Epoxy School Blog

Decorative epoxy flooring - colours, techniques and practicalities.

So you've worked with epoxies for a long time and done some decorative work along the way, but do you really understand colours? Do you feel confident creating designs and putting them on a floor?

Let me start by saying I was educated as an engineer, so I have no right to understand colours. Even worse, I started out in the epoxy field working almost exclusively with dull, industrial grey coats. You might remember a recent post (Metallic epoxies – the smiling contractors!) where I said it was only after starting my journey into decorative epoxies years ago that I began to realise resin flooring could be fun, exciting, and of course, colourful!

It goes without saying that understanding colours and how to make them work in a practical sense didn’t come easy; however, I’ve spent a lot of time chipping away at this topic and gradually built up a valuable knowledge base. If you have loads of time, patience, and maybe even money, then you too can learn the hard way. Alternatively, you can just learn from me!

So, what are some of the key points I’ve learnt about colours, techniques and how to get the most out of decorative epoxy flooring?

Turning descriptions into floor ideas

First of all, you need to be able to understand the language of colours before you can dream up flooring designs. If you’re like me and lived in a plain colour world – and yes, I consider flake or coloured quartz as plain colour flooring – then you either need to have an untapped natural flair for this or you need to train your brain on how to interpret colours. “Hold on a second here, I’m not colour blind”, I hear you protesting. Good! That will help, but it’s not really what I’m talking about. Interpreting colours goes deeper than knowing the difference between red and blue. I’m talking about the ability to give a client what they want based on common descriptions they use, like wanting a floor that’s “warmer”, “cleaner”, “brighter” etc.

Turning flooring ideas into flooring designs

With resin flooring, you typically have no more than one millimetre (40 mils) of floor coating to produce depth, intensity, variations and highlights. To be able to do that effectively you have to be clever with the way you combine resins, pigments and application techniques. Only by understanding finer points like how the texture of a basecoat affects the appearance of the topcoat, or how pigments flow and settle in different resins, will you ever be able to consistently deliver suitable flooring designs for your clients.

A decorative epoxy design showcasing the striking effects possible.

Turning flooring designs into actual floors

Interpreting the colour language used by clients and skilfully whipping up their dream floor on a sampleboard is an achievement in itself, however it all stops there if some important practicalities are ignored. To put it simply, you must only do on a sampleboard what you can reproduce on a floor.

There are a few things that will dictate whether or not a flooring design can be scaled up from a board to a floor. Ask yourself: are the application techniques I used possible on a large floor? Will they deliver a consistent and reproducible effect? Will it take too much time or perhaps even drive you crazy with “fiddly bits”? How thick is the total film build and what does that mean for material costs? Can you compete price-wise with established flooring alternatives like tiles, carpet, timber and vinyl?

Again, all these aspects of decorative epoxy flooring didn’t come naturally to me. I spent many late nights experimenting with colours, application techniques, designs and have only learnt the practical side by costly trial and error. If you’d like a quick and easy shortcut through all that pain, please have a look at the Decorative Epoxy Flooring Master Class in the Epoxy School shop. It passes on all of my knowledge and understanding of decorative epoxies, as well as the designs themselves, so that you don’t have to learn the hard way like I did.

Take care and talk to you later,


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Health and safety - epoxy sensitisation

Have you ever had, or heard of someone, get a skin rash when working with epoxies?

Well, that skin rash could well have been a form of epoxy sensitisation. In simple terms, epoxy sensitisation describes the process in which your body becomes more and more sensitive to epoxy products and/or the chemicals used in them. Perhaps the most common sign of epoxy sensitisation occurs on the skin via rashes, however irritation to the eyes, nose, throat and lungs can also occur.

The funny thing about sensitisation in general is that everyone reacts differently. Some become sensitised to certain chemicals very quickly, while others can experience high-level exposure their entire life and never feel a thing! Another quirky fact is sensitisation typically isn’t localised, i.e. the symptoms don’t always line up with the cause. I’ve heard of contractors being hospitalised, unable to see out of either eye, yet they didn’t get product anywhere near their face.

A skin rash typical of epoxy sensitisation.

