Instructables
This is how to make an excellent excuse for driving a lag bolt into your wall, the Concrete Lightbulb Wall Hook. Functional yet sylish, it gives a nice industrial design feel wherever you mount it.

Last winter after breaking out the serious cold weather gear, I found myself fighting the coat rack next to the front door. It was, to put it bluntly, failing miserably. Tipping over, breaking off, it was a mess. I swore before the next winter I would drive some serious hooks into the wall that would handle all my heavy overcoat needs. I just haven't seen any kickass hooks yet that I liked enough to justify making serious holes in my walls.

Cut to the last few months. As mentioned in my blog ( here, here, and here) I've been playing around, trying to make a concrete lightbulb. Why? Because I find the contrast of blending a new material like concrete in an everyday shape like a lightbulb to be a great design element. So while messing around with these guys, I realized this would be a great excuse to drive lag bolts into my wall for hooks. By embedding a lag bolt into the concrete lightbulb, I could make a wall hook that was useful enough to handle anything I wanted to hang off it. Thus this project was born.

This is an entry in the Etsy/Instructables SewUseful Contest, so if you love this idea but don't want to make it yourself, not to worry! I have them for sale in my Etsy Shop. Click here to order yours today! Yes, it's an entry into a sewing contest without any sewing. Sometimes you just gotta.

Check out my other entry into the SewUseful Contest (also without sewing!) - "Big Brass Ones"
 
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Step 1: Tools and Materials

Picture of Tools and Materials
You will need a work area where a little sand and concrete mix or glass shards is not an issue. Make sure you have a small brush and dustpan available at all times. Normally you wait till the end to shatter the lightbulb, but it can happen at any point in this process. So be ready for cleanup from the very start.

TOOLS:

- Small pair of pliers

- small pair of wirecutters

- small screwdriver

- carbide scribe. You can use something like an awl or even a long skinny nail, but I found my trusty old scribe to be invaluable in this.

- plastic tub to mix the concrete in. I used an empty five pound tub of spreadable margarine.

- a scrap of wood to mix the concrete with. You could use an old wooden spoon or something like that if needed.

- plastic spoon to put the concrete mix into the lightbulb.

- A measuring cup and measuring spoons for adding the correct amount of concrete mix and water.

- a toothbrush you won't be using for your teeth anymore.

- coffee stirrer and plastic cups you "borrowed" from Starbucks

- Gloves and safety glasses. A must because the glass bulb often breaks and little shards go flying in all directions, including straight at your eyes.

- Misc. items like Sharpies, some rags, etc.

MATERIALS:

"Concrete" is a mix of cement, water and aggregates. My research showed that a sand mix, AKA mortar mix, is good when using a smooth surfaced mold like the inside of a lightbulb. It gives a very high shine when cured. A sand mix is different from your generic concrete in that the aggregates doesn't have any gravel, just various sizes of sand. I decided to do it with mortar mix instead of your standard bag of generic concrete.

- Quikrete Mortar mix. I got the ten pound bag at the local home improvement store for $2. This is enough to do over a dozen lightbulbs. I could have purchased the 60 pound bag for $7 at a much lower cost/volume, but this project really doesn't need that much.

- Lightbulbs. Just the cheapest standard sized incandescent lightbulbs you can find. I got mine at Walmart. A pack of four for 77 cents. Can't beat that with a stick.

- Water. You'll need about 4 tablespoons worth. I kept a bottle of water nearby on the bench and refilled it from the tap when needed.

- Lag Bolt. I'm using a 5/16" lag bolt, 3.5" long. 5/16" was the largest sized lag bolt I could fit into the lightbulb without cutting off the head. I didn't want to do that because the head gives the bolt a lot of grip when embedded in the concrete. With a lag bolt 5/16" in diameter, I can drill in the wall a 1/4" hole to get a good balance between grip and ease of installing. In other words, it turns easily into the wall yet holds really well.

Step 2: Hollow out the light bulb

In the beginning I found the directions at TeamDroid to be a great help on how to do this. Now that I've done it over a dozen times it's routine. With practice this becomes quick and simple. There is another instructable describing how to hollow out a lightbulb here to get another perspective on it. Teamdroid linked to a GE tech spec on your standard bulb here.

A lot of the time you are poking around inside the lightbulb trying to break off the internal glass bits. Do this over a trashcan and often shake the lightbulb out over the trashcan to get rid of the glass shards. Wear safety glasses at all times. More than once some glass flew up towards my face when I was doing this.

