Step 11: Foam in Place

A can of household insulating foam will hold the bottle in place and keep your cold beverages cold. 

Note: There are two types of  foam available.  One cures rigid and the other remains soft (like seat foam).  Given the possible expansion of carbonated beverages, the soft foam was used for this project.

With the plastic bottle and o-ring in place, turn the tank over and fill with foam through the Bottom Hole.  

Note: Be sure to plug the tank's drilled-out pressure relief Valve Tube, or foam will flow out this hole.  A small wad of aluminum foil stuffed in the hole works well.

Insert the applicator straw to the bottom of the inverted tank and slowly spray the foam.  It will expand, so several small shots, a minute or so apart, will help to keep from grossly over filling the tank.

Note: This foam needs moisture to cure so, the inside of the tank was spritz with a water mist before foaming, and in between the several small shots of foam.

After the foam expansion slows (minute or so), scrape off the excess foam.  Leave about 1/2 inch of foam above the tank.  This foam will be used to  adhere the Bottom Cap.  
While the foam is still tacky, press the plastic Bottom Cap in place on the bottom of the tank. Clean off any foam that may squeeze out.

Be prepared when using this foam! This can be a messy operation.

Urethane foam sticks to everything; including skin.  Once cured, the only way to get it off skin is to let it wear off - there is no solvent.