Epoxy sensitisation – what I’ve learnt

Obviously the thought of an itchy skin rash or swollen eyes isn’t very pleasant at all and if you want a long, successful career in epoxy application, you must protect yourself. Here are a few key tips I’ve learnt about avoiding epoxy sensitisation

  1. Treat every chemical as though it will cause sensitisation and avoid skin contact. Wear long sleeve shirts and pants. If you get product on you then remove the item of clothing and wash the affected area with soap and water. If you wear short sleeve shirts then use barrier cream on your arms and hands.
  2. Start wearing gloves. Many contractors shy away from using disposable latex gloves because they can be hard to change when hands become sweaty. An effective way around this is to put on a thin pair of cotton gloves underneath the latex gloves as the cotton absorbs the sweat and makes it easy to change. Double gloving is also an easy way to keep clean – if the top gloves get dirty, just rip them off and keep going. While on the topic of latex gloves, buy powder-free gloves as users can actually develop sensitisation to the powder/sweat combination produced while they work.
  3. Work as cleanly as possible and wipe dirty items on rags, not shirts or pants.
  4. Some chemicals will cause sensitisation much quicker than others. Generally it’s not the epoxy resin (Part A) that causes the problem but the curing agent (Part B). Some curing agents are more reactive than others and can cause sensitisation quickly if not handled carefully.
  5. There are certain parts of your body that are more sensitive than others when it comes to skin contact. The underside of your forearms is a common point of exposure and often the first area to show up in a rash. It goes without saying that you must wash your hands before eating or going to the toilet as these regions are also very sensitive.
  6. Wear a mask. This should be a given for solvent-borne users to avoid breathing in harmful solvents, however even solventless epoxies give off a small amount of vapour that can build up in confined spaces and cause problems.

The final tip I want to give is the one that you must take away from this post if nothing else: whatever you do, do not use a solvent to remove epoxy from your skin! The solvent breaks down the epoxy and makes it much easier to remove, but it also makes it much easier to penetrate through the skin and enter the body. This fact should be kept in mind for solvent-borne epoxies – these products already have solvents in them, which makes skin contact even more dangerous in this context.

Once sensitised to epoxies...

Ok, so you get that epoxy sensitisation isn’t a good thing and you know how it can be avoided. What happens if all that fails and you become sensitised; or you’re reading this and are already sensitised? If you are sensitised to epoxies then there it generally goes one of two ways –

  • You might be lucky and only develop sensitivity to a particular raw material within the epoxy – something that isn’t found in every product. In this case you can find a suitable alternative that did the same job and continue working (as long as you worked clean).
  • You might be unlucky and become sensitised to the epoxy resin, which is a much bigger problem because it could mean every product is off limits. This situation is the real tragedy of epoxy sensitisation because it can ultimately strip a contractor of their livelihood. Their body is telling them it can’t cope with the chemical exposure and unfortunately the only option at this point is to seek another profession.

Avoid epoxy sensitisation from the start!

As I said before, if you want to work in the epoxy industry over a long period then you need to develop the right habits from day one: work clean, protect your body, clean up without solvents and read material safety data sheets to understand what the potential dangers are. If you ignore any or all of these things, epoxy sensitisation could make your life misery and even spell the end of your career.

Take care and talk to you later,


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Epoxy troubleshooting - solvent entrapment

What is solvent entrapment and why is it bad news for two-pack epoxy coatings?

If you thought solvent entrapment had something to do with solvent becoming trapped in a film then you’d be 100% correct. There’s nothing tricky about the name, that’s for sure! Just like anything though, knowing what it is and what it looks like is the easy part; knowing why it happens and how to avoid is where the gold really lies.

Basically, solvent entrapment can be boiled down to one thing: the solvent not having enough time to evaporate from the film before the hardening process goes too far. When applied correctly, two-pack epoxies containing solvent normally have enough time before this happens, however if they’re applied too thick or in cooler, damper conditions, the components can crosslink before the solvent escapes and this can lead to a variety of problems.

Although solvent entrapment can happen in solvent-based or water-based products, the way it affects the film is more a factor of how much solvent is used rather than the type of epoxy.

Solventless epoxies and solvent entrapment

As I’ve already written in a previous post (Solvents – their purpose in solventless epoxies), some solventless epoxies can have a small volume of solvent added to extend pot life or drop viscosity. Despite the very low solvent content (typically 5% or less), solvent entrapment can still be an issue and tends to compromise a film in two ways -

  1. Soft spots – solvent trapped in the film can create a physical barrier to crosslinking in isolated sections and stop these spots from fully hardening (hence the term “soft spots”). This phenomenon is even more likely if acetone or MEK is used because they belong to a group of solvents called ketones that block the chemical reaction with the amine.
  2. Blistering – if the solvent has a relatively high boiling point and won’t evaporate quickly then you not only raise the risk of trapping it in the first place, but you’re also more likely to see blisters develop. This happens because solvents with higher boiling points are often hydrophilic, which means they attract water and could draw enough to form visible blisters.

