Who This Checklist Is For
If you're using olin epoxy resins for production work—whether it's coatings, castings, or composites—this checklist is for you. Not for hobbyists doing weekend projects. I mean people who buy by the gallon (or drum), who've had jobs where the cure didn't happen, where the surface looked wrong, where they had to scrap $500 worth of material because of something stupid.
I'm a senior production coordinator at a mid-size industrial shop. I've been handling olin chemical orders for 5 years. In that time, I've personally made (and documented) 14 significant mistakes, totaling roughly $7,200 in wasted budget plus two blown client deadlines. Now I maintain our team's checklist. This is the epoxy-specific part.
Here are the 3 most common—and expensive—mistakes I've seen, with the exact steps I now use to prevent them.
Mistake #1: Assuming the Notched Squeegee Is Optional
Back in 2021, I had a job applying a self-leveling olin epoxy floor coating over a 2,000 sq ft concrete slab. The specs called for a notched squeegee to maintain consistent thickness. I thought I knew better. 'A smooth squeegee will be fine,' I told myself. 'It'll spread more evenly.'
It didn't.
The coating pooled in the low spots and ran thin on the high spots. We got fisheyes and bare patches. When it cured (which it did, eventually), the surface looked like a topographical map. The client rejected it. We had to grind it all off and reapply.
Total waste: $3,200 in materials + 40 hours labor + 4-day delay.
Here's what I do now:
Step 1: Match the Squeegee Notch to the Resin Viscosity
Not all notched squeegees are the same. Olin's epoxy systems have different viscosities depending on the specific product (their bisphenol A resins are thicker, while some of the modified ones flow more freely). I learned this the hard way.
I keep a laminated reference card taped to our mixing station:
- High viscosity (like heavy paste): 3/8" or larger square-notch squeegee
- Medium viscosity (like honey): 1/4" V-notch squeegee
- Low viscosity (like water): 1/8" or smaller V-notch squeegee (or use a roller)
Checkpoint: Before you start, confirm the resin's viscosity at your current ambient temperature. Yes, temperature changes it. More on that below.
Step 2: Test the Spread on a Small Area First
I once ordered 5 gallons of an olin epoxy system for a 50 sq ft test section. I was in a hurry. I didn't test the spread rate. The notched squeegee I chose (a 1/4" V-notch) gave me a spread of about 40 sq ft per gallon at the recommended 20 mil thickness. But the job required 30 mil. I ran out of material halfway through.
Now I always, always do a 4x4 ft test with the exact squeegee and resin I'll use for the main job. Measure the material used. Calculate the coverage. Adjust if needed.
Checkpoint: Your test should confirm: coverage rate in sq ft per gallon, actual thickness (measure with wet film gauge), and work time in minutes.
Step 3: Angle and Speed Matter
Here's one most people don't think about: the angle of your squeegee. If you hold it at 45 degrees, you get a different deposit than at 60 degrees. I discovered this after our third rejected floor job. A rep from a manufacturer (not Olin, but another brand) showed me.
Now I use a simple jig to maintain consistent angle—just a piece of wood with a notch cut at 50 degrees. Saves my arm, saves my material.
Checkpoint: Practice the pull at a consistent speed (about 1 ft per second works for most systems). Too fast and you leave thin spots. Too slow and you get excess buildup.
Mistake #2: Ignoring Cure Time Variables
How does epoxy resin dry? That was the question that ended up costing me a client. A potential client sent us a sample of their product to encapsulate in an olin epoxy system. They wanted it cured and shipped in 24 hours. The spec sheet said 24-hour cure. So I mixed, poured, and set it aside.
18 hours later, it was still tacky. Not cured. We missed the deadline.
The numbers said the data sheet was correct. My gut said it felt too cold in the workshop. I went with my gut. Turns out the data sheet assumed 77°F (25°C). Our shop was running at 62°F (17°C) because of a heating issue. At that temperature, the cure time roughly doubles.
Lesson: The data sheet is a guide, not a guarantee. You have to account for your actual conditions.
