# How To: Cold Burning Coals



## loach160

*How To: Hot Burning Coals*










*Hot Burning Coals*

The Hot Burning Coals prop is a dramatic effect that is fairly simple to build. The “coals” can be placed under a cauldron, in an open fire pit, or just about anywhere you need to have fire in your haunt without the heat.

*The Supplies*


1 string of 50 orange LED Christmas lights
1 can expanding spray foam
1 12 inch square piece of wood or plastic
1 can black spray paint
masking tape
assorted plastic bottle tops and/or bottoms
box cutter or scissors

*The Build*










Start out by gathering up some small plastic bottles and cutting the tops and/or bottoms off of them. Using the masking tape, attach the bottle parts to the square. Then, unwind the lights and “drape” them over the square. Try shoving some of the lights up under the bottle parts for a more interesting effect.










The next step is to coat the entire prop in expanding spray foam. Before you do this, it is very important that you double-check the lights to make certain they work. Once the lights have been sprayed with foam, it will be impossible to access the bulbs. It is also important to stick the power plug off to one side. This view of the underside of the prop gives you an idea of how things look "inside".










Go easy on the foam, spraying a little bit at a time. If you’ve never worked with expanding foam before, take some time to get used to how quickly it grows. You want to have the lights coated, not buried. The goal is to create coal-like lumps in the foam. Whatever you do, do not touch the foam with your fingers until it is totally dry. The prop will need to sit overnight to dry all of the way through.










Once everything has dried, go ahead and plug in the lights to get a look at the coals. If you’re happy with the shape of the “lumps”, spray everything with a light dusting of spray paint. The paint will help to disguise the foam when it is out in the daylight or if it is hit with any of the other effect lighting in your haunt.










The final step is to find a spot to display your prop. In our haunt, we have a small pile of coals underneath our seeping smoke cauldron, but you could place your coals just about anywhere. Using more lights and more foam, you can create a larger scale prop to make a lake of fire, a lava-spewing volcano, or even a pit to burn someone at the stake. The only limit is your own imagination.










As a side note. I used plexiglass just because I had it laying around. plywood would do as well. When the foam dried, the ends did warp a tiny bit. Probably from the heat of the foam. 

Also, at the end of the Halloween season, Big Lots has a 50 to 90 percent sale off there halloween lights. Run don't walk. I like using LEDs instand of old style lights because of saftey and longevity. LEDs don't get hot like conventional bulbs.(other then the resisiter getting warm.) So the risk of a fire is greatly reduced and after 3 years of using LEDs I have yet to replace a single bulb and considering this prop is encased in foam, theres no chance to replace the bulb.

This year I will be adding blue LEDs to the center of the lights. I will post pics when I'm Done. 

I LOVE this site. EVERYTHING I built I got the idea from this site. Have fun !


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## beavervw

Love this effect! Awesome job!


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## Terra

This would look great in the lava room I'm planning. Thanks


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## Revned

Awesome job, Perfect for around the Devil ground breaker I have thought about building.


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## halloween71

Great tut!!


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## doto

I too am hoping to add this effect in an underworld.

Revned,
I'd love to see your groundbreaker if you go through with your plans.



> Awesome job, Perfect for around the Devil ground breaker I have thought about building.


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## DaveintheGrave

Looks fantastic! Thanks for the How-to!


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## BadTableManor

Cheap, easy, and effective = perfect!!! Thanks for posting!


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## jpbaily1

Great idea with the plastic bottles, that is how I did mine as well last year for my skeleton bbq.

Click on the link below.

http://www.halloweenforum.com/tutorials-step-step/98244-glowing-coals-effect.html

John


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## TrickRTreater

Wow that is clever as hell!

I'll have to remember that if I ever want to do a campsite haunt with my Jason Voorhees costume.


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## broevil

This is a great idea, I have to find a place to use it!


