Jurassic Spark: Giant Biting T-Rex Build & Game

How to host an epic dinosaur adventure game & build a giant T-Rex head with biting action! The T-Rex materials cost around $10 if you can liberate some cardboard (tips included).

My absolute favorite childhood birthday party involved playing a game my Dad and I modeled after the Jurassic Park movie. It was a blast! All the kids loved it and I've always wanted to recreate it. Now that my own kids are old enough, I decided it was time to see if I could improve upon a game we created decades ago.

I hope that lots of people will want to host a Jurassic Spark party and continue the creative process. Please share your improvements and changes :) I would be happy to help in anyway that I can.

Step 1: How to Use This Instructable

I've worked hard to try and make it as easy as possible to throw a Jurassic Spark party and avoid my mistakes. There's a lot of detail here so I've also included a listing of steps below. Feel free to browse the images for a quick overview (they are all annotated).

This instructable will show you how to:

run the Jurassic Spark game.
(optional) build a giant T-Rex head.
(optional) project the design files onto a wall without a laser printer or transparency sheet.
(optional) build a dremel/rotary tool table for fast cardboard cutting.

The custom design files, tools and materials are listed separately for each part of the build to make it easier to customize the event for your party.

Please don't be discouraged if you don't have some of the materials listed - just get creative. It's also OK to skip a few of the more involved props like the giant T-Rex head. The majority of fun comes from just playing a really exciting game that actively involves both kids and parents. We didn't have half of the stuff in this instructable when I was a kid and it was still super fun.

Step Listing:

Game Mechanics
Dinosaur Pen
Game Batteries
Power Station
Future Power Station
Dino Tails
Small Dino Heads
Game Tips
T-Rex: Materials & Tools
T-Rex: Projecting and Tracing
T-Rex: Cutting
T-Rex: Gluing the Head Layers Together
T-Rex: Gluing the Jaw Layers Together
T-Rex: Finishing Touches
Dremel / Rotary Table Build
Party Notes & Feedback

Step 2: Game Mechanics

The mechanics of the game are pretty simple, but really fun. We all had so much fun that the kids and I are already planning on hosting another one. I'd like to keep on improving the game so I sent out an anonymous survey afterwards and the feedback was really encouraging (more details later).

Scenario: The Jurassic Spark electrified fence has lost power and many dangerous dinosaurs are on the loose. Can our brave explorers (kids) find the high power batteries to energize the fence before it's too late? Watch out for the T-Rex! CHOMP!

There are 3 main roles involved in the game: explorers (kids), small dinosaurs (adults), and the terrifying T-Rex (adult)!

To win: the explorers need to find and return the 6 high power Batteries back to the Power Station to energize the electric fence before the dinosaurs tag all the explorers. The dinosaurs are there to make it a fun and exciting challenge!

Getting tagged: When a dinosaur tags an explorer, the explorer has to freeze and put their arms out like in freeze tag. Frozen explorers are encouraged to yell for assistance "Help! Help! A dino chomped me!" and can be unfrozen by being touched by another free explorer.

Tail stealing: The explorers are not completely defenseless however. The small dinosaurs have tails that can be stolen and they hate that! "Roar! Who stole my tail!?" Tail lacking dinosaurs must return to the dinosaur pen before they can regrow their tail and return to hunting. This is a very important part of the game as it brings balance and a whole lot of fun. It also encourages lots of exciting team building as kids will often gang up on a dino to take it down or distract it. Once the electric fence is powered up, dinos that have their tails stolen are trapped in the pen until the game ends (usually only a minute or two).

T-REX: To up the level of excitement, we add a T-Rex wild card into the mix! The T-Rex cannot be stopped and loves chomping on explorers! There's nothing quite like seeing a giant roaring T-Rex head chase or stalk their cute tiny prey :) While the T-Rex head is super fun and creates a lot of very memorable photos, it is totally optional. When I was a kid, we just picked the largest adult with a good booming voice and it still made us run for our lives!

There are additional game tips further down in the instructable.

Step 3: Dinosaur Pen

The outline of the dinosaur pen was created with snow fence wrapped around a grouping of trees and attached with twine. The bright safety orange color and mesh worked great for this. A few strands of Christmas lights were woven into the fencing to light up when the fence was energized. The final magic touch that transformed it into a legit high voltage fence was the custom designed warning signs attached to the fence with binder clips. The signs also help make it clear that the fence is part of a game for any curious people passing by. There are two versions you can download: full color and outlined for hand coloring. We positioned the dino pen around some trees for shade, but with good visibility into the main field so they could enjoy watching the last few dinosaurs being chased down. I'm glad I surveyed the park beforehand so that I could take my time picking a good location.

