Introduction: Resin LED Napkin Holder

Picture of Resin LED Napkin Holder
I had been playing with resin and LEDs separately for a while.  Then I saw the Rainbow LED Paperweight instructables and thought 'Wow, you can combine the two!!!'  I looked around the house for a useful application and noticed I had a plain, dull wooden napkin holder.  I wanted to make something with more flair. 

I experimented for a while with various positioning of the battery, switches, etc as I found that to be the hardest thing to add.   The instructables will show the various places that I placed the battery and switches.

NOTE:  These napkin holders can be made without adding any LEDs or electronics!  Refer to the Embellishment and Other Details Section for ideas to add color or embed objects in the resin.


MATERIALS

Basic to all napkin holders:


1. Environmental Technology Epoxy Resin - I buy 128 oz at a time since I use alot of it.  Amazon has pretty good prices - it fluctuates up and down (between $72 to $78 dollars).  I try to catch it when the price falls below $73. 

Mixing cups, stir sticks, etc to mix the resin.  I also have a timer to make sure I accurately mix the resin.

2. Fit and Fresh sandwich holder - I found this at Target.  It was perfect size and also makes a super shiny finish!  I didn't have to use release spray and it pops right out when cured.  I had two of them - a purple one and a clear one that created same results.

3.  Batteries - I've used 12 volts and 9 volt batteries

4.  Switches

5.  Wires, soldering iron, etc

6.  Slow or fast rotating LEDS.  I bought them both on Amazon.  Resistors


3 types of napkin holders in this Instructable along with the additional material (if any):

1.  Sound to light skull napkin holder
Velleman Sound to Light Kit.  I found this at my local Fry's store for less than $5.  It comes with a 9 volt battery holder.  Refer to the Additional Info for Sound to Light Napkin Holder Section. 

2.  Plain flashing light napkin holder

3.  Waterfall napkin holder
Woodland Scene Water Effects, Vallejo Water Effects.  Refer to the Additional Info for Waterfall Napkin Holder Section for more information.

Optional:  Embellishments and other Details

1.  Battery covers

You can create a resin sculpture to sit over the batteries.  The resin sculptures can have additional LEDs beyond the ones placed in the napkin holder walls.  Refer to the Embellishments and Other Details Section as well as Battery and Switches Section for more information.

2.  Alcohol ink and other colors

I added blue swirls of colors in the base by using alcohol ink. 

3.  Objects to embed

In the 2nd napkin holder pictured, I had embedded some fake flowers at the base.  You can choose to add items to embed in the napkin holder base or walls.

Step 1: Basic Instructions

Picture of Basic Instructions
1.  Plan ahead.

a.  Decide where to place the battery and switch. 
Refer to the Batteries and Switches Section for additional information.

b.  Determine colors or embellishments to be added.  Determine how to hide the battery compartment.
Refer to the Embellishments and Other Details Section for additional information.

c.  Determine LEDs to use or if using a light kit.
Refer to the LEDS and Wiring Section for additional information.

 
2.  Prepare the molds to be used.

Napkin holder wall - Decide how thick the walls of the napkin holder will be.  I marked a line about 1/2 inch high all around the sandwich holder to mark the width of the walls. I marked an x to the side that will always be used as the bottom of the napkin holder wall (since it is retangular and not square and I don't want to accidentally place the LEDs on the wrong side).
 
3.  Create the cardboard battery holder.  Refer to the Batteries Section for additional details.

4.  Prepare the LEDs to be used.
 
I marked the cathode of the LEDS with black marker. I used masking tape to tape the 2 LEDS (side by side) to the side of the sandwich holder marked with an X. The 2 LEDS will be connected in series so the cathodes were placed on the same side (so the anode of the first LED will connect to the cathode of the 2nd LED).
 
5.  Mix the RESIN.
 
Follow the instructions that come with the resin that you use. I used the Epoxy Resin because it has low odor (good news for the winter) but takes about 24 hours to cure. I have problems with the odor of Polyester Resin. 