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## rawhide

i LOVE that idea!!
and you did a great TUT with easy to follow instructions 

now i know exactly what im going to do to the fireplace. 
my fireplace is made of fieldstone and the mantal is 6" thick wood and all looks very old. so a bunch of bottles and jars and cauldron and the glowing coals and some cats, rats, crows, cages, spiders, flicker candles, and a stand i plan on making of bones to hold a "recipe book" and an old decreped woman standing close by will hopefully make a good scene.

im wondering if i place a few logs in with the coals and string the lights and a lil foam on them too if it would look like the logs are on fire as well???
has anyone tried that yet?


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## savagehaunter

That is a wonderful prop. I tend to go a little wild with the Great Stuff foam. I am going to have to try this.


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## Beyond_Redemption

Love this idea. Gonna try it for sure this year.


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## loach160

jpbaily1 said:


> Great idea with the plastic bottles, that is how I did mine as well last year for my skeleton bbq.
> 
> Click on the link below.
> 
> http://www.halloweenforum.com/tutorials-step-step/98244-glowing-coals-effect.html
> 
> John


Actually, I got the idea from your post. belated thanks


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## Si-cotik

nice, simple yet effective just the way i like it


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## bootoyou

What a cool effect, I never would have thought that the light would go through the foam so well. That looks so great, you just improved my groundbreaker scene tremendously. I will have to spread the string out over more area, but you can always add another string. Awesome, thx


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## Si-cotik

a question, what is the purpose of the plastic?


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## jpbaily1

I just used it to give height to the otherwise flat & 2D look that you would get by not using the plastic.

I suppose that you could go with just the foam, but it wold take a lot to get any depth form it.

Plus it may not let the lights show through if the foam is too thick.

John


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## Si-cotik

that makes sense of course


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## jpbaily1

It was a logical inquiry. :0


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## Predator35

Thgat is a pretty cool idea. I to love this site, cannot wait to build some things and show them off.

Daren


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## Raven's Hollow Cemetery

Nice job. I did this effect a couple years ago with the standard incandescent strings & small limbs to make it look as though the fire might rekindle itself. As best as I can tell, there has been no detrimental effect from using the standard strings.


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## loach160

Raven's Hollow Cemetary said:


> Nice job. I did this effect a couple years ago with the standard incandescent strings & small limbs to make it look as though the fire might rekindle itself. As best as I can tell, there has been no detrimental effect from using the standard strings.


The only resons I prefer LEDs is longevity and no heat from the bulbs. incandesants are definetly cheaper though. Its a personal preference


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## Raven's Hollow Cemetery

loach160 said:


> The only resons I prefer LEDs is longevity and no heat from the bulbs. incandesants are definetly cheaper though. Its a personal preference



Oh yes, LED are the way to go now w/ 50k+ hours mtbf ratings. The strings of LEDs were pretty scarce in this town when I made mine, so I just ran with what I already had on hand. 

Either also works well on a hell hole for that fresh lava splashed look.


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## Xane

I used LEDs but the directional light was a problem. I had to change all of them to make sure they pointed directly up at the foam, so if I did it again I'd make some kind of little frame with clips to aim the lights correctly. I also think I made the foam too thick so I plan on thinning it for this year.


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## Raven's Hollow Cemetery

That is one downside to the majority of LED's. Their lens is usually focused to a 15-25° angles of dispersion, especially in the less expensive LED's found in strings. Wide angle lenses of up to 120°'s can be found, but they're typically found in SMD packaged variants (self adhesive strips is what you can more often than not find them on for consumer applications). 

For persons without access to a reflow solder station or extremely steady hands & a fine tipped soldering iron, the strips are a much more viable option. Ebay is a great source for inexpensive SMD LED strips btw. I'd highly recommend the versions in the ultrabright 5050 SMD package. Like these:

http://shop.ebay.com/i.html?_nkw=Or...d+strip&_osacat=0&_trksid=p3286.c0.m270.l1313


I'm in the middle of constructing a custom 1920 x 1200 resolution projector, using these very same strips in the white 9500K color temp range.