First, grip the metal circle with a blob of solder in the middle at the bottom of the lightbulb with your pliers and gently pry it up from the dark purple glass insulator. This is pulling a wire in the middle that you want to break, so just pull it off.

Once that is done, take your carbide scribe and over a trash can, pry into the hole you just made in the purple glass insulator and break up that purple glass. You want to remove all the purple glass insulator from the lightbulb body. I use the scribe to start some cracks and lift off a section of it, then I follow up with the screwdriver to get the rest. Turn the lightbulb upside down and shake out all the glass bits that have fallen inside.

Inside there is a small glass tube that pokes up into the glass insulator. You might or might not have already broken that off by now. If not, just lever the screwdriver against it until it snaps loose. Empty into the trashcan.

Now you have a hole in the bottom of the lightbulb. At this point I take my pliers and gently bend over the metal tabs on the inside of the hole so there is no "lip" on the inside. Later when you have broken up the rest of the inside pieces, there isn't anywhere for the bits to catch and stay in the lightbulb when you shake it out.

There should be a wire visible inside that's soldered to the side of the metal screw piece. Take your wire cutters and cut the wire as close to the side of the bulb as possible.

Now, the inside has a glass cylinder you need to break off and clean up the edges to finish the job. Take your scribe or screwdriver and put it down into the lightbulb until it meets resistance. Tap it gently until something breaks. Then using the screwdriver, lever against the side of the lightbulb to clean out whatever remaining glass bits are left. You want the neck of the lightbulb to be clear from the hole all the way down the body. Turn the bulb over and shake it out one more time to get rid of the last of the internal glass pieces floating loose.

Take a toothbrush and while dry, push it into the lightbulb and start loosening up the dry white powder. Especially in the neck of the bulb. Don't worry if you can't get the stuff the toothbrush can't reach at this point. I found the bulb cleans out easier if you do loosen up the white powder in the neck before it gets wet.

Now take it over to the sink and add a little soap and water. Scrub around with the toothbrush and shake the bulb to get the water everywhere. Pull out the toothbrush and then wash out the soapy water from the bulb. At this point it's all nice and clean inside without any soapy residue. Set it aside to dry out. Now it's time to mix up the concrete.

Step 3: Mix up the Concrete

This is the part that's more art than science. I've found that in the small batches this project calls for, it's very easy to add too much or too little water to the mix. When you are mixing an entire sixty pound bag of concrete, being off a teaspoon on the water doesn't matter that much. When you are mixing up just a cup of concrete, that teaspoon starts to matter.

Mortar mix when cured in a glass mold like we are using gives a very nice gloss surface. The lower the amount of water you use, the smoother and like glass the surface is, and the stronger the resulting cured concrete is. However, the lower the amount of water you use, the harder it is to have it fill in the gaps on the sides and it leaves lots of holes and divots. It's getting the mix liquid enough to spread out but not too liquid that it looses it's strength is one of the issues on the water to dry mix ratio. Finding the correct compromise between these two issues is really a matter of practice and personal taste, I would suggest you play around with it in multiple bulbs if you are interested in getting the best result you can.

The ratio I've found works well is about 1.25 cups of the mortar mix and a hair under four tablespoons of water. So measure out a little under four tablespoons of water and put that into your plastic tub. This is more mortar mix than you need to fill a lightbulb, but there is always some spillage and trying to reduce the amount means even more accuracy on the water measurement. This is a good place to start.

Slowly mix in the mortar mix a little at a time. Let a little bit get wet, then a little more, then a little more while stiring the hole thing. It's a bit like making biscuit dough at this level, but your pouring the dry into the wet instead of the other way around. The consistency should be good enough that the mortar mix wants to stick together in one large clump, but it isn't sopping wet. If you feel you need to add more water or mortar mix to get it correct, then go for it. Just do it a little bit at a time. A small amount of either material make a large impact at this point.

Once it's at a consistency you like, keep stirring nice and slow for a few minutes. You want everything to be throughly wetted as much as possible.

Important! At this moment the clock starts and you have 30 to 45 minutes to finish the lightbulb before the mortar mix starts to harden up.

Once you have throughly mixed up the mortar mix, bring out the lightbulb and start filling it up.

Step 4: Start filling up the lightbulb with the mortar mix.

You are working on a time limit at this point as the mortar mix starts to set. If you can get it all done in thirty minutes or so it should be fine.

Put your lightbulb into a small plastic tub with the hole pointing upwards. When you are adding the mix there is always spillage and you don't want that all over your work area. I put a little bit of sand in the bottom so it will stay straight early on, once you add a few spoonfuls of the mortar mix it stands up straight on it's own.

