View Full Version : 2pt Epoxy in Syringe Dispenser - Shelf Life after 1st Use ?

12-30-2013, 02:21 PM
After not using epoxy in a long time, I have a need.
However, upon looking at choices available, I find
that the resin and hardener is commonly packed
together in a syringe that promises equal portions
and thorough mixing.

Are these effectively single-use applicators? Or are
they able to dispense portions and then be stored
for weeks until the next job presents itself? If the
latter, are they ready to go or is cleaning/clearing
of the mixer section typically necessary before the
materials will flow?

With the traditional two-tube approach, shelf life
was eff indefinate. Never noticed a problem w/
mixing small portions.


brian Rupnow
12-30-2013, 02:26 PM
I use the 5 minute 2 part epoxy in the syringes all the time. It does dispense equal amounts, but you have to squirt it on a piece of metal and mix it with an old screwdriver before applying it to anything. Shelf life of stuff remaining in the twin syringes lasts almost indefinitely.---brian

12-30-2013, 02:26 PM
They don't mix in the container. Depending on the design you just squirt some out on a flat surface and mix or install a mixing tube on the outlet and it mixes when you dispense. Either way they are good for multiple applications.

12-30-2013, 02:28 PM
Some brands are more shelf-stable than others. You may have to try several kinds before you find your ideal.

12-30-2013, 02:41 PM
I was under the impression there is a swirl agitation mixing action
taking place in the syringe needle and expected that material left
here would harden, blocking future use. Guess not.

FWIW, since posting I discovered LePage offers a carded prod called
Speed Set Professional Epoxy where the resin/hardener comes in discrete
118 ml containers.

I'll give one of the syringe packaged products a try.

Ken R.


12-30-2013, 03:18 PM
There are single-shot dispensers like you describe. I have had little luck getting them to remain useable.

I keep a couple of tubes of epoxy on hand (wood-specialty, metal-specialty, and plastic-specialty) and the corresponding hardener. I find for what I do this is more than sufficient.

12-30-2013, 03:51 PM
The dispense and mix (via a swirl tube) types are one time use. In a like manner there are larger systems with a disposable mixing nozzle, which is discarded after use.

Bob Fisher
12-30-2013, 03:52 PM
The twin tubes have been disappointing long term for me. I have found at the box stores a Loctite epoxy in two squeeze bottles. Easy to use and ready the next time. Also a LOT more epoxy than the twin tubes. For about fifteen bucks more cost effective. Bob.

12-30-2013, 03:53 PM
In my experience, the syringes do dispense equally the first few times. But then invariably one or the other dispensing tubes will get partially clogged so the proportions become unequal.
As for shelf life, I've had success even years after first opening. It's always the clogging that prompts me to discard the whole unit. Tho I probably have occasionally noticed slower curing from real old stuff.

12-30-2013, 04:31 PM
I would advise that you visit a hobby shop. There is something called 'quick cure', which comes in separate tubes. It's available in a couple of sizes, plus different setting times. One is a 5 minute, another is 15 or 20 minute, and there is the slow variety as well. It's more bang for the buck in quantity, and it seems to be good quality stuff.

There was something called Zpoxy as well, though I think it was pricier.

I'm not aware of any dual-syringe thing that mixes for you, except for the larger, 'construction grade' tubes. Those have a rather long mixing tube, which gets tossed after one use. Some of them come with two mixing tubes, but otherwise are designed as one-use. They might be the best in terms of quantity for dollar, but are useless for small jobs. I have wondered though whether the epoxy in some of those is 'high grade'- it would seem that is the case at least for some of them.

If you're having to mix anyway- well it's a personal preference, but I don't prefer the dual-syringe dispensers. I can measure out equal quantities easily enough, and I prefer being able to cap individual containers separately.

Thought I'd add this- at work we use what is called backing- it's a 1/8 thick mdf with a durable white coating on one side, used in kitchen cabinets. We always have lots of waste. Time to time I cut the waste up into 3 inch squares, and that's what I use to mix epoxy on. Works great, doesn't absorb either component, and it's a toss away after that. I've probably used about 300 of them in the past couple years- good for mixing body filler as well. I like the fact that they are solid enough to handle, and in my case are free. Visit a cabinet shop and they'll probably be happy for you to take some of that away.

Paul Alciatore
12-30-2013, 05:16 PM
Yes, those mixing attachments for twin tube dispensers are one use only. And it is a pretty good idea to remove that attachment from the tubes immediately after use if you want to prevent the epoxy from hardening back to the tube openings. The amount of time before the mixing attachment is blocked by hardened epoxy is dependent on the hardening time of the epoxy and can vary from 5 minutes to several hours.

