So I mentioned using a scale to measure the epoxy when building rods in another thread and received a few different responces regarding. I thought I would make a new thread to discuss what people consider to be the pros and cons.

I personally favor the scale as I just don't like fooling with the syringes. I buy the small bottles of epoxy because I dont build large qtys of rods. So getting the syringe down in the bottle without getting epoxy all over it is difficult. Plus I always end up either losing them or getting mixed up and @#$%& up the wrong part into the syringe which runis it. Or I forget to wipe it down and end up with a mess. Plus when the bottle is running low air bubbles can be a pain.

The scale to me is just more efficient. The one I have measures down to .000 gram..... or maybe oz I cant remember. You put your mixing cup on top, zero the scale, then pour the first part. Next zero the scale and pour the same amount. Remove the cup, mix and you are good to go. I also love to use the scale for mixing the smaller amounts of 2k clear coat I spray over rods that are painted.

13.00 for the scale and its a winner in my book..... any pros / cons

Most epoxies we use in rod building are geared to be measured by volume.
The two parts have different mass so that would worry me with a scale: 50/50 mass and volume are not the same.

Thats just a little too much equipment for me, I have no problems with the syringe, and a mixer, But still I think your method will work, I guess it does for you, Tight wraps!

I agree with Lou. I have actually used scales and had the finish not set properly because it was measure by weight and not volume. (In my case the finish didn't harden) I think alot of it depends on the finish you use. I have used some and scales worked fine. I just go with the syringe now and wear rubber gloves.

Casey,
If you want to use scales, use scales. It is your call.
But, as others have posted, be sure to check with your particular vendor for the correct weight mix ratio for your particular epoxy finish. It will not be 50:50 by weight.

Here is a table from United Resin Corp - of various resins and weight mixing ratios:

[www.unitedresincorp.com]

==================================
I called Flex Coat to get the weight mixing ratio of both Flex Coat heavy, as well as Flex Coat lite - epoxy finish.

They indicated that you should use the following ratio for both Flex Coat, as well as Flex Coat lite.

10 grams of Part A
8.38 grams of Part B.

If you want to mix larger or smaller volumes, simply multiply or divide this ratio as needed.

So the ratio for Flex Coat by weight is

10 A : 8.38 B

---------------------
I am sure that other vendors can supply similar information for their particular product.

Roger


Just ask the vendor and the vendor should always be able to supply the answers for their particular product/s.

I use the Yorker caps for my epoxy and I cut them down until my syringes fit into them. Invert the bottle /syringe and draw out whatever you need, with no mess.

I just weighed new 2oz. bottles of epoxy. The hardener weighed 1.77 oz and the resin 2.20 oz. so there is a definite difference in weight. Enough to make a difference? Don't know, but it will harden given enough time. I've purposely mixed some pretty far out ratios to see if it would still harden and it does, if mixed properly but you are deviating from the 50/50 mix that the chemists have determined to be optimal. This will affect the strength of the hardened mix.

My worst test mix?

80% resin and 20% hardener. It took three days to harden but it did harden. Smooth and glossy just like a piece of glass. In fact a week later, I flexed it and it shattered... just like a piece of glass.

Not something that we would want a rod. I use syringes at 50/50 and will not deviate from that ratio. It's not just about hardening , it's about strength too.

Jeff Frei
a hobbiest in
Westfield, Wisconsin

The information and experience offered in this thread is why every rod builder should haunt this site.

Great info fellas!!!!

I guess what has been throwing me off is that the bottles I have laying around both state 1 fluid oz in each bottle. the bottles are of the same size etc and are labeled to have the same amount per weight in each bottle. My thoughts were "well if the bottles are exactly the same and they contain the same amount of fluid in each per the mfg they must be able to be mixed using a weighted measure"

Looks like I may have been mistaken. I will have to look into doing the calculations before mixing


thanks

A fluid ounce is a measure of volume not weight.

Russ in Hollywood, FL.

