Ariel #414

[mbd]

I've got four pots that I used for mixing various batches, and none have hardened - and I don't think even I could screw up mixing four different batches!

Ummmm... I've been wrong before, too.

So, I'm using West System epoxy (availability, reputation, documentation, marketing , etc.) They have this handy "pump system" where the 5:1 ratio of resin and hardener is measured for you - all you have to do is count the number of pumps of resin and hardener. Not so bad. Worked great the first time I tried it. About as idiot-proof as they could make it really.

Well, after finding the epoxy still tacky last night, four days after finishing the job, I began combing through old emails and rereading the West System User guide, trying to figure out what the heck was going on. Then it hit me. 5:1 ratio. 5:1 ratio. Wait a minute! The pumps... The @#!$# pumps! I had actually done it. I had outsmarted the idiot-proof "pump system".

I don't know, I guess I was really preoccupied with other things, like: Am I doing the scarf joints properly? Should I be using the 17oz biax, or the 8 oz cloth now? Have I washed and ground down the previous layer enough? Can I get this done before dark?

And I kept thinking 5:1 ratio, 5:1 ratio. Don't screw it up. So that's what I did: 5 pumps of resin, 1 pump of hardener. Over and over and over again. I did indeed mismeasure every single batch of epoxy I mixed last weekend. ALL of them. The entire day's worth of epoxy and glass and filler on the starboard side deck. What I did in reality, was mix a whole bunch of 25:1 resin goo.

Needless to say, I'll be learning how to remove and clean up uncured epoxy this weekend...

[tha3rdman]

geesh, Before you go stripping off all that mess, I'd call West Sys, and see if theres and easier way even baking it would be easier then scraping all that crud. I wonder if some time at 140 deg, or so, would cure it.

[ebb]

yea, I'd call them too!

It is not unlikely that misbatched epoxy will go off eventually, just a matter of time. Don't do anything radical yet! Might depend on how far off your part A to your part B was.... Call the product tech! Maybe the set can be speeded up with a heat gun.

Project looks first class!

Instead of the pumps you might try the graduated translucent plastic quart containers that most alternative suppliers have. I get mine from TAP. Ounces and milleliters printed on the straight sided container makes it simple to get the proportions visually.

You go for the amount of epoxy you think you need (in your case) marking off with a sharpie 5 measures plus one measure - whether they're 2 oz each, 1 oz each, 1/2 oz or milliliter multiples. It's no brainer, I make myself mark off the proportions every time I mix a batch: 5 equal spaces to one equal space, whatever the quantity.

(I'm a two to one fan, but the point is you look at, actually thru, the container as you pour Part A up to the 5 part mark -where I've made a longer line with the marker - and then top off with the hardner. This would work especially well if you are using epopxies with differing proportions.

The marker lines wipe off with denatured alcohol, my cleanup solvent of choice. I'll often clean out the container with paper towel/rags and use it again. Depends on the timing. I keep similar 1/2 gal buckets to mix powders into a batch: silica, fairing compound.

I have trouble trusting the pumps. If you keep them in the cans over a period of time, Part A will gum up and the squirts will not be true measure. Also if you have the cans around for awhile you want to screw the cap on. What do you do with the pumps? Toss em? Unless you want to go thru the mess of cleaning them and wasting solvent.)

[mbd]

I tried the heat gun earlier in the week. It thins the mixture when there's not enough hardener to "kick" - which incidentally is the way West suggests removing it. I also tried the heat gun on one of my used mixing pots to see what would happen. It just made it runny.

Ebb, I've got lots of the clear buckets with marked measurements. That's how I started out, but pouring the resin and hardener from the jug and cans was a messy and wasteful affair, and I invested in the pumps.

I also called West with a "hail mary" and took little comfort when he said, "You're not the first to do it." In light of the fact that I used the slow hardener, the temps are hovering around 60 and it hasn't started to cure yet, he said I'd be better off removing the questionable stuff, which I'm inclined to do anyway because we're talking about the structural integrity of my deck.

Ironic. In the software biz, I strive to write "idiot-proof" code 40 hours a week and I've concluded many times over - you just can't save some people from themselves...

[ebb]

Hey Mike, Guess you have to make up a proportion code sheet.
Like 72 squirts part A / 14.4 squirts part B = 8 oz
100 squirts pt A / 20 squirts pt B = 12 oz
ETC

Had to find a supplier for empty F-style gallon cans to screw in the pumps. Befor I nixed the pumps. But I got to like the wider mouth cans - you can look down the hole to see what's doin in there.
I buy Part A in 5 gal bombs weighing 600#, it seems -so I have to decant with a funnel into smaller containers. No fun when the big one is full. I got a big mit and find it pretty easy to pick up a rectangular can by its side and tip it into the quart container - laboratory style at eye level one in each hand. Not you? You only need to have it half full, weight wise. Anyway you probably aren't set up for continuous use like 338 is.

Spent an inordinate amount of time last few years with a gallon can in one hand and a quart container in the other. The wider mouth means that the syrupy epoxy pours out rather than BLOB - which indeed can get messy.

Earlier threads point out that 2 to 1 and 1 to 1 epoxies are better to use. And easier to measure. One reason is that they are more tolerant of mistakes because they are essentially the same stuff in each container but one has the hardner. Been said these epoxies are in a premix state already on their way to set. Sometimes indicated by zero induction time. This might have been true yesterday, but today there are 100s of new epoxies!

You're absolutely correct. Personally haven't been saved at least a thousand times!

[mbd]

Earlier threads point out that 2 to 1 and 1 to 1 epoxies are better to use.

I was real close to going with Mike G's FGCI epoxy, got a catalogue and even called and talked to them. But in the end, the ready availability of West won out.

In retrospect, I suppose I'd rather my recore were delayed because I was waiting for a delivery of epoxy...

[mbd]

Not so bad really. The 25:1 ratio goo was basically resin and was nowhere close to hardening. I was able to just peel of the fiberglass cloth and biax strips I had laid down, scraped off what I could, then wiped it all down with acetone. I could have been a lot worse...

Lesson learned.