Article written by: Terry Morris, Terry Morris Productions, Sept. 2000
|Hello all, I have been
asked to elaborate on epoxy doming like shown on the key chain I did
First a simple explanation, epoxy doming is the effect of placing epoxy on the surface of most anything that has an edge, like labels, cut metal and such, surface tension will keep the epoxy from running off the edge of the item, that is until it's mass exceeds the strength of the surface tension, when the epoxy hardens it leaves a clear glass like dome covering the item.
To see the effect simply place a penny on a flat level surface, then using an eye dropper put some drops of water on the penny until the surface is covered. Keep adding one drop at a time until it forms a bubble of water on top of the penny. Now, imagine if that water were actually clear epoxy and you let it harden, the penny would then be epoxy domed.
The epoxy used in doming comes in a few varieties:
2 part mix
It is not the same stuff as you get at a hardware store, it is made for the main purpose of doming, it hardens to what they call "water clear" and the surface tension is higher than normal so you can get a good size bead or bubble.
All of these have pros and cons.
Two part mixes: These are easy to use, pretty cheap, and are UV resistant, they also come in varying hardness but are usually semi soft. The down side is that you must mix them, you have a limited time to complete work until they gel (between 10-20 minutes) they then take 24+ hours to cure and are not real hard. When I mix up the 2 part stuff I put it in a small 2oz. squeeze bottle that has an .063 Luerlok tip (used in the epoxy business) these are cheap enough that I just toss the whole bottle and tip when done (cost about $1), I mix up 1-2 ounces at a time, 2 ounces will do about 20 key chains.
Low intensity UV cure: These use a standard black light (UV light) to harden the epoxy (takes about 20 minutes), it is relatively easy to use, has an unlimited work time (won't harden until exposed to UV light) and is very hard when cured (like glass). The down sides are that you must work in low UV lighted room (no sunlight or fluorescent light) they cost a little more than 2 part but less is wasted because any unused portion can be used again later (2 part mixes harden no matter what) also they are not UV stable, that is they will turn yellow after 6 months in direct sun and crack in about a year of sunlight.
I like using low cure for items like key chains and labels (for indoor use) as well as name badges and even trophy plates. I also use 2 part mixes for outdoor use items, like on cut vinyl letters for vehicles (this is a whole industry unto itself) and other items that either might get UV exposure or that I want/need to be slightly soft and flexible (you can press your fingernail into it, though it will usually heal itself.
High intensity UV cure: This comes in both hard and soft forms, cures in 15 seconds, and pretty much is like low intensity version. The down side is same as low except the light source is also very expensive ($1,000 to $5,000) and it generates a lot of heat while curing, this means it cannot be used on paper products and things that can't handle quick heating to 200+ degrees F.
In industry the high intensity cure is most often used in high production plants like those that make lapel pins and large quantities of key chains. The 2 part mix is used a lot for automotive emblems and short run promotional items. Low intensity cure is kind of between the other 2.
I have used the gun system, there are two problems with them, the first is they charge way too much for the amount of epoxy you get and when you open a tube you must use it all!! If you leave the tube part full it will go bad in a few days do to exposure to air, also you must use a new mixing tip each time you epoxy, the tip cost money as well and makes the whole thing very expensive.
On average you can figure a tube system will cost you $10 a tube to use, for the same amount of bottle epoxy where you mix it yourself will cost you about $2 or less if you buy in bulk, that is a significant difference.If you have problems with bubbles, you are probably getting these due to humidity, I bought a d-humidifier to help, you need to have humidity of 50% or less, basically the higher the moisture in the air the more bubbles you will have.
Epoxy doming is a great addition to color sublimation, I use it a lot with Mates to make fantastic stickers, I also print on cut sign vinyl (using an Alps MD-5000) and then dome them to make stickers with wild vinyl (metallic, Metal flake, holographic, Pearls....).The 2 part mix I use is a product called 3DV (stands for 3 dimensional vinyl) sold by Sign Mart (800-533-9099 or CA residents 800-696-9470) and the UV resin I use is sold by Deco-Coat 1-888-EPOXIES. Deco-Coat also carries the mix stuff but I tried their cartridge mix system and did not like it, I have not tried there mix by hand stuff. If anybody has any questions please fell free to ask, also if anybody wants to see a sample, send me a self addressed stamped envelope #10 or #6 3/4 to:
Just put a note in with it requesting a domed sample.
The above article is: Copyright 2000 Terry Morris, all rights reserved and may not be copied or reproduced without the written permission of the author.
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