These mixing attachments are probably for industrial users who use the epoxy in a time intensive environment where the time involved in mixing the epoxy is more expensive than a new tube of the stuff. They have a bunch of them on hand and just toss them out when they harden. Personally, I am frugal and never use them. An awful lot of epoxy is wasted in the mixing area of the swirl tubes. But if I was to set up an assembly line that used epoxy I would consider them. With proper timing you could probably use most of the epoxy before tossing it.

I have been inspired to write up my frugal method for mixing and storing epoxy and when I add the photos I will post it.

12-30-2013, 05:22 PM
A while back I gave up on the twin tube epoxy dispensers - they ended up being single use most of the time. I went to "Double Bubble" http://www.mcmaster.com/#double-bubble-adhesives/=q1d9eq for a while which works fine.

Just now I am trying Bob Smith epoxy http://www.amazon.com/gp/product/B001NI8MLM/ref=oh_details_o04_s00_i02?ie=UTF8&psc=1. Just used it for the first time today - seemed to do the job OK, we'll see how long the individual bottles hold up for the long term.

12-30-2013, 06:20 PM
I would advise that you visit a hobby shop. There is something called 'quick cure', which comes in separate tubes. It's available in a couple of sizes, plus different setting times. One is a 5 minute, another is 15 or 20 minute, and there is the slow variety as well. It's more bang for the buck in quantity, and it seems to be good quality stuff.

Hobby shops carry Bob Smith Industries epoxies, sometimes under a private label (but there will be a 'BSI' label on the bottle). It's really good stuff as is their cyanoacrylate adhesives.

12-30-2013, 06:30 PM
I find this type still works fine after being opened for years, it may take a little while longer to harden tho.

From Poundland here in the UK, so you guessed it it cost 1.

Tits on the tubes can only go on one way round so no mixing the tops up and if it does ever go off it's only a 1 ;)

12-30-2013, 07:21 PM

They have a 30 min version as well up to 9oz, lasts forever, especially if kept in the freezer, and you can control the mixing rate.

12-30-2013, 07:23 PM
Well waddya know- my epoxy is from Bob Smith Industries.

12-30-2013, 08:06 PM
I've been dealing with a company named Fasco for years in S. FL. The man that founded the company was a chemist and I spoke with him several times. During one of our conversations he told me that if you have epoxy that gets hard in the container it's till good. All that need happen is to warm it in the microwave. I've done this and it works well. I have epoxy that is probably 20 years old that is still good. Although I haven't tried it, the new company owner told me that metal cans of epoxy can be warmed in the microwave by putting the metal container inside a plastic one. If you do heat epoxy to rejuvenate it just be certain not to over heat it, only warm it and leave the container open so it can vent. Also be aware that if you use it warm it will set up faster.

12-30-2013, 08:21 PM
Devcon has an incredible selection of epoxies.
Want to patch your bronze propeller while underwater?
You get a choice of freshwater or saltwater and fast or slow cure.
And it gets more exotic than that.

12-30-2013, 09:26 PM
We use the twin syringe at work, and shelf life depends on the last person that used it. If they were CAREFUL to get the cap back on correctly (instead of backwards), and not cross contaminate when wiping off the tips, all is well. It will live to fight another day. If it was Chris or Bob, it's a goner.

12-30-2013, 11:21 PM
Whenever I use one of the twin tube deals, I cut them in half with a jewelers saw first. Then I can easily apply equal amounts from the individual syringes. The viscosity of the two is different and therefore they do not dispense equally. I do try to avoid using them though.

12-31-2013, 08:48 AM
There's a trick when you squeeze out the stuff to smear off perpendicular to whatever flat surface you're mixing on, and if you cross the streams like Ghostbusters then its a goner. Never let a droplet of the monomer or the catalyst get a mm closer than they were in the package, ever, then it'll last for years and years.

After maybe 3-5 years, either opened or wasting away on the retail shelf, the monomer starts thickening up, you'll lose some strength but probably not enough to matter. The catalyst usually doesn't change characteristics as it ages, and it doesn't seem to lose potency.

I store all my tools and stuff by activity/project not by type like a central glue storage, so I've had plenty of experience with old epoxy and I'd say hardening will be the least of your concerns, the unholy mess of a single or dual leak is a filthy toxic waste nightmare. You're probably about 5 times more likely to open up a box and find a puddle, or worse, other stuff embedded in a solidified puddle, than to find a hardened double tube. You can put a rubber band on it, which will get brittle and snap and there's a puddle. I end up with a loop of small solid hookup wire twisted into place to clamp it, not very elegant but it works. That and put it in a plastic bag or a little kitchen tupperware box to contain the inevitable leak.

