KISS (keep it simple, stupid) at its finest here.

As absolutely awesome as the GVG is, I always wished it had a greater internal volume. My biggest issue (like many others) was properly controlling breath speed and depth, vaporizing the spice, and getting the whole dose.

Now having very easily turned my bong into a mega GVG, getting that whole hit will be easier than ever. Does this replace the GVG? Perhaps. A GVG is certainly more portable and is truly a purpose built vaporizer. IMO, this works just as well as it is identical in principal, if not better because of the volume of vapor it can hold per toke.

This may vary from bong to bong, but it worked pretty much perfectly for my stem size given the diameter of the ceramic discs. Like I said, this is my first bong and I dont know if stems between different bongs are the same interior diameter or not.

What you will need
1. A bong with stem (downtube) being separate from the bowl section. No water of course in the base.
2. 1 metal screen
3. 2 ceramic discs (I use the smaller size - 7/16 aka 14mm)
-Have 1 disc loaded with your dose of spice and 1 totally dry to be used as the heating element, like the top plug of a GVG

First
What you want to do is remove your bowl section from the stem.

Secondly
Take your first ceramic disc with your pre-melted spice and drop it in so the edge is facing you (so air can pass along both sides of the flat portion of the discs as pictured) Photo is oriented looking straight down the tube from the top.

Next
Curl your metal screen a tad around the edge to give it some curvature like a contact lens, then place it into the top of the stem and press it in lightly.

Laslty
Take your second and blank (non spice containing) ceramic disc and press it in and onto your metal screen. I press the disc in enough so that it has no possibility of falling out when red hot (this could be a SLIGHT issue during blastoff Make sure its in sufficiently )

Go time!
Heat the top disc as you would in a GVG, and breathe in intently. The bong will fill heavily with dense white vapor. We know what happens next...or do we?

It should be perfectly easy for anyone to take an entire breakthru dose in one hit, two max for sure (25-35mg of freebase). The spice disc in my stem is 1 inch away from the heating disc, so it will be very difficult to burn any spice.

It is very easy to retrieve your parts from the stem once cool, simply turn the stem upside down to remove the top disc (let it cool first), then you can pick the screen out with tweezers, a pin, or your pinky if you can.
Then, simply keep the stem upside down and tap the bottom with your finger and it should let the spice disc loose. If not, you could always stick something that wont damage the glass to pop it out, like perhaps a chopstick or pen.

Perfect? Sorta, it works just as well as a GVG with the added benefit of the volume being several times greater. I know some may have concerns about spice migrating to the cool glass from the disc, but if you dont have any spice on the sides of your disc, you should have no worries because the flat sides will never touch the glass! Why would there be any spice on the sides of the discs anyway? Spice should be on the flat top/bottom sides if anything. The only thing touching spice will be the hot air passing by the flat sides of the discs, carrying your spice toward your lungs

Happy travels!!!

good stuff HumbleTraveler, i did a similar thing, i have a metal downpipe on my bong so i just screwed the filter of a VG onto the bowl, like so..



could you find an attachment that would allow you to drop the GVG filter/housing into the stem?

There was an attachment someone had posted once that would allow that, but I wanted to see if this would work first. I know I tried popping that top plug in, but it didnt fit right

I always use a Volcano vaporizer liquid pad for the screen, cut it to fit, works the best.