Materials: fence material, bit of twine, Christmas lights, warning posters (see files), binder clips.

Tools/Equipment: scissors / knife for cutting twine.

Preparations: survey the park for a good location (30 minutes), coloring the posters (1 hr), assemble fence on site (20 minutes of enlisted volunteer time).

Fencing alternatives: ropes, extension cords, cardboard boxes arranged as the corners of a rectangle, a grouping of trees...

Christmas lights alternatives: see Future Power Station step below. I'm actually really excited about this alternative!

Step 4: Game Batteries

We used six 591 mL Gatorade bottles filled with different colors of Jello, plain Gatorade, some food coloring & milk (to make it a touch cloudy) & Jello chunks. The kids insisted on putting banana peels in the yellow one. I chose the Gatorade bottles because they were durable, cheap, had a good shape/size, and even had a lighting bolt molded into the bottle to boot! The Jello was more visually interesting than regular food coloring and milk, but only a bit. I think I'll experiment with more non-Jello options next time.

My kids had fun making the Jello beforehand, but I'd love to mix the colors during the event so kids can get involved with choosing colors and shaking the bottles... Opt for brighter colors of Jello if you go that route (the dark purple and blue don't light up as well). Note that each Jello packet only makes 500 mL and the bottles are almost 600 mL. I just topped up with the blue Jello. You could maybe add another 100 mL of water to the recipe instead. I chose to make the Jello in a bowl and then spoon it into the bottles in chunks so that it would look more like a rough cut crystal like thing.

Abandoned plans: I had originally been planning on putting waterproof flashing lights inside the bottles because that would look freaking awesome, but the white lights I had (even with new batteries) couldn't illuminate the colored Jello or water well at all. I did have one red light that would light up the red bottles really well at night, but it wasn't very impressive during the day. It went from "WOW! Let me see that!" at night to "Oh… that's kinda neat" and it really wasn't worth the effort.

Materials: 6x Gatorade bottles ($6), 4 Jello packets ($4), 3 drops of food coloring, water, tablespoon of milk, 2x banana peels.

Jello Tools/Equipment: something to boil water, fridge, containers, fork, spoon

Preparation time: making Jello (30 minutes), letting Jello congeal (4 hours), spooning Jello into bottles (20 minutes), drinking all the Gatorade (20 minutes), pondering life choices (1 hour)

Battery alternatives: tennis balls, soccer balls, ...

Step 5: Power Station

NOTE: This step describes what I did for the Power Station, but not what I would do again in the future. See the next step for that.

I used a small old cupboard and cut circles into the top with a 2.5" hole saw. I chose this because I could safely store a car battery and inverter inside it to power the Christmas lights for when all the game batteries were returned and the electric fence was energized. Keep in mind that kids may come running full tilt at the power station so remove any sharp edges or tripping hazards nearby. I'm already scheming lots of ideas for how to improve the power station for next time. We ran this event late spring just after lunch and the Christmas lights could be seen OK, but only because the fence was in the shade. They would look a lot more interesting around supper time in the Fall.

One important feature of the old cupboard was that it had handles that I could tie/lock together to guard against any kids trying to actually lick the power source or set the park on fire. We also had some grandparents watching out just in case, but I felt better knowing that the knobs were secured. Apart from the 120 volts output by the inverter, car batteries can be dangerous even with their low 12 volts because they can supply a huge amount of current. A fellow coworker nearly wrote off his car when the metal hose of a 12 volt air compressor shorted across a spare car battery in his trunk. Pretty serious fire damage.

Abandoned plans: before I discovered that it would take about 1.21 jigawatts of power for some heavy duty lights to make the Jello filled bottles illuminate in any worthwhile manner during the day (even in the shade), I had planned on running some 120 volt light bulbs (LED) underneath the bottles to illuminate them from below to get an awesome glowing effect. This cupboard was perfect for that because I could easily drill and mount the light bulbs just below the holes for the Gatorade bottles and all the 120 V wires would be kept inside the fully enclosed cupboard. I really should have made that Jello sooner :P

Jurassic Spark - Power Station panels.svg
Download

Step 6: Future Power Station

I'm actively brainstorming new ideas for the next generation of Power Station. I really would like to see lots of people try out Jurassic Spark, so I'm going to ditch the 120 volt inverter and heavy car battery for more accessible, transportable and safer options. I would love your suggestions!