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## scarybella

top work. looks like another project for me to do before october lol


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## Predator35

I just made a set-up tonight.It is in the drying stage, will paint it tomorrow
.Thanks for posting this idea.


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## halloweenscreamqueen

I've done several versions of this. The only suggestion I'd add is that you lightly spray with several shades of grey spray paint when everything's dry. It really adds a lot and makes it look more believable in the daylight. Cheers!


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## loach160

I agree with halloweenscreamqueen. Go lightly, with several shades. Post it when your done so we can see.


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## Badwolf

This looks great! How do you manage to get the cauldron to sit on the "coals" without wobbling?


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## tinafromidaho

Hooray, I made burning coals. I used the flicker lights around the very outside so it will look you know, flickery.


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## tinafromidaho

It looks much better in person than in that picture, It will be perfect under my cauldron. Now I think I am going to make a rectangle shaped one to make some kind of static BBQ for my butcher shop area.


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## Predator35

did you use flickering christmas lights?


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## tinafromidaho

I used these.


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## Raven's Hollow Cemetery

Badwolf said:


> This looks great! How do you manage to get the cauldron to sit on the "coals" without wobbling?



I used several 1 1/2" to 2" fallen tree branches, then attached them to a base of 3/8" CDX plywood while winding the lights around them. Being careful, ofc, not to let a bulb get stuck between the branches and plywood. To attach the cauldron, I just pre-drilled some holes straight through the cauldron & branches. Then used 1" O.D. washers w/ drywall screws to attach the cauldron. Works beautifully w/ my stirring cauldron, having no wobble problems whatsoever. 

I have some new ideas to integrate, and hopefully I'll find time this year to do so.


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## loach160

Badwolf said:


> This looks great! How do you manage to get the cauldron to sit on the "coals" without wobbling?


When the foam is dry to the touch but moist under its shell, you should be able to push it down. (about 10 min I think) If you let it dry overnight its too late. The foam will be hard.


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## Badwolf

loach160 said:


> When the foam is dry to the touch but moist under its shell, you should be able to push it down. (about 10 min I think) If you let it dry overnight its too late. The foam will be hard.



Okay that's kind of what I imagined. Thanks for the info, I'm going to try this one!


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## Raven's Hollow Cemetery

I wanted mine easily removable in case of a malfunction. To each their own.


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## rebelxwing

Such a realistic technique, I love it! I wonder if lightly sanding each individual LED to diffuse the emitted light might make them look less focused under the Great Stuff? I am a real fan of using LEDs myself due to their long life and their low current draw... means I can run my entire haunt with 2 heavy-duty extension cords!


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## Raven's Hollow Cemetery

rebelxwing said:


> Such a realistic technique, I love it! I wonder if lightly sanding each individual LED to diffuse the emitted light might make them look less focused under the Great Stuff? I am a real fan of using LEDs myself due to their long life and their low current draw... means I can run my entire haunt with 2 heavy-duty extension cords!


Yes, you can sand them to diffuse the light. The downside is that it also drastically cuts down the light output. The simple way to get around it is using wide angle LED's instead. SMD types in the 3528, or 5050 package are well suited to this idea. With dispersion angles of up to 120 degrees. 

SMD LED strips of upwards of 5 m. in length (and smaller ofc) are easily purchased through Ebay very inexpensively, compared to what they sell for at retail establishments in the U.S. Although, I'd hurry if I were planning to order from overseas, as shipping times are highly dependent on the workload that the Custom's office has at the particular port of entry.


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## imindless

Did you use Great Stuff Gaps and Cracks or Big Gap Filler? 

I bought the Gaps and Cracks and fear it will be to stringy and I should have gotten the Big Gap instead. (I think they were out of Big Gap at the time and thats why I got the other one). Just thought it would be a good question and others might wonder since they have a variety of options.


