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I have made pretty  big spider (about 5-6 feet across) and the cost was less than $35. The item is light, big, weatherproof, creepy and cheap. Cheap being the key word. I would make Ebenezer proud.

Items you'll need:
3 Balloons
1 plastic garbage bag
1 can black spray paint
1 can gray spray paint
Duct tape
Glue gun and glue sticks
8 eyelets
8 short pieces of wire
Orange felt or craft foam
Utility knife with expandable blade
3 cans of spray foam insulation
1 tarp...yes this is a messy project
4 eight foot lengths of pipe insulation

Step 1: Lash Legs Together

Lets start with the legs. I used the foam insulation tubing you can find at Homo Depot. An eight-foot section runs about a $1.10. Get four of em. You will start by lashing them together in the middle and reinforce the lashing a couple times on the sides evenly. Ya don’t want your speeder to go all Jimmy-legs on you before you want em to.

Step 2: Create the Balloon Body

The basic shell for the body was made out of balloons inside a garbage bag. Cost…pennies.  I placed the balloons inside the garbage bag to have more control, but more importantly to try to keep the balloons from popping before the project is completed. Believe me I was insanely paranoid about them a poppin’ and treated them as a fledgling mom would treat a newborn. Well a newborn wrapped in a garbage bag. You will want the ass or “Abdomen” be comparatively larger than the rest of the body. The pointy end where you tie the balloon will be in the back where the webs would come out.  I used two small balloons to create the rest of the body. A bit of spider trivia…insects have three segments to there body: Head, thorax and abdomen. Spiders aren’t technically insect they have a classification all there own, “Arachnid”. The head and the thorax are one single element called a “cephalothoraxes” . the two smaller balloons will be made to look like this second body area.

Step 3: Attach Legs to Underside of Spider Body

Using twine, fasten the legs to the body. This will be on the underside.The string will eventually be hidden.

Step 4: Mark Your Leg Joints

Legs have joints so you need to mark them. This is on the underside.  Two marks dividing the leg into thirds. It’s easier to work with if they are marked in case you go astray or get distracted.

Step 5: Cut a Notch Into Leg Joints

I cut notches in the foam tubing so the legs could bend. This is on the underside.

Step 6: Cut a Slit in the Legs Near Body

The legs will need to bend away from the body. I slit the tubing close to body to accommodate the bend. In hindsight I should have cut a slit on the top of the legs to accommodate the joints. Unfortunately I started on the joints first so this tidbit of information came a bit to late.

Step 7: Close the Leg Ends

I closed the ends of the legs with duct tape and fastened a reinforced eyelet on both sides of the tubing. This goes back to the jimmy legs. I am going to have to position em and I don’t want the foam coming apart.

Step 8: Wire Your Legs

Having galvanized wire on hand, I threaded a loop of wire through each of the eyelets. Use heavy wire or a coat hanger. This wire will be used to anchor the spider and has to be tough enough to stand up to abuse.

Step 9: Flip and Position Body

Your going to start working on the body now. All sorts of mess making stuff is going to happen from this point on. I placed a tarp over a scrap piece of  particle board.  The tarp was an added paranoia moment where I didn't want any wood shrapnel causing the body balloons to pop. I used the wire loop to position the legs where I wanted them in relation to the body and staple-gunned them to the tarp and board.

Step 10: Start Foaming the Body

Now this is the relatively uncheap element of the spider equation. Spray foam insulation. Ya know the kind you get at any hardware store.  About six bucks a can and they make it in different grades of expansion  and rigidity. There was a learning cure here. For the body I sued a medium expanding semi-flexible spray foam for the body. That was one entire can…you really don’t get a lot of mileage out a can.

Step 11: Foaming Head and Legs

I went to a different hardware store for the more foam for the legs and underside. This foam expanded more and was much more rigid. I foamed the legs and head on the top. Making sure to have a bigger dollop on the bend of the joints.  This was another entire can.