Christmas lights alternative: I'm actually really excited about this to be honest. Forget the Christmas lights! Instead, I'll cut out and hand color a few of these awesome looking lighting bolts to attach to the fence when energized or give to kids to run around the fence like angry little electrons eager to zap any dinosaurs that try to escape!

Cupboard alternative: tallish rubbermaid container with neat cardboard graphics on all sides. It needs to have a bit of weight (maybe filled with winter clothes?) and stability so that it isn't easily knocked over when batteries are returned.

Battery bottle holder alternative: I'm sure not everyone wants to drill large holes in furniture or lug it around. You could skip the battery bottle holder altogether in a pinch, but it was pretty gratifying to slam that battery back down into place. See attached photo. The green layers are just to give additional depth and have simple straight cuts for ease.

I'm also contemplating cutting up some 2" lengths of 3" diameter PVC/ABS and hot gluing them to the top of the Power Station.

spite_lightning.svg
Download

Step 7: Dino Tails

We cut up a single large orange garbage bag into roughly 3' long strips about 3" wide and it worked wonderfully! I really liked how it would float out behind a running dinosaur kinda like a real tail and also allow kids to grab it from farther away (safer & easier). It's pretty easy to cut with scissors and doesn't need to be perfect at all.

Materials: 1 large orange garbage bag ($0.50). Example bag, and another.

Tools/Equipment: scissors or utility knife for cutting bag

Preparations: cut into strips on site (5 minutes of enlisted volunteer time)

Step 8: Small Dino Heads

Definitely not required as it's usually pretty clear when someone is pretending to be a dinosaur :) We only made 6 for the small dinosaurs. The kids really enjoyed coloring them before the game. I didn't get pictures of the best ones as kids took them home, but I did get to keep the heavily shanked (ahem perforated) ones. The small dinosaur would reach out with them while chasing the kids around or use them to peer out from behind trees to be a bit spooky. I'd still recommend tagging with hands though as cardboard can have some rough edges. I think the heads might have also helped some parents feel more comfortable being goofy dinosaurs at the start.

These dino heads have much smaller teeth than the T-Rex and are difficult to trace around a 1/4" cardboard template. Instead, make your master template out of thinner cereal box cardboard and use a marker for tracing. If you were going to make a lot of these, you could try spray painting over the template.

Materials: thin cereal box cardboard for template, print out (LINK), marker

Tools: X-Acto knife, cutting mat/scrap corrugated card board

Jurassic Spark - small dino outline.svg
Download

Step 9: Game Tips

Announce what is happening to keep kids focused. "One more battery left! Find that battery!" or "The fence is powered up! Get all the tails!"
Don't make it too difficult to find the batteries and avoid places where kids might get hurt (branches in eyeballs, near roads, active volcanoes…).
After about 15 minutes, start giving out hints as to where the batteries are. It's really nice to share these with the youngest or most timid kids to help get them into the game.
Be flexible and adapt on the fly. A few kids felt a bit shy and wanted to team up with their parent to be a dinosaur instead of an explorer. It was really cute watching them run around holding hands. Even though they were slower, they also had someone to watch their tail.
Set game field boundaries. This will depend on the age and number of the players. We had about 20 kids (aged 3 to 7) and 7 adult dinosaurs playing on a field of around 200 by 300 feet. Where we played, there was a path encircling the park and we made sure everyone knew all the batteries were hidden inside the path boundary.
Consider making the area near the Power Station a tag free zone to help prevent injuries. This will give kids a chance to slow down and get in control before reaching the power station box. We never officially mentioned this, but all the dinosaurs stopped chasing when the explorers got close anyway.
We made a rule that an explorer can only return 1 battery per round so that more kids got a chance.

Step 10: T-Rex: Materials & Tools

Time to build the giant T-Rex head!

Two important pieces of advice to keep in mind through this build: "we aren't building a piano", and "all you need is done". Your T-Rex's imperfections give it life and make it look interesting.

The materials are very cheap, but it does require a lot of cardboard and cutting. You'll need about 30 square feet of ~1/4" corrugated cardboard (next step has calculation spreadsheet). Make sure you get at least a few pieces that will fit an entire T-Rex head template (without jaw). Most furniture stores/IKEA will happily give you more than enough cardboard for free.