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## loach160

Gaps and Cracks


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## halloweendemon

loach160 - This is amazing! I figured I would give it a shot tonight, even though I am not very good at creating decorations from scratch. However, this is almost fool proof. Absolutely love my results! Thanks!


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## Jaybo

Has anyone tried this technique with a different color? Maybe blue LEDS and paint the foam white? I might try this on a small scale with some RGB leds just to see what different looks you can get.

You could coat some haunt walls with this and then make the leds pulse with a PWM controller.

Lots of possibilities with this.


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## Raven's Hollow Cemetery

Yes, sort of. Though not w/ LED's (they would work fine, I just used what I already had on hand). I used the toxic green colored strings of lights I use at the bottom of my cauldron and drilled a few holes in the side to push them through into foam-o-fill to give it a self luminescent look to the spills over the side. Worked out just as well as the coals do. But you would ideally want them closer together so there is no gap in the intensity of the lighting when used like I did.


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## tinafromidaho

*Here are my burning coals*















My coals I used regular orange lights and flicker lights.


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## chop shop

Great Tutorial! Thanks.


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## pinkprophet

THANK YOU for the step by step!!! For the past few years, we have used glow stix to get the effect of fire...it just doesnt come close to what we needed. Awesome job!!!


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## kmg3333

How did you get the top of the coals level enough to hold the cauldron with out it tipping over?
Thanks!
Karin


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## RandalB

Just finished this one with the kids. Looks fantastic and was super easy. Great Idea to the OP. We did a cut out of a 55 gallon drum cauldron on a piece of cardboard and went from there. 

RandalB


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## loach160

kmg3333 said:


> How did you get the top of the coals level enough to hold the cauldron with out it tipping over?
> Thanks!
> Karin


When the foam is dry to the touch but moist under its shell, you should be able to push it down. (about 10 min I think) If you let it dry overnight its too late. The foam will be hard.


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## loach160

Shows us your coals


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## The Pod

I soldered together 45 red LEDs instead of using xmas lights. (copied the Efx-Tek WickLED circuit). 








Then wired everything to a Efx-Tek Prop1 and used the candle program to create a random flickering/fading effect of the coals.


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## Samhain1031

I've seen this for the first time from a couple of different sources this year and I have to say, every time I see it, I'm impressed.


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## LT Scare

Samhain1031 said:


> I've seen this for the first time from a couple of different sources this year and I have to say, every time I see it, I'm impressed.


Yeah, I first posted this in 2009 right here on HF. It's had a few hits:


http://www.halloweenforum.com/tutorials-step-step/86951-glowing-hot-coals.html


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## Deadview

This is one of my projects for this year, it looks simple and effective. I need to locate Blucky and a 5v 5a motor for my stirring cauldron, great work !


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## SavageEye

The Pod said:


> View attachment 100821
> 
> 
> I soldered together 45 red LEDs instead of using xmas lights. (copied the Efx-Tek WickLED circuit).
> View attachment 100826
> 
> 
> Then wired everything to a Efx-Tek Prop1 and used the candle program to create a random flickering/fading effect of the coals.
> View attachment 100828


Hey Pod, I would love to see a tutorial on your design. Where did you get your LED's? Is it true that some LED are ok for dimming while others are not? Thanks!


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## Patrick

Very Nice. Will defineately be doing this for my haunt.


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## Raven's Hollow Cemetery

SavageEye said:


> Is it true that some LED are ok for dimming while others are not? Thanks!



The LED's themselves can all be dimmed to a certain extent via current limiting, or voltage drop. They however, are not as linear as an incandescent type lights. To dim them further (say around < 20% of total rated output-just a rough estimate % wise), you must use a PWM type dimmer. Otherwise they will flicker noticeably, or not light up at all past a certain drop in voltage.