Step 12: Foam the Underside

After curing I flipped the spider and used another can secure the legs and complete the body parts as best I could. I didn’t do the entire underside because no one should be able to see it once the spider is completed and mounted.

Step 13:

After more curing,  give it overnight, I shaved the body to give it more definition. The foam comes out in can be best described as those cheap fire work snakes on a bigger scale. The texture is cool and could be left alone. Working with foam leaves a lot of  “maybes” in the fray. Maybe it will form to shape I want it. Foam has the tendency to have a mind of it’s own. Expanding and sloping around. Another reason for the tarp, this stuff just seems to stick to almost everything. Wear clothes that you don’t care if they get messed up. If you have rubber gloves, use them to. If you get this foam on your hands it doesn’t wash off and your hands will be sticky for quite some time. I guess you could use it for own Spiderman touch if you liked to look at it that way. I didn't.

I used an expandable utility knife type cutter. I positioned the blade all the way out and had a long razor knife.  Worked very well for carving. The Rigid foam seems to carve better than the flexible foam.

Step 14: Reinforce Leg Bends

More of the learning curve. Even with the notches and foam, I had a degree of Jimmy-legs.  I should have notched them on the top and semi-filled the joints. I ended up hot-gluing the notches together to keep the legs bent to where I wanted them

Step 15: Reinforced Gluing of Leg Foam

Remember where I said that this spray foam insulation would stick to about everything?  Well it turns out that the foam tubes have a slick factory sheen to them and the foam doesn’t stick to it like it would anything, and I mean anything that you wouldn’t like the foam to stick to.  This was the rigid foam. I may have had better luck with the flexible foam. Lesson learned. I ended up having to hot glue the foam back on to the legs. Time consuming and hot glue consuming. As a side note, if you have a temperature setting on you glue gun, use the low setting. The hot setting makes the glue so hot that it will start to melt the foam tubing and cause poor adhesion. Another lesson learned.

I learned a nifty trick on this one. You want to glue the foam back onto the legs and who wants to just sit there and hold the piece on.  If you choose to use rubber-band to hold them in place there is a trick so don’t have to go the entire length of the leg. Wrap the rubber band around where you need it and hold the ends together with a bulldog clip. Works very well and easy to put on and remove.

Step 16: Paint the Underside

Now time for painting. I used Rust-Oleum flat black enamel.  I used flat black, because I think that a gloss would make it less creepy and obscure details. I don’t recommend Krylon brand. The spray nozzle for Krylon directs the spray in a band vs. a circle spray  pattern. It might be good for lawn furniture but not necessarily for spiders.  I sprayed the underside first. Looks like a dead spider.

Step 17: Paint the Top

I let it dry overnight and sprayed the top. Walk away for a few hours and inspect for missed areas and touch up where needed.

Step 18: Paint Depth to Your Spider

I used a grey primer to give more slight definition to the body and hit the “joint-bulbs” and feet. Not to worry if you spray to much gray. Just spray some more black to get the desired look.

Step 19: Get Your Eyes On

A spider needs eyes to see and I am cheap cheap cheap. I wanted eyes that were glassy and reddish. My solution was to use the dropped glass ball things that you can get at the dollar store. Normally I hate these things and cant see any nifty applications for these travesties of the craft world. I hot glued redish craft foam to the flat back side and trimmed. I then glued them to the spider.

Step 20: Wrap Up With Teeth

The mandibles were created from a flat piece of foam insulation that I had left over form another project.  The teeth were carved form the same insulation. They were both painted and glued into place.

Step 21: Finished Project and Mounting

I mounted the finished spider to the gazebo on our property. The metal loops on the ends of the legs were staple gunned into the shingles. It took a couple staples per leg, but they allowed on to re-position the placement of each leg, and surprisingly these multiple staplings have held this spider in place even in high wind.
<p>Thank you for these easy to follow instructions. I think even I could make one of these later this year; it would look great, lurking just inside the gateway!</p>
Wow...I really like this and will need to make one for 2013's haunt. Great tutorial!

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