12-31-2013, 02:43 PM
I use "Post-It" note pads to mix small batches of epoxy. Just tear it off after using and you have a new clean surface for next time.

Paul Alciatore
12-31-2013, 03:55 PM
Mixing Epoxy, My Method

1. Use a pad of sticky notes (usually the 2" x 2" size) for a disposable mixing surface and the back end of a six-inch, cotton swab with a wood stick for mixing it (Photo 1).

2. Squirt the required amount of each part of the epoxy onto the note pad, either with a twin tube dispenser or from separate tubes.

http://img.photobucket.com/albums/v55/EPAIII/Photos%20for%20Tips/P01x06n11_zps9a557f00.jpg (http://smg.photobucket.com/user/EPAIII/media/Photos%20for%20Tips/P01x06n11_zps9a557f00.jpg.html)

3. Use the rear end of the cotton swab to mix the epoxy. Use two actions in order to get a complete and uniform mix. First, mix for a few seconds with the stick at a shallow angle (10 to 25 degrees) to the pad (Photo 2). Second, lay the swab’s stick down flat on the pad and push the partially mixed epoxy back to the center using a contra rotational action on the swab stick to sweep the edge of the pad clean as you do this (Photo 3). Do each of these two actions in turn for three or four cycles until the epoxy is completely mixed. Using several of these mix and scrape cycles insures a through and uniform mixing with no pockets of unmixed epoxy or hardener remaining on the pad.

http://img.photobucket.com/albums/v55/EPAIII/Photos%20for%20Tips/P03x13n14_zpsdb4d2911.jpg (http://smg.photobucket.com/user/EPAIII/media/Photos%20for%20Tips/P03x13n14_zpsdb4d2911.jpg.html)

4. For many applications where the epoxy needs to be precisely applied, the stick of the cotton swab makes a very handy applicator. A volume of epoxy can be scooped up on the side of the stick and spread uniformly over an area (Photo 4). You can rotate the stick while in contact with the epoxy to get a uniform layer all around it. Or a small drop can be picked up at the tip and dabbed onto the parts (Photo 5). The small stick of the cotton swab can reach into most holes to apply the epoxy inside them. Or they can be coated with epoxy and used to wipe it uniformly around a cylindrical part. If you need a really small dot of epoxy, you can pre sharpen the end of the swab’s stick to a point, before starting (Photos 1 & 5).

5. When the epoxy is applied and the parts are laid aside for hardening, lay the end of the swab's stick in the puddle of remaining epoxy (Photo 6). You can then use it to easily judge when the epoxy has hardened without sticking your finger or something else that must be cleaned, into it.

http://img.photobucket.com/albums/v55/EPAIII/Photos%20for%20Tips/P05x18n23_zpsb300b44d.jpg (http://smg.photobucket.com/user/EPAIII/media/Photos%20for%20Tips/P05x18n23_zpsb300b44d.jpg.html)

Using a fresh piece of paper towel or rag for each part, wipe the excess epoxy or hardner from the openings of the tubes. For twin tube dispensers, wipe once only with each fresh towel or rag to prevent cross contamination. Replace the cap or caps on the epoxy dispenser(s). Be careful to place the correct caps on each tube, otherwise the epoxy will harden in the throat of the tube and it will be useless. If you are using a twin tube dispenser, LOOK before trying to recap it. It is easy to get the cap backwards and once the hardener in the cap hits the other tube, it will harden it. More than once I have had to throw away a twin tube that had been recapped improperly (by others, of course).

When I store epoxy and super glue, I take care to store the tubes or other containers with the openings facing UP (Photo 7). This prevents the adhesives inside from oozing out and hardening. This is especially effective for longer-term storage of super glue because it leaks out very easily if the opening is horizontal or pointing down. I have stored open tubes of super glue and epoxy in this manner for over a year and still been able to use them.

http://img.photobucket.com/albums/v55/EPAIII/Photos%20for%20Tips/P07x20_zpsafbdc55f.jpg (http://smg.photobucket.com/user/EPAIII/media/Photos%20for%20Tips/P07x20_zpsafbdc55f.jpg.html)

If you are as frugal as I am, break off the protruding length of the cotton swab, which can be used at a later time for a cleaning or other task (Photo 6). Tear off the top sticky label sheet with the leftover epoxy and discard it. Or perhaps someone can find a use for even that: if you do, please share.

This method has been used successfully on all types of epoxy that are supplied as thick liquids. By following these procedures I have been able to reliably dispense and mix small to moderate quantities of epoxy and successfully store the remainder for long periods for later use. The epoxy and super glue I used for the above photos were both first opened well over a year ago and both are still just fine for use.