Take a plastic spoon and scoop up a level amount of the wet mortar mix. Holding the end of the spoon over the hole in the lightbulb, use your finger on the other hand to push it down into the hole. Some will spill over the edges of the hole, that's ok. You made almost twice the volume of mortar mix as will go into the lightbulb.

After four or five spoonfuls into the lightbulb, you want to vibrate it so the mortar mix liquefies and spreads out evenly on the inside. Shake it back and forth to make it liquefy. If there is an air bubble visable on the side that just won't fill in no matter how you shake, tap it repeatedly with your fingertip. moves the the bubble up and the liquid towards the tapping.

Do these steps, a handful of scoops and then much shaking and taping to fill in the gaps and make it all liquid like until you reach half way up the neck of the bulb. At that point it's time to add the lag bolt.

Step 5: Put in the lag bolt and finish up adding the mortar mix.

Before putting in the lag bolt, mark off with a sharpie where 1.5" is from the pointy end so you know how far to push it down.

Put the lag bolt into the mortar mix. Because the lightbulb shape has some undercutting with the mold, the mortar mix wants to clump up in the middle of the bulb and not grip the sides. You can use the head of the lag bolt to tap down the pile in the middle of the bulb so it starts filling in all the gaps.

Keep adding mortar mix around the lag bolt to fill it up. Holding the lag bolt firmly to make sure it does not rattle, keep shaking the bulb and tapping the sides to fill in gaps and liquefy the mortar mix.

Take a coffee stirrer you "borrowed" from Starbucks and use that to tap down the mortar mix. You want to keep adding the mix, tamp and fill, tamp and fill. Finally the entire bulb is all done and you are tamping on the top. You want the mortar mix to be level with the top of the hole but not sticking out in a bulge.

When you are all done, put the lightbulb with the lag bolt pointing up in a spare plastic cup. The ones I used where also borrowed from Starbucks. Take a rag and clean up the metal threaded part of the lightbulb as well as you can - you don't want the mortar mix drying on it.

Set this to the side for at least 72 hours to let the mortar mix cure. I normally write the date it was made on the glass with a Sharpie so I can keep track.

Step 6: Crack the lightbulb

Let the mortar mix cure for at least 72 hours. A few days more is a good thing.

This is the part where you are breaking up the lightbulb glass into little bits and pieces on purpose.

Glass will be flying in all directions, wear safety glasses and at least one glove (like in the pictures) at all times!

Over a trash can, hold the bulb in one hand that has a glove on it. I've tried to use gloves on both hands at this stage and didn't have the fine control I wanted. You might be able to do it.

Taking a hard metal object, start striking the side of the lightbulb. I'm using my carbride scribe. The glass with start to crack and form spider web fractures. Keep hitting. Eventually small pieces will fall and/or fly off of the bulb. When you have formed a good number of cracks around the bulb, take a toothbrush and scrub it vigorously over the entire bulb. . This will brush into the trashcan any glass grit or loose pieces.

Then take your carbide scribe (or awl or sharp nail) and start to pry up the edges of the glass left on the bulb. Some of it will come off in large chunks, some of it will come off a little piece at a time. Try to aim for the trashcan but know that it won't all go in there, some of it will pop up and go in any direction. If a large piece of glass doesn't want to come up and doesn't have any cracks in it, beat it with the metal object some more to create the spider web. Every so often take the toothbrush and rub down the lightbulb to get rid of any ground in glass or loose bits.

When all the glass has been removed from the lightbulb, take your scribe and carefully go around the neck of the bulb where the metal met the glass. Make sure there are no loose glass shards under the lip of the metal. Shake and tap the bulb to see what floats loose. When you are done, take a shop brush and run it over the entire bulb one more time to get any glass grit or loose pieces out of the holes in the concrete.

It's done! The mortar mix often leaves pits and holes even with all that shaking and tapping you did, but I think it adds a bit of character to the whole thing and makes each one you do unique. Feel the glossy smooth glass finish on the bulb and how it reflects the light. Now it's time to mount it!

Step 7: Mount it on the wall

Now that you have this killer Concrete Lightbulb Wall Hook, it's time to mount it into the wall. The steps here are fairly simple.

1) Find the stud. This wants a wood stud in the wall. There are multiple ways to find a wood stud, I'm using a cheapie stud finder.

2) Drill the hole. Using a 1/4" drill bit, drill a hole 1.5" deep into the wall.

