Thread: Measuring small amounts of epoxy?

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Measuring small amounts of epoxy?

Has anyone discovered a handy way to measure small amounts of epoxy. I'm getting tired of throwing away mixed but unused goop.
I've got a small digital scale but while the 2/1 by mix by volume is dandy, the mix ratio by weight is something like 100/44 or so and seems awkward. My fault of course - always math challenged. My H.S. Trig teacher can attest to that. It's expensive stuff and throwing away half or more of a very small batch is irksome.
More than a few of y'all probably have this handled. What say you?
Tom

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Re: Measuring small amounts of epoxy?

You can get plastic syringes of various sizes at the pharmacy. Keep resin in one and hardener in the other and mix by volume.

Last edited by Gib Etheridge; 11-12-2017 at 06:29 PM.

3. Re: Measuring small amounts of epoxy?

What epoxy are you using? That seems a very odd weight vs. volume discrepancy, but maybe West just makes it easy by being 5:1 by either weight or volume.

All that said, I just use a cheap digital scale that measures in very small units --grains, if I want-- and write out, on scratch paper, what the numbers will be ahead of time, so I don't have to figure it out on the fly. E.g., I'll write down "15 -- 18", so I know that once I reach 15 of resin, I should put in enough hardener to make the scale read 18. My brain moves too slow to do otherwise. Might that make it easier? Write out a table:

100 -- 144
75 -- 108
50 -- 72
25 -- 36
etc.

Alex

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Re: Measuring small amounts of epoxy?

I do this a lot using the ratio by weight suggested on the epoxy containers. I pour the resin and activator into respective ketchup dispensers that have caps. ( I store them of a shelf with caps on...haven't noticed any degratition.(about 1\$ each ..wally world) this makes it way easier to meter out the materials with very little spillage.....on a electronic scale i weigh a "disposable condiment cup( about 1\$ for 20....T.Y. dollar store) write the weight down ( I think this is called "tare") and then pour out the required amount of resin into the cup. weigh and write that down as well. calculate the needed amount of activator (by weight and add to the same condiment cup until the target weight is achieved. Then mix n serve! I use this method for balsa model construction. and being very cheap, am thrilled that it's worked out way better than it sounds.
Last edited by the_gr8t_waldo; 11-12-2017 at 06:53 PM.

6. Re: Measuring small amounts of epoxy?

For small amounts I use small el cheapo plastic measuring spoons and mix by volume.

7. Re: Measuring small amounts of epoxy?

Post #4 is the way I mix small amounts for luthierie work. P.S. five minute, 30 minute, 1 hour epoxy is crap unless you don't care about strength of bond.

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Re: Measuring small amounts of epoxy?

Originally Posted by Pitsligo
What epoxy are you using? That seems a very odd weight vs. volume discrepancy, but maybe West just makes it easy by being 5:1 by either weight or volume.

All that said, I just use a cheap digital scale that measures in very small units --grains, if I want-- and write out, on scratch paper, what the numbers will be ahead of time, so I don't have to figure it out on the fly. E.g., I'll write down "15 -- 18", so I know that once I reach 15 of resin, I should put in enough hardener to make the scale read 18. My brain moves too slow to do otherwise. Might that make it easier? Write out a table:

100 -- 144
75 -- 108
50 -- 72
25 -- 36
etc.

Alex
Shouldnt that be

100...44
75...33
50...22
25...11

9. Re: Measuring small amounts of epoxy?

I prefer syringes and mainly use the 60ML size for 2:1 epoxy. Its easy to measure a few ML with smaller size syringes and 90 ML will be sufficient for a fairly large job. Each syringe is clearly marked for resin and hardener that is stored between jobs in a tin can with a formed hardware cloth screen isolated area in the bottom of each can to allow drips to fall out of the way. These typically last for several months without needing cleaning or replacing. I have not found any other way that is nearly as effective for very small jobs. Epoxy is kept in a heated storage box in cool temperatures to prevent crystallization as well a easier pumping. Except for actual building of a boat or other large jobs, this covers well over 90% of my use.

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Re: Measuring small amounts of epoxy?

I think what he means is add whatever amount of resin you think you'll need, note the weight, then multiply that weight by 1.44 and add resin to reach that total weight.

100 grams of resin, times 1.44 equals 144 grams total for the mix.

That's by weight, with the brand that he's using, which is mixed by volume at 2:1. The .44 is because the hardener is less dense than the resin, so half the volume of hardener weighs less than half the weight of resin.