Solvent-borne, water-borne epoxies and solvent entrapment

If those are the main dangers of low-level solvent entrapment in two-pack epoxies, what happens when the solvent content is much higher, for example 70% in a solvent-borne or water-borne epoxy? In this situation, you typically see a different outcome. Rather than a small pocket of solvent permanently held captive in the film, the majority manages to gradually work its way out as the film tries to crosslink and what you end up with is a porous, sponge-like structure across widespread areas. Instead of a strong, hard film, you’re left with a much softer, weaker version that is also commonly affected by a large number of shrinkage cracks (called “mudcracking”).

It’s important to mention at this point that extra care must be taken with water-borne products and entrapment problems because of the lower volatility risk I touched on in my comments on blistering. Water will not evaporate as quickly as organic solvents and therefore these kinds of products are more prone than others.

Mudcracking in a water-borne epoxy.

Solvent entrapment traps

OK, so you’re probably thinking, “If I stick to applying as per the manufacturer's specification, I should not run into trouble, right?” In theory that’s correct, but sometimes it isn’t always that straightforward. For instance, what happens on a slab with “minor” depressions that exceed the allowed thickness? That’s just one scenario where you could unwittingly be heading for a problem and the only way you could avoid costly defects there is to have a good understanding of why solvent entrapment occurs in the first place.

Take care and talk to you later,


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Selling epoxies - how time off will boost your epoxy business!

I recently took my first break since launching Epoxy School and I must say it put a few things into perspective.

We work in an industry where it’s customary to take the work whenever and however it comes, putting in long, strange hours and even giving up our weekends to get it done. As business owners, it’s fair to say we bury ourselves in our job – to the point where we feel guilty if we’re NOT working!

A key to boosting your epoxy business

I decided to write this article as I relaxed on the couch during my break and thought about all the business owners I’ve met over the years that didn’t take any time off at all. What impact would it have on them in the long run? Was that level of output sustainable? Did it actually help them “get ahead” or did it hold them back in some way? It may sound ridiculous to some, but once again I came to the conclusion that taking time off really is a key to making more money in your epoxy business.

A hypothetical epoxy business owner on holiday, relaxing on the beach.

How time off makes money

The way I see it, taking time off can you boost your epoxy business by allowing you to –

  • Relax the mind. A relaxed mind makes fewer mistakes and that alone will save money! A relaxed mind has better planning ability and far more creativity, which is a big part of how you make money. A relaxed mind also stresses less, which allows you to think about the “right” things and not get bogged down with the small stuff that doesn’t matter.
  • Let the body recover. The human body is a phenomenal bit of gear. You can punish it in all sorts of ways, yet it still bounces back if you give it enough time. Unfortunately most of us don’t and that’s when we strike trouble. Not only does a worn-out business owner work less efficiently day to day, they also run the risk of a catastrophic breakdown sooner or later. As a business owner, you’ve got to acknowledge your health is your number one asset – if you can’t keep working the whole show stops!
  • Get your equipment serviced. When you’re busy you can easily forget about the maintenance that stops your equipment from packing it in when you least want it to. Surface preparation gear is probably the main concern here because it’s a mind-numbing task and you tend to focus on chopping down the trees rather than sharpening the axe, so to speak. Your vehicle also sits in this category. It not only gets you from A to B, it’s often your travelling showroom as well and what people judge you on first. Make sure it’s running well and representing your business in the right way!
  • Think about your future. Go see a financial planner or your bank manager and see if you can sharpen things up there. Also, look ahead and think about what your epoxy business might look like in the future. Where do you want to take it and how can you start moving in that direction? When would you like to get off the tools? Can you continue to make money if you’re no longer working?
  • Think about other elements of your epoxy business. Obviously your employees are a key part of this process. How can you give your employees time off as well so that they can recover and be at their best for your business?
  • Spend time with the people that matter most to you. It is why we work, after all! Let them motivate and re-energise you and clarify exactly why you’re out there working your butt off.

