While commercial vaporizers use it, I don't believe that PVC is safe enough for this purpose. Don't use it. As you can see I I've read about leeching in medical products (while they were using specific chemicals), and also read that the PVC should not be heated over 180F which is not enough. Silicone tubing can be bought online. I use thin copper tubing.
Where I live smoking tobacco is restricted to people 18 and over. If your under 18 don't make this, don't smoke, or vaporize, or whatever. While vaporization may reduce the health hazards associated with inhaling plant material, I'm certain that it does not completely eliminate them. Don't smoke. It's addictive and bad for your health. Depending on what region or country you live in, it may be illegal to consume specific herbs. Make sure that the herbal blend you choose is legal in your region. This guide is not intended to assist in the illegal (And highly immoral) consumption of banned plant materials.
This vaporizer is a fire hazard. It's cheap and easy to make, but there's a trade off. This one cost me about $25. A similar commercial vaporizer would cost 150-250$.
You might consider buying one of those wall timers so that if you leave your vaporizer plugged in by accident it will only run as long as you set the timer for. This is a must if you plan on vaporizing any herbs which may induce forgetfulness. Don't start a fire!
Further I've been warned that copper fumes are vary dangerous. I don't think copper will fume at the temperatures I'm subjecting it to.
That said the consensus among many smokers is that the most sure healthiest thing to smoke out of is glass. If you find a good way to do this with glass, more power to you! For now my brass on glass design might be the best DIYers can hope for.
One more warning: Don't use a soldering iron that has come anywhere near solder. Solder is super poisonous nasty stuff. Just buy a new one. They are really not that expensive.
Step 1: Materials.
This is for the socket where you plug your vaporizer into. With the timer you set the timer for as long as you plan on using your vaporizer so that it shuts off automatically. If your at all forgetful this is a must. Some herbs have even been suggested to bring about forgetfulness. If you plan on vaporizing any such herbs the timer is must!
A (few) bottle(s).
I used a large 1.75 liter Gvori vodka bottle.Gvori is my favorite vodka, and their bottle is awesome. Other bottles should work, but you'll want to vary the end of the fitting that goes against the bottle (more on that later). This should be free. If you don't have a good bottle laying around someone near your probably does. Since breaking a bottle is a chaotic thing you will want to have back-up in the case your first doesn't work (it probably won't).
A soldering iron (at least 40 watts).
I used a generic radio shack one. It cost about 7$. A radio shack one is probably best since their design is so simple. Anything more complicated will only get in your way.
Thin copper tubing.
I used 1/4 inch. It's flexible, but don't bend it into too sharp of an angle or you will get a kink (they're almost impossible to get out).
A brass or copper fitting.
I used a copper fitting I picked out which allowed the copper tubing to barely slide through it on the narrow threaded end, that was big enough on the other end to make a good bowl and fit against the neck of the bottle. The one I bought from lowes is labled 3/8" flare X 3/8" FIP. I would suggest looking ahead in the instructions before you purchase any type of fitting for this project.
Two pairs of pliers, at least one of which is needle nose
A serrated knife or dremel for cutting through the plastic handle of the soldering iron.
A coat hanger.
The type bought at smoke-shops to go in the bottom of a pipe.
Step 2: Preparing Your Frame
This part is a little dangerous. Wear eye protection.
Break your bottle.
This will take multiple attempts and a little luck to do successfully.
Originally we intended to use a glass cutter to mark where we wanted the glass to break. That proved to be useless once was actually started hitting the bottle (plus its super hard to get a good score on a curved surface like this) so in the end we just gave the bottle a quick tap with the hammer, and the gods of chaos decided this was the shape we're using. So long as you have two open ends of glass to work with, you're good.
I prefer this "bar fight" shape for aesthetic reasons.
A tip from Shady180:
I've always had luck with cutting bottles by using a large metal hose clamp (available at any auto parts store) around the outside. Tighten the hose clamp snugly up against the side of the bottle then use a utility knife to score the glass along the upper edge of the hose clamp. The steel edge of the clamp serves as a nice straight line and prevents the knife slipping. After scoring, use a small hammer (tap hammer or peening hammer) to break the glass along the scored edge. Works great.