Warning: do not be seduced by super thick/strong cardboard that you may find. While it is very strong, it's also a real pain to cut and can be hard to press flat while gluing. We are going to have more than enough strength by simply laminating 1/4" sheets with alternating grain directions like plywood.

Materials:

30 square feet (AKA lots) of 1/4" corrugated cardboard.
10x hot glue gun sticks 4in x 0.43in ($3.50).
10x sheets of large green construction paper ($2) or pencil crayons/markers and white paper.
2x sheet of white construction paper (teeth & eyes).
1x sheet of black construction paper (eyes & eyebrow).
1x 1/4x2.5" hex head bolt or stove bolt ($0.5). See note 1 below.
2x 1/4 washers ($0.25).
1x 1/4 nut ($0.12).
white glue / glue stick.
clear tape.
masking tape (for tracing).
1x 8.5x11in transparency sheet or large clear plastic lid for projecting

Tools:

hot glue gun
(optional) another hot glue gun
X-Acto knife
pencil (for tracing and poking through cardboard at pivot point).
marker for tracing template although you could use spray paint if you had some. Pens and pencils do not trace around a template well as they poke through.
(optional) see also rotary tool cutting step.
enough bricks or heavy text books to flatten the head pieces during gluing.

Note 1: the length of the bolt does actually matter. We are going to counter sink it through the finished jaw so that there is no metal protruding in case an excited kid head butts the T-Rex. See photo. 10 layers of 0.25" thick corrugated cardboard works out to a 2.5" bolt.

Step 11: T-Rex: Projecting and Tracing

You'll need to decide how large you want your T-Rex to be. I wouldn't go much bigger than ours (see images) for a 6' tall person. Otherwise you'll have a hard time chasing kids and handling it. Wind may become an issue too.

If you have access to a laser printer and some over head transparencies, use that. It works great. Skip down to the projection step.

DIY Transparency Sheet: If you don't have a laser printer and transparency sheets, you can place a piece of regular printer or loose leaf paper over top of your computer monitor. Turn the brightness up to high and it will show up well enough. Trace it gently with a pencil and then darken later if needed. I was surprised how well this worked. You might run into issues with a touch screen.

You'll then need a flat clear plastic storage container lid like this one. You can then either cut out the paper and tape it to the lid, or place the paper underneath the lid and trace it with a marker. Tracing with a marker won't give dark lines, but it allows additional guide line markings for the pivot point.

Projection: affix your transparency to something moveable (I used two large recycling bins) so that you can easily set the distance to the wall (I used about 4'). Then place a smartphone with its flashlight turned on about 18" behind. You can prop the phone up in a basket or use a small tripod and smartphone holder ($1.25). Note that you cannot use a lamp with a frosted/diffused bulb as it will create a very blurry projection.

You can then trace your projection directly onto your actual head and jaw cardboard pieces, but it can be a bit difficult as you likely won't have a single cardboard piece to fit both the head and jaw. If using separate pieces, I would flip the projection upside down so that the larger head piece is resting on the floor and the smaller jaw piece is taped to the wall. The first time I did this, I projected for the head, traced it, cut it out, and then adjusted my projection for the jaw so that it would sit on the floor and noticed that it didn't look right. Oops. My two different projections had different angles and distances which resulted in different scales and skewing on the wall. Twenty minutes later, I resolved to trace them both with the same projection setup next time. If your masking tape isn't up to the task of holding the jaw piece on the wall, you could also trace onto a few taped together sheets of paper.

Remember: this doesn't need to be anywhere near perfect. We are going to butcher our beautiful tracings soon anyway in the cutting stages!

Tip: it can sometimes be hard to see your traced pencil marking on the cardboard/paper. If you turn on the room lights or use another flashlight periodically, you'll see the projected lines disappear leaving only your pencil markings.

Bonus Tip: use your projection for lots of fun shadow boxing with the kids!

Step 12: T-Rex: Cutting

I roughly modeled the design in Sketchup (see .skp) and calculated (see .xlsx) that we have to cut about 100 hundred linear feet of cardboard! I had never cut this much cardboard before and tried a few different methods (detailed below in this step).

The most important part of this build is to alternate the corrugated cardboard grains between layers for maximum strength. I actually fudged this on a few layers and it still worked out fine. Just don't have all the grains in the same direction or it might not hold up too well.

In the 3D photos, the green sheets of cardboard have the grain running horizontally (⇉), and the brown sheets have it running vertically (⇈).