I mixed about 5 ounces at a time (mixed more when needed) using a 5 ounce glass measuring cup.  Refer to the Resin instructions regarding the recommended thickness or amount to use at one time.

I warmed the Epoxy resin in a water bath before mixing it to increase clarity. The bottle should be warm (not hot) to the touch when mixing. 

For the instructions below, make sure the sandwich holder molds are sitting on a level surface.  Otherwise the parts will come out lopsided!

Napkin holder wall:
Pour the resin into the sandwich holder mold up to the marked line and let it cure for 24 hours.  I used the same sandwich holder for both walls (to make it same as possible). I waited until the next day to remove the first wall and repeated the procedures for the 2nd wall.  I had to mix slighly more than 5 ounces of resin. 

Add embellishments/color at this time if desired for the walls.  I left mine clear.

Napkin holder base:
Pour some resin in an empty sandwich holder mold - about half a centimeter high or so.  If you have an extra sandwich holder to use as a mold, you can do this step at the same time as the napkin holder wall.  Wait for 24 hours for it to cure. This thin layer of resin will prevent the other parts of the napkin holder from poking through the napkin holder bottom.

After curing for 24 hours, place the cardboard battery holder where desired on top of the thin, cured layer.  I placed a bottle in the battery holder to hold it down so it would not drift and move over the resin.

Pour another thin layer of resin into the mold and allow it to cure.  I do this because I wanted the battery to rest deep in the napkin holder. 

Add embellishments/color at this time if desired for the base.  I used various ones for the base.  Refer to the Embellishments and Other Details Section for additional information.

The rest of the napkin holder base will be poured when the LEDS are wired.

 
6.  After the napkin holder walls have cured, remove it from the mold.  Do not remove the napkin holder base from the mold yet.

7.  Wire the LEDs. Refer to the LEDS and Wiring Section for additional details.  Be sure to test it!

8.  Place the wired napkin holder walls into the base mold.  Refer to the pictures if the details do not make sense.
 
The back wall was placed flushed with the edge of the base.  I decided how much napkins I wanted to hold and placed the front wall in the base.  My 2 walls were placed about 2 inches part.  This left a large space in the front of the napkin holder that can be embellished.  The wall placement is also influenced by where the battery holder was placed. 

Arrange the wires so that it sits flat along the base.  The back wall wires were run under the front wall if the battery holder is towards the front.  If the battery holder is between the two walls, run the wires towards the battery holder. 

Masking tape was used to tape the walls to the mold so that it stayed upright and not move when the resin is poured.  Make sure the walls are straight and level in the mold.

The wires should sit as flat as possible so that the resin will cover it.  However, because wiring is not completed, be sure the wire ends sit above the resin that will be poured (towards the battery compartment).  I used masking tape to keep it from falling into the resin. 

If you plan on adding LEDs outside of the walls (example - adding another LED in the Death Star), and it will be a stationary part of the napkin holder, then wire it now.  Refer to the Embellishents and Other Details Section for more information as well as the LEDs and Wiring Section.

If the switch will sit on the base, then add the wires to the switch.  I didn't wire the switch to the battery yet.  Instead, I taped the end of the wire that will go to the battery so that it sat above the resin.  Be very careful when pouring the resin that it does not get into the switch!  I put some putty around the switch but have had problems with resin still getting in.  So just be careful.
 
9.  Mix the resin and pour to the desired height for the base.  Be sure the resin does not cover the switch if it was added.  Also be sure the resin does not flow into the battery holder!  Allow 24 hours to cure.

10.  After the base as cured, remove it from the mold.  Remove the battery holder with pliers from the base. 

11.  Wire the batteries and the switch.  Refer to the LEDs and Wiring Section for more information.

12. Position the battery and switch in the napkin holder.  Add a battery cover if desired.  Refer to the Embellishment and Other Details Section for more information

Step 2: Batteries and Switches

Picture of Batteries and Switches
Batteries to use and battery holders
I attempted to use a 9 volt battery holder (either with or without a switch) and found it to be too large.  I opted to use a battery holder clip instead to connect my 9 volt battery. 

