West System 320 Small Batch Epoxy Scale

[Ziggy]

A precision scale is almost essential when mixing small amounts of epoxy, like I do 90% of the time. The West system scale is a nice idea, in a postcard-sized, compact package, 0.1 gram resolution, and a 2 year warranty. It's not cheap, as it retails for ~$46 at West Marine. My major issue with it is its "convenient" auto-off feature, which seems to always shut the scale off about half-way through measuring resin. This typically ruins the batch unless you happen to recall the weight of the container. An added annoyance is that a very similar looking American Weigh Scales AWS-100, with 0.01g resolution, claimed 0.02g accuracy, and a 10 year warranty, retails for about $10-$12 on Amazon.

What do you use to measure epoxy?

[minaret]

A metered mixing machine. But I'm guessing if you think $46 for a scale is expensive, then a $500 mixing machine is not for you. What's wrong with the usual pumps that come with WEST? Just calibrate them and go, works just fine for small batches.

[44'cruisingcat]

I just used digital kitchen scales. Worked fine for over 400 litres of epoxy - never stuffed up a batch.

[Ziggy]

Originally Posted by minaret

[...]I'm guessing if you think $46 for a scale is expensive, then a $500 mixing machine is not for you.

You got it!

The metering pumps work fine for larger amounts, but there is some waste since you need to prime them first to get an accurate measurement and they dispence about an ounce per stroke. But often I find I need only a few grams of epoxy. For example, this afternoon I was trying to mix a very small amount to fix a piece of plywood cabin sole which was beginning to delaminate.

When you work in a boatyard, the customer bears the cost of all materials, including any that are wasted, and the labor costs are often much higher than the materials anyway, so a large capacity gear pump makes a lot of sense.

[cszosler]

Originally Posted by Ziggy

What do you use to measure epoxy?

hi, for small ammounds i use siringes, for resin size is 5x of the size for hardner. there is no left overs in measuring cups fouling proportions of the mixture.
west system shall be measured by volume

[minaret]

Originally Posted by Ziggy

You got it!

The metering pumps work fine for larger amounts, but there is some waste since you need to prime them first to get an accurate measurement and they dispence about an ounce per stroke. But often I find I need only a few grams of epoxy. For example, this afternoon I was trying to mix a very small amount to fix a piece of plywood cabin sole which was beginning to delaminate.

When you work in a boatyard, the customer bears the cost of all materials, including any that are wasted, and the labor costs are often much higher than the materials anyway, so a large capacity gear pump makes a lot of sense.

You refer to the 300 series mini-pumps. They do indeed require priming and are less than ideal for very small batches, as you say. The pro answer is a WEST System 309-3 High Capacity Gear Pump. This is the expensive solution I mentioned earlier. The idea is not to have the client eat the cost of waste, quite the contrary, it's to reduce waste in a setting where we use hundreds of gallons of WEST a year. The gear pump will meter very small amounts correctly measured, I think it delivers 1 oz. per stroke, IIRC. This reduces wastage in mixing small batches dramatically, and completely removes the possibilty for operator error. It's a no-brainer in a pro setting, where we might have a designated mixing guy mix a whole drum of resin in a day. Real time saver. You can get them in 5:1 or 3:1, or even for Proset if you are ordering wholesale industrial. The 306-25 and 306-23 mixing pumps are an attempt to provide a more economical version for the more casual user, but I find they don't compare. If you use a lot of WEST the 309 series is the way to go, IMHO.



http://www.wessex-resins.com/westsys...equipment.html

[Ziggy]

Minaret,
You're like a chef working in a 400 seat restaurant trying to advise someone how to equip a kitchen in a low rent studio apartment . The cost of one 309-3 pump is almost 5% of the value of my boat!
Z.