3) Screw it in. The hole is big enough that you can can screw it in, but the bite is good enough that it can hold just about anything you want to hang off it. Heavy overcoats, small children, whatever strikes your fancy.

4) Hang your hat. Or you could use it as a hat hook. It's all good.
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SIRJAMES091 month ago

AWESOME! :0)

I need to make 1...or 3....dozen. :0)

these would make great stocking stuffers for Christmas!! Birthday presents! I can think of a million & one reasons for giving as gifts!

TY for sharing. :0)

When separating the glass from the concrete hanger, I was thinking, about why you can not use a rag to wrap the hanger/bub in?

It will stop the glass from flying, contain the glass in 1 area/spot/whatever, and when finished, just toss the rag into the trash.

Granted, you still have minute particles of glass to deal with, but as you said, a shop brush should take care of that.

caperuzita1 month ago

Nice Idea!!!

In one side I've been thinking on how to recycle soiled light bulbs but I didn't find it any easy myself.

In the other I love to hang my stuff on doors to get them more availableand keep a roomier wardrobe, but this kind of hungers aren't so easy to find, most of them fall down to the floor within the first week.

Good luck selling them!!

oldaugie2 months ago
This looked like fun so I gave it a try. unfortunately I could only find hydraulic cement which sets in about 5 minutes. to add to my woes, I got the piece all put together (bolt not straight but, all else looked good for a first try) but then dropped it the following day. the bulb came off easily but it is !missing the shininess of the one in the 'ible. Someone suggested using polishing compound which helped some but I think I'll end painting this one to cover the flaws.

After painting, I intent to drill through a porcelain fixture and insert the cast into it as if it were a real light. I wonder how many folks it'll fool! perhaps I should use space under the porcelain fixture as a safe. talk about mixing content.

For a first try not too bad though. I've now got some mortar mix and am anxious to give my next one a try.

Does anyone know how to safely dismantle a cfl? I think one of those would be fun to try as a cast.

happy casting
temp_1560090207.jpg
kculver13 months ago
Instead of a toothbrush & soapy water table salt will take that white residue right out just put a spoon full of salt in the light bulb hold ur thumb over the end & shake it it will clear it right up!
SIRJAMES093 months ago

Cool!

the way we go through lightbulbs around here, I won't have to buy any...

Very nicely written, very educational,....can't wait to make a few(dozen) myself. :P

gungajin4 months ago

Absolutely great! This is one of the finest exponents of creative thinking. Reminds me on Picasso abstract paintings: so simple, everybody can do it. But only good old Pablo actually could.

thundercookie4 months ago

one question, how do i make it?

pbminecrafter4 months ago

nevermind

pbminecrafter4 months ago

one question, how do i make it?

crhay4 months ago

This is a fantastic idea actually! My husband and I are trying to go with a very contemporary, modern style in our home. Having concrete lightbulbs for coat hangers would go perfectly with our theme. I will have to check first, but I think that my husband will love them too!
Cambria Rhay | http://www.heritageblds.com

aloew4 months ago

I wonder if a different, less messy (no broken glass each time) way to do this would be to perhaps make a 2-part urethane mold of a lightbulb. You get the same accuracy, and can pull many parts from the mold over time. Also, there are good concrete mixes that will cure in under an hour with very nice results.

karcsika9224 months ago

This was my first instructables that I watched here,back in the days. Now I found it!

blending of concrete in an everyday shape like a light-bulb is genius. congrats..

challes16 months ago
I hope you don't mind...I placed a link to your site on my site... http://cehalles.wordpress.com/2014/03/13/my-simple-creations/...I needed good instructions for hollowing out the light bulb and urs are very clear...thanks
xsmith4567897 months ago

That is a pretty awesome idea. I love to learn about little things like this that really improve on a lot of the things you would just buy in the store without thinking about it. I'll have to try that.

Thanks!