If you look at the list above, I’m sure even the biggest workaholics among us could appreciate the benefits of taking time off and how it can help you make money. The hard part is, I believe, having the courage to take your nose away from the grindstone and give it a try. As a wise man once said to me, “there’s a time to work and a time to play. Don't mix them up!”

Take care and talk to you later,


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Epoxy troubleshooting - UV exposure and indoor epoxies.

We all know epoxies will yellow outside, but it may come as a big surprise to hear indoor epoxies aren’t entirely safe either!

As already discussed in a previous post (Epoxy secrets revealed – do UV-stable and low-yellowing epoxies exist?) , all epoxies will break down in direct sunlight and much of this has to do with a chemical structure that isn’t very stable when it comes to UV light. Because of this, and their excellent all-round performance in other areas, epoxies are naturally better suited as indoor coatings and are widely used in factories, warehouses, commercial kitchens, offices and homes. But, don’t be fooled! Just because these films are applied indoors, doesn’t mean you can’t be burned by UV exposure (pardon the pun).

Roller door line showing indoor epoxies can yellow.

UV exposure can still happen with indoor epoxies!

Here are a few points on what I’ve learnt about indoor epoxies and UV exposure – 

  • Although UV exposure can lead to other film issues, the main danger indoors is yellowing. You’re not likely to see obvious signs of chalking or cracking because indoor coatings generally don’t have to contend with rain or extreme temperature fluctuations. 
  • The way UV exposure occurs indoors is through windows (and large entrances such as roller doors, although that’s a more obvious danger). Luckily, there are countless combinations of glass and nowadays it’s not uncommon for it to be laminated and contain some form of UV blockers, which significantly reduce transmission levels. Double-glazed and tinted windows do the same thing. The last point to consider with UV exposure through glass is the aspect. In the southern hemisphere, northerly facing windows allow maximum UV light exposure. 
  • A forgotten source of UV light indoors can be fluorescent tubes. I’m no lighting expert, but as I understand it a new fluorescent tube has a lining on the inside that gets “excited” by UV radiation, converting it into the white light we see. Over time this lining degrades, which allows the UV light to escape from the tube and come into contact with indoor coatings. Likewise, IR heat lamps in bathrooms can also cause problems. IR is a bandwidth that gives off heat, not just visible light, however it’s possible enough UV is given off to discolour vulnerable surfaces.

Final thoughts on UV exposure

With this post and the previous one, we’ve covered a fair bit on UV exposure and yellowing. While there’s much more to say on this important topic, for now I’ll close with a few scattered notes to also think about – 

  • To repeat a well-worn line, it’s important to understand and accept all coatings will yellow to a degree. Some will more than others and you must do your homework when it comes to product selection. 
  • Any colour with yellow in it will tend to show less yellowing. In other words, yellowing in beige, green and even some greys won’t be anywhere near as noticeable as other colours and this can be used to your advantage where UV exposure is a concern. White is clearly the worst as a telltale, although that doesn’t stop it from being a very popular choice! 
  • Yellowing tends to stand out more when side-by-side with a clean section. For example, an old mat or pot plant at the entrance of a plain glass door will reveal a very neat yellow border when removed. 
  • Zinc oxide, a widely used filler to help reduce the effects of UV light, has a high natural affinity for lead. While there are grades available with low lead content, they’re not always the first choice for manufacturers trying to keep costs low and that’s something to keep in mind if you’re trying to avoid hazardous materials.

Take care and talk to you later,


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Metallic epoxies - the smiling contractors!

For a brief change of pace, imagine for a minute you were handed application notes by a manufacturer that included Step 1: Start smiling!

It just so happens that I was reading the instructions on a bottle of calming bath foam (my wife's by the way) and the usage instructions kicked off with this rather unusual request. I couldn’t help but laugh when considering what sort of reaction the same instruction would get in the typically dour epoxy industry. Everyone would probably think the manufacturer had gone mad!

When I thought about this idea a little further, there’s only ever been one epoxy field I thought could legitimately include smiling as part of the instructions. In fact, I actually saw grown men turn giddy like school kids during a training course I was conducting!

Industrial epoxy contractors weren't smiling

Before I go into details, I’ll firstly say that I’ve worked with a lot of different contractors over the years and many were in the ugly end of industrial flooring. I’m talking about aggressive chemicals, horribly corroded concrete and demanding conditions with high-pressure shutdowns. The only time I saw an industrial epoxy contractor come close to a smile during these times was when they got paid for the job. I must say, I didn’t find too much to smile about myself when doing that sort of work!

