stone fireplace

JahJahwarrior

Active Member
I need to build a stone fireplace. I have a base of a fireplace that we could build around if necessary, it was a wood/fake brick thing--the fake brick stuff broke while it was stored....so we want to rebuild it as a stone fireplace. Fibreglass is cumbersome to work with (I rebuilt a boat floor with my dad recently with it), so I was really thinking foam might be the way to go....does anyone have any advice or know of a helpful website?
 
Get some foam, and some green glue (made by 3m) and build up about an inch or two of foam, get some surefoam shapers and go at it. If you really want to be exact get some rosco foam coat to finish it off.
 
another cheap source. Mak a home depot run, purchase some 1" or 2 " blue or pink polystyrene foam. < usually in roofing / insulation > cut it into your desired rock shape with a band saw then form the individual rocks with a shur-form, sander, grinder < with sand wheel attachment not a ginder wheel> attach individual rocks to fireplace using acrylic latex chaulk,or spray adhesive < not 3M spray77 that will eat the foam.>. After "Rocking" your fireplace mix up some of Vans scenic dope.< recipe below.>
slather it on to the rocks using a variety of brushes, rags, expirement to see what kind of textures you can build up.let it setup. hightlight, shadow, airbrush if desired and you'll have a fireplace indishtinguishable from real rock. you can also attach the sheets of foam directly to the fireplace then carve the rock or brick pattern into the sheet. this technique is very affective if you want a variety of depths for the mortar lines.

Vans Scenic Dope:
3 qts flat latex paint < any color, good place to use up all the left over paints from the scenic painters shop>
3 - 5 tubes acrylic latex painters chaulk ( often called Alex chaulk)
1 cup Joint compound

mix it all up in a 3 gallon bucket using a drill motor and mixer attachment. mix very thouroughly add tints if necessary to establish color for base coat. Add more joint comound for stiffening but don't add too much or the final product will be very "cracky" especially on thicker areas. you can speed setup time by adding 1 cup of "rock hard" water putty. play around with different mixtures for different effects. it's a lot cheaper than Roscos Foam Coat and with the additon of a little more chaulk it's very waterproof


Good luck !. Have fun!
 
Another way to texture your foam is with paint thinner. take a paint brush and flick it or paint it on the foam (not a lot is required) and the paint thinner will eat the foam in an artistic way. It's cheap and really quick. you can paint it with your normal latex paint afterwards and it looks really realistic.
 
Another way to texture your foam is with paint thinner. take a paint brush and flick it or paint it on the foam (not a lot is required) and the paint thinner will eat the foam in an artistic way. It's cheap and really quick. you can paint it with your normal latex paint afterwards and it looks really realistic.

If you do do this, be sure to do it in a very very well ventalated area, because the gasses given off by both the paint thinner the the decomposing foam are not fun. Also, be sure to where gloves, resporator, and all that good stuff.
 
Another way to texture your foam is with paint thinner. take a paint brush and flick it or paint it on the foam (not a lot is required) and the paint thinner will eat the foam in an artistic way. It's cheap and really quick. you can paint it with your normal latex paint afterwards and it looks really realistic.

Dangerous and toxic. Flicking acetone or Lacquer thinner around is not really healthy and the reaction with the foam makes a really toxic enviroment. If you really want to go with a chemical solution for texturing the rock I suggest using Brake fluid. The problem with all forms of "chemical texturing", is controlling the reaction, with a scenic dope, mine or roscos, you control how much texture you get by applying more or less dope. With "chemical texturing" the depth at which the acetone, lacquer thinner, will stop eating away foam Varies greatly according to ; Density of the foam, Temperature, Realative humidity, and I beleive the price of tea in China is figured in there somewhere. To be really effective at texturing with acetone or lacquer thinner you need to apply it in a very fine mist < also reffered to as Atomizing > When in the form of a fine mist < read atomized >
Acetone and Lacquer Thinner have the following negative qualities:

A. They tend to stink to high heaven < causing the girls in the front office to come and complain that you are stinking up the entire building>

B. They are extremely toxic. < necessitating the use of Respirators which makes you get respirator hair, from the strap. Thus making you look silly when the girls come in from the front office to complain that you are stinking up the whole building >

C. They tend to be extremely explosive. < So that when the girls from the front office come to complain that you are stinking up the entire building, and then begin laughing at you, < because your hair is sticking up all over the place, because you had to where a respirator> the static electricity from there synthetic sweaters rubbing against there buffont hair-dos creates a spark and blows up the entire scene shop.