<p>that is hysterical. </p>
I need to find some darn cans like this
Use disposable gloves to protect your hands and mask off the tank just above the plastic bottom piece to lessen the clean up of the tank.
<p>you want real winter gloves not latex. this gas is so cold it will give you frost bit. Propane hitting your skin will do nothing unless it's cold from pressure. but anything in a can is cold under pressure. latex gloves would be like putting your seatbelt on just before you drive into a brick wall at 150mph. rather pointless isn't it?</p>
<p>I don't want to repeat myself over and over, but as i read these posts i realize these people have no idea how chemicals and pressure works. so that being said, anyone that thinks their can is empty after it runs out of fuel and cuts, drills, or hacks their way inside with out properly draining COULD lead to and explosion, even under water. Do it the way I just told you and you'll be fine. I've done it a few dozen times. if you don't believe me I can show you how to do it email me. cmharding@yahoo.com</p>
My dad and i are thinking about building a Rat Rod if you dont know what this is Google it but we were thinking about using this idea as an over flow for the car would you reccomend this i wouldn't know what to put on the inside of the tank since there would be hot liquids draining any suggestions?
<p>Nothing at all. these are made of aluminum and disperse heat very quickly, if you needed a tank these work great. I have one on my kids go cart as a fuel cell, just drilled out the guts through the top valve and put a cap on, drill a hole in the bottom and screw in a nipple the size of your fuel like and use plumbers thread tape. been 2 years works fine.</p>
You should be able to leave the bottle empty, just don't cut the bottom out of it.
I was nervous trying this out, but really all you need to do is attach the propane to a blow touch head, lantern, or camp stove to get rid of the propane inside and then use the pressure relief vulvae to let out anything more, and then take the vulvae out. I put my canister in water like NelsonStudios recommended. You should where a mask, and possibly winter gloves, feel free to correct me, I don't know a lot about this, but I know propane can do weird things and can spray really cold stuff that could burn/freeze your skin instantly.
<p>There won't be enough to hurt you if you followed throu on leaving the valve open. You will smell it, but it's no worse than what you smell everytime you walk by a gas stove. I think the underwater cutting is a bit extreme, you figure if the valve is left open and you take a file to it long enough to get a tiny hole started, at that point there is no possible way for any pressure to come back. or explosion, like i said if you used a power tool be aware that friction causes heat and sparks. yeah stick with what reiff said, do it in the kitchen sink. I know most of you won't find that necessary but there's always a couple people that don't follow instructions very well.. so yeah a hack saw, file will work fine just go slow till you puncture the tank. I shoot these empty tanks with guns everytime I go practice shooting and they do NOTHING except look like swiss cheese afterward.</p>
<p>These little disposable cans work great for projects. I saw a post before I looked here on how to safely cut one of these in half. There was noting online on how to do it except don't because you 'll blow yourself up. well this is what I did. put the torch back on and left it open. Propane is heavier than air so you need to turn it upside down so the nozzle is facing down. then I have a triangle file in my jewelry files and I just filed until there was a hole. There was no noise of gas escaping, just could smell propane a bit strong after breaking throu but it's not enough to explode esp with the nozzle left open. locked. I know at least 9 of 10 of you are going to ask me why I would need to cut one? Well these tanks are pressure tight and finding something that can hole that kind of pressure when building tools or projects come in handy. it all depends on scale. they use the 20 lb tanks to make little kilns. I want this one to make a mini soup can forge, but mine is high Quality, spent the money on 3000 degree fire cement and Aluminum brackets. I am building this for my garage so I can heat steal on a small scale cheap and efficiently, It's a cheap way to get into metal fabrication without spending more than 10 or 20 dollars. </p>
<p>You can look up on youtube how to make a soup can forge but these cans would be so much better, they look to be aluminum. I just wanted to give someone instructions on how to do this without hurting yourself. Can Must be completely empty and left open on the valve. then file with low pressure the closer you get to the inside. worst case scenario would be to make a spark and it would throw a little flame out of the hole but it will not explode if you cannot light the torch with a lighter after left open. so make sure the valve is open and just use common sense. I don't suggest anyone under the age of 18 do this. have an adult or even take it to a shop to have it cut open. the only way to let the pressure out is through the topvwith an attachment.. thanks</p>
I know you are about to have 9 million tell you propane and air is a bomb but before that starts I would like to offer a practical solution. When you unscrew the valve submerge the tank and water to fill it. This will expel all residual gasses and make the tank totally inert for any further construction purposes.
I will do that, good idea, but this goes out to anyone, but I'm having trouble getting the pressure relief valve out. I don't know if any one has a suggestion.
excellent idea, thank you!
That is a great suggestion!
ok how the thing. be u cut the tank. and b4 u remove the valve. put the tank into 5 gallon bucket filled with water. then remove the valve. then only with the tank still under water. drill a hole. in the bottom near where yr going to cut the tank. that way u can be sure the tank is empty of propane and filled with water. b4 u cut the hole. an not being taken to the hospital e-room for 2d - 3rd freeze burns. witch are worse than burns.
good job you should look into marketing this people will buy anything LOL and perhaps you can find a vendor to make a custom sized inner reservoir and insulate with a cheaper less messy means like fiber batting good luck <br>PS. filling with water and then bumping will assure no gas is left in the vessel. Rust should not be a problem if you are spraying water inside to make foam work anyway it will speed up your process a little. cheers!
Since you're already shrinking the bottle, instead of insulating it, couldn't you heat the PET, and then pressurize it such that it conforms (mostly) to the interior of the propane tank, and therefore get more &quot;bang&quot; for your buck? (pun intended)
If you have no intention of insulating it, then sure, that should work. However, then you would essentially be making a large can of soda with the outside metal being cold and 'sweating' in the heat instead of more of a thermos keeping your drink cold. I do like the thought that the bottle would be larger, though.
Do you think that if you put the pressure release valve back into the canister and drilled a hole in the water bottle and mounted it in the bottle and sealed it off were it enters the bottle. Than doing that makes it you can put a &quot;fizzy&quot; drink in it when you go to open it it doesnt explode on you or have it fizz up a bunch. Would that work? or would that work better if you used a metal can and did that and used some sork of glue or compund to seal it in the plastic/metal bottle?
