epoxy tip

[WoodenBNut]

I am sure you already know about this -- but I thought I would post this handy tip anyway: Here's a tip for storing and measuring out small quantities of epoxy & hardener (will work for CPES too) - like when you need a small amount of epoxy for screw hole filling, etc. I bought 2 plastic bottles (hold maybe a 1/2 pint or pint each) with large caps on top that have a small pour spout with a cap for the spout. You can get these in the home (household/baking) section of most large grocery stores, etc. I think a lot of people may put syrups in them, etc around the kitchen. So when you want to measure out a small batch of epoxy resin/hardener, you can just count the drops of resin, and then add the appropriate drops of hardener from the other bottle. Nice, as you get very little if any waste and the measuring in drops seems to be pretty acurate. I think I paid around $1.50 for each bottle. *The large diameter caps make it handy for filling them with epoxy resin/hardener from your large epoxy storage containers.

[JimConlin]

Careful!
For this to work, the two materials need to have the same characteristics as fluids- viscosity and surface tension. In fact, these vary widely among epoxies and hardeners.

Epoxy costs about $7 per pound for the name-brand stuff. Okoume plywood is about the same. Why all the effort at stretching it?

[imported_Jimmy]

Because if you waste a pound for every pound you use is twice as expensive, that's why. (Okume plywood is another thing that is really expensive, I'm not sure it that comparison is a good justification for wasting epoxy, which is difficult to mix in small quantities).

Another trick I use is if you have a small amount left over, you can put it in the freezer. Since curing depends on temperature, it is good for several days (at least for gluing and filling). This seems to work better with smaller amounts since it is difficult to warm a large amount up to usable temperature without it starting to cure.

[ 06-01-2005, 11:20 AM: Message edited by: Jimmy ]

[WoodenBNut]

I used these "kitchen / baking" plastic bottles with West Systems Epoxy resin & hardner. ** It is rough to lug along my 5 gallon tub of resin. Recently when varnishing a transom, I needed a small amount of epoxy mix to fill the exhaust trim ring screw holes so I could later redrill and put in new screws. So I just brought my handy "kitchen / baking" plastic bottles along (instead of the 5 gallon tub) and mixed a ratio of 5 drops of resin to 1 drop of hardner (West Systems ratio) and a little silica filler(so the mix would not run out of the holes) and injected it into the exhaust screw holes. The resin to hardner mix ratio must have been right/close because the mix seemed to cure very well.
I like it and it seems to work very well for those small epoxy jobs.

[Dan Lindberg]

I had also has success mixing epoxy by the drop, except I get the "drops" from a syringe. I have access to 10 ml syringes and usually keep a few filled with resin and hardener. I often mix 10cc batches and this makes it easy..

Dan

[ 06-01-2005, 01:18 PM: Message edited by: Dan Lindberg ]

[Bruce Hooke]

Good idea! For most uses were tiny quantities of epoxy are needed a perfect cure is probably not that important. However, if someone really cares they could test the setup by weighing, say, 100 drops of resin and 100 drops of hardener and then adjusting the number of drops you use to compensate for any weight difference found. Of course, for this to work you need to have a scale that can give you a weight reading that is, say, plus or minus 5% or so of the weight of 100 drops. If that is an issue you could, of course, go to a higher number of drops but it might get a bit tedious! :D

Do be careful that the plastic you use will not disolve in epoxy. There was another recent thread on this...

[Figment]

When working with small batches, small errors of measurement have much greater impact on the final result. Epoxy systems that work at a 2:1 or 1:1 mix ratio are far more trustworthy than a 5:1 system in such applications.

I like the 50ml beakers that Jamestown sells by the 100-count. 20ml of resin, 10ml of hardener, and still plenty of room for mixing in fillers.
I admit that there are plenty of occasions that only require about 5ml of actual material and the other 25ml is "wasted", but if I figure my time is worth at least $10/hour and fixing the results of a bad mix will take the better part of an hour, I don't mind "wasting" $1.75 worth of epoxy.

[ssor]

Farm supply shops always have 10-12 cc syringes. A piece of 1/4 inch o.d. vinyl tubing fits the needle chuck and you are good to go.

[Dave Lesser]

Check the Epoxy eats Polycarbonate (http://www.woodenboat-ubb.com/ubb/ultimatebb.php?ubb=get_topic;f=6;t=004247) thread for some cautions about storing epoxy in plastic containers.