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## loach160

hey pod love the creep. I used the burning coals effect but I did it an hour before trick or treaters came and it didn't turn out the way I wanted it. I used about 3 to 400 leds with 200 of them being blue. I layered the lights, as I used 2 cans of spray foam. It Looks fine at night but in the daylight not so much. I will be redoing this project over again this winter. Pics of progress to come.


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## loach160

What did you encase the LEDs in?


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## loach160

The Pod said:


> View attachment 100821
> 
> 
> I soldered together 45 red LEDs instead of using xmas lights. (copied the Efx-Tek WickLED circuit).
> View attachment 100826
> 
> 
> Then wired everything to a Efx-Tek Prop1 and used the candle program to create a random flickering/fading effect of the coals.
> View attachment 100828



What did you encase the LEDs in?


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## SonofJoker

This is a great idea! I may have to add this to my list of things to do! Thanks!


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## Ilean

Sweet! I'm posting to follow this and use it later!


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## stev1955

Thanks for posting this.


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## jmowbray

Hopefully some one will see this before tomorrow when I have to go shopping. I'm in need off some help. Which of the 20 kinds of foam do I need? 

This is what I get when I search HD:

http://www.homedepot.com/webapp/cat...=None&Ntpr=1&Ntpc=1&selectedCatgry=SEARCH+ALL


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## Jaybo

jmowbray said:


> Hopefully some one will see this before tomorrow when I have to go shopping. I'm in need off some help. Which of the 20 kinds of foam do I need?
> 
> This is what I get when I search HD:
> 
> http://www.homedepot.com/webapp/cat...=None&Ntpr=1&Ntpc=1&selectedCatgry=SEARCH+ALL


This is the one you want.


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## jmowbray

Thank you so much Jaybo!!!


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## Growler

I made mine and found out that you do NOT want to spray it all with flat black paint and then paint it with primer grey. Now it's so dark, I barely get any light out of the coals excpet a very few crevices that didn't get paint. Anyone know what I can do except sand it down and then lightly paint it again? Guess too much paint isn't that good. I was worried it would be too bright.


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## cheou812

Made the same mistake with using too much paint on my foam. Tried sanding it down...helped some, but ended up just doing a total "Do Over". Haven't seen this mentioned yet....but any time you work with Great Stuff Foam......Please, Please, Please.....WEAR GLOVES!!!! Latex type work great. You get this stuff on your bare hands, you will NEVER get it off! Been there, Done That!


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## loach160

Try using 320 grit sand paper that might help. I will be re-doing my cauldron creep cauldron fire and this time I will be using my air brush and not and aresol can. Another quick note is make sure you use the split wiffle balls or the ends of soda bottles this does help the light pop out of the foam. Never worry about it being to bright, you can always paint over it to dull it up. I always have the lights plugged in when i'm painting. This helps me see where I need to be light handed with the paint. MIST or DUST the paint on instead of painting it on. Just hold the can a little further than you normally would and push down on the nozzle for a second or two. Try and paint the crevices instead of the bubble tops. I know the foam looks unrealistic in the day and while painting it you would feel a need to paint the whole thing, but don't if you can help it. Buy the way MORE lights don't help either. (tried that) Hope this helps.


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## 805Demon

Thanks for the excellent tutorial! Was exactly what i needed for my cauldrons.


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## Zombie4*

Finishing my glowing skid mark using this technique.


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## loach160

That Looks AWESOME!!!


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## jscaldwell

Is there any concensus yet on whether it is a good/bad/neutral idea to use incandescent lights rather than LEDs? I'm looking for orange lights that have an ability to pulse or ebb like real coals do...

Thanks for any help or suggestions.


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## hjg0989

This is what I used mixed with non-flashing candy corn and red lights. It looks good. I covered the lights with a Dollar Tree clear shower curtain before spraying the Great Stuff. Once that dried I used black and a bit of white spray paint.






Celebrations Euro 120 LED 8 Function Euro Lighted orange Halloween Lights 1 pk - Ace Hardware







www.acehardware.com


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