Syringes are even easier though, no need to consider the weight of the container.

11. Re: Measuring small amounts of epoxy?

I did the same as post #6. Got a plastic set of measuring cups and used a tablespoon and a 1/2 tablespoon.

12. Re: Measuring small amounts of epoxy?

I think what he means is add whatever amount of resin you think you'll need, note the weight, then multiply that weight by 1.44 and add resin to reach that total weight.
Yep.

But what I was saying was that I'd probably write out a table of pre-determined weigh points, that I could refer to every time, to make fast batches easier: e.g. when the scale reads 75 with the resin in the cup, add hardener until the scale reads 108.

Alex

13. Re: Measuring small amounts of epoxy?

So I was using an electronic scale to measure some epoxy and as I was adding resin it "auto shut off".... grrrrr, Luckily I was watching and could just add the previous amount when I turned it back on.

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Re: Measuring small amounts of epoxy?

Originally Posted by Pitsligo
Yep.

But what I was saying was that I'd probably write out a table of pre-determined weigh points, that I could refer to every time, to make fast batches easier: e.g. when the scale reads 75 with the resin in the cup, add hardener until the scale reads 108.

Alex
i see where you’re coming from, that way you’d only need one set of scales.
Last edited by andrewpatrol; 11-12-2017 at 08:20 PM.

15. Re: Measuring small amounts of epoxy?

Originally Posted by the_gr8t_waldo
I do this a lot using the ratio by weight suggested on the epoxy containers. I pour the resin and activator into respective ketchup dispensers that have caps. ( I store them of a shelf with caps on...haven't noticed any degratition.(about 1\$ each ..wally world) this makes it way easier to meter out the materials with very little spillage.....on a electronic scale i weigh a "disposable condiment cup( about 1\$ for 20....T.Y. dollar store) write the weight down ( I think this is called "tare") and then pour out the required amount of resin into the cup. weigh and write that down as well. calculate the needed amount of activator (by weight and add to the same condiment cup until the target weight is achieved. Then mix n serve! I use this method for balsa model construction. and being very cheap, am thrilled that it's worked out way better than it sounds.
Uff-da! Much as I like a 60ml syringe, they are hard to fill, a pain to reinsert the plunger without making a mess and you can't stand them up.

For those of us who would rather work for hours to save \$15 on a digital scale that turns itself off half way through weighing the epoxy (which post?) there is always the DIY ratio scale. Who needs grams when you have 3 washers worth?
http://www.duckworksmagazine.com/05/articles/scale/
Ketchup bottles are passe when you can recycle more creative squeeze bottles.

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Re: Measuring small amounts of epoxy?

Originally Posted by Tom Robb
Has anyone discovered a handy way to measure small amounts of epoxy. I'm getting tired of throwing away mixed but unused goop
Understood. I use the little hand pumps that create about 1.5 oz. of mixed poxy. Even so, there are times when that jigger of poxy is too much. In that case I delay poxy application and prep several other pieces for poxy application so no poxy goes to waste.

And, I always reserve a constructive use for excess poxy such as the notorious glob http://boatbw.blogspot.com/2015/03/glob-blog.html

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Re: Measuring small amounts of epoxy?

I don't know what you mean by small amounts of epoxy, but I like to use West G-Flex when I need less epoxy than one pump of 105 resin would give me.

G-Flex is mixed 1:1, and what I do is what I have seen professional boat builders repeatedly do in instructional videos.

I just squeeze a line or two of G-Flex resin in the bottom of my container, and then squeeze out an equal amount of hardener.

If I am mixing more epoxy or feel a need to be more exacting with my epoxy ratio, I use a set of metal kitchen measuring spoons and cups I got at the hardware store.

No need to make it more complicated than that. Doesn't take rocket science. Easy-peasy.

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Re: Measuring small amounts of epoxy?

Originally Posted by MN Dave
Uff-da! Much as I like a 60ml syringe, they are hard to fill, a pain to reinsert the plunger without making a mess and you can't stand them up.

For those of us who would rather work for hours to save \$15 on a digital scale that turns itself off half way through weighing the epoxy (which post?) there is always the DIY ratio scale. Who needs grams when you have 3 washers worth?
http://www.duckworksmagazine.com/05/articles/scale/
Ketchup bottles are passe when you can recycle more creative squeeze bottles.
I like this. I'm stealing it.

So, that square nut is what you use to balance the empty cup?