I also used a 12 volt battery holder in some cases because it is so much smaller than the 9 volt battery.

Create cardboard box holder to hold a space in the resin for the batteries.

I created a cardboard box battery holder to create a sunken space in the resin where the battery would later be added. 

To do this, take the battery or the battery holder that will be used in the napkin holder and place it on a piece of cardboard.  I used a 12 pack coke box.  If using the 9 volt battery, attach it to the battery clip to make sure you have enough room.

Cut a retangular shape around the battery/battery holder to be used.  Make sure it is large enough to fit the height of the battery so that the batter will sit deep in the resin base.  Also make sure the length is long enough to fit the battery and the wires.

Cut slits for the 2 the ends of the box (refer to diagram).  I used an exacto knife to lighly score along the fold lines to make sharp folds.  Fold the ends up.

Lightly score the fold lines along the length of the battery/battery holder, and fold up the 2 sides.  Also lightly score the corners where it will wrap over the 2 ends and fold it.

Trim as needed around and tape with packing tape.  Tape the entire perimeter of the box well with the packing tape.  Make sure there are no holes so that resin can seep in. Try to smooth out the tape as much as possible.

When placing the cardboard box battery holder in the resin, you will need to place a small object in the box to weigh it down so that it doesn't drift out of place in the resin.

Where to place the battery

I tried different areas to place the battery. 
 
Glue to the side:

One of the first ones I created, I didn't have any 'holes' in the resin base.  Instead, I glued my 9 volt battery holder and the switch I added to the side of the napkin holder base (see 2nd picture).  After gluing, I colored some air dry clay black and molded it around the battery holder and switch.

Create hole in the front:

Use a cardboard box battery holder to hold a space in the front of  the napkin holder base.  Use a battery cover to hide the batteries. (See 1st picture)

Create a hole between the napkin holder walls:

Use a cardboard box battery holder to hold a space in between the 2 walls in the base.  Use a thin battery cover.  Napkins themselves would then hide it all. (see 3rd picture)
 
Where to place the switch

 
I also experimented with different areas to place the switch.

Set the switch on top of the resin

In the first picture, the switch was placed on top and resin was poured around it to keep it in place.  When using this method, be careful that the resin does not get into the switch or else it will be stuck in position and you won't be able to flip it on/off.  You may try to add putty around the switch to prevent resin from seeping in.

Set the switch on the side of the base

The switch can be glued to the side of the resin base. 

If the cardboard battery case holder is placed close enough to the side walls (so that there is a sturdy yet thin wall), then a hole may be cut in the sides to insert the switch through (refer to picture).  The switch would then be glued from the inside of the hole.  I find this to be the nices place to put the switch.

Set the switch inside with the batteries (not pictured)

The switch can be glued inside the battery holder area.  Create a long enough cardboard box holder so that both the battery and the switch be be placed within the sunken hole.
 
Battery Cover

 

Woodland Scenic Water Effets

If the battery sits in between the walls of the napkin holder, then create a thin flat battery cover is required.

I was able to create one using Woodland Scenics Water Effect.  Take a piece of parchment paper, and paint a retangular piece of the Water Effect using a brush.  Use a fairly thick amount of the Water Effect.  After it has dried, peel it from the parchment paper and trim it to size to fit over the hole.  Take some of the water effect and apply it like glue to one edge of the hole, and attach the cover (refer to picdtures).  This will create a flexible flap. I was also able to add a little bit of alcohol ink to give it a blue color.  The water effect will dry translucent.

You may also try cutting a piece of clay to fit the size of the hole to make a cover.

Resin Sculptures or Objects

Resin scultpres can also be created to cover the battery.  Refer to the Embellishments and Other Details Section for more information.

if the resin sculpture or object is not long or large enough to cover the hole, then a base may need to be created.  One way to create base is to use resin.

Brush some resin on to a piece of parchment paper.  Allow it to partially cure (to a soft flexible constistency).  When the resin is partially cured, it can be shaped into a retangular piece and trimmed.  Once it is fully cured, it will be hard and difficult to trim.  Place the object on top of the resin piece.

