Quick and easy finishing with the Earlex HV5500 Spray Station
For this first blog we are going to talk about finishing a little bit. I’m actually completing an entertainment center for my living room. It’s quite a big piece made out of 4 modules. Finishing such a piece, or rather pieces here, can quickly become puzzling and look endless. The finish applied by hand will be mostly dried before application is over on other faces of the same module. It was how things were for me before. That was 3 years ago when I discovered a little gem introduced to me by a forum member of the website La Mortaise (www.lamortaise.com).
Allow me to introduce my best friend for finishing: the Earlex HV5500 spray station. (http://www.elitetools.ca/en/product/earlex-hv5500-spray-station/).
With this little gem I can coat a whole module on all of its faces within 15 minutes. Before that, that called for a job of at least an hour per module.
Speed is nice but how does this little wonder works exactly? The system is made of 2 main components: the turbine and the spray gun. Both of them are linked together by a hose that takes air from the turbine to the gun. It looks quite like what car body painters use but in a much compact and simpler fashion. The system is what we call a HVLP. This acronym stands for “High Volume Low Pressure”. The turbine produces a large volume of air which is then pushed in the hose at a low pressure, around 10 pounds per square inch. The biggest advantage of this low pressure is the very low fume effect while spraying our workpiece. In fact there is so less fog effect that it doesn’t require a full-fledged spray booth with a dedicated ventilation system and so on as long as you’re using the right finishing products.
For my part I work in my shop down the basement using only water based products so there is no risk for my health, environment or explosion. I only take precaution to hang tarps from the ceiling joists in such way that they form an enclosure around the workpiece to finish. Doing so will result in having any fume ending on the tarps instead of my tools. But let’s come back to how the system works… The turbine shoots air through the hose on to the spray gun. Once at the gun the air stream follows some small pipes integrated in the gun so it creates a pressure inside the cup hanging below the gun that propels the finish to the tip upfront the gun and from there to the workpiece. That’s the theory behind the system. But what are the advantages to use such system?
There are numerous advantages and I will list a few of those here:
- As said before, speed is undisputed key feature. You can cover a large surface in matter of a few minutes.
- No brush stroke marks. Don’t try to lookout for brush marks on finish or stain as you’ll have a hard time finding since there is none!
- Reduced drying time between finish coats. As for an example: when I applied varnish on my workbench (3 coats), manufacturer recommended to wait for 3 hours between coats so varnish would be dry when touching. Well, with the HVLP application, varnish was dry on touch after less than an hour. Finish coats can go on at a much faster pace that will reduce total time needed to finish your project.
- Access to a wider range of products. Products such as some lacquers are specifically made to be sprayed on and cannot be applied with a brush or rag.
But every medal has its downside. There are some minor inconveniences:
- The cost. You must buy the system at first along with some accessories such as spray tips, cleaning kit, finishing products that you wouldn’t use otherwise and so on.
- The cleaning of the spray gun once finish applied. It’s not much longer than cleaning a brush but it does require some careful attention due to the number of parts involved.
- The small mist produced during spraying. It will vary depending on ventilation of work area, product being used, air flow setting on the gun, etc.
Where working with the HVLP requires some acclimation is how you work. You must learn how to work with the tool itself (the spray gun), distance between the gun and the workpiece, way of moving your arm and the gun in relation to the workpiece, how to adjust air flow, choosing the right spray tip and product viscosity. There are some nice books on spray finishing. My reference book is the one from Jeff Jewitt titled “Spray finishing made simple”. It covers most of the aspects mentioned above in a well-documented and very easy to understand approach.
I’ll try to summarize briefly on those points. While spraying you must keep the gun 6 to 12 inches away from the surface being sprayed. Too far and the finish will hit the surface mostly dried out. Too close and the coating thickness won’t be uniform and will take longer time to dry. The gun must move parallel to work surface. If your arm moves doing an arc of a circle, distance between gun and workpiece will vary and may lead to some of the problems just mentioned before. Air flow also directly affects quantity of finish being sprayed on. The bigger the air flow, the wider the pray pattern at the spray tip will be allowing to cover a wider surface at once. Note that some products will require a larger or smaller air flow in order to get perfect results. As with anything you have to make some tests on scrap pieces before hitting the trigger for real. Depending on the product being used, spray tip and viscosity will play a major role. A high viscosity product such as latex paint is thicker and requires a larger spray tip otherwise you’ll have to dilute the product according to its manufacturer’s recommendations. A lower viscosity product such as shellac will require a smaller tip or the quantity sprayed on will be far too much.
The Earlex spray station HV5500 comes a 2.0mm spray tip and needle kit. You can also get separately 1.5mm and 1.0mm spray tip and needle kits. Also included is an easy-to-use viscosity measuring cup. Simply dip the cup in the finish, take it up in the air and measure time it takes for the cup to stop dripping in a continuous flow. The longer the time, the thicker the product. You’ll then have to use a larger tip or dilute product. If time is too short use a smaller tip.
As with any tool safety precautions are a must to protect our health. Personnaly I use earmuffs, safety goggles and cartridge mask. Here is why:
- Goggles: the small mist may irritate eyes or product may turn to a fine dust and gun tip. Eye protection is essential. If you use solvent based products because you work outside, chemical burning risk is something you cannot ignore.
- Earmuffs: the turbine is as loud as an average shop vacuum. Because you must have the turbine close at hand it can become annoying after some time. Earmuffs help reduce noise exposure and those help to stay focus.
- Cartridge mask: Although I only use non-toxic water based products there is still the fine mist or fine dust that I don’t want into my lungs while working. It’s just an additional safety measure.
As I said before, this is just an introduction to spray finishing using HVLP system. It’s a very large subject for which some private furniture crafting school offer specific courses or training. Don’t be afraid, it sounds intimidating but it is not. With a little practice and patience, you’ll get great results. I learned it all by myself and I’m aware of many people who did the same. You just have to try it and jump in to get hooked on! Until next time, I wish you luck with your finishing projects!