Now cover the sharp edges with electrical tape so you don't cut yourself.
Step 3: Preparing Your Heating Core.
Break open your soldering iron.
This will vary based on the model of soldering iron you use. On mine there was a metal tube which holds up the tip and heating core. I opened this up by prying at the seem using needle nosed pliers. The handle need to then be cut open. Remove the little grip piece first. I sawed perpendicular to the handle. This meant that I needed to cut the wires to the soldering iron in order to remove the heating core. This increases how much of a fire hazard your vaporizer will be. You could alternately cut parallel to direction of the handle and then pry it open. This wouldn't require you to cut the cord to the soldering iron core, but it may be more difficult.
Tape up the soldering iron leads. The core, as you can see, is a core with two wires running off of it, these wires then hook to the plug cord. There's exposed wire where the two woven leads meet the plug cord. This is to save radio shack some money (that's what that little yellow thing in the iron was for). Don't worry about the specifics of the iron, just make sure that before you plug anything in you've put electrical tape over any exposed wires. If you cut your iron cord, fix it up now. Solder it, or use the twisty caps, and then make sure you put some electrical tape over it!
Step 4: Bend Your Coat Hanger.
Start by bending a spiral shape which will fit around your heating core and keep from touching the glass directly. You can make two if you like to make the core sit better, but I feel fine with one. Use your pliers. The inside loop of the spiral should fit over the heating core snugly, and the outside core should fit snugly into the neck of the bottle. Insert your heating core into your bottle with the cord running out the large side of the bottle.
Bend the coat hanger around the neck of the bottle several times and then shape legs, and feet for it if you so desire. The angle the bottle sits at doesn't matter much but if you make it too steep your core will slide out the back.
Step 5: Assembling Your Whip and Bowl.
Your bottle needs to be cleaned to remove any glass particulate.
The copper tubing needs to be cleaned to remove any grease and/or copper dust.
The brass pipe fitting needs to be cleaned to remove any gunk on it.
Don't clean your heating core, doing so will probably destroy it.
you screen doesn't need to be cleaned because it should have been clean enough when you bought it.
Flange one side of your 1/4 copper tubing.
Do this by sticking a small enough pair of needle nose pliers in the end of the tube and twisting.
Take your brass fitting (mine's from lowes and its labeled 3/8' flare x 3/8' FIP), and slide it over the copper tubing from the not flanged end, down the copper tube, and to the other end of the copper tubing. Make sure the larger side faces outward. The flange should be big enough to not allow the brass fitting to slide completely past the flanged end of the tubing. Put your screen in the open end of the brass fitting. your plant material will go against the screen inside the large side of the brass fitting.
Pro tip: Is should be flanged as far out as will fit in your bowl. Since this is the vessel through which the air will pass, if it's too narrow your plant material will not vaporize evenly. It is not flanged enough in the picture.
Step 6: Final Check, Tuning, and Operation.
After the initial burn off, your vaporizer should take from 10-15 minutes to heat up.
Pack your bowl with your herbs. Compress them against the screen.
Put the copper end of your whip in your mouth and put the other end against the bottle. At this point bend the thin copper tubing in such a way that its comfortable for you to sit and hold of the bowl against the frame. You may need to cut the pipe. If you do so make sure to wash it before using it. Again don't make bends that are too sharp because it will kink your tubing.
With the copper tube in your mouth and the bowl full of herbs and the whip pressed against the heating frame; inhale slowly. You should be able to taste the herbs, but they should not taste smoky. If its hot enough you should be able to see vapor if you exhale toward a light source (it will be faint).
If you don't see vapor you might not have been paying attention. If you were paying attention and exhaling toward a light source the air passing over the herbs was not hot enough. Wait a few more minutes to see if your vaporizer gets hot enough. If that doesn't work, Moving the heating core closer to the end of the bottle increases the heat of the air. Inhaling more slowly also increases the heat.
When your herbs taste popcorny it's time to put new one's in.
If your smoking tobacco, don't bother saving the left overs. They may look only slightly used, but almost all of the psychoactives have been used.