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Re: Measuring small amounts of epoxy?

Never had any issue using a small digital scale for batches smaller than a medicine cup.

20. Re: Measuring small amounts of epoxy?

Originally Posted by MN Dave
Uff-da! Much as I like a 60ml syringe, they are hard to fill, a pain to reinsert the plunger without making a mess and you can't stand them up.
Why would you ever need to reinsert the plunger when there is no need to take it out?
Don't ever need to stand a syringe up either. Drop it into a tin can with a wire grid above the bottom to let the tip drain the excess off. Never any need to get your fingers in the mess.

The hole in the tip can be drilled out larger and if the resin is kept warm, it flows in and out much easier. Hardener is less viscous than resin and flows easier anyway. No problem if an air bubble gets in (which it often does), just use a mark at the edge of the plunger and accuracy does not suffer. For small amounts of epoxy, none of the offered methods come close to a syringe for convenience and accuracy.

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Re: Measuring small amounts of epoxy?

I use small mix n measure cups. They have markings for different ratios on the side, eg 1:1, 2:1, 3:1 etc. The cups are available in different sizes. I switched to using these when I started having issues with my hardener pump. The resin pump never has issues but the hardener dries out and the nozzle clogs so I didn't trust it to be accurate anymore. I still use the resin pump to put the resin in first up to the required mark, then I just pour in the required amount of hardener (there is a corresponding mark for the hardener to fill up to). Once cured, leftover can be popped out of the cup and the cup can be reused several times. I'm in Canada and these containers are what happened to be available at my local boatbuilding supplies store (Noah's), they bore the store's logo so I'm sure these are available widely in the US.
http://www.e-encore.com/mixn-measure-containers-lids

22. Re: Measuring small amounts of epoxy?

I like this. I'm stealing it.

So, that square nut is what you use to balance the empty cup?
Yes the nut is the tare. There are detailed instructions in the link I put above the picture. http://www.duckworksmagazine.com/05/articles/scale/

Originally Posted by Tom Lathrop
Why would you ever need to reinsert the plunger when there is no need to take it out?
Don't ever need to stand a syringe up either. Drop it into a tin can with a wire grid above the bottom to let the tip drain the excess off. Never any need to get your fingers in the mess.

The hole in the tip can be drilled out larger and if the resin is kept warm, it flows in and out much easier. Hardener is less viscous than resin and flows easier anyway. No problem if an air bubble gets in (which it often does), just use a mark at the edge of the plunger and accuracy does not suffer. For small amounts of epoxy, none of the offered methods come close to a syringe for convenience and accuracy.
Good advice. You have some good tips on handling that some of us might not have thought of. (like me) Heating the resin might be considered more of an inconvenience by some than by others. Heating resin in a water bath in an unheated shop without running water can be an issue. The DIY balance is a form of entertainment for a dyed in the wool tinkerer. As for bubbles in a syringe, as long as they stay in the syringe, there is no loss of accuracy since the air just moves with the resin.
Last edited by MN Dave; 11-13-2017 at 12:14 PM. Reason: i liked the gif

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Re: Measuring small amounts of epoxy?

I fill my syringes by sucking fluid up into them with the plunger.

When not in use they are stored vertically with the capped tip upwards. Any air rises into the tip where it can be pressed out with the plunger while holding it vertically.

24. Re: Measuring small amounts of epoxy?

Epoxy, both stock and the ready to use material and syringes are kept in a separate cabinet under a workbench. All are kept at the temperature required to prevent crystalization by an incandescent light bulb. 40 watts is usually all that is needed in coastal NC in winter. There is always some residue around the tip after pumping out and if kept vertical with the tip up, that will run down on the syringe and make a mess. All these techniques just kind of grew over the years but are the cleanest and most accurate found so far.

As Gib said, air bubbles are no problem if they are not pumped into the mix.

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Re: Measuring small amounts of epoxy?

I really like your recycling effort, Dave. will probably employ it when the time comes up. Early on I used a home made balancing set up..imho it's a bit more suitable for larger quantities. most of my current needs are for under a fluid oz. batches.( resin and activator) fwiw dept. I sometimes hit the "tare" button at each stage after duly recording information , this way i only have to concern myself with measuring the next component.

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Re: Measuring small amounts of epoxy?

Wow, the wisdom of the crowd works pretty darn well.
Thanks everyone!
Tom

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Re: Measuring small amounts of epoxy?

Catering shops and party shops sell little, light 'shot' cups with volume marking from 5ml to 30ml. They cost a few cents each.

