Aerowerx
Well-Known Member
Introducing the new improved fat free high fiber Aerowerx Epox-O-Lator v3.0 balance scale!
You can make your own, too! The basic idea came from here and here.
One important factor is the length of the balance arm and the height of the pivot point above the balance arm. The larger these are the more sensitive it will be. Also, the pivot point should be as low friction as possible. I suppose you could use use a bearing, but I don't think that is necessary, as this one is quite sensitive---the air from my fan was making it move from 8 feet away.
In this one the pivot is a finish nail through two pieces of aluminum angle:
The beam on mine is about 26 inches long. Probably that is more than is needed, so you can make yours as long as you want. Just remember, the longer it is the more accurate it will be. The thing is put together with hobby store epoxy and wood scraps, so is quite cheap to make.
So, how do you calibrate it?
One one end of the balance beam draw a line an inch or two in from the end. This will be where you put your mixing cup:
Carefully measure the distance from this line to the exact center of the balance beam, which should be directly under the pivot point. On mine it is 12.0 inches. At the other end of the balance beam, draw a line the same distance from the center:
Label it 'H' for hardener. I also like to label it with the type of epoxy, in this case T-88.
Now the tricky part...
You carefully measured the distance from the center to each of the marks, didn't you? The mark labeled 'H' represents the total weight of resin and hardener (I'll explain why it is labeled only 'H' later).
From the thread on weight vs volume, I will be using a ratio of 1.00 to 0.86. This is the same as 100:86, or 100 parts of resin and 86 parts of hardener by weight, making the total weight of epoxy 186 parts. The amount of resin is only 100 parts, or 100/186 times the total weight. So make a mark 100/186 times the length measured (6.45 inches on mine), on the same side of the balance beam as the mark labeled "H". Label this mark as 'R' for resin.
Now you are ready to go.
Place a cup on the first mark (on the right on mine). Take a small weight and put it on the left side. Move it around until the beam balances with an empty cup.
Take some convenient weight, that represents how much epoxy you want to end up with. Place it on the mark labeled 'R'. I use socket wrenches, since they are convenient and come in different sizes.
Put resin in the cup until the beam balances.
Move the same weight to the mark labeled 'H'. Now add hardener to the cup until the beam balances.
Mix and enjoy!
One thing you may have to do, which I haven't done yet. You may have to put a small weight on the balance beam so it will balance by itself. When you find the correct spot, epoxy it in place. After applying the epoxy, verify the position of this weight while the epoxy is still wet, then let dry.
You can make your own, too! The basic idea came from here and here.
One important factor is the length of the balance arm and the height of the pivot point above the balance arm. The larger these are the more sensitive it will be. Also, the pivot point should be as low friction as possible. I suppose you could use use a bearing, but I don't think that is necessary, as this one is quite sensitive---the air from my fan was making it move from 8 feet away.
In this one the pivot is a finish nail through two pieces of aluminum angle:
The beam on mine is about 26 inches long. Probably that is more than is needed, so you can make yours as long as you want. Just remember, the longer it is the more accurate it will be. The thing is put together with hobby store epoxy and wood scraps, so is quite cheap to make.
So, how do you calibrate it?
One one end of the balance beam draw a line an inch or two in from the end. This will be where you put your mixing cup:
Carefully measure the distance from this line to the exact center of the balance beam, which should be directly under the pivot point. On mine it is 12.0 inches. At the other end of the balance beam, draw a line the same distance from the center:
Label it 'H' for hardener. I also like to label it with the type of epoxy, in this case T-88.
Now the tricky part...
You carefully measured the distance from the center to each of the marks, didn't you? The mark labeled 'H' represents the total weight of resin and hardener (I'll explain why it is labeled only 'H' later).
From the thread on weight vs volume, I will be using a ratio of 1.00 to 0.86. This is the same as 100:86, or 100 parts of resin and 86 parts of hardener by weight, making the total weight of epoxy 186 parts. The amount of resin is only 100 parts, or 100/186 times the total weight. So make a mark 100/186 times the length measured (6.45 inches on mine), on the same side of the balance beam as the mark labeled "H". Label this mark as 'R' for resin.
Now you are ready to go.
Place a cup on the first mark (on the right on mine). Take a small weight and put it on the left side. Move it around until the beam balances with an empty cup.
Take some convenient weight, that represents how much epoxy you want to end up with. Place it on the mark labeled 'R'. I use socket wrenches, since they are convenient and come in different sizes.
Put resin in the cup until the beam balances.
Move the same weight to the mark labeled 'H'. Now add hardener to the cup until the beam balances.
Mix and enjoy!
One thing you may have to do, which I haven't done yet. You may have to put a small weight on the balance beam so it will balance by itself. When you find the correct spot, epoxy it in place. After applying the epoxy, verify the position of this weight while the epoxy is still wet, then let dry.