To have a well supported articulating jaw, I knew that I would need to sandwich the moving pieces like jaw/head/jaw or head/jaw/head. I tried both with just a single layer of each and thought that it looked much better with the jaw on the outside. It also meant a lot less work & material as the jaw pieces (x6) are much smaller than the head pieces (x4).

I would recommend cutting a single jaw and a single head piece and see how you like them and how they fit together. You may want to move the pivot around a bit or tweak the teeth. I tried a version with perfectly matching head/jaw teeth, but it looked rather boring. I like the chaotic mess of teeth! After you're happy with your changes, use those as your master templates for the rest and trace with a marker. To test the pivot, I just gently pushed a standard pencil through the jaw and then the head piece.

Tip: spin the pencil a little bit while pushing through the cardboard (kinda like you're drilling).

The jaw filler pieces' dimensions aren't critical - they are just there to make the jaw wide enough to sandwich the head nicely. I actually used some very slightly thinner cardboard for the jaw filler so that the outside jaw pieces would be a tiny bit snug on the head to provide a bit of opening/closing friction and also extra support. To make a filler piece, trace your jaw template, cut off the teeth, and then cut it back far enough so that it doesn't get close to rubbing on the head when the jaw opens and closes.

Cut List:

2x head (vertical grain ⇈)
2x head (horizontal grain ⇉)
3x jaw (vertical grain ⇈)
3x jaw (horizontal grain ⇉)
2x filler (vertical grain ⇈)
2x filler (horizontal grain ⇉)

The head pieces are rather large and can be cobbled together from smaller pieces if you have trouble finding cardboard large enough. Definitely try to have at least one full head piece.

Cutting Options

#1 Rotary Tool Table & End Mill bit - this is the choice that I settled on because I already had the materials and knives were too slow. It took about 45 minutes to build, but allowed me to cut at around 1" per second or faster and was rather easy. It was nice being able to use two hands and not have to continually reposition myself or the work piece like I did while using a knife. I've included optional build instructions following the T-Rex build.

#2 CANARY Corrugated Cardboard Cutter. I would love to try this knife! Not everyone has a rotary tool and it would be great to have a low cost option to recommend.

#3 An X-Acto knife (like this one) worked OK (still using a sawing motion). I wasn't getting much backside tear out because of the pointed tip, but it was relatively slow due to the short blade and sawing motion. I was cutting around 0.2 inches per second and needed to go faster - the party was the next day! It could totally work if you are patient and the have time. I've since read that you may want to have a few spare blades in case they dull during the project.

#4 I initially started with a long blade Olfa utility knife (like this one) using a sawing motion. It didn't go very well. It handles long straight cuts amazingly, but having to constantly change direction for the teeth (which were originally rounded) was a real pain. You also have to be careful when punching through that you don't cause a tear out the back side. Wouldn't recommend it.

Step 13: T-Rex: Gluing the Head Layers Together

Grab 'yer hot glue gun and let's go!

Actually... hold on a second. If there was one section to pay close attention to, this is it.

Each head piece is rather large and requires a lot of glue (about 1.2 sticks) in a short amount of time (30-45 seconds). My 30 Watt Stanley GR20 could barely keep up. It would be a lot easier with two glue guns.

My glue pattern was to go around the entire outline about 1 inch from the edge and then zig-zag the interior. I chose to do it this way so that the interior glue would for sure still be hot when I pressed the other cardboard piece on top. I did have one large delamination (see photo) at the edge (possibly caused by the super thick cardboard I've already warned you against), but it was easy to reach and repair.

Update: I would recommend gluing closer to the edge if you can (two glue guns will help here as you'll have more time for precision). I did this on the small jaw pieces and they are still holding tight a few weeks later. However, the larger head pieces are feeling a bit looser and I've had to repair a few more edges.

Practice lining up the piece you are going to press down into the glue a few times. I thought I would be able to slide it around a 1/2" or so, but the glue is very tacky and was already starting to dry. I could barely slide it 1/8".

Ready, set glue! I've never blasted out an entire glue stick in such a short time. You might want to turn a fan on for ventilation.

After you've laid down the glue, quickly line up and lay down the other head piece into the glue and then start applying the bricks/weights. I let it sit clamped for about 10 minutes, but I would probably let it sit for the full 20 minutes if the cardboard's shape is bent and fighting the clamping.

Remember: keep your next glue stick handy for a quick reload!

After the stress of trying to glue two full sheets together, I decided I needed to work in sections. It goes a bit slower, but is a lot easier. The attached photos show examples of where you can bend or cut so that you don't lose much strength. The important part is that the bend/cut goes with the grain. If the cardboard already has a bend somewhere else, use that instead. I did some bending and some cutting. I liked bending instead because then you only need to line it up once and then unfold in sections.

