I wrote this as an email to Sean Macy – one of the coaches for the Dublin XC program – in answer to a question about fluoro free top-coats. I’ve shared it at least a half dozen times since, instead of writing something similar from scratch. I figured I’d save everybody some time and just post it as an article, even though it was written as an off-the-cuff email. I have made some edits for context and accuracy, and to avoid lawsuits.
It’s going to be a challenge for everybody to come up with common lexicon about layering wax, and what constitutes a “top coat”. With fluoro, it kind of boiled down to chemical differentiations. “Top Coats” were the products with 100% per fluorinated ingredients – not mixed-chain ingredients. They didn’t mix with the paraffin based under layers, and so it was a pretty clear differentiation.
With fluoro free, the vast majority of products that are being offered are paraffin based. The only clear exception that I’m aware of is the Rex N-Kinetic stuff, which is not in a wax base. But everything else is wax based, as far as I know.
With paraffin waxes, there are a couple of different ways they can work. Under the right conditions of heat and fluidity the wax can dissolve into solution in the base of the ski. It actually dissolves like sugar into tea. This is what we normally call “saturation” or “penetration”, and it doesn’t really have anything to do with “pores” or little microscopic holes in the base material.
This wax in solution changes the bulk properties of the base, and also helps to protect the base and keep it operating well. Those bulk properties DO contribute a meaningful and important part of the performance equation. However, the big majority of performance on race day comes from the surface layer of wax that is left on the base.
For years we sort of assumed that this surface layer was functionally just going to be whatever portion of the bulk wax had remained on (or precipitated to) the surface of the ski. And then we figured that our fluoro top-coats formed surface layers on top that had good durability because of the fluorine chemistry.
However, as we’ve worked more and more with paraffins and application methods over the past few years, it’s become increasingly clear that we’re working with thin-film layers that can add up – sort of the way you add up kick wax. Even when we finish the layers with brushing, we’re adding a “ply” to whatever was there before. And these layers DO seem to work together to build a complete solution. And not only that, but these layers seem to be surprisingly durable.
Now – to be clear – the performance of unfluorinated wax films does degrade more quickly than fluorinated wax films. But it doesn’t appear to be because they “wear out”. It seems to have more to do with the accumulation of pollutants and impurities. In fact, the best way I’ve seen to reduce the speed degradation is through really careful management of the film thickness – we want to keep it really thin!
OK – so what about these thin-film applications? How do we work with them?
Well, clearly the liquid applications are one way. As you’ve noted, some brands have long drying time, and this is problematic insofar as it forces some adjustment to your timeline on race day. However, the products are very effective and worth accommodating. Also, it’s worth noting that some of the products are based on an alcohol solvent and those ones dry really rapidly. In particular, Star, and Start both have alcohol based solvents and they are very fast drying and effective for race day use.
The other leading contender for thin-film application is the fleece-applied stuff, like Ulla. Star also has fleece applied products this season (one of the prototype products in this line was among my final four in fluoro topcoat testing at the Dublin eastern cup last season).
When we talk about fleece applied wax, it’s worth splitting the conversation into two parts. The first part is fleece. We started really aggressively testing film application and finishing methods last season, and we found that a lot of products respond VERY well to roto fleece finishing. For instance, all the Star liquid paraffins did much better when we finished them with fleece (until it got really wet, when it didn’t make a big difference). The same was true of the Rex liquids.
I think that the fleece is a super effective way to organize and refine the thin-film application, and to ensure appropriate thickness of the film (which is not very thick). By “organize”, I mean that I think the directionality of the roto-tool aligns the product with the direction of travel in much the way the hand-corked fluoro blocks has done for years. In other words, I think we’re getting some mechanical efficiency out of the modified application, at a molecular level. In our testing we’re tried all sorts of methods or thinning out and organizing these thin films, including various brushes, cork, felt, etc. The fleece seems to be a clear winner in our testing, the vast majority of the time.
Then we also have the fleece-applied wax. And obviously the fleece is part of the equation there. The difference here is that the wax needs to be formulated to “work” with a fleece application method. This is been a “thing” for quite a few years with products from Yes and Masterwax doing really well in certain portions of the ski world. Ulla has been “in the lead” with respect to developing fluoro free products organized around this fleece application. Star is newer to this, but has sort of jumped right toward the front of the pack in my testing.
For paraffin wax to work with a fleece application it needs to have the right viscosity and response to the specific conditions caused by the fleece. A lot of paraffins just get super gummy and gross. You don’t want to try fleece a stick/gummy layer! I haven’t found a lot of solid block-form paraffins that respond well to fleece finishing (I’ve tested it on ironed paraffins, after scraping and before brushing, as well as trying the regular fleece application method on a variety of paraffin blocks). However, the liquid applications DO seem to respond well. Even when it’s a liquid application of the same glide compound that doesn’t work well in block form. Go figure.
So.. what is a “top coat”? Well, at this point it’s whatever thin-film layer you put on last, I guess. I think that we’ll see a TON of experimentation with layering of these thin-film applications. And I don’t think it’s always going to be multiple layers of the same thing. I don’t know exactly how it will all play-out. Nobody does. There is a lot of experimenting to do. But I will start the season with a whole bunch of roto fleeces (the very low volumes of wax in these thin-films means that it’s really difficult to avoid cross-contimating applications if you’re not dedicated fleeces to a single product). I will continue to work extensively with a wide range of products that are designed to be applied AFTER the ironed paraffin.
I’m really happy with Star Next paraffin as an ironed layer. That all absolutely be my basis for testing of this ironed layers. I truly believe that the race-day magic will come from surface layers though.
I will absolutely continue to test liquids from Star, Vauhti, Rex, Rode, Start, and others.
I will continue to work with Ulla products – they’re organized entirely around thin-film applications and prefer that you don’t iron wax into the base. Individuals and teams who adopt the system 100% seem to do really well with it. Teams that test it in a more traditional system have more hit and miss results – but still with plenty of hits.
I am leaning really heavily on the performance of the new Star fleece-applied blocks that we started working with last season. Those are exciting for me.
I will test many different layering combinations. Many.
Standard starting point for me in the Star line will be:
1 – Next Paraffin ironed, scraped, brushed. This establishes my bulk property baseline for the wax job.
2 – Next liquid, finished with fleece. We tested this alone against the ironed paraffin, and in combination, and the combination ALWAYS won testing, all season long.
3 – Fleece applied blocks, additional layers of liquid, and all manner of other craziness.
Question – can we skip step #2 (liquid) and just work with fleece-applied blocks. In other words – can we do an ironed layer, and then ONE “top-coat” of our choosing? Yes, absolutely. But I’ve seen a lot of evidence that layering the top coats will yield some advantages. Diminishing advantages, for sure. But every step is a step, even if the differentiations gets smaller. So it comes down to how far you want to chase things.
OK – maybe more information than you were looking for. But there you go!