Introduction: Epoxy Coasters
Have you ever stumbled across some coasters and wanted to keep them either because they were amazing or as a souvenir, yet once you get them you can't use them or show them off because of how fragile they are? Well in this Instructable I will show you how I've been preserving my coasters.
This process should take about a week to do, with the biggest time consumers being waiting for things such as epoxy and polyurethane to dry. It should cost (assuming you already have the tools) about 65 dollars to do 10 coasters, and after that the biggest cost will be the epoxy which is about 30 dollars for easily 15 coasters.
Step 1: Tools and Materials
For this project you will need the following tools:
A way to cut the hole in the wood: Jigsaw, CNC, etc. You need away to precisely cut a hole in the wood for the coasters.
Sand paper: Used to sand the wood before applying polyurethane as well as helping sand any epoxy issues. I recommend for the wood going from 60 grit to 200grit so it's smooth and the polyurethane applies easily.
Precision knife: Good precision knives to easily and effectively cut the masking tape. I highly recommend these over a scissors for more precise cutting.
Epoxy: I highly recommend going with Alumilite Epoxy because of it's cost as well as the fact that when doing smaller mixes (around 1oz) it doesn't lead to issues.
Spray bottle: This is used with isopropyl alcohol to lightly mist the drying epoxy to help get rid of air bubbles, make sure to get a good bottle that can evenly mist your coasters.
Wood: I recommend the Menards 6mm craft plywood because the 6mm size because its a very good ratio of wood to coaster that doesn't make these look bulky.
Masking tape: Get a good brand that will resist the epoxies ability to seep into it, as well as matching the look of your wood in case some gets stuck under the epoxy.
Brushes: Small foam brushes are great, and you will need about 8 of them from start to finish.
Polyurethane: I went with a clear gloss oil-based polyurethane.
Parchment paper: This is wonderful because the epoxy, polyurethane and Mod Podge does not stick to it so if any leaks your projects, and your work space will be safe and your project won't have residue stuck to it from rags, newspaper, etc.
Mod Podge: Used to preserve the coasters and prevent the epoxy from discoloring them.
Coasters: A very important part of this project, make sure they aren't damaged or in bad condition. Never been to a place where they won't (when asked) give you a few for free.
Step 2: Preparing the Coasters
Lay out your parchment paper so that all of your coasters can easily fit on it and, using a small foam brush, paint the coasters with the Mod Podge.
Be sure to do at least 3 layers of Mod Podge on both sides of the coasters, as well as the edges. when you are applying Mod Podge to the edges of the coaster, do not spin the coaster between your fingers, I've done this and it resulted in the coaster ripping. The best way to the edges is to hold it with 2 fingers and lightly dab the edges with a brush, then transfer the coaster your other hand to get the rest of the edges. To see if you did the Mod Podge correctly, hold the coaster up to a light and the entire surface is shiny, any dull areas indicates a lack of Mod Podge.
If you don't cover the coasters enough the epoxy will seep into the coaster and discolor it. The Junkyard coaster above is a comparison between an original coaster, no Mod Podge and only 1 coat of Mod Podge. You can clearly see the discolored spots. You can also see it on the coaster I ripped.
Thankfully the Mod Podge dries quickly (about 10 min) so if you are doing a large batch you should be able to just keep going since by the time the last one is done, the first one should be dried. You can re-use your brushes with the Mod Podge as many times as you like since it is easy to clean off of it provided you don't let it dry.
Step 3: Cutting Wood
Cut out the squares, each square is 4.5x4.5 inches. After cutting the squares, match them to a coaster and number them to keep them together since the Mod Podge causes the coasters to swell/deform slightly each coaster will need a unique cutout.
After cutting out the frames, lightly apply 2 coats of polyurethane to the entire frame, making sure to get the inside as well, this is to prevent any epoxy from soaking into the wood and discoloring it.
Step 4: Sealing the Coaster Edges
Now that you've got your coasters covered in Mod Podge and your frames have 2 coats of polyurethane, it's time to begin taping and sealing.
Apple a single layer of tape to the top and bottom of the coaster. When you do this you should have enough excess to fold over and cover the edges, but it's very important that the surface of your frame remains flat or the epoxy will not be level.