A description of the various common types of plastic and their recycling identifiers can be found here (http://www.wasteonline.org.uk/resources/InformationSheets/Plastics.htm#_Types_of_plastic) .

[WoodenBNut]

I guess I "lucked" out because the pint bottles I bought from my local Meijer store to store and measure out small amounts of epoxy resin & hardner were polyethylene not polycarbonate. So they were not attacked/disolved by the resin/hardner. But thanks - a very good point!! I'm going to stop and buy another set of those bottles on my way home tonight for storing & measuring my Smith's CPES (for small quanitites of CPES).

[StevenBauer]

I use these for small batches of epoxy:

http://www.leevalley.com/images/item/woodworking/finishing/56z8202sb.jpg

They are $2.95 for 100. If I just need a little I'l put a teaspoon of hardener in then add resin to the tablespoon line (2 to 1 mix). If I need a larger batch I can fill one cup with hardener and two with resin. If you need multiple batches but don't want to mix one huge batch you can line up, say, 4 cups of hardener and 8 of resin and just pour them into your mixing cup three at a time. I don't think I'd trust the drop method without using Bruce's test first.

Steven

[ 06-02-2005, 05:49 PM: Message edited by: StevenBauer ]

[AlanWS]

I use the same cups. How carefully I measure depends on what I'm using the epoxy for: if it needs strength, the proper ratio is very important. If it just needs to fill space, you don't need to be quite as careful. If you use those cups, one thing I discovered is that the markings on the inside become impossible to see once they are wetted with epoxy. This probably depends on the epoxy, but they are completely invisible with system 3 epoxy. So you need to have the cup sitting flat, and pour epoxy in carefully.

Another option, if you will need several small batches over a day or two, is to mix up a bigger batch that you can measure accurately, portion the mixed epoxy into small cups, seal them in ziploc bags to protect from water, and store it in the freezer as soon as it's mixed. Depending on the speed of cure, it can keep for several days there, and it's very convenient to take a small container out of the freezer, warm it up in your hands until it flows easily, and use it. I keep it in the bag until it's warm to prevent condensation of water.

[JimConlin]

This is beginning to make mouse milking look like a productive activity. ;)

[StevenBauer]

:D

[Tom Lathrop]

I think some of you are being too critical of boatnut. I like his idea and although I normally use epoxy in large batches, there are lots of instances when just a tiny amount is needed. Having a couple of small plastic bottles handy for a few drops is not only more conserving than any of the other mixing ideas but is far cleaner.

This means that no gloves are needed and there are no cups with wasted epoxy to discard if you just have a couple drops on a flat plastic sheet and an ice cream stick for a mixer. If these materials are in your tool kit, it also means no trips back to the epoxy station to fetch the stuff.

I do agree that 5:1 is a risky ratio to use for such small amounts.

[ 06-03-2005, 08:11 AM: Message edited by: Tom Lathrop ]

[Andrew]

I've used those graduated basting syringes for 1:1 epoxies, one for each part. Store bulb up and don't suck the epoxy up into the bulb. smile.gif

[Paulyboy]

Originally posted by AlanWS:
I use the same cups. How carefully I measure depends on what I'm using the epoxy for: if it needs strength, the proper ratio is very important. If it just needs to fill space, you don't need to be quite as careful. If you use those cups, one thing I discovered is that the markings on the inside become impossible to see once they are wetted with epoxy. This probably depends on the epoxy, but they are completely invisible with system 3 epoxy. So you need to have the cup sitting flat, and pour epoxy in carefully.

Any chef will tell you when using graduation marks to measure, the ONLY way to get accurate results is to make sure the table is flat and level. Maybe thats why all my cakes are wet and lopsided, just like my counter.

[AlanWS]

Of course it must be level when you read it. I was just trying to say that if you wet the numbers while pouring, or pick it up and tilt it, you can't read it even after it's level.

[Paul Scheuer]

I used to have a local source for Pettit epoxy in transparent squeeze tubes. The 1 : 1 mix made it easy to lay out parallel beads of resin and hardener. My source went away and I have to send off for it, but I believe that it's still available. It wasn't particularly inexpensive, but I hardly ever mixed more than I needed.