Metallic epoxy contractors were smiling

Anyway, all this changed when we entered the decorative field and started conducting epoxy training courses for our metallic epoxies. For the first time ever I had contractors hanging on my every word and eager to give absolutely everything a try. I don't know if it was because they could see themselves doing something other than boring, thankless grey floors or what? Maybe they had some untapped artistic talent buried deep down and this was their chance to finally let it out. Whatever the reason, these guys became genuinely excited and were beaming the whole day.

Industrial contractors learning metallic epoxies.

Chase your smile!

This experience was a real mind-opener for me personally on the wider topic of job satisfaction and enjoyment. Despite what the industrial field had previously taught me, watching the transformation that came over the participants that day proved there’s no reason why epoxy contractors can’t love what they do as well – it doesn’t have to be all doom and gloom.

In my opinion, the key is to keep learning and keep trying new things. From what I’ve seen in my epoxy training courses, metallic epoxies tend to have a similar affect on everyone and bring out a real creative passion that can border on addictive. Of course, it doesn’t necessarily mean it’ll be the same for you; you might even love the nitty gritty stuff. The point is, if you’re not smiling with the work you’re currently doing, you’ve simply got to get out there and find a better fit. Who knows, you too might be able to start work every day with a smile.

Note: I’ve converted the same metallic epoxy training course that made these guys so enthusiastic into modules in the Epoxy School shop. If you’re interesting in learning a new skill with metallic epoxies, please take a look.

Take care and talk to you later,


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Epoxy secrets revealed - environmentally friendly epoxies or "Greenwash"?

With environmentally friendly attached to so many products these days, I can’t help but wonder whether it’s become just another meaningless buzz word for marketers.

Taking a step back, green products aren’t about feel-good “tree hugging” in my opinion. There’s absolutely no point making an oven cleaner that doesn't clean your oven, so I see the green product movement as the search for better performance while being safer for both man and environment. With numerous raw materials and manufacturing practices proven undesirable in this regard, the epoxy industry is the perfect candidate for a push toward environmentally friendly products and momentum has been slowly gathering.

The environmentally friendly response

In response to trends like this, you find that coating manufacturers tend to do one of two things. Some go for Option 1, which is to spend their time and money developing new technology, in this case environmentally friendly epoxies, aimed at the future market. When the surge in demand inevitably comes, these manufacturers have proven, genuine technology ready to offer a hungry market. On the other hand, some go for Option 2. These manufacturers see an opportunity to cash in immediately on the budding trend by promoting their existing products as compliant in any way they possibly can. This is called Greenwash and it’s a problem we need to look at.

What Greenwash looks like

Greenwash occurs because, to put it bluntly, some companies take the easy way and just make their products sound green. For example, I recall a manufacturer that reduced their solvent content from 20% to 10% and pumped it up as environmentally friendly. Another did a similar thing to gain green certification with one product, yet sneakily promoted their entire range fell into line. These might be steps in the right direction, but a joke if you’re serious about making green products that are safer for both man and environment.

What makes that kind of practice even worse is the fact these “green products” only address higher profile dangers like solvents. There are all sorts of unpleasant chemicals and wasteful manufacturing processes that conveniently get ignored when the easy option is taken. These all have an impact on the environment and have to be considered in order to offer genuine environmentally friendly epoxies.

In addition to all that, we’ve also learnt from exposure to asbestos that it’s pointless just looking at the front end of product usage. We need to measure the entire lifecycle, including the removal, recycling and/or disposal.

How to avoid Greenwash

So, how can you tip-toe through the marketing to find genuine environmentally friendly epoxies? The answer is the same with any form of marketing: don't believe popular product perceptions or the manufacturer’s spiel unless the claims can be fully supported. One way to do this is to look for green products that have been independently audited under an internationally recognised standard. Even then, it pays to do a bit of research on what the standard is about because they’re not all equal as far as testing is concerned. Failing that, you could even ask the manufacturer if they have an environmental disclosure statement, but, once again, look for those that have been independently verified.

GECA logo - a program that looks to certify environmentally friendly epoxies.

Take care and talk to you later,


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Solvents - their purpose in solventless epoxies

Solventless epoxy means without solvents, doesn't it? So why would I need solvents when using them?