Xavier Smith | http://www.jbsroof.com

x burn9 months ago
brilliant
angry king1 year ago
i use your idea to make this
DSCN2794[1].JPG
Adorei a ideia. Parabéns!
bluumax1 year ago
I was reading another instructable on concrete balls and remembered this one. Anyway I saw a post about using expansive cement and thought if it doesn't expand so much it trashes the metal, doubtful, it might make this a lot easier as it breaks the glass away for you. It has a nice looking finish too.
http://www.instructables.com/id/making-concrete-balls/?comments=all#CRUYNAPHH11IFXA

noahspurrier says: "I make cement spheres the same way! I use pure expansive cement (AKA expansion cement) with no aggregate, which creates a different look. It has no aggregate and no voids. The expansive cement has one advantage in that it actually cracks itself out of the glass mold."
qewt1 year ago
Love that sheen on the concrete!
arth1 year ago
could you use plaster of paris instead of concrete?
oooohhhh....
http://www.best.kg/
I might try this with an energy bulb for that twisted look. :)
catmanduud2 years ago
its cool but whats it for
See the last photo?
blazygut1 year ago
lets just be concrete here,for a second
benny80253 years ago
I made a door handle of gypsum instead of concrete. I wanted the glass to be on the handle, but the gypsum got realy hot under the hardening, and the glass cracked. So I took the glass of and the result was better than i hoped for
P1070238.JPG
nice
Benny8025,what is gypsum? Plaster of paris? I know it's found in drywall.
Where did you buy it for your project?Thanks Elljayq
Hobby shops
Chad Baxter2 years ago
I mean, what's better than breaking glass right?!
bbondy2 years ago
Hi Sir! it's a very provocative tutorial and very nice product as a result. I tried once with colored grout as an exercise and I want to show you the result.
http://goo.gl/DvwYx
as you see the area around the metal circle is not connected well because i didnt clean the internal glass completely (little bit hard).
Now I have the other lamp with bolt and the wet grout in it. i cant wait to see the result by tomorrow. thank you and keep posting other tutorial. :)
bbondy bbondy2 years ago
ah i see we can post image in this comment. here it is
IMG_20120916_205923.jpg
This is beyond awsome! May I ask what your inspiration was? i might try to do an installation using a ridiculous amount of these...maybe 200-250?
whamodyne (author)  SleepyWindows2 years ago
My inspiration was a desire to play with form and iconic shapes in ways that made people stop and think about it for a moment. That and a need for a serious hook to hang stuff on.

If you need 200+ of the wall hooks, I would be happy to supply them if you want. I still make and sell these and by now have made hundreds of them, one at a time. I could do a serious batch run if you wanted that. Please send me a note if you are interested. - Ray
Skymeat2 years ago
I just made a couple of these. Great idea! I changed the recipe a bit, which might make it safer and a bit easier.

1) I used a pair of dikes to snip off the metal button on the end of the bulb. This exposes the bare blue glass and has a dimple for a small tool.

2) A very small drill bit was used to tap against the exposed hole, creating cracks in the glass (Hold the bulb and bit in one hand and tap the bit on a concrete floor, most any other surface won't work. Just do it 20-30 times and let gravity do most the work)

3) Once the blue glass cracks use needle nose pliers to pick at the fragments, the first one is the hardest. Just get the blue glass at this point.

4) You should have the blue glass out and be looking into the sealed bulb. Insert the needle nose pliers as deep as they'll go and give a little tension on the handle till the inside breaks.

5) Use the needle nose closed to ream out the glass, you'll end up with an almost perfect hole. Just go a little at a time. Don't try and do it all at once.

6) Clean it out. Fill the bulb with a couple tsps of Morton salt. Cap the end with a thumb and shake it. Dump out the salt and repeat a few times. It will be perfectly clean and shiny.

7) Rinse and prepare concrete. The inside can still be wet, it's getting filled with concrete anyway.

8) I used off the shelf concrete mix (5000psi), but screened it to 1/8" (took out rocks larger than 1/8", so mortar mix is about the same thing) But I mixed it a bit wetter than the photos here. The consistency was about like wet oatmeal, and was pourable (Not easy to do, make it a bit too wet and add spoonfulls of powder to get there). I used a funnel to pour the mix into the bulb.

9) Wait 7 days. 3 day cure is a bit too soon to be really hard. Best if you wait 28 if you want a very hard concrete but no one will do that.

10) Break the glass off. I used a 5 gallon bucket filled with water and submerged the bulbs and tapped gently with a steel bar. I mostly brushed off the remaining glass with the leather gloves I was wearing.

11) Dry thoroughly. The concrete sucks up a lot of water. This is where I am now. I plan to let them dry for a couple weeks in a warm dry location then seal. I was left with very smooth and perfect bulbs without any bubbles and certainly concrete in the 7000psi+ range :)

I would love to see some photos of this. May I suggest you make your own instructable?
cincymikeb2 years ago
walked into the bathroom this morning and was GLAD to see a burnt out bulb !
Yaaay another wall hook !
yea, recycle
mganpate2 years ago
its very nice consept kindly share the pdf on mahesh.gan.143@gmail.com
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