For those worried about the propane tank blowing up on them, I must tell you this story. When I was much younger and took more risks, I lit a candle next to a full 16.4 oz canister of propane on a stump about 100 yards from the road in a remote hunting area on the west coast, I walked back up the hill and shot it with a 270 rifle. When I hit it the compressed gas instantly put out the candle and the canister propelled off about 20 feet. No explosion, no fiery flames (much to my disappointment). That same camping trip several hundred yards from camp was a river, I built a raging fire way out on a rocky shoreline, far away from anything that might catch fire. I put a full canister of propane on it and ran to a safe distance, I waited and waited and waited some more. Finally after almost 15 minutes of this thing sitting on a hot fire, the secondary valve gave and it proceeded to blow a 3 foot flame to the side of the fire making the sound of a jet engine. That lasted about 10 minutes before it ran out of fuel. No boom, no bang, just more disappointment. So be paranoid, be safe, stay alive and remember the key elements for a good boom, oxygen and fuel, or really good compression before release (blast off). In my personal opinion, the worst that could happen from you igniting the contents of a spent or un-spent propane canister is a quick short blast of flame, not a big badaboom. You want it to go boom? Fill it full of black powder and light it because propane isn't going to do the trick. True story, this was long ago enough that the statute of limitations has long worn off for my stupid experimentations. But be safe anyway, just thought I'd share some life experiences with you all.
Awesome idea, I will definitely be trying this out. Genius!
not a bad idea, but they say that plastic pop bottle should not be reused since they leach toxins from the plastic.
If they weren't safe than millions of people would be sick from them already. Is the they in your' post a conspiracy enthusiast? Also if you're worried about the heat releasing toxins remember this, that bottle was molten hot 700+ degree f plastic once or twice before. I'm not worried about it, you can if you want.
when nukein the bottle do we have the lid on tightly loosely or not at all cuz i just had mine on tight and it exploded and yes i mean the plastic bottle not the propane can
Of course it exploded!!! Hot air expands, furthermore, you are trying to shrink it. Air needs to escape in order for that to happen. I hope no one got hurt.
You can use thinner or acetone to get this stuff off you skin,
Thank you. I have been looking for a way to make myself a new festival mug. A few mods and I'm on my way. Stellar instructable!<br>
hmmm i just thought of sumthin sum1 shuld find a way to ''charcoal'' ice
Looks like ice cream!
dont eat it tho
great idea!<br> <br><br>a few production ideas/notes.<br><br>When the Schrader valve is first removed... Use the opening to fill the container with water. when completely filled, reinstall the valve, and you're now &quot;safeish&quot; for cutting. Without this step, there is a SMALL, but real chance that some gas remains in the container, and an errant spark can make it go 'POP' or, in worst case 'BOOM'.<br><br>#2... instead of all the tiny holes, to remove the valve...a hacksaw can cut through that brass pretty quicky, then a hole-saw will net you a clean, perfectly sized hole, with one go. If your plastic bottle neck is larger than the thread diameter, you can skip the hacksaw and take the entire valve/thread assembly in one quick drill.<br><br>#3. when foaming with the bottle in place, make sure the cap is ON the bottle.<br> otherwise, it is possible that he foam might crush the unsupported plastic a bit. Not critical, but useful.<br><br>#4 Acetone works wonders at removing UN-CURED expanding foam.<br> if it has cured... then remove as much as you can and head to the drugstore(or beauty supply, or just about anywhere) and get yourself a pumice stone. sandpaper works for those of us with &quot;manly tough hides&quot; and a little less common sense. Abrade MOST of it off... then let exfoliation, and everyday abrasion do the rest.<br><br>#5 using MINIMALLY expanding foam will cure some of the issues observed by the OP. and the cans CAN be used multiple times, you just have to get the foam plugs out of the nozzle and straw (nozzle is easy, with a paperclip. usually easier just to use a new straw. free from your local fast food joint)<br>
Wholesaws are hard to get started when there is already a hole bigger than your starter drill bit. Wouldn't a step bit be better? Great instructable!
no. in fact it would completely eliminate the purpose of the holesaw.<br>My process would NOT USE the pilot bit. Just the outer bit.<br>this lets you cut just a small amount of sheet metal.<br>using a step drill, you'd be drilling away all of the brass stem.<br><br>It's a drinking bottle, so if the hole is a little off center, it's no big deal.<br>let the stem guide your holesaw, rather than the 'starter drill bit'.<br>
Or...you could drill a bunch of little holes around the base of the stem and.... Hmm...where have I heard that before... ; ) The point is, its good to have options. Thanks for all the good points. In fact everyone scores a point!<br><br>Now for a minor point of clarification: After an extensive Mass Spectrometrical Analysis, it has been determined that the stem is not brass but is indeed steel; just like the rest of the tank. (At least that's what my magnet told me)<br><br>Seriously, a Heartfelt Thank you for your comments. <br><br>H. P. Stoutharrow
metallic analysis global nerd equivalency tool
Drilling the little holes was an ingenious idea!
in the past when I have needed to make a hole but there is already a hole too big for the pilot drill in a hole saw I have used metal or wood with a hole cut in it useing the holesaw then placed this securely over the job to be drilled &amp; used it as a guide <br>But the other way would be to insert some wood into the tank through the bottom hole to drill into to locate the hole saw
Good idea, thanks for the tip!
I had some foam explode on my hands. It sure does look ugly but it only took a few days to wear off.
I have decided that expanding foam is the devil when its gets on your fingers and pumiec stones are annoying and sand off everything, but what you want them too. Calices or foam or paint.
Thanks for tip about water; I'm awfully timid around explodable stuff but do want to try this project!<br><br>I do not have 'manly tough hide'. I have used sandpaper on my skin and I have used Pumice stone; I think Pumice is rougher. <br><br>The only problem with the MINIMALLY expanding foam is that it isn't as much fun!
&quot;FUN&quot; and painful stuff often go hand in hand. :-)
The 20 oz. bottle looks more like a 1 Liter bottle.
if any wanted to use a hot liquid you could always use a metal energy drink can with a screw off top since the venom ones hold the same amount a water bottle would
What did you use to cut the hole?
I used a hacksaw and kept spraying the blade with wd40. It took time but came out well! I then used a dremel to smooth the edges. I had problems drilling out the side valve so I used the dremel again with a cut off blade!
Cool project!! I was just wondering if you could use the bottle blanks that RichardBronosky suggested, ( http://j.mp/icok9j ) could you heat them up, insert them from the top without cutting the bottom off and then with an air compressor and some wading around the bottle opening shoot air int the bottle blank until it takes the form of the whole bottle?

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