Step 1: Know Your Ambient Temperature and Humidity
Olin's technical data sheets (available on their site) specify temperature ranges for optimal cure. Most of their room-temperature curing systems need 65-85°F (18-29°C) and relative humidity below 70%.
I now have a digital thermometer/hygrometer at each mixing station. I log the readings before every batch. If the conditions are outside the range, I don't mix. I either adjust the environment (space heater, dehumidifier) or wait.
Checkpoint: Temperature of the resin and hardener itself matters too—cold drums need to be brought to room temperature before mixing. Takes at least 24 hours for a 5-gallon pail.
Step 2: Understand the 'Pot Life vs. Cure Time' Trade-off
Most epoxy resins have a finite pot life—the time you have to apply it after mixing. They also have a cure time to reach full properties. The numbers are related. A fast hardener gives you shorter pot life but faster initial cure. A slow hardener is the opposite.
I once used a fast hardener for a large casting because I wanted to rush the job. The mix started exotherming (getting hot) after 10 minutes. I couldn't pour it fast enough. It hardened in the bucket. $400 of material wasted.
Now I always calculate: pot life >= application time + 30% buffer. And I check the recommended mixing ratios on the olin packaging—they vary by product.
Checkpoint: If you need a long work time, use a slow hardener. If you need fast demold, use a fast hardener—but work quickly.
Step 3: Verify Cure by Touch and Test
Don't trust the clock. Trust your senses. A properly cured olin epoxy should feel hard, not tacky, after the specified time. You should be able to scratch it with a fingernail only with difficulty.
If it's still soft or tacky after the expected cure time, something's wrong. Possible causes: wrong mix ratio (most common), low temperature, high humidity, expired hardener (it does expire).
Checkpoint: Do a small test sample alongside your main job. Test its cure before you handle the main piece.
Mistake #3: Relying on Thumbscrews Instead of Proper Demolding
This one I'm embarrassed to admit. I was making a series of epoxy parts using a silicone mold. The parts were supposed to release easily. But after 24 hours, they were stuck. I tried prying them out with a screwdriver. I broke two parts. $680 worth of castings, ruined.
I'm not a mold design expert, so I can't speak to complex release mechanics. What I can tell you from a production perspective is: proper mold release is not optional. Even for parts that 'should release easily.'
Step 1: Use a Compatible Mold Release Agent
Olin epoxy systems bond to many surfaces. If you're casting into a mold, you need a release agent designed for epoxies. I use a semi-permanent release, applied in multiple thin coats. Let each coat dry before applying the next.
Checkpoint: Test the release agent on a scrap piece of the mold material first. Sometimes there's a chemical incompatibility.
Step 2: Consider the Draft Angle
This gets into technical design territory. A draft angle of at least 2-3 degrees on vertical walls of your mold helps the part release. I learned this from a tooling engineer after my failure. Now I check the mold design before we start.
Checkpoint: If you're making your own molds, include draft angles. If you're buying molds, verify they have adequate draft.
Step 3: Tap, Don't Pry
When it's time to demold, use gentle force. Tap the sides of the mold with a rubber mallet. Use compressed air to break the seal. Never use metal tools against the part or the mold. That'll damage both.
Checkpoint: Have the right tools ready: rubber mallet, plastic wedges, compressed air nozzle.
One More Thing: The Quality Perception Link
Every time you make one of these mistakes—the uneven surface, the failed cure, the broken part—your client sees it. They don't see your process or your tools. They see the result. That result is their impression of your entire operation.
When I switched from using a cheap, unbranded squeegee to a properly notched one from a reliable supplier, our client feedback scores improved measurably. The $30 difference per tool was nothing compared to the cost of a redo.
Is cheap ever acceptable? Sometimes. Depends on the application. But the point is: the output quality is the brand. Period.
Bottom line: These three checkpoints have saved us a ton of time and money. I keep them printed out near the mixing station. I hope they save you too.
Pricing note: Resin costs and tool prices are based on our shop's purchase records from 2023-2025. Verify current pricing with your supplier.