No-Mess small batch epoxy

[Zeroignite]

Epoxy can be kinda nasty stuff. Getting it on the skin is definitely not good for you, plus it just feels icky. In parts or mixed, it sticks to any surface it comes into contact with, and can be hard to remove from unwanted places. Epoxy is also a key adhesive for rocketry.

So, here's how I do it in a way that's basically guaranteed to not leave any mess.
This is for small-batch 1:1 structural epoxy. Things will be different if you're mixing several ounces of the laminating stuff.

You need nitrile gloves, aluminum foil, and something to mix with. It's also good to have paper towels and isopropanol in easy reach, since that's one of the few things that can clean off epoxy goop.

Take some aluminum foil and fold it in half. I like to pinch one corner up into a little boat. For a stir stick, cutting the head off a q-tip gives an even mix and can be a handy applicator.

Put a glove on one hand (likely your dominant side). This hand only comes into contact with places or things epoxy is supposed to get on, and nothing else. Putting the glove on one hand only serves as a useful reminder not to touch anything you shouldn't.
The other hand is free, and should never contact the epoxy at any time.

Put down equal parts of your epoxy of choice. I personally have a lot better success getting the mix ratio right when the resin and hardener come separately, rather than using those single-unit syringe dispensers. In either case, hold the container upside-down for a while first, so the air bubble inside inside floats up and away from the nozzle.
Mix.

How you apply depends on what you're doing. Headless q-tip is pretty great for precise application, but don't underestimate just using a finger when laying down fillets. In any case, remember: glove is for epoxy only, not-glove is never near epoxy. If it starts to gel at all, stop and make another batch --- better to waste a bit then to mess up a project.

Once you're done, put everything you used for application and masking down into the mix boat.

Then, using the gloved hand, pick up the foil and everything else, crumpling it together as you do so.

With the clean hand, grab the glove by the cuff and fold it inside-out, moving downwards. Best I can describe the action is it's similar to rolling on a condom.

Once it's folded over completely, the epoxy is entirely contained within a little nitrile baggie! No mess, no drip, no fumes, no skin contact.

 

[Rex R]

I understand that vinegar can be used to clean uncured epoxy off skin. I haven't tried it. vinegar is supposed to stop the curing action w/o carrying bad stuff through the skin, whereas acetone and alcohol* merely delays curing.
*I use vodka .
Nice tip by the way
Rex

 

[fyrwrxz]

Very cool technique, Z! Here's another old school trick: Take a ziplock sandwich bag and roll it down on itself half way. Take a toothpick and 'tent' the bag open. measure your base and catalyst in the bag. Remove toothpick. Roll the bag back up trying to keep as much air out as possible. Knead the bag to mix components completely. Work the epoxy into a corner and twist the bag into something that resembles a baker's icing bag. Leave a small pocket of air ahead of the epoxy and just snip the smallest corner out of the bag. Viola'! Fin fillets, sled tubes, etc. Let the remnants in the bag cure out as a test sample. It's how I found out Proline 4500 doesn't stick to that type of plastic. (which lead to making molds, but that's another story)

 

[Zeroignite]

Nice tip, fyrwrxz! Dunno if I'll end up using it when I do well with sticks and fingers, but seems like a really neat way to do work in the field.

 

[matthewdlaudato]

Nice tips. Lately I've been using these mini-muffin cup liners and inserting them into a standard epoxy cup for my small batches. For the T-88 that I use on some builds, I eyeball 1:1 directly into the liner, mix it with the hobby stick and apply. When I'm done I wipe the stick clean so I can reuse it, and just throw the liner out. Both hands gloved always for me. The epoxy cup remains clean and reusable.

 

[CarVac]

For a while I reused the same epoxy cup about ten times. I let the Popsicle stick cure in the remaining epoxy, and then just flex it to remove the hardened epoxy.

 

[matthewdlaudato]

For a while I reused the same epoxy cup about ten times. I let the Popsicle stick cure in the remaining epoxy, and then just flex it to remove the hardened epoxy.