Step 14: T-Rex: Gluing the Jaw Layers Together

Follow the same general advice as gluing the head pieces together.

There is only a bit of special advice here regarding lining up the pivot holes properly.

I glued the right jaw and filler layers together one by one letting each layer dry: jaw, jaw, jaw, filler, filler, filler, filler. Then I stopped and glued the left jaw layers together. At this point, I poked holes through all the pivot points and got ready for gluing the two jaw assemblies together. I wanted to ensure that the pivot holes stayed lined up during the gluing, so I assembled as shown in photo 4 where the pencil is keeping the head and both jaws lined up, but the left jaw is hanging up. Just before gluing, I slid the left jaw up the pencil and placed some scrap cardboard underneath it to keep it up. This allowed me to layout the glue on the filler piece, and then rotated the left jaw into place without smearing the glue. Once I was happy with the rough alignment, I pressed the elevated jaw down, slid out the scraps and placed on the weights. Time for a drink!

Step 15: T-Rex: Finishing Touches

This is where the T-Rex comes to life!

I decided to make it look more cartoonish than realistic to not scare the kids too much.

We used construction paper and white glue for the head, but didn't have enough for the jaws so we colored white paper. I would have preferred glue stick instead, but all of ours were dried out.

Once the glue has setup, take an X-Acto knife and cut through a singlelayer of cardboard so that we can counter sink the jaw bolt. One tip for lining up the head and jaw pivot holes is to make guiding marks so that you can get close right away. You can hand tighten the bolt to add add/reduce jaw opening friction. Just don't over tighten.

Don't forget to buckle up your T-Rex for the ride to the park :)

Step 16: Dremel / Rotary Table Build

I really loved this for cutting the large T-Rex head pieces. Especially around the teeth as I never had to readjust the work piece. It will cut any direction you move the cardboard. You can even start cutting right in the middle of the cardboard. You can make this real quick and dirty in about 30 minutes.

Materials:

3/8 or thicker OSB/plywood. The thicker, the wider you can have the saw horses apart. I used a scrap of 5/8 OSB.
4x 3" wood screws
2x short screws
9" of metal strapping
1 wood shim
2x 9" lengths of 2x4 scraps

Tools:

Anything to make a hole about 1.75" round. It can be really messy. I made it again by stitch drilling a circle with a 3/8" drill bit just to prove it.
Drill
Sander or utility knife
Safety glasses & hearing protection (it is pretty loud!)
Rotary Tool / Dremel
Milling/cutting bit
2x saw horses

Drill a hole way bigger than the spinning parts of the rotary tool so you don't have to worry much about alignment. Don't cut it so big that the entire rotary tool can fall through though. The size of the hole doesn't really matter because the milling bit cuts sideways and not up and down like a jig saw.

Position one of the 2x4s alongside your over sized hole. Screw two of the 3" screws through the OSB and into one the 2x4.

PRO TIP: many people suffer from loose screw syndrome. Now that could mean a lot of things, but in this case I mean fastening two pieces of wood together with a screw, but the wood isn't secured together tightly. You can often see a visible gap between the wood pieces. We need some tightness for this build. You can either pre-drill your holes, use a clamp, or simply back the screw out again, hold it tightly and drive that screw home until it sinks in about an 1/8".

Now for the slightly tricky part. We are going to toe screw the next 2x4 onto the first one using the remaining 3" wood screws. See pictures for tips.

Then secure the rotary tool to the 2x4s with some metal strapping and shim as required to make the cutting bit perpendicular to the OSB surface.

Sand down any rough edges around the hole to prevent cardboard from catching on them. I don't have a power sander so I just used a utility knife and it worked OK.

Step 17: Party Notes

The first hour of the party the kids made dinosaur crafts like coloring in these masks and the small dino cardboard heads. This gave the adults time to assemble the rest of the game props.

We hosted the party right after lunch as it was the best time that worked so we just served dinosaur teeth (water melon slices), oranges, and dinosaur plops (cookies).

We suggested that kids wear sun hats so that they would look like little archaeologists running around :)

Don't forget to offer the kids an action photo with their favorite T-Rex!

Supplies: food, table cloth for picnic table, coloring supplies, scissors, scrap cardboard pieces to lay on the ground and color on top of.

I've also attached some graphics you may want to use for making your own invites.