That's our english unit system for you and why the metric system is liked by scientists/technical people. Look at the house measuring cup it is in volume and ounces. If I remember right the bottles are often labeld in ounces but it may be ounces of weight of pure water. Put something else in the bottle besides water the actual weight will be different from the label. That saying next time you buy some new bottles of epoxy, check to see if the level is the same in each bottle. If they are the same measure the weight of each bottle. Likely will be different. The ratio of the two weights A/B or B/A is useful next time you want to use scales and weights to get the right mix.

Ed Hickl Wrote:
-------------------------------------------------------
> That's our english unit system for you and why the
> metric system is liked by scientists/technical
> people. Look at the house measuring cup it is in
> volume and ounces. If I remember right the bottles
> are often labeld in ounces but it may be ounces of
> weight of pure water. Put something else in the
> bottle besides water the actual weight will be
> different from the label. That saying next time
> you buy some new bottles of epoxy, check to see if
> the level is the same in each bottle. If they are
> the same measure the weight of each bottle.
> Likely will be different. The ratio of the two
> weights A/B or B/A is useful next time you want to
> use scales and weights to get the right mix.


Yeah, I beleive I will do something very similar tonight. Ill take each bottle and fill up a syringe to weigh. This should give me a pretty clear indication as to how far off they are.

This has been an interesting read that I would never have realized to be a factor without this forum

Casey,

This exact same topic has been discussed here no less than a dozen times. It seems to come around again every so often with the same (good) information presented.

............

Simply drill a hole into the tops of your epoxy for the syringes to fit snugly in. Tip upside down and withdraw the amount you want. Store with syringes in top. No mess and perfect measurement every time.

______________________________________
Super Tight Lines......Don



Edited 1 time(s). Last edit at 11/01/2012 04:54PM by Don Morse.

I am in the "drill a hole in the cap" camp. I also hated dipping the entire syringe in bottles and having to clean them off. I then moved to measuring spoons. Then I read about the drill method.

My syringes fit tight in the holes so you can invert them when drawing out product. The syringes are stored in the caps at all times. The syringes never get messy and never have to be cleaned. The syringes never get mixed up as they ae stored in their respective bottle cap. You do not have to think about how much of ach product to use since you are going for a 50/50 mix.

Best of all...it is a free fix.

Lou is correct. The only way the mass ratio can be equal to the volume ratio is if the two liquids have the same density. The reason for the directions on the bottle mentions volumes is the knowledge by the manufacturers that the vast majority of rod builders do not have a balance (or scale).
If you place a hole that is slightly smaller than the end of the syringe in each of the caps on your two epoxy bottles, you can insert the syringe in the bottle and invert it. You can then draw in the volume of epoxy hardener needed and place it in the mixing cup. Then you can reinsert syringe in the hardener bottle until you next use it. Then repeat this same process with the resin bottle and a new syringe. No mess no fuss.

Mike Blomme

3X on drilling the caps & using syringes

Just in case anyone was curious how much of a difference there was when mixing small quantities I performed a little experiment.

measured and weighed 3ml of flex coat high build.

one measured .111 oz the other .100 oz

So indeed a difference. Is it enough to make a difference, who knows... Will I be more accurate in my mixing methods.. yes

the syringe is the way to go for the mesurement some times you have to heat it up a little as when it is cold it will not flow very well
,l take your time an try to keep the bubbles out it will help in the end

The syringe is the quickest, easiest most accurate way. Drill hole in cap so the syringe tip fits in snugly. Invert bottles, draw out finish put in cup. put syringe back in cap (withdraw plunger a little ways and repeat with other bottle. No need to ever clean syringes. when you empty bottles, just put the old caps/syringes on new bottles. Another good option is this [www.mudhole.com] Also, use syringes without the rubber tips on the plungers. The tend to stick and dry out

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!!

Another with the syringes in the caps. The hole size is 5/32 inch and Flexcoat syringes fit perfectly. No mess, no fuss, no cleaning and no mixing up syringes if you put them straight back in the caps. Also cheap and easy.

ESFNEM Col
Port Kembla, NSW
Australia