In floor coatings, organic solvents are used to thin the resin so it applies easily and forms an even film. Some products require more than others depending on how thick the resin is to begin with and what else is added.

With solventless products, they’re formulated with a lower viscosity so they can be used without the addition of solvents. That being said, they can still play an important part in solventless epoxy application.

Vinegar in a bottle - can be used for epoxy clean up but not epoxy thinning.

Solvents for epoxy clean up

Most manufacturers talk about “epoxy thinners” as a general term for solvents, however I like to be a bit more specific. When talking about solvents for epoxy clean up, I talk about two separate stages.

The first is when the product is still fresh and within working time, the other when it’s gelling. My preference for epoxy clean up in the first phase is methylated spirits (or denatured alcohol). The smell isn’t strong, it’s readily available and, most importantly, it’s not as nasty as some of the more aggressive solvents.

Once the product has entered the second phase, I look for acetone or methyl ethyl ketone (MEK) as they’re more powerful solvents than methylated spirits. There are plenty of other solvents on the market that’ll do the same job, but I tend to stay clear of options like methylene chloride and xylene because of safety concerns.

At this point it is worth stating the number one rule with respect to epoxy clean up: do not use a solvent on your skin. Yes the solvent will break down the epoxy and remove it from your skin, but breaking it down also helps your skin absorb it more efficiently, which isn’t good news. Only ever use warm, soapy water to clean epoxies off your skin.

Solvents for epoxy thinning

The purpose of epoxy thinning when it comes to solventless epoxies is generally for spraying or making the product easier to roll in cooler conditions. It’s worth noting that a small amount of solvent has a big impact on a solventless product, so 2-4% by weight is typically enough and certainly no more than 10%.

Solvents for extending pot life

Acetone and MEK belong to a group of solvents called ketones that extend pot life by blocking the crosslinking reaction with the amine. By adding a small amount in the bucket you can extend pot life dramatically and give yourself more time for application. Once the product has been rolled out, the reaction reverses and the solvent evaporates off as it normally would, which means this little trick doesn’t extend the working time as much.

Water as a solvent

Water doesn’t mix with epoxy naturally, however there are a number of ways formulators get around that to create water-borne epoxies. Most people assume these coatings are the ultimate in safety and environmental friendliness because they contain only water, however the fact is many have organic “co-solvents” to help the products flow and form a nice film. Next time you open a bucket of water-borne paint, pay attention to the smell. It’s definitely not just water in there!

Take care and talk to you later,


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Epoxy product selection - Technical Data Sheets and MSDS

When it comes to epoxy product selection, everything is not always as it seems.

A product may sound like it hits the spot – it may have the right speed, viscosity, hardness etc. – but behind this ideal exterior there can lay some important fine print not all salespeople like to talk about. Knowing your way around a couple of key documents will help unearth these potential sticking points yourself and make sure it’s the product you want to be dealing with.

Let's start by looking at a Technical Data Sheet (TDS).

Technical Data Sheet clues

When searching for certain products, you’re typically drawn to things like speed, gloss levels, chemical resistance etc. If you’ve been handed a Technical Data Sheet by sales person, the chances are these will all check out ok. It’s in other places, however, that you should look a little more closely. Personally, I always head to the Limitations section on Technical Data Sheets first because you learn more about the product here than anywhere else, particularly its quality and overall suitability for you.

A classic example in this sense is the mention of an induction time. Letting a product sit for 10 minutes before application is there to control blushing and is a legacy of older curing agent technology, both of which mean you can probably find a better alternative elsewhere. What else could show up on a Technical Data Sheet and make you think twice? There are plenty, but warnings on using the product below certain temperatures or above certain humidity are common, so are the appearance of surface haze in some conditions. The point is this section is usually full of information you’ll want to know when going through the epoxy product selection process.

Material Safety Data Sheet clues

The next key document I rely on for epoxy product selection is the Material Safety Data Sheet (MSDS). The regulations controlling what has to be declared on a MSDS vary from country to country and manufacturers will mostly reveal only what they have to. Despite this, reading the MSDS can, at the very least, give users an idea of some risks that could influence epoxy product selection. Covering all of these is a large topic well beyond the scope of this post, however I’ll highlight a couple of epoxy users might want to consider. 

