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Glowing "hot" coals ...

132K views 252 replies 106 participants last post by  ThakingDbb 
#1 · (Edited)
I searched the site for all the key words I could think of but didn't find anything like this so here goes ...

First, want to give credit to someone named "Goldie" at Instructables . com for the basis of this idea. My changes are not earth shaking - more like adaptations to create a "heat" source for "cooking" up some goodies in cauldrons in our new Witches Coven.

Here is a pic of the final results in low light with Cauldons setting on the prop.




Materials:
  • A "fire bed" shaped per your needs, made of anything from foam board to 1" plywood. Whatever suits your needs and how well you want it to hold up year after year. - Craft store or Hardware store
  • Several strings of lights to your choosing. I used one string of 150 Orange lights with a controller (button selects differnt flashing patterns), two strings of 50 orange lights, two strings of 25 purple lights and one string of 50 orange and purple (same bulb) lights. I think that last string was not necessary. - available anywhere - got programmable lights off of ebay, be patient there
  • Wiffle balls of as many different sizes as you can find. I found softbal sizes, hardball sizes, and golf ball sizes. I also used a few orange pingpong balls. The quantity will depend on your taste and the size of your fire bed. I suggest you buy one package of each size and add more later as you like. - most came from Walmart
  • Fire grate - optional dependent upon your application. I used four tree supports landscapers use to hold up a newly planted "small" tree. - Landscaping section of a large hardware store
  • A few Screws. - hardware store
  • One piece of 3/4" plywood about 12" x 14" (very optional). - hardware store or your scrap bin
  • A small bottle of acrylic craft paint in gray - think ashes. - Craft Store
  • Great Stuff expanding foam - my "fire bed" required alomst all of two cans. - hardware store

Tools required.
Something to cut your "Fire bed" to the size and shape for your application. Could be an exacto knife or a Utility knife for cardboard or foam board to a circular saw or jig saw for plywood shaping.
A good Hot Glue gun and lots and lots of sticks.
What ever you need to cut your grate if you use one. I use my sliding compound miter saw and a drill press (for the vericle supports), but you could get by with only a hand saw.
Screw driver

Steps:

1. Decide / cut to size and shape, your "fire bed." Keep in mind that the larger the "fire bed," the more components you will need, but the greater the impact, IMO. Also, I think the programmable lights really improve the affect but should NOT be used without some other lights staying on all the time.

For the picutured prop, I used a rectangular sheet of 1/4" plywood about 4' 6" long by 20" ... because that's what fit the intended display space.

2. If you intend to use a grate, determine where you want the verical supports and mark those locations on your bare "fire bed" material. Our plan required extra support in the middle where we have a "boiling" cauldron of eyeball soup brewing - filled with water and floating eyeballs. Water is heavy and could ruin the prop if the grate breaks. BTW the pics don't show this well because the water was low and the mist was high at the time.

3. Cut your wiffle balls in half. If you want your surface to be uneven, cut some balls at 3/4 of their height rather than half.

4. Spreadout the lights on the "fire bed" in a very irregular. Take care not to infringe upon the vertical support areas. I tried to group a good mix of the different featured lights as much as possible, but some remained by themselves and that's ok too. Have one of the cut wiffle balls handy to give you and idea of the space needed for the groupings.

Most crutial here is the placement of the control box for the programmable lights and the accessability of the male plug that will power the strings of lights. Try to have enough length to it that it can extend away from the prop to better hide the power source ( I didn't do this well on mine).

More in the next post.....
 
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#236 ·
It's called Great Stuff. You can get it just about anywhere, but it runs a little on the expensive side if you're on a budget. If you have a Habitat for Humanity ReStore near you, check there. I got slightly damaged cans for $2 each.

I found out what was causing the smell in my first set of coals. It wasn't the Great Stuff burning. It was the heat from the string lights being held in starting to melt the wires. It's a HUGE health hazard to your guests, so you need to be careful to either use LED lights that don't heat up, or use my method of chicken wire to build open space so air can flow in there and keep the lights cool.
 
#238 ·
Great Stuff is great, but you need to know:
VERY MESSY
VERY sticky
The thicker you lay it on, the longer it takes to dry
Will always shrink - I made about 200+ skulls with it using fine sand molds. The skulls would shrink and deform - actually look cooler IMO - for about two days.