For sealing up the inside of the frame and coasters its time to do a little epoxy work. Mix up a small amount of epoxy and once it's ready lightly dip your popsicle stick into it.
You want enough to form a drop but not enough for it to fall off on its own. Then dab that drop near the edge of your coaster and gently push it towards the edge, forming a bridge over the gap between the coaster and the frame. This part is pretty easy once you get the hang of it, the goal is not to rush, but to be steady. For coasters that don't fit the frame very well (as seen above) I recommend doing these near the end when the epoxy starts to harden more. If you cant form that bridge don't worry, just get some on the frame and the coaster, then once its dried, flip it over and do it on the other side.
Step 5: Inspecting and Pouring
After your epoxy has cured for about a day it's time to inspect for holes and pour the first half of the coaster.
First inspect the underside of your seal for any leaks, this happens and isn't a big deal since you were using small amounts, the parchment paper will prevent it from sticking to the table and the masking tape will prevent it from sticking to the frame. Some of these can be pulled off (as seen above) while others will require a little love from a Dremel or sandpaper (next step for more of that).
Hold the coaster up to a light source and gently use a small object such as a paperclip to prod for any holes, and mark where there are holes for resealing.
Before you begin pouring make sure that your surface is level, and that the frames themselves are level, epoxy is a self leveling substance so if the surface isn't level, you'll find out the next morning, as show above.
When pouring, start in the middle, pour a bit and use your stirring stick to spread it out. Often times I ended up pouring too much and needed to spoon it back into the cup. The best way to see if you poured too much epoxy is to get eye level with your coaster and see if it's raised up above the tape.
Once you've poured all of your epoxy, after 10 minutes or so, lightly mist them with the isopropyl alcohol, this will help with air bubbles.
Step 6: Screwing Up
Now that you've poured your epoxy, it's time deal with all of the wonderful mistakes.
For the drips in the seals and leaks, you can easily sand them off. If you sand off the entire layer and do a full coat you will be fine, but as seen in the red coaster, if you just try to "patch" the epoxy, it will look pretty bad. You can also do this for the uneven coasters such as the Junkyard one.
For sanding epoxy the first thing you need to do is get the surface damp. This will prevent the dust from getting into the air and will instead just go on your workbench and hands (wear gloves!). Do this in small amounts, keeping the epoxy wet and making sure to not hit the frame, just the epoxy. Also avoid angling the Dremel too much or you risk breaking the sanding band which can cause injuries.
Once you've ground the epoxy down to where you can apply epoxy over it you need to sand it so it's smooth. Get the epoxy damp and begin sanding, starting with around 60 grit and working your way up to 350 or higher. you want it as smooth as possible so there is no open pockets for air or dust to get trapped in.. Be very thorough on dust removal, use brushes, vacuum, etc since the dust is what will stand on the most when you reapply the epoxy.
Step 7: The Next Layer
Now that you've fixed any issues with the other side of the coasters, it's time for the final layer. Just like before make your epoxy and pour it onto the coasters, making sure to spread it out and avoid pouring too much. The coaster above is the one with the massive leak with epoxy just applied to it, see how invisible it is? It gets even less noticeable as it dries.
Step 8: Polyurethane
Now that you've got epoxy on both sides of the coaster, it's time to apply the final coats of polyurethane.
Remove as much of the tape as possible with your fingernails. Be VERY careful if you decide to use the precision knife here as it can easily scratch the epoxy. This is why you use tape that matches your wood, in the event that some is trapped under the epoxy it will blend in very well.
Once you've removed all of the tape it's time to apply the polyurethane all over the coaster including the epoxied part. Apply a heavy coat and using a light, find the lines (as seen above) and apply more polyurethane to these areas until they are gone. Let it dry and do another coat, 2 per side. This is dont to prevent it from sticking to things like beer bottles or coffee cups.
Note: I tried using spray lacquer instead of polyurethane and it resulted in a cloudy look and was very sticky, do not use spray lacquer.
Step 9: Testing and Improving
Now that you've got your first batch done it's time to test them out! Using a variety of containers, (cans, bottles, coffee mugs) ensure that they function as designed, be sure to thoroughly test them!
Enjoy and please leave any comments or suggestions!