Dispensing Epoxy?

iggyskier · Post by **iggyskier** » Sat Feb 09, 2008 2:13 am

So trying to find an easier way to dispense the epoxy I am using.

I am using QCM 00-43 with the 00-32 hardener.

Pouring it out of the gallon bucket is really annoying, so I got some 1 gallon containers with 1oz pumps attached.

Sadly, even when the epoxy is heated up, the pumps are not able to accurately pump out exactly 1 oz each time, and if the epoxy is not heated, the pump will not work at all.

Any ideas on a good way to store/dispense this epoxy? I know a lot of people using west systems use the pumps, but that route hasn't seemed to work with this QCM stuff. Thanks

G-man · Post by **G-man** » Sat Feb 09, 2008 7:38 am

Yes, it's mighty thick stuff. I just use a soup ladle to place a random amount (one ladle... about 200 grams) in a paper cup, then weigh the cup/contents and write on the cup how much hardener to add. Luckily, the hardener is thinner and easier to measure and add. I've only used QCM resin, but if other brands aren't as thick, maybe that is partly why it's difficult to get the cloth to wet-out with QCM.

G-man

SHIF · Post by **SHIF** » Mon Feb 11, 2008 2:31 pm

The QCM resin is rather thick and cannot be pumped. The QCM curing agent is easily pumped with the West Systems pumps or similar. You need to get a nice digital gram scale so you can zero it out (tare). A postal scale could work, albeit not as well unless it has a tare function.

I use 5-oz paper cups to mix several mini-batches of QCM epoxy during ski assembly. I first calibrate the pump by dispensing the curing agent into an empty cup and weighing the amount dispensed by one full pump motion. Do this a few times and average the results. Return the curing agent back into the can after calibrating the pump. My pumps dispense 26 grams of curing agent per full stroke.

Using a metal scoop to dish out the resin, I first prepare several cups with precisely 104 grams of resin in each prior to making one ski. I was told (by Roy) the mix ratio is 4:1 by weight and so far this has worked quite well every time.

During the lay-up process I dispense curing agent into the cups one at a time, as needed. I typically use five such mini-batches to make one ski (650 grams total epoxy weight). This amount allows for complete wet-out of the fabric and excess resin squeezes into the plastic sheeting wrapped around the assembly in my heated pneumatic press. You may wish to prepare six or seven such cups just in case. Unmixed resin can be returned to the can later.

I think the QCM epoxy wets-out quite well. It pours like warm pancake syrup when mixed. It spreads easily using a soft plastic spreader tool.

Good luck,

-S

iggyskier · Post by **iggyskier** » Mon Feb 11, 2008 3:42 pm

I will look into the scale option. I like the epoxy, just wish dispensing was easier.

I am picking up more next week, so maybe while I am there I will ask what they suggest.

camhard · Post by **camhard** » Mon Feb 11, 2008 5:26 pm

This is what Roy at QCM told me when I asked about how to measure the epoxy:
"you should always measure hardener and epoxy by weight. All our data sheets refer to weight ratios.
Volumetric ratios are not even available. ( we could calculate them from their Specific Gravities , but they would be odd numbers.)

The world uses weight to measure epoxy and hardener ratios.

we have a 1200 gram scale that we sell for about $220"

That seems pretty expensive, but I havent really looked around for scales yet; I was hoping more of the 100-150 range.

iggyskier · Post by **iggyskier** » Mon Feb 11, 2008 5:33 pm

camhard wrote:This is what Roy at QCM told me when I asked about how to measure the epoxy:
"you should always measure hardener and epoxy by weight. All our data sheets refer to weight ratios.
Volumetric ratios are not even available. ( we could calculate them from their Specific Gravities , but they would be odd numbers.)

The world uses weight to measure epoxy and hardener ratios.

we have a 1200 gram scale that we sell for about $220"

That seems pretty expensive, but I havent really looked around for scales yet; I was hoping more of the 100-150 range.

wow. thanks for posting! Good to know. I guess I will check some scales on ebay....

iggyskier · Post by **iggyskier** » Mon Feb 11, 2008 5:38 pm

camhard wrote:
That seems pretty expensive, but I havent really looked around for scales yet; I was hoping more of the 100-150 range.

seems like lots of scales on Ebay in the $60-90 range that hold 2000-5000 grams.

G-man · Post by **G-man** » Mon Feb 11, 2008 8:18 pm

I use my wife's food scale. It's digital, weighs in grams or ounces, zeros out at any stage, and was only 30 bucks at a kitchen store. I just lay a piece of plastic food wrap over it when I use it so I don't get it all goobered up with epoxy. The scale works very well.

G-man

kelvin · Post by **kelvin** » Mon Feb 11, 2008 9:30 pm

I use this $20 scale from Harbor freight. Works pretty well. Sometimes they have 50% off sales and I think I got it for $10.
http://www.harborfreight.com/cpi/ctaf/D ... mber=95364

I also got this $7 infrared thermometer, that isn't too bad.
http://www.harborfreight.com/cpi/ctaf/D ... mber=93983

-kelvin

Mud · Post by **Mud** » Tue Feb 12, 2008 6:27 am

Hi All,
First post.

I am gathering equipment to start building and the scale question came up.
What range should I get? The more it has, the less accurate it is.
There are a bunch to pick from on ebay for around $50, just pick your range.
Thanks, Doug

rockaukum · Post by **rockaukum** » Tue Feb 12, 2008 11:32 am

Scales are found at most stores. It is my belief that you don't need to spend lots of money on them. You can go to a office max or that type of store and get one (commonly use for postage). Harbor freight is a great option also for the losw cost but use caution on the quality of the unit.
rockaukum

knightsofnii · Post by **knightsofnii** » Tue Feb 12, 2008 5:13 pm

i just placed an order for some mr fiberglass epoxy to do some experimenting with,
and mr fiberglass added the pumps to my order when i didn't even ask for them.
granted they're only 7bucks, but should i bother?

i'm used to the pour into big cup, pour big cup into small cup on scale method. and with a digi scale i trust it way more than some pumps designed for patching boats and other odds and ends. i told them this and since have not gotten a response, oops

.

krp8128 · Post by **krp8128** » Wed Feb 13, 2008 8:29 am

knightsofnii wrote:i just placed an order for some mr fiberglass epoxy to do some experimenting with,
and mr fiberglass added the pumps to my order when i didn't even ask for them.
granted they're only 7bucks, but should i bother?

i'm used to the pour into big cup, pour big cup into small cup on scale method. and with a digi scale i trust it way more than some pumps designed for patching boats and other odds and ends. i told them this and since have not gotten a response, oops .

Thumbs up to both the Mr. Fiberglass Epoxy and the pumps. I used both for 2 pairs of skis and had no issues whatsoever.

danishstock · Post by **danishstock** » Sun Feb 17, 2008 6:56 pm

I am using MAS epoxy which comes with calibrated pumps for each container. A 1 pump to 1 pump ratio is as easy as it gets. Am I the only one using MAS?

knightsofnii · Post by **knightsofnii** » Tue Feb 19, 2008 7:11 pm

well i decided that worse case scenario the pumps will make for cleaner dispensing so i got them anyway, they're on the way:).

still getting a digital scale, might be times when i want to experiment and deviate from what they recommend.

i do know that a little too much hardener in the mix can make for a quite interesting reaction!!!

Ski Builders Forum

Ski Builders Forum

Dispensing Epoxy?

Dispensing Epoxy?

I use QCM like this...