Personally, I'd rather not have to go through all that.
 
Last edited:
I know that I'm a rookie on here and all but I found that when I made our fireplace out of foam that imperfections in the faom was always a key point for me. As your shaping it put imperfections in it, don't make everything the same.
 
I know that I'm a rookie on here and all but I found that when I made our fireplace out of foam that imperfections in the faom was always a key point for me. As your shaping it put imperfections in it, don't make everything the same.
What type of foam were you using ? what ind of imperfections ? do you mean like voids ? Those sometimes happen when gas bubbles are caught during the extrusion process. I really prefer to you EPE , extruded polyetheline Foam, The consistency is nicer, it's very available and wht with roofers and insulations contractors using it everywhere the price is great. It is possible to acheive a smooth quality texture like EPE by using Styro-foam, but it takes a long time and lots of careful sanding. Styro-foam also out gases too many toxics for me.

One other safety tip i forgot to mention. when cutting foam, on the table saw, be extremely careful. Foam tends to heat melt and stick to the blade. It gets very sticky and can kick-back with very little provocation. You might think that getting hit with a kick-back from foam wouldn't be that bad, beleive me it is. Also be very careful when running your hands along the finished surface of EPE. Beleive it or not you can burn the Crap out of yourself very easily, friction burns that is. I don't know why this is I think it's a combination of the insulating properties of the foam and the micro-cellular structure of the foam. It would be fun to learn why Maybe Jamie and Adam could help ?
 
I might, Let me check my archives at home. You Might not have to "paint" the entire object depending on the color you use to base the rock with. the last rock I did was a big one that had to sit in water for 8 weeks I detailed it an airbrush painted a few Lichen on it, and glued down some moss. For brick it's just process of painting in the grout.
 
The pink insulation foam that you can get from any Home Depot, Lowes, or Menards is the kind that we used, generally the 2" thick kind if I am remembering correctly. What I mean by imperfections was that each ston is different and unique. Little groves or small pocks into the foam like an actual stone would have. It takes time but makes it look nice. As for cutting out the foam and shaping it we used Stanley Cushion Grip Multi Saw or a nice wallboard saw. It worked really well for shaping purposes. If you want pictures of what the stones looked like just drop me a message.
 
If you just want the red brick look, you can go to LOWES and go to the back where they have the PegBoard. And they have big sheats of fake brick 4' X 8' for like $12.
 
I've done a few different ways.

I've built a chimney and fireplace out of 2" Dowboard pink or blue Foam. Then, I cut out the shape of the rocks with a band saw and painted them to resemble stone.

This set is hard
Second, I've use chicken wire fencing and bent them into rock shapes. I stapled them to a hard flat or a wood frame. I then used strips of muslin covered in fast set drywall mud (20min). Then you place over the chicken wire.

This is just as hard
Third I've paper mache rocks. Sometime I use chicken wire other times I have used newspaper crumpled up for a base.

I love Rosco foam coat but it is expensive to use.
 
Vacuform coems in white only, then you scenic paint it.

JH
Most all commercially availible vaccu-form is white as it's made from white polystyrene, but if you do it yourself there are a wide variety of colors to choose from, as well as different types of plastics and finishes. If anyone needs tips about Vaccu-forming, building machines or working with a wide variety of materials please feel free to contact me. I've built several vaccu-form machines and have done literally thousands of pulls.< got a gig from Nike once had to make over 1400 body forms in man, woman and child sizes. using 1/8" black hair cell ABS Yikes ! careful what you ask for...> I was in the middle of one production run when a Guy from Michael Curry designs walked in with my boss and said ," here we need x of these and y of these and z of these." I finished the job and forgot about it, 6 months later I'm watching the Salt Lake Olympics and there are these Antelope, Horse, and bird heads paradeing around the opening ceremonies ! Quite a feather in my cap !

Sorry, I read the magic words Vaccu-Form and had to relate that .
 
