I use quite a bit of epoxy one way and another but the only thing is that many jobs only require small amounts. The pumps that come with the epoxy are great at dispensing out the correct proportions but I find that I often end up wasting more than I actually use. Epoxy is expensive stuff so it pays to mix up only what's needed, after all you can always mix more if you run out. I've lost track of the amount of the expensive stuff that I must have thrown away over the years, so with this in mind I decided to do something about it. I made some scales for measuring out a few ounces at a time.
OK they may not be very elegant but these scale do work well and are actually very accurate. Made from some scraps of ply and a short off cut of three eigths bar that I had lying around the workshop they are simple to make, all held together with epoxy......what else!
You will have to excuse the rough drawing but there is a pdf for you to download of the main dimensions that I used here. With more time I am certain that it would be possible to make some better than mine but they do work great. I tend to use the Epiglass epoxy which has a mix ratio of 4 to 1 (resin to hardener) but other makes of epoxy are available with different mixing ratios so you need to bear this in mind. The balance bar just sits on a pin of scrap steel bar and as this is just a loose sliding fit it would be more than possible to make more than one balance bar for different mix ratios, just don't get them mixed up of you will have all sorts of problems. It might be a good idea to mark them with a red sharpie or whatever.
I am sure that there is some mathematical formula for calculating the balance point but once I had made the balance bar I put 4 screws in one Dixie cup and 1 in the other then using set of calipers with sharp points found the pivot by trial and error, moving it a little at a time until the cups were in equilibrium.
You will notice that the calipers are off center as one would expect, closer to the heaviest end. With the position of the pivot point thus determined I went a and drilled a hole on the drill press slightly larger than the diameter of the steel pivot bar.
One final point and that is while you could just sit the Dixie cups on a couple of pads this is is not as accurate as boring holes for them to sit in. With the holes the cups are positively located, can't spill and most importantly it is impossible to make an error in the quantities. If the cups were to just rest on pads moving the cups inboard or outboard would have a bearing on the effectiveness and accuracy of the balance thus making errors likely, remember we are only mixing small quantities here, just a few ounces at a time.
Tip of the day
An old time carpenter taught me this trick years ago. When you need to divide a piece of material in half or find the center for any other reason, angle your ruler across the work until the number are easily divisible by 2 then place a mark with your pencil. Nothing could be easier and you won't have to try and mathematically work out what half of three and nine sixteenths is for instance.
Works every time..perfectly.
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