How about making the general shape from chicken-wire, then covering it with hessian scrim (don't know what it's called in the US) dipped in plaster of paris? Lightweight, you could paint it to suit, and if you had a light inside it wouldn't shine out through the sides.

Found a picture of scrim

Here is a link that might be useful: Hessian scrim

Hi Andrea! My mom pointed me here, she's been doing hypertufa stuff for a while. :)
I made a volcano last year for my annual Luau party, using chicken wire, and expanding foam - that Great Stuf that comes in the yellow can. The really neat thing about it is that it makes really organic puffy texture that really looks volcano like. I had to use 4 cans on my volcano, but I have some ideas on doing it with less next time. (The foam went right though the chicken wire, which made it need to have multiple layers)
I left a few places with just red cellophane so light would shine though, and lit it with multiple strands of xmas lights on different blinks and one solid, so it alternately glows brighter occasionally. Put my fog machine in it on a long timer, so every 15 minutes or so it blows. :)
I have pictures, but they're not on a web page, but that sounds like a great project for me to do today, so I'll post the webpage later.
Also, I'm in San Diego, so if you'd like to come see it, shoot me an email. :)

These are great ideas! I hadn't thought of putting lights on the inside. Runningdog, I had those same thoughts about building the volcano and I've used that method on other projects. Slapping the pop on as fast as you can before it sets is a lot of fun, but my garage was such a mess! I had flung pop all over my garage cabinets, not to mention my clothes and hair.

Mieko, how big is your volcano? I want something spectacular but after Halloween, storage is always an issue. I made a huge ugly face last year with a gapping mouth, which everyone loved, but my son refuses to throw it away. So this ugly chicken wire and pop creation sits in his backyard slowly disintegrating.

My preference is to make a gargoyle or turkey vulture hanging off the roof, but a volcano is what they want. I'd love to see the pictures. What part of SD are you in? I live in Mira Mesa.

Andrea,

I was about to say there's some great idea I saw on here where someone made a cool smokin' face last year but then I found out it was you!

Just spinning off from Mieko's idea and thinking about something collapsible, I'm wondering if you couldn't make a sort of collapsible volcano wireframe and then cover it with a texture blanket--I'm not sure, could you use that cheap wide weave net you get at the material store (forgot the name of it), fit it like a wrap blanket over the wireframe and add a texture to it that wouldn't crack when you remove it. I wonder if the Great Stuff would stick to it and not crack? Maybe incorporate some bead foam to it, spray paint would add texture by dissolving it...just spinning ideas...

Yeah, storage is an issue, the volano is about 3 feet tall and has a footprint of about 18 inches by 18 inches. I haven't found any way of storing mine, so it sits in the corner of my living room.

I like the looks of that scrim, If you built a more involved but collapsable frame, you might be able to use the great stuff over the scrim and just piece it together.

I got the webpage together, but am having technical difficulties with RoadRunner on getting it hosted, but it should be up soon.

I'm in Tierrasanta, not too far, so we could probably meet up. :)

Oh, this is FUN!! And now I want a tufa one next to my pool...

As for making one to store, how about making it in three sections. A top "cone", a middle open circle and a larger botom circle. Engineer the sides of the circles to "lean" inwards for that volcano shape, but be large enough at the top to keep the next layer from sliding too far down.

Then, when the party's over, disassemble and store the pieces inside each other, in reverse order.

I could do that for my tufa version, iffen my engineer DH would help with the dimensions.

Take pics, we wanna see it!

Rockyn, if I make it in sections like you've suggested, then I can make a much bigger volcano and store the pieces like nesting bowls. A 5 or 6 foot structure would be great!

Last year when I made the big face I used sticky drywall tape which made a good backing to hold the pop. Would cheesecloth work as well? It would be easier to apply and would cover a larger area of the chicken wire.

Andrea

The cheesecloth will grab hold like a maniac. It loves POP. :-)

Andrea, I saw this effect I thought about your project again. Check out the bottom of this page under Fire.

Here is a link that might be useful: Fire effect for volcano

Have to put in my 2 cents. You can also use Rigid Wrap over your chicken wire! You can buy this at Hobby Lobby.

I love the idea of the flicker lights for the fire effect, but if I can't find them Mieko's idea with the Christmas lights will work too. It looks realistic enough. I don't think we have a Hobby Lobby in Southern California, at least I've never heard of one. Our big hobby and craft store is Michael's so I'll call them and ask about rigid wrap. Only 6 months left before Halloween so I'd better get movin on this project. It's just a shame that Halloween is only one day, however it falls on a Tuesday this year so we can have a party on Saturday and celebrate till its Tuesday!

If you have a bit of a breeze hanging strips of mylar around and behind a light will make it flicker very much like a candle. It looks very cool.