If you do do this, be sure to do it in a very very well ventalated area, because the gasses given off by both the paint thinner the the decomposing foam are not fun. Also, be sure to where gloves, resporator, and all that good stuff.

I'll second that, wear the Tyvac suit and a resperator. All I have to do is see white (Expanded Polyeurithane) and I want to caugh. Far too many shows and constructions before I got smart.

So far lots of ideas - green adhesive, or believe it's a form of contact cement a blue one that best bonds, otherwise there is lots of home center "panel adhesives" that are designed to stick foam to surfaces. Liquid Nails and other types of general purpose adhesives will at times work, and at times not - depends upon what lot number of construction adhesive you have. Some burn up about the foam, others stick to the foam really well. Could also spray foam adhesive the panels to a surface for a really good bond. Silicone being the next option probably won't work well. Gorilla Glue as theory in doing foam should work well, so does 3M "Foam Fast" spray adhesive.

For shaping, the past I did sand paper by way of various disk or belt sanders, chain saws, grinder with chain saw blades, shur-form and rasps, Grandpa's meat cutting knife, an electric knife, a hot knife, a very sharp paint scraper used as a draw knife, a table saw, blow torch, spray paint, a variable speed router and lots of other tools to shape foam.

As a starter, determine what form of foam "expanded polystyrine" - the white dots in a sheet or "extruded polystyrine" the blue, pink, amber and other colors of it. Both work well but at times what works for attachment and or shaping for one won't with another. The white foam makes for a more textured surface faster but the extruded types are easier to shape. Spray paint with them can make for just as much texture. There is other types of foam also such as would be used to make piers and floating docks. Beyond this, even the padding used in a sofa is foam (don't attempt to cut it with the table saw) it will at times work and can be shaped.


Spray paint is a curious thing that does not get along with foam. Sculptural Arts type coatings, Jesso - from an art supplier, and various Rosco type coatings work well with foam, so in also texturing your surface would a spray paint primer. IT's another technique. Prime the surface, fill in holes and cracks, make the surface solid than paint as needed.

In coating, it's often a question of a hard surface in making the foam a solid, or a more rubbery coating that will allow for flexibility. Could be done both ways and there is various coatings out there that will get you the Audrie II type foam coated so it's a solid surface of plant or some others that are solid like plaster. Options abound. For a simple fireplace, one would assume just a primer be it spray paint or from Rosco if not even Jesso would be fine.

Another coating could be a combination of plaster or paris, Sobo or other flexible white glues, and some joint compound. Should work well as long as the surface is not bumped much or much moving thus bumping around. Use only as much water in this compund as necessary to make the powders paste and if possible water down the glue rather than the plaster.
 
Last edited:
So, it looks as if the adult help for the production has some ideas for a fireplace and he'll be building that. We have some logs that look decently realistic, and there is a small AC motor that turns a plastic cup type thing aorund an orange lamp to make it look like embers in the fire. It looks pretty good, but the AC motor is shot I believe. It vibrates somewhat, but I cannot get the shaft to turn. There seems to be no way to open it, it's riveted shut. It's a very small very low RPM AC motor. Does anyone have any clue where I could get a replacement? There is a sticker that says Underwritiers Laboratories.....Firelogs Inc. but I cannot find anything about Firelogs incorporated anywhere....
 
Check here at Grainger
http://www.grainger.com/Grainger/ww...operator=prodIndexRefinementSearch&L1=Motors,

Those are typically inductive "C-frame" type motors. You could probably scrap an old clock < a 110v clock> and pullthe gear motor out of it. you want a very slow rotation on those. Do not attemptto plug it into a dimmer though, unless you are using IPS. You can control the lamp with a dimmer but the inductive motor must be run from straight A.C.. be sure to check that the motor and lamp power wiring is not tied together, they sometimes are. Putting an Inductive load on along with the lamp will really screw up most dimmers, not to mention it'll probably burn out the motor real quick too.
 
my dad suggested an old clock. I cannot find anything with a low RPM on grainger under C frame, the lowest is around 1700 rpm :) I don't want to build a gearbox for a fireplace. Yes, the lamp is wired in with the motor, I won't dim it. Thanks for the tip!
 

Users who are viewing this thread

Back