 

Step 3: LEDS and Wiring

Picture of LEDS and Wiring
DISCLAIMER- I'm a novice with LEDS and electricity (with information gleamed from 'Hacking Electronics' and 'Make:Electronics' ) so the information may not be 100% correct :( Please be kind.  I did verify the napkin holder lights were all functional!  Even witness it glowing for few hours at a party.

LEDS and Reistors

Each napkin holder wall had 2 LEDs and a resistor.  The 2 LEDs were wired in series and a resistor was added on the negative side (except for the Sounds to Light kit.  Refer to that particular section regarding the wiring).

The 2 walls were then wired in parallel (refer to the diagram).

Optionally, additional LEDs and a resistor were added to the resin sculptures (refer to the OPTIONAL portion of the diagram).  If 2 LEDS were used in the resin sculpture, they were wired in series and the resistor was added on the negative.  These were then wired in parallel to the 2 walls.

I used mostly slow flashing and fast flashing LEDs (3.0-3.6v forward voltage, 20 ma forward current) ( http://www.amazon.com/microtivity-IL604-Slow-Rotating-Resistors-Pack/dp/B007RO9X82 ) and either 9 volt battery or 12 volt battery. 

Here are the resistors I used depending on the number of LEDs and battery used to go with the diagram:
2 LEDS in series + 200 ohm 1/4 watt resistor for 9 volt battery
2 LEDS in series  + 300 ohm 1/4 watt resistor for 12 volt battery
1 LED + 330 ohm 1/4 watt resistor for 9 volt battery
1 LED + 470 ohm 1/4 watt resistor for 12 volt battery
 

Wiring

I don't wire everything all at once - so I may use longer than required strips of wire that is trimmed as needed later.

Testing

Test all the individual LEDs to make sure they work.
 
Attach to the battery and make sure it works before soldering and proceeding:
 
After wiring the LEDs in series for the individual wall or in the resin sculpture
 
After wiring the LEDS from the walls in parallel to each other
 
After wiring the optional LED in the resin sculpture to the walls in parallel

 

Step 4: Embellishments and Other Details

Picture of Embellishments and Other Details
1.  Resin 'sculptures'.

Resin sculptures can be added to:
 
a.  Hide the batteries.  In that case, it would not be a fixed part of the napkin holder and can be moved.

b.  Add decoration and be a fixed part of the napkin holder.  The scuplture would be added to the base along with the resin and cured as part of the base.
 
You can either add LEDs to the scultpure  (as in the Sound to Light Napkin holder) and wired in parallel with the walls, or no LEDs (as in the Waterfall Napkin Holder).

In the picture of the Death Star napkin holder, I added a fast flashing LED within the Death Star to contrast with the slow flashing LEDs used for the napkin holder walls.  I wished I had captured it on video because it looked awesome.  The Death Star was added to the resin that was poured to the base since I glued the battery holder to the side.

To add the LEDs to the scultpure mold, pour the resin into the sculpture mold and tape the LED so that the light is embedded in the resin, but the legs are sticking out of the mold.  Fix the legs on the outside of the mold with masking tape to keep it from falling in.

How to make the sculptures:
 
a.  Buy a mold

For the Death Star, I bought the silicone ice tray mold from my visit to Forbidden Planets. I have seen it on Amazon and Think Geek as well.  Plastic mold trays should not be used as the resin heats up and may warp or melt it. 

I do find that some silicone mold, like this Death Star, will give a thick, frosted appearance.  To clear this up, I painted a thin layer of mixed resin over it.

c.  Make your own mold
 
For the skull in the picture, I created a mold using used the World's Simplest Silicone Mold instructables out of just a tube of 100% silicone caulk, blue dish soap, and water.   It is pretty stinky but works great.  I made a one part mold (versus 2 parts) that was flexible enough for me to remove the skullfrom the bottom (so cover skull with the silicone from the top with opening at the bottom). The skull came from a broken wobble head speaker.
 