Rick

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Re: Measuring small amounts of epoxy?

I find that a stick is the best thing for mixing the resin and hardener, so just use sticks marked up with the correct ratio (by volume) as a measuring stick to gauge the amount before starting to stir.
This does mean the mixing container has to be cylindrical, but no problem to get or even make them to almost any size needed.
I find that off-cuts of tubing in various diameters of alloy or pvc work just fine to make very small mixing pots......just close one end with tape.
Mixing sticks can all be marked with the same measured ratio, and the size of the chosen container varies the quantity.

29. Re: Measuring small amounts of epoxy?

I find that off-cuts of tubing in various diameters of alloy or pvc work just fine to make very small mixing pots......just close one end with tape.
That's perilously close to genius. I'll be trying that one.

I may see if I can work up a variant for varnish cups. Maybe cling wrap instead of tape? Time to experiment...

Alex

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Re: Measuring small amounts of epoxy?

Originally Posted by Pitsligo
That's perilously close to genius. I'll be trying that one.

I may see if I can work up a variant for varnish cups. Maybe cling wrap instead of tape? Time to experiment...

Alex
Previously I had been told that it was dumb to be pen marking lolly sticks and making small pots.

For years I had been using a well calibrated scale ( when using large volumes of resin paid for by my employers), before using the pumps that I got with a kit of WEST epoxy.

The first time there was a malfunction and the mix would not cure, I reverted to measured mixing by the above method, which was merely plagiarised from the part paint mixing sticks that I had been using in the automotive industry.Admittedly, the paint sticks were proprietary printed ones, rather than pen marked by carefully measuring with the aid of a millimetre ruler.

Tins (cleaned and saved bean tins) are just right for the average glue batch, and tube off-cuts are good for smaller mixes.

A roll of packaging tape is always a requisite, so 3 or 4 patches are enough to seal the end of a tube when cut and sanded clean.

For the very smallest pot, like a 3/4 inch diameter number, the sticky base helps to hold the mixing stick still , while the resin is pumped and the hardener is being added drop by drop.

After the first mix, resin hardens to make a solid enough bottom for re-use, and after a while a collection of numerous size pots are available at hand.
Last edited by Lugalong; 11-14-2017 at 09:38 PM.

31. Re: Measuring small amounts of epoxy?

I also use syringes, I prefer the smaller 10 or 20ml sizes. Any more than that, and the calibrated pumps are sufficient. I work with West Systems. Hasn't failed me yet.

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Re: Measuring small amounts of epoxy?

About the epoxy kit pumps -- there' the plan that they will reliably deliver the same volume whenever depressed a certain distance, then what happens is not always exactly what's expected.
To some people this might not matter a great deal, but to others, the knowledge that dispensed ratios are accurate. is worthwhile knowing.

This is no doubt why some people find calibrated syringes useful.
I just find a marked mixing stick way more practical.

33. Re: Measuring small amounts of epoxy?

It was meant to.

Tins (cleaned and saved bean tins) are just right for the average glue batch, and tube off-cuts are good for smaller mixes.
For me, I use either 1qt yoghurt tubs, 1pt self-serve deli tubs, or the cups from liquid laundry detergent bottles. The tube off-cuts sound as though they might be good for varnish cups because one could later remove the tape, peel out the skin of last coat's varnish, and re-use them without worrying so much about contamination. For final coats a new container would be best, of course, but for build coats it might suffice. I run out of second-hand tubs pretty quickly during maintenance season.

Alex

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Re: Measuring small amounts of epoxy?

Originally Posted by Lugalong
About the epoxy kit pumps -- there' the plan that they will reliably deliver the same volume whenever depressed a certain distance, then what happens is not always exactly what's expected
Been using Sys3 and West pre-calibrated pumps for decades. Other than the occasional sticky pump, never had a problem.

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Re: Measuring small amounts of epoxy?

Originally Posted by Mo 'Poxy
Been using Sys3 and West pre-calibrated pumps for decades. Other than the occasional sticky pump, never had a problem.
Yep, the 'sticky' pump is a problem for me.......I can't be sure that the volume delivered is what I want it to be. There has to be a lot of trust in the plastic mechanism, otherwise it leaves me wondering whether or not a little less hardener has been delivered.
For the decade that I used an ultra sensitive scale, trust was based on the instrument being regularly checked.
For the decade that I have been using a marked stick, the checking happens while pumping and decanting.

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