I'm a big Portal fan, and I've been wanting to make my own lemon grenade ever since I spotted this one last year. That one has a soundboard in the display base, but mine makes a "tick-tick-tick BOOM" sound when you pull the pin and press the handle, which is a fun little extra. (Here's a quick video of it in action.) It's a simple mod that shouldn't cost you more than $10 in materials - not including the display - and only requires a few hours to do.
(You can also see this tutorial on my blog, Epbot, where I have a few extra process photos - and I'm actually giving away one of my two lemon grenades over there next week, so feel free to mosey on over if you'd like a chance to win.)
Ok, let's get started!
Step 1: Materials
This is a simple mash-up of a toy grenade with a fake lemon, so obviously you're going to need a toy grenade and a fake lemon. :) I found my grenade (which comes with the speaker and sound effects) at a costume shop for $2.99, and the lemons are from Wal-Mart and I think cost about $2 each.
Other than that you'll need a small screwdriver to disassemble the grenade, a thin utility or craft blade, and beading pins to hold the two pieces together. Oh, and also a Dremel to drill the holes for the pins.
If you want to paint your grenade topper as I did, you'll also need matte black spray paint and some painter's tape.
Step 2: Disassembly
Take your toy grenade apart, being careful to keep the speaker, switch, and battery compartment connected. You're going to be sticking the battery section inside the lemon, so snip any extra plastic pieces off of the outside of the casing to get it as small as possible.
Next cut a hole in your lemon for the battery case, stopping to check the fit every few minutes. Since the lemon's inside is Styrofoam, I found it helped to use needle nosed pliers to pull out the crumbly foam bits once I'd sliced through the thick exterior skin.
You want the battery pack to be completely flush with the outside of the lemon, so keep digging away 'til you get there!
Step 3: The Grenade Topper
Snip off the top section of your toy grenade, trying to keep the "prongs" on each side roughly the same length. (I used a metal file to smooth out the sharp corners and rough edges, but that's optional.)
Now's the time to paint, if you're going to. My grenade was army green, so I taped off the gun-metal sections and painted the rest matte black, including the handle and pin (although I later replaced the pin with a metal one.)
Step 4: Mash 'Em Up!
Ok, now's the tricky part: sticking the two parts together.
With the battery box inside the lemon, use a sliver of tape to hold any excess wire wrapped around the top of your speaker (see my photos). This is to keep the wires from getting in the way when you stick the top on.
Essentially you'll be sandwiching the speaker between your lemon and the grenade topper. Check out my first photo, where I'm holding one half of the grenade top in place, to see how everything fits together. You'll need to have the top assembled before putting it on the lemon, though. (Clear as mud? Yes? Good.)
I attached my top with metal bead pins. To do this, you'll need to first drill holes in the "prongs" of the grenade topper at a slight angle, so your pins will enter the lemon at roughly a 45 degree angle. The angle is necessary so the top won't just pull off the first time you pick it up.
I don't have a photo of this step because it took too many hands to do it, but next I held the two pieces together while my husband John inserted the pins through the grenade prongs and into the lemon. So grab a friend to help out, if you can.
Step 5: Make It Pretty!
Once your pieces are together, it's time to decorate! I made a stencil by printing the Aperture logo on plain paper & cutting it out with a craft knife. I also added a small "flammable" symbol to the grenade head, which I printed and laminated with a bit of packing tape for some shine.
I replaced the grenade's plastic pin with a cotter pin (available for cheap at any hardware store) and keychain ring. I feel like the metal makes the whole thing look a little more real and substantial, but of course you can always keep the plastic pin and ring.
Step 6: Display and Commence Bragging
I used a softball display case (found on ebay for just under $20 with shipping) and ordered the plaque from a local trophy shop for about $8 - so, yeah, the display is WAY more expensive than the lemon grenade itself. Even so, that's only about $35 for the completed piece. Not too shabby!
Fun Fact: That patent number is actually from the game, although I don't know if it holds any special meaning beyond that. You can find it in the upper righthand corner of the games' closing credits. I love adding extra nerdy details like that to projects. :D
I hope you guys enjoyed!