2.  Embed objects

Various objects can be embedded into the resin.  In the Death Star napkin holder pictured, I had added artificial flowers to the base.  You will have to check to see if the items can be embedded without ill effects.  Example - real flowers must be dried before it can be used as it can become moldy.
 
3.  Add color
 
In the Waterfall napkin holder, I added several drops of alcohol ink in various spots and swirled it with a toothpick (see picture of blue swirls in mold)

For deeper colors (to hide the wires), I have used Jacqard Pearl-Ex powdered pigments (found at Hobby Lobby) as well as mica powder by Slices of the Moon (found on Amazon).  To use this, pour the resin in a cup and scoop the desired amount into the cup and mix well before pouring into the mold.

The one pictured with the red and gold colors was one of my earlier experiments.  I used 2 different cups filled with resin.  I mixed red mica powder pigment in one and gold pearl-ex in the other.  After mixing the powders thoroughly in the resin, I poured both cups of the colored resin at the same time into the mold, and swirled them around each other.  I was careful not to mix them too much together because I didn't want to combine them into one color.  When poured in the base, it hid the wires well.  

For the walls, I poured a layer of color and allowedit to cure before adding the LEDs.  After the colored layer cured, I poured a clear layer of resin over the colored resin and inserted the LEDs into the mold.
 

Step 5: Additional Info for Sound to Light Napkin Holder

Picture of Additional Info for Sound to Light Napkin Holder

I love this Velleman Sound to Light kit that I found at Fry's for under $5.  I also saw them on Amazon at a higher price.  You can also find the schematics online if you want to build one yourself (http://www.vellemanusa.com/support/downloads/?code=MK103).  It was fast and easy to solder and the circuit board was the perfect size for the napkin holder. 

Kit Modification:

I modifed the kit slightly:

1.  I substituted 2 clear red and 2 clear yellow LEDs for the 4 solid red leds in the kit.  The 4 LEDs in this case are connected in series so be careful in substituion of LEDS.  It runs off of 9 volt batteries.  The red and yellow ones I used have a forward voltage of 2.2 to 2.8.  I believe the flashing leds as well as blues and greens have higher forward voltage so I could not substitute them using 9 volt battery.

2.  I did not solder the 4 LEDS to the board as the instruction indicates.  Instead, I soldered wires to the positive and negative LED slots.  I marked the negative wires with a black marker to help me wire them to the LEDs in the 2 walls later.

3.  I did not use the battery holder that came with the kit because it was too large.  Instead, I created a cardboard box around the 9 volt battery itself (refer to the Battery Section), and used a battery holder clip instead (see picture).  Make sure to tape the cardboard well with the packaging tape.

Wiring:

When I soldered the components to the board, I did not solder the battery holder clip directly to the board.  Instead, I soldered 2 wires that will be connected to the battery later.  So the assembled board contained all the components except the LEDs and the battery leads (wires were soldered in the slots instead).

After soldering the components in place on the board, I wrapped the wires (did not solder because testing only) from the LED slots on the board to the 4 LEDs and tested it to make sure it worked before continuing!

Wiring the LEDs within the napkin holder walls was also done differently than the other napkin holders.  I soldered wires to each leg of the LEDs (I didn't connect them together in series).  The wires from the LEDs that were embedded in the walls were later joined to the wires coming from the circuit board (see diagram).

Additional Skull resin sculpture for battery cover:

I also added 2 flashing LEDs to the Resin Skull that was used as a battery cover.  I connected the skull LEDs in series with each other and added a 200 ohm resistor on the negative side.  I then wired the leds from the resin skull to the postive and negative lead of the batteries (see Optional portion of the diagram).

Pouring Resin for the Walls:

Tape the 2 LEDS in the mold and pour the resin (refer to the Basic Instruction Section).  Allow 24 hours to cure.  Repeat for the 2nd wall.

Pouring Resin for the Base:

First pour a thin layer in the mold for the base (refer to the Basic Instructions Section and allow to cure).