Firstly, there’s the corrosivity rating. While there are a few non-corrosive curing agents on the market, the remainder tend to be lumped together in a generic classification for transport purposes and that can be dangerous in my opinion. The alarming fact is there can be big differences in the degree of corrosivity from one curing agent to the next, even if the MSDS has them all listed as a Class 8.

If working with extremely corrosive materials isn’t your cup of tea, how can you tell from an MSDS if something is acceptable or not? The key is to read what the product does with respect to skin contact. On the lower end of the scale are irritants, meaning skin contact can lead to temporary irritation, usually in the form of a mild rash. Then there are sensitisers, meaning increased sensitivity to the product can be experienced over time if exposure continues. On the harshest end are the corrosive materials, which can cause chemical burns when in contact with your skin. Taking a look at what you’re dealing with in this way will quickly tell you what you need to know.

The second area users should consider with epoxy product selection is toxicity because some components are toxic in very small doses. Hopefully no-one ingests (drinks) these materials, but the risk of breathing in vapour or ongoing skin contact is very real, especially over the long term, and has to come into the equation when deciding if a product is one you want to work with.

A few of the hazard symbols that can be found on the MSDS of epoxies.

The take home message from this post is that reading just some basic information in Technical Data Sheets and Material Safety Data Sheets can help you make the right choices when it comes to epoxy product selection. For those wanting to learn more about this topic, there is a training module in the Epoxy School shop that goes into much greater detail (click here).

Take care and talk to you later,


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Epoxy troubleshooting - inter-coat delamination

I think one of the worst nightmares in floor coatings is inter-coat delamination, or in simple terms, one coat failing to stick to another.

Not only is there the immediate problem of removing the failed coating, but the even bigger concern of why it didn’t bond in the first place. After all, if you can’t get to the bottom of why it happened now you’ll almost certainly have a second failure on your hands!

So, what are the typical causes of inter-coat delamination with two-pack epoxy coatings and how can you prevent it from happening?

Product re-coat window and coating adhesion

When most two-pack epoxy products cure, they form a smooth, hard film that isn’t the easiest to stick to. To get around this, manufacturers talk about applying following coats within the re-coat window – a period where the film hasn’t fully reacted yet and can therefore form strong chemical bonds with coat on top. If this re-coat window is missed, you’ll need to rely more on physical bonding by sanding the film and establishing a mechanical profile for the next coat to cling to.

A TDS showing the re-coat window of an epoxy coating.

Amine blush and coating adhesion

I have already written a post on amine blushing in this blog (Epoxy troubleshooting – amine blush), so please have a read of that for a more comprehensive discussion of this problem. For now I’ll just say that the waxy film created through the blushing reaction can be a powerful barrier to epoxy adhesion.

Incompatibilities and coating adhesion

Incompatibility can occur in several ways. For instance, some products may contain additives or modifiers that interfere with coating adhesion in general. In other cases it might be more specific, such as incompatibilities between two products or even two technologies. Some of these incompatibilities are well known, while others aren’t. For example, I’ve seen plenty of contractors caught out by using cement-based levellers under impermeable coatings and experiencing coating adhesion troubles because they didn’t allow sufficient time for drying.

Solvent entrapment and coating adhesion

This topic can get a little complicated and I’ll cover it in more detail in post shortly. Briefly, solvent entrapment can occur when another film is applied before all the solvent (organic solvents or water) in the first film has had a chance to evaporate. In this situation the solvent can become permanently trapped, which often leads to soft spots, blisters and inter-coat delamination.

Contamination and coating adhesion

Even though the period between coats is typically a matter of several hours, contamination and the impact it can have on coating adhesion is definitely still something to be wary of. Off the top of my head, I can think of a couple of instances where contamination between coats led to substantial coating adhesion problems. The first was a cool room floor in a meat processing plant that had condensation run off the walls and sneakily deposit a load of oil and fat that wreaked havoc. The second also involved oil, however this time it was a very untimely crack in a pipe that left an uncured floor completely immersed. Contamination can also, of course, be air-borne so be aware of anything that could land on the floor in between coats as well. 

I’ve never personally been a part of a project where the two-pack epoxy coating came off in large sheets, however it is definitely possible because I’ve heard from contractors that have. Rest assured they didn’t have fond memories! The threat is very real and you’ve got to make sure you’re aware of the potential causes of epoxy adhesion issues to avoid such a disaster.

Take care and talk to you later,


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