Wear disposable rubber gloves and I recommend you coat them with WD40 (I also used WD40 on my sand molds to minize the wasted sand)

Do not expect to change the shape of the great stuff by touching it to move it. Better to spray too much, then cut down with a knife (cuts VERY easily when dry) later.

Walmart has a GE copy cat brand of Great Stuff that is about a $1 or so cheaper than GS. It seems to have identicle characteristics.

I STRONGLY recommend you work in the confines (no wind) of your garage and on a plastic drop cloth.

You can paint the dried GS with spray paint, acrylic or whatever.

In my experience, NONE of my LEDs covered in GS have gotten too hot. However, there have been some reports of this being a problem. IMO it's best to use pieces of a milk carton or whatever, to create air pockets around a group of bulbs before you spray, then poke a hole thru the GS as a vent. Several have reported this is not necessary - it may not be for most lights. My oldest "Glowing hot coals" use this process. They are about 5 years old now and still function perfectly despite being stored out side, wrapped in a couple of plastic bags.

Hope this helps.
 
#239 ·
Do not expect to change the shape of the great stuff by touching it to move it. Better to spray too much, then cut down with a knife (cuts VERY easily when dry) later.
You can actually do this to some extent if you wait till it skins over, but not fully dries. You should be able to pinch, crease, dent, and dimple it to add more texture, or squash down parts that are too high. You won't be able to make huge changes, but you can add subtle details this way. Just be sure a good thick skin has formed and wear gloves in case any squeezes out.
 
#241 ·
As I posted in the "other" hot coals thread, LED's & even plain old string lights are usually perfectly fine in Great Stuff/Foam-O-Fill. I've been running a similar method for years with plastic dipped orange light strings, and when disassembled after 2 years and nearly 200 hours of run time. There is no signs of even minor scorching and I didn't bother with whiffle balls or plastic bottle tops. Mine were in direct contact w/ the foam unlike many others, but I didn't use a cheap light string either. Mine (I have 3 different effects using this method) were made with the more expensive Walgreen strings, although I forget the manufacturers name offhand.


I'd be more suspect of that foam skull &/or the light string used itself being defective/cheaply made than the Great Stuff. You can see in Sliders pics above that the foam skull is getting hot enough to crack the paint which indicates it's not the Great Stuff alone, but the lights themselves. I'm not suggesting you shouldn't test first, I'm just saying that there's some other circumstances going on which aren't indicative of the general results many have had with this effect.


My hell hole from 2010, after disassembling for a makeover after Halloween last year. Lights in direct contact with Great Stuff. Note, no scorching, burning, etc...









The different effects they're used in...





Better pic of the coals...





Used in the coals under the cauldron & the glowing overflow on the cauldron...





In summation, I've used this effect quite a bit with no problems. Which is what leads me to my conclusion about it being the only possible variation being the light strings used, since I used the exact same brand of foam & 3 different types of that particular brand. In other words, only use higher quality incandescent light strings &/or LED strings.
 
#242 ·
Just a hint website ShopWildThings dot com does have orange light cellophane gels if you can't find anything else for coloring white lights.
 
#246 ·
I'm in the middle of revamping my Hell Hole, & thought I'd share how the lava flow is turning out. For the most part, it's sticking with the same formula. Built in sound (demonic whispers, screams of tortured souls, and such), starter flicker circuits x2, & the piped in fog of course. Plus the skeleton is getting the leering effect for a little more animation & I'm considering swapping to aural exciters instead of the traditional speakers. :D



I need another string of lights before I can do the inside of the "hole", but I think it's turning out pretty realistic. What say you?


 
#250 ·
Many thanks Dave! I keep saying I'm going to do a tutorial on this thing, since so many have requested it. Now's about the perfect time to do so, I'd guess. :D


The only thing that worries me, is that most aren't going to go through the trouble of digging a 2 1/2' diameter, 2' deep hole that it needs to sit the basket down in. I'd be disappointed if no one bothered to give it a go.
 
#251 ·
I like the green around the rim of the cauldron. I made my glowing coals by taking a big chip bowl on the ground. Then covering it with plastic wrap. Then great stuffed the upsidedown bowl. Once it was set some orange and black spray paint layers for coals. No this is where it really got cool, I put 2 strings of orange string lights and 1 string of "random sparkle" white Christmas lights and I swear it looks like real fire glowing. I'll try and post pic or video soon.
 
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