Second, place the cardboard battery holder in the mold (refer to the Basic Instructions Section).  If the battery holder will be in the front next to the assembled board, make sure there is enough room for the battery holder as well as the circuit board. Pour a thin layer of resin into the base around the cardboard battery holder.  Weigh down the battery holder so that it doesn't drift in the resin and move.  Allow the resin to cure.

The assembled board will sit on the surface of the resin and not be completely covered.  To rest the circuit board so that it does not sit too far in the resin, set the walls in place in the mold since it sits deeper in the resin. Place the walls in the base mold and run the 4 wires from the LEDs in the back wall under the front walls.  Tape the ends of all 8 wires above the resin so that it would not be submerged yet in the resin to be poured.  

Set the circuit board temporarily in the mold to make sure there was enough room for it on the front of the napkin holder, adjust the walls as needed, and then remove the circuit board. Tape the walls in the mold to make sure it stays in position and make sure it is leveled. Pour a layer of resin (almost to the full height) and allow it to cure.

Wire LEDs to the circuit board

After the resin has cured, test all 4 LEDs before soldering (to make sure the wires are correctly paired).  Wrap the wires from the the assembled board to the wires from the LED in the walls.  Be careful you have the correct wires paired.  Connect the battery and make sure it works.  After verification, solder the wires together.

Insert board in base

Place the assembled circuit board in the base mold and carefully pour  a thin layer of resin.  Be careful not to get resin over the top of the microphone or the potentiometer.  Unfortunately, resin did seep into the POT and so I am no longer able to adjust the sensitivity. I poured enough resin to keep the board in place.  Allow 24 hours to cure.

After the base has cured, remove it from the mold.  Remove the cardboard battery cover with pliers.

Wire the battery cover (optional) and the battery leads

If you placed optional LED in the battery cover resin sculpture, then wire it now.  Refer to the diagram.  Wire the switch and the battery leads.  Before soldering everything, connect a 9 volt battery and make sure the switches and lights all work.

Place switch

The cardboard battery holder was placed close enough to the sides of the base so that the battery would still be held in place but the wall was thin enough to cut through to insert the switch.   First I drilled a hole with a small hobby drill.  I then used a file to enlarge the hole.  I repeated the procedure to create another hole close to the first hole.  I then used a dremel and inserted into the holes created to carefully enlarge it so the switch could fit through.

After the switch hole is created, use hot glue and glue the switch in place.

Step 6: Additional Info for Waterfall Napkin Holder

Picture of Additional Info for Waterfall Napkin Holder

Refer the Basic Instructions Section, Battery Section, LEDS and Wiring Section, and Embellishments and Other Details Section to create the napkin holder.  This section will refer only to the water effects added.

I did use blue alcohol ink in the base of the napkin holder to make it look like water.

Additional Material

Water Effects - I used both Vallejo and Woodland Scenics
Plastic strips - these can be found on product blister package.  I believe some people use plastic soda bottles.
Super glue
Resin sculpture - I used the Death Star to 'splash' into the water.

Instructions:

1. Brush a layer of Vallejo Water Effects on both walls. Also brush a layer of the Water Effects on the the base of the napkin holder.

2.  At the base of the 'waterfall', Apply a thicker clump of Water Effects to create the 'foam'

3.  The Death Star was then created with resin and the Death Star mold.  No LEDS were added to the Death Star.  You can use whatever object.

4.  Cut strips of plastic to make a skeleton for the water splash around the object (ex.  Death Star). Assemble the strips into a semicircular pattern and glue together with super glue.

5.  Glue the object (ex. Death Star) to the middle of the plastic.

6.  Add Water Effects on the plastic strips and around the object with a brush.  I also used the Woodland Scenic Water Effects  after the Vallejo Water Effects dried around the Death Star because it much thicker in consistency.

The Water Effects typically take 24 hours to dry depending on the amount and thickness used.

Comments

This is very cool! Love the water effects and the Death Star!

Thank you! Resin is awesome to play with and looks nice lighted.

Yeah, LEDs and resin go together so well!

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