For bigger batches I have done that too & will just trim the stick off so I can reuse it.

 

[Coop]

Neat trick! I usually mix on ice cream container lids --and like Carvac, pop off the mixing stick and epoxy remainder to toss...


Later!

--Coop

 

[G_T]

I donno... I have the philosophy that if one needs safety equipment to work with an item (nitrile gloves) then having that safety equipment come into contact with whatever item is to be avoided is already a violation of good practice. One is trusting the safety equipment as a first line of defence, rather than as a last line.

I do a fair bit of stuff with epoxy and have done so for many years. Ideally the gloves stay clean. If I contaminate a glove, I swap the glove. That's just a basic chemical practice, IMHO. When one first works with laminating resin with a dye added, it becomes clear how easily it gets spread around to unintended areas. It can be an eye-opener for good chemical handling practice.

That said, epoxy isn't nearly as bad as some other chemicals we might be using on occasion. Curatives for R45 for example... There are also epoxies available now that are less toxic and less likely to cause allergic reaction. But I've seen that more with ones formulated for the European market which has more stringent safety regulations.

Old playing cards make nice surfaces for mixing epoxy. Aluminum foil can crinkle up during the mix, and can puncture on occasion when scraping the surface which is required for a good mix. Not that I haven't used aluminum foil quite a number of times... Just that is is down on my list of preferrable surfaces.

Often times when epoxy gets where you don't want it, the best thing to do is just let it cure. Then peel or scrape it up. Of course that depends on whether you're working on a surface where you can get away with doing that. A lot of my epoxy work is done on top of HDPE sheet, or waxed mylar. Epoxy removes easily enough from these. Heck, with the mylar, just flex the sheet and the cured epoxy blobs pop off.

Gerald

 

[fulldec]

I mix small batches of epoxy on a pad of "Post-It" paper, about 4"x6" Has enough mass to stay put while mixing and laying on the bench. I usually leave the used epoxy on the pad until cured just to know when it is done. Pull that sheet off and toss it when all done.

Also, vinegar does work well to clean uncured epoxy. I prefer it, it doesn't seem to dry my skin like alcohol does (either one ends up on my skin even if I am not cleaning epoxy off my skin).

 

[blackbrandt]

I tried the baggie method last night, and I LOVE it. It is also nice because I can lay the bag down on my bench while I am working on something, then pick it back up again.

Matt

 

[Wizard]

In addition, I find that wooden chopsticks (from Pei Wei) make excellent mixing sticks/applicators. You can shape the ends if you want, and if you wipe them off after each use they work many times.

With regards to gloves, sometimes the point of the glove is to act as a barrier when contact is necessary, not just if contact is accidental (for example, a glassware base bath). That said, if I need to use them for that, I'm using a better glove than a disposable. As epoxy is generally much less toxic than some other chemicals we use, I'm fine with the disposables for that. However, once its on the glove, it tends to spread to other surfaces very fast, so I swap out as soon as I can if I get epoxy on them (deliberately or otherwise). I use a very thin pair of cotton gloves under the nitrile as it really helps in removal (and you can leave them on), especially if you are in a hot/humid environment. Trick I picked up from working in dryboxes.

David

 

[o1d_dude]

I keep an opened paper bag and can(?) of baby powder handy.

If I get epoxy on my nitrile disposable gloves I just shake some (a small quantity) baby powder on my hands over the paper bag and rub hands together. End of problem.

Not very worried about the epoxy fumes, etc. It's the CA that gives me grief.

 

[K'Tesh]

My mixing cups are upside down empty Yoplait yogurt containers. My mixing sticks are coffee stirrer sticks I saved from the trash following a presentation at school. I've learned how to reuse my stirrer sticks, after the epoxy cures, just cut off the thickened tip, and you've got a fresh stick again.

The stirrer sticks also make great standoffs for any rocket's launch lugs that need to be elevated to clear small details, or slightly mismatched thickness in body tubes (namely my clear payload sections made from florescent light guards).