forcefully into that helmet could cause some serious distress

[Deutschmann]

I never had a problem, but it wouldn't hurt to put a filter from a painter's mask or something in there, just to be safe (I appreciate the irony of the word "safe" in this context).

[Goodhart]

:-) 

 

[darkevilapie]

good job, me and my frend made something like this: we called it the diving bucket. but then we made a better one that doesnt uses large amounts of balast toget down. we used a gas mask from a army dump. maybe i should put it on instructables. also we used a pump for inflating airthingies and we are making an light for visior

[Deutschmann]

Yes, post it, definitely!  Sounds way more awesome than mine!  Funny enough, I have an old air force high altitude breathing mask, but its probably not waterproof, and I would not want to try anyway.  It could be worth something!

[darkevilapie]

 ps. ow and i have clocked the time i was underwater: 43 mins (my frend was tyred)

[darkevilapie]

:D thanks mate i will make an instructables.  and i think ur mask would do fine: if water gets in then the air will  pump it out :P
and im making more upgrades: my mask is about to get an auto pump made of an airco fan (the inflator of airthingis blew up) and the lights work underwater and our newest idear is an vacumcleaner for underwater to suck up stuff thats buried under sediment :) like my watch :(

[Deutschmann]

Cool.  What do you plan to use it for?

[darkevilapie]

wel i want to clean up our water so we can swin in it (lots of broken botles and iron shards in the water) and we just like to build things, we made more stuff and im planning to make a few instructables: this underwater breading mask (made a new 1)  , an crossbow (extreme power ) and more stuff if you think you want it here ( pipe for smoking or sommething like flametrower)

[burnerjack01]

Another version is to use a 5 gallon bucket with a weighted collar. Bolt in a clear plastic viewing window with air hose entering from the bottom. CO2 will be forced out the open bottom.
 With ALL of these devices it is imperitive to adhere to these safety rules:
Never use alone but under ACTIVE supervision.
Never use any kind of compressor that uses oil AT ALL. This leads to suffication by coating the lungs preventing respiration. You cannot be saved once the lungs are coated.
Stop immeadiately if your vision becomes cloudy. I have played with this type of activity during my preteens and luckily survived.

[Deutschmann]

I prefer to just use a transparent helmet, as cutting a hole in an opaque bucket not only limits your field of vision, but also creates the possibility of a seal failure.  As for oil, I don't think most bicycle pumps have any; it would work its way out of the system to quickly to do any good, and I'm sure something bad would happen if you got oil inside a bike tire.  This device is perfectly safe if used intelligently.

[engineer_01]

I can hold my breath for 2 minutes

[Deutschmann]

I could stay down longer than that, I just haven't tried; My friend can't pump much longer than that, but I couldn't hold my breath anywhere near that long; we're both wimps.

[stephenniall]

Hehhe i got a idea to run a compressor as the pump And Put a tap Wher eyou are so you control it

[Deutschmann]

I'm thinking of doing that, but all my compressors are the 12V car kind. I'll probably get around to it as soon as I find a 12V wall plug that has enough amps to run them.

[stephenniall]

you should make a compressor tank out of a propane tank (search for ible) and do the tap to that after filling

[Deutschmann]

Might be cool. I'll have to try it; not really necessary at the depths I use this assembly at, but it would still be cool.

[agis68]

dude i had the same idea like you, but with some other details. 1 the container is metallic, inox maded to carry perssurized coffee (Illy). 2 i didn't use it for helmet but i place two belts from car safety belts so i can carry it. The air remains pressurised in the container and i can use it for 15-25 min. The basic is that has portability. I paced all the container in a solid base of cement and iron so now it can be sink. I don't use it for deeper than 4 meters cause the air pressure change dramatically....

[Deutschmann]

Sounds cool, way better than mine. You should post it!

