Has anyone ever measured out their finish by weight instead of volume? A 1:1 ratio is is the same if both liquids have the same density, but it is not if they do not. I have accurate digital scale and have been thinking about using it to weigh out my finish but do not know if this would work.

They don't weigh the same. You'll end up with more hardener in all the epoxys I've tried (most of the major brands on the market). It's too bad, because it is a very easy way to mix. I guess you could figure out the weight of each part and then the right ratio, probably something like 1.2:1.

Thanks for the info. I figured it was too good (easy) to be true. I guess it is back to the measuring spoons.

Dick,
I was just talking to my brother last night who uses the West Epoxy system. He has built several very large projects - including several boats. For these projects, one is talking about using gallons of epoxy to finish the job. He has used a digital scale for measuring out the quantities for all of his big projects.

I think - that generally speaking - measuring syringes just make more sense for most rod builders. I know that the syringes that I use can measure quantities of epoxy that will end up curing before I can use all of the epoxy for a normal finishing job on a single or multiple set of rods. Also, with the syringes there is no tool cleanup so less waste of finish.

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For measuring epoxy for handle work, I use 1 inch diameter syringes, from which I have removed the tips. I then have drilled a 3/16th hole in the end of the syringe to allow the thicker epoxy to flow.
The epoxy that I use for handle work comes in large jars, so by just dipping the very end of the syringe into the epoxy, I draw up the required amount into the syringe, a quick wipe with a paper towel of any excess on the outside of the syringe and that is the only clean up required. Again, very little waste and ease of use.

For any of the epoxy syringes, I keep a separate holder for each syringe - properly marked - so that there is no need to clean the inside of the syringes between uses. The finish does not harden in the tube - since it is not mixed. If some time has gone by between syringe uses, I may have to remove the syringe body from the syringe and put the end of the syringe into the particular epoxy to act as a lubricant for the syringe.

Good luck
Roger

NO! I asked Ralph O'Quinn about this at the Rod Expo last year and he said to never do it. He said they formulate their epoxies to be measured by volume, not weight.

Just measured (weighed) TM HB on my scale. These were two unopend 2 oz bottles .. the resin weighed 86.1 grams and the hardner weighed 74.1 grams. Too much math involved to figure out the correct ratio. (lazy!) I will just stick with my normal methods.

I think that the eaiest, quickest and most accurate method is drilling a hole in each cap just big enough to tightly fit a syringe tip into. Invert the bottles and draw out the amount of finish you want and squirt into a mixing cup. Stick the syringe back into the cap and draw back an inch or so and place on a shelf until next time. When the bottles run dry take the caps/syringes off and place on new bottle. Never have to clean the syringes and you can't mix them up or lose them. I've been using the same syringes/caps for at least a couple years and NEVER clean them. Quick, easy, no mess, no fuss and consistant, no brainer measurements every time no matter how little you mix.

Mike (Southgate, MI)
If I don't want to, I don't have to and nobody can make me (except my wife) cuz I'm RETIRED!!

Update.
Note, I was referring to the West systems of epoxy:

[www.westsystem.com]

With the West systems of epoxy, a 1:1 ratio is NOT used.

A different ratio is used for volume and another ratio is used for weight.

Take care
Roger

I've heard from a few friends that use the weight measure. As one pointed out, it's such a waste to mix finish when you are only refininshing a single guide if you don't. You end up with a bunch of finish that you don't use and ordering it much more often then you really should.

Using the weights allows you to precisely mix even very small amounts, assuming you have a scale with enough precession. I'm sure Ralph and all the guys in the finish business are happy to see us mix quantities larger than we ever need. After all, they make their money selling finish. Imagine how quick you'd go through a bottle of finish if you always mixed using the recommended 3 ccs of each part.

Using Dick's measurements above, you'd use a 1.16:1 ratio for TM High Build (pretty close to my 1.2:1 guess). For every measure of hardener you use, you'll use 1.16 of resin. As an example, let's say you use 20 grains of hardener, you'll need 23 grains of resin. This makes it very easy to mix the right amount of finish for even the smallest jobs. Qualifier - the above assumes that the containers are the same weight with equal volumes and that the difference in weight between the two bottles accurately reflects the difference between the two parts.

This is a good place for technical data sheets. I've seen some epoxy systems that do give the weight measurement ratio.

Example: I have some silicone mold making product:
Mix ratio by volume: 1A:1B
Mix ratio by weight: 100A:130B

I'm sure if you contact the manufacturer/original point of sale for the technical data sheets they can probably tell you the proper mix by weight ratio.

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I routinely mix tiny batches with the syringe method posted above with absolutely no problems..I will often mix parts equal to the FIRST little mark on the syringes.

Mike (Southgate, MI)
If I don't want to, I don't have to and nobody can make me (except my wife) cuz I'm RETIRED!!



Edited 1 time(s). Last edit at 12/17/2009 08:54PM by Mike Barkley.

Alex Dziengielewski Wrote:
-------------------------------------------------------
> This is a good place for technical data sheets.
> I've seen some epoxy systems that do give the
> weight measurement ratio.
>
> Example: I have some silicone mold making
> product:
> Mix ratio by volume: 1A:1B
> Mix ratio by weight: 100A:130B
>
> I'm sure if you contact the manufacturer/original
> point of sale for the technical data sheets they
> can probably tell you the proper mix by weight
> ratio.
West gives this info with their epoxys. I wonder if we can get the information on the most popular finishes.

I have not experienced mixing small batches using the syringes as long as I am very careful to mix 50/50! Keep in mind the smaller the batch the less tolerance for measuring errors.