storing the epoxy

i am new to the use of epoxies in this quantity.  i have just used the pumps and mixed my first batch.  now that that is done, to store the epoxy containers, should i remove the pumps?  if so, how do i clean them? or do i leave the pumps in and cover the pumps lightly to prevent any contamination?  i will be using them soon, within a week.

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RE: storing the epoxy

I can't speak to long term storage, but I left my pumps in place for months on end.  I did begin to have trouble with their operation after about a year, so maybe they should be stored for long term.  I am sure someone here has the answer to that.

One thing that I did do for storage is turn the pump head around facing backwards so if there are any errant drips, it goes on the bottle, not the surface it's sitting on.

RE: storing the epoxy

Leave the pumps in and use when needed.  Once your project is finished and you need to store the epoxy, clean the pumps by pumping white vinegar through them and put them in sealed plastic food storage bags, one pump per bag.  The sealed containers of epoxy should store well for a couple of years.  I have MAS epoxy with the pumps in that I have used from time to time over a two year period.  The pumps and the epoxy still work fine.  Good luck.  Jer

RE: storing the epoxy

Thanks for your answers.  I wilol keep the pumps in.  i like the idea of turning the pumps 180 degreees.  i am building 2 matunucks and will post pics as progress continues.


RE: storing the epoxy

I routinely cut the fingers off a latex glove and pulled them over the pump-ends to seal them from air..., worked pretty well but you have to replace the "fingers" often.

About halfway through my build I tossed the pumps and started using plastic measuring cups or small plastic glasses (measuring cups are a dollar at the dollar store, making them disposable).  I found my pumps were spitting irregularly and I feared a mis-ratio mix.  Using smaller epoxy containers makes pouring it into the cups fairly easy and accurate.

Good luck,


RE: storing the epoxy

Larry,  i have read here several time about the pumpsspitting and mixed by the container marks.  mixed a bit too much, but you learn.  i think i will find some smaller cups especially now since we are gluing pieces together and then the tacks. 



RE: storing the epoxy

There's 3 main reasons why pumps spit:

1. Hardener loses some of its volatiles (this is what makes it turn amber as it ages) and it thickens and clogs the pump.

2.Epoxy gets cold and crystallizes and the crystals clog the pumps

3. Liquids go out, no air comes in and a partial vacuum fights the pumping action.


For 3, just screw the pumps on loosely so air gets into the bottle. For 2, put the bottle, pumps and all, under a heat lamp for a day or so to melt the crystals. For 1, the easiest thing to do is to buy a new pump.



RE: storing the epoxy

Can't wait to see your his and hers pictures on here. 

RE: storing the epoxy

I use an inexpensive battery operated electronic balance that I purchased online: My Weigh i1200. It weighs to 0.1g with a capacity of 1200g.  I have had it for two years and I am still on the original batteries.  I prepared a table based on the densities of the resin and hardner.  I got the values either from the bottles or at the manufacturers site; I do not remember.  I pump the desired amount of resin into a disposable cup, weigh, look up how much hardner is required and then pump that in on top, stir for two minutes and use.  It is especially useful for small batches, i.e. less than a full pump.  The pumps are quite accurate, but are occasionally off due to bubbles or perhaps idiosyncratic use on my part.  However the final proportions are right-on every time.  I do not trust a measuring cup because the high viscosity makes a complete transfer almost impossible.  Epoxy is great stuff.  I wish I had discovered its full potential years ago.  I imagine my house might have been 10% epoxy by now.   

RE: storing the epoxy

So long as Part A and Part B are stored separately, out of the sun, you have a couple of years minimum, without a problem.

But, it can test your nerves. It can turn brown-ish, crystallize, and other scary-looking stuff, before it's finally landfill.

Your mileage coul;d vary, but, I admit it: I cannot turn Hunter Thompson nightmare-looking goop loose on my hand-shaped floating furniture.

 So, I try to be honest-with-myself: I buy what I need, than-and-there, for the gig-at-hand. No false economy. No wastage. No heart-attacks.

That said, my funky family is always breaking stuff. Plates, bowls, hideous hummel statuettes of too-cutesie cupid-things. Aweful stuff, believe me...

Yet, somehow, inexplicably, it "must be fixed".

So, all those drips, goops and oozes, in the botttom of sundry crusty old goop-bottles, fiinds a purpose.

Proving, as always, that nature abhors a vaccuum...


RE: storing the epoxy

I also prefer using the electronic balance as Joe suggested, especially when I have to mix larger quantities of epoxy.  I found I was getting 10% more hardener than needed using the dispensers.  This was probably due to my technique and the viscosity differences of the materials.


If you are mixing with a gram scale then you can use the MAS specifications of specific gravity for the Slow Hardener 0.998 g / cc and Low Density Epoxy 1.08 – 1.13 g /cc.  So now I mix by weight at a 2.2: 1 ratio and use the dispensers for dispensing small quantities to accurately reach the target weights.


Now storage is just keep it from getting too cold.

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