Electronic Scale for Weighing Epoxy

I use the West System pumps, but one full pump is way too much epoxy, so I measure with a small scale. I mix up less than ten grams total for a wa handle. To get the epoxy in the handle, I put the epoxy in a small plastic bag, maybe 1.5x2” or so, and cut off a corner to make it into a sort of piping bag. Then I insert the bag into the handle opening and squeeze. Works well for me even for narrow openings around 1.5mm.
 
There are cheap little scales that do grams well.

Look for the scales taht have 0.0 gram resolution

They often have different ranges
I have two scales

0-200 grams 0.0 readout

0-2,000 grams whole number readout.


0.01 gram resolution is pretty damn small, that's high dollar lab scale territory.
If you're not paying for it, it's probably not working well.


Buy a couple of check weights to check the scale with
One at each end of the range to make sure it's linear
1 gram and 200 gram weights are cheap,

$20 Canadian $ with free shipping for a whole weight set.

More if you get one that's NIST traceable.


Cushing H. said:
Usually i eyeball it also… but when i am making a wa handle, it takes a greater volume to fill the cavity, and eyeballing it just becomes a little less precise (hard to judge) because of the way the two layers sit in the small dixie cups i use.

I use gflex .. it only says 1:1 … but does not indicate by weight or volume. I think there us a fair amount of leeway in the actual ratios. Like i said, im just after reducing the occurance if where one bottle is empty and there is still a fair amount of resin left in the other bottle
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There is definitely tech data for weight ratios.
 
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12345678910 said:
There are cheap little scales that do grams well.

Look for the scales taht have 0.0 gram resolution

They often have different ranges
I have two scales

0-200 grams 0.0 readout

0-2,000 grams whole number readout.


0.01 gram resolution is pretty damn small, that's high dollar lab scale territory.
If you're not paying for it, it's probably not working well.


Buy a couple of check weights to check the scale with
One at each end of the range to make sure it's linear
1 gram and 200 gram weights are cheap,

$20 Canadian $ with free shipping for a whole weight set.

More if you get one that's NIST traceable.




There is definitely tech data for weight ratios.
Click to expand...
Actually, you can get by without the calibrated weights: one ml of water = one gram. That is how i finally proved to myself that my whole digit resolution scale is so far off in the 1-5 gram range.
 
Years back I used the pumps when I was building boats (typically mixing from a 16 to 24 oz at a time).
For scales I just eyeball it but can see the benefit of an accurate measure for something like a Wa handle fill quantity.
Pumps needed to be weighed or measured as they could get a bit off with their output. Regular cleaning helped,but still needed to verify.
 
12345678910 said:
It would be really interesting to compare that to NIST weights.
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I would think a true NIST weight, traceable to standards, and clean and well maintained would technically be much more accurate. With the syringe you have its own inherent accuracy of the markings (accuracy of something like 0.05ml), plus you also have variability due to the user ability to see/control the location of the plunger.

But the accuracy of the weights is way overkill for my needs. I tared my container, put in one ml … the scale indicated zero. Put in ANOTHER ml of water … the scale still read zero. Got to 4ml of water before the scale read even 1 gram
 
PEU said:
And you can go 20 more without a hitch, thats completely fine. I moved to syringes and a scale because I buy epoxy by the kilo, so I put enough on a couple of syringes, mix exactly what I need and waste almost nothing, just a saving and efficiency thing.

Pablo
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I've been building laminated fiberglass traditional bows for close to 20 years now. Let's just agree maybe that glue is really important for this task. A working limb that flex's and recoverees to it's original shape Thousands of times over and over. Maybe just maybe more so than attaching scales to a knife blank. I"VE NEVER had a glue failure or actually any failure in that time simply doing volume measurements. I'm talking multiple level spoon fulls of equal volume to do a layup to make a bow. I'm guessing most glue failures is from poor prep, poor temps during glue up, not enough of mixing the two parts or excessive clamping pressure. YOUR mileage may vary.
 
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I don't believe we need that kind of accuracy for epoxy. I mix 5 grams of epoxy and 4 grass of hardener for full tang scales with liners. I've eyeballs a 50-50 mix and gotten anywhere from 9-12 grams. For me the scale saves a bit of waste
 
Cushing H. said:
I would think a true NIST weight, traceable to standards, and clean and well maintained would technically be much more accurate. With the syringe you have its own inherent accuracy of the markings (accuracy of something like 0.05ml), plus you also have variability due to the user ability to see/control the location of the plunger.

But the accuracy of the weights is way overkill for my needs. I tared my container, put in one ml … the scale indicated zero. Put in ANOTHER ml of water … the scale still read zero. Got to 4ml of water before the scale read even 1 gram
Click to expand...


Yes, that's out of whack.

have you tried that again, but tared in the middle of the range ?
 
12345678910 said:
Yes, that's out of whack.

have you tried that again, but tared in the middle of the range ?
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Well, the container i used (and tared to) weighed several tens of grams, if that is what you are asking?

Pablo threw out right away that kitchenscales are only accurate to like 5 grams … which is in line with what i saw
 
Cushing H. said:
Well, the container i used (and tared to) weighed several tens of grams, if that is what you are asking?

Pablo threw out right away that kitchenscales are only accurate to like 5 grams … which is in line with what i saw
Click to expand...

Depends on the scale

These do gram tenths for cheap

www.scalesgalore.com

Ohaus Economical Hand-Held Series Electronic Portable Scales

www.scalesgalore.com


they also have one that looks the same, but range is 0-2Kg, but only reads in whole ones.
 
A suitable scale for weighing epoxy should cost around $15-20. Amazon has hundreds of them. They claim .1gram accuracy. Even if it is much less accurate, it is still close enough for epoxy weighing. We aren't weighing tiny amounts when mixing resins.
 
I really appreciated the side discussion on dixie cups and silicone cups for mixing and mini funnels and stir sticks.

I bought one of these mini gram scales on ebay 20 years ago to measure arrow components for my bow. Can set the scale to grains or grams....15.43 grains in a gram. So good and accurate for what we are doing.

Funny part was I had to pick it up in the States and the border agents were sure I was dealing drugs and the scale was for measuring them. My car got a good search and sniff from the dog that day. I was thankful I didn't get a cavity search!!
 
Randydb said:
I really appreciated the side discussion on dixie cups and silicone cups for mixing and mini funnels and stir sticks.

I bought one of these mini gram scales on ebay 20 years ago to measure arrow components for my bow. Can set the scale to grains or grams....15.43 grains in a gram. So good and accurate for what we are doing.

Funny part was I had to pick it up in the States and the border agents were sure I was dealing drugs and the scale was for measuring them. My car got a good search and sniff from the dog that day. I was thankful I didn't get a cavity search!!
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Oh funny. I remember back then the boarder inspections were really focused on drugs. I suppose they did not quite buy it when you said you were using it to measure out portions of epoxy??? :)
 
I have long hair, goatee and earings. Look more like a dealer than the teacher/educator that I am. They found it hard to believe that I was weighing arrow components down to the grain, But having matching arrows makes a big difference in flight and accuracy. Just like a 180grain bullet flies way different than a 150 grain bullet.

Different time crossing border....agent says, "Anyone ever tell you that you don't look like a principal?"
Me: "Yes, and they told me I didnt look like a teacher before that."
Agent with a grin on his face: "Ever cause you any problems?"
Me now grinning: "Only when I cross the border!"
Good laugh and he sent me on my way.
 
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