[zxcv]

One Major caution, Do not hold you breath coming up! This can kill you or cause other serious injuries even at very shallow depths. Air compress at depth, and if you fill your lungs at the bottom of the pool (or sea,) and then come up, the air in your lungs expand and well you know what balloons do when too much air. You don't need to make it air tight, the old diving bells divers used leaked like a sieve. The flow of air in would simply bubble out excess at the shoulders. The face was sealed, and opened to talk, and the suit was very heavy due to the compensation of the lifting of the air. As far as Pressure and not being able to take a breath sucking on garden hose, your design would be fine, as the pressure in the helmet (even open on the bottom) would be the same as the diver at that depth. For tankless diving, I would suggest using something that would give clean fresh air. A modern system using a standard regulator with a clean air pump at the top would be sea breath. I don't endorse them or anything, there are many companies doing this, they just came to mind. Basically they use an electric pump sending 15 pounds of pressure into an air hose. At the end of the hose is a regulator that matches the air pressure to the depth of water you are in. A scuba lesson or two and you are good to go. A scuba diver will regulate the pressure in his head by holding his nose and equalizing it. I have no idea if you could do this with a helmet, or if you would just have to descend very slowly. One more note, even trained scuba divers can die from certified equipment, DIY scuba is highly dangerous.

[Deutschmann]

As stated, I don't use this apparatus at very low depths, so many of the problems you describe aren't an issue. As for airtight helmets, you're right that some old, stale air must be allowed to escape, but if air escapes too fast, the water level in the helmet rises and ultimately engulfs your head. You should endeavor to make a helmet that doesn't leak too badly except around the shoulders.

[zxcv]

As long as the area above is airtight, by pushing air in, it bubbles over the bottom. Just like a glass of water is water tight on the sides and the bottom, over filling it spills over the top, your helmet simply needs not to leak from the top and sides. The bottom can be completely open. We have roughly 21% oxygen in the air, your breath out still has roughly 16% oxygen? But your breath out has Carbon Dioxide. The Carbon Dioxide (not lack of oxygen) is what tells your body to breathe out. Unfortunately it is the CO2 in your blood that makes you breathe, You can't really taste CO2, smell it, etc. Hyperventilation will trick the body, but that is a different subject. You can get an idea (dont try this alone) by taking a large trash bag, and have some air in it, and then take a breath, breathe in and out of the bag. You might smell the bag a bit in the test, but eventually the buildup of CO2 will give you the same feeling you will get if your rig is not working underwater. The "Couch Test" is usually the first test, second is the swimming pool test, and it looks like you are not planning anything more. A normal breath is about half a liter, you breath 9 to 20 times per minute, to sustain normal breathing, you will have to have a pump capable of at least this amount of airflow (use the 10 liters per minute.) To do a couch test on the pump, If you don't know the volume, hook the hose up to a kitchen trash bag, then you can breathe in from the bag, and out through your nose, if your pump will work, the bag will always be inflated. Next you will want to do a bit of exercise doing this same thing as there will be more stress underwater than resting on a couch. Also there will be the air pressure to push it down X feet underwater, and this would simply be a volume test. Disclamer: Again DIY scuba is risky and potentially suicidal. I never suggest anything above or below this to actually be done. Stay in bed. Of course half the population will die in bed (theirs or a hospital version.)

[desel3]

uhhh i don't think this i safe at all.

[Deutschmann]

You're sort of right. But as long as you don't do anything dumb, like use it in the ocean, you should be all right. There are safety precautions that can be taken. Used properly, its as safe as something of this nature can be.

[mr.incredible]

Very nice job. The hand pump probably wont poision you. It will taste/smell bad. Just don't do it around any source of air contaminants like smoking or gas engines. A cheap diaphram compressor would be better. You can pickup a 12v mini at Harbor Freight for about $10US. With that and a 12v adaptor or a battery, you might get enough air flow. Just make sure you have plenty of air flow, especially at depth. If you don't get good air flow, make a PVC air tank. You can start the pump before you dive. Wait until you build up about 60 PSI. Keep the pump running into one end and slowly bleed the air out of the other end to get the air flow you need. The presure in the tank will bleed off quicker than it can be replenished but you will get good flow, I would guess, for about 15-20min. The larger the air tank the longer you can stay down. Good to know info: -It takes 14.7 PSI of air pressure to push air to 33 ft. I wouldn't let the air pressure in the tank get below 20 PSI. If it gets low take a break and build it back up again. -It will take about 64 lbs per cubic foot of air to sink this thing. Make sure you don't get tangled up in the weight or the strapping that holds the weight. - Even with the compressor rig, DON'T DO THIS ALONE. Make sure you have a friend(s) around just in case some thing goes wrong. It's more fun with friends around anyway. - DON'T TRY THIS ANYWHERE BUT YOUR POOL. The open water including lakes, rivers, ocean, will have other hazards you will not be prepaired to deal with.