ProXL
ProXL
One of the chief bugbears for automotive refinishers and car body repair shops is the length of time that primers, paints and lacquers need to dry before the next coat can be applied. These delays cause bottlenecks in spray booths and hamper productivity, but recoating too early can trigger more serious problems.
One solution to this problem is to use UV-curing primer. Let’s take a closer look.
Like any surface coating that is applied wet, automotive primers are a combination of liquids and solids. The liquid elements are there to hold the solids in a suspension until the primer has been applied, and then the drying or curing process can begin.
This process requires the evaporation of the liquid element to turn the primer into a layer that is comprised solely of solids. With a conventional 2K primer, air drying can take 60 minutes and even with a heated booth may require a 30-minute bake cycle. Single-component (1K) primers dry faster, but they still take at least 10 minutes to dry and are more prone to shrinkage.
If primer is sanded before it is fully dry, it won’t sand cleanly and is more likely to clog fine sandpaper.
If evaporation isn’t complete before the next coat is applied, the liquids may become trapped underneath the new coating. The topcoat may acquire a dull or hazy finish, or even form blisters, and when this happens the paint has to be stripped back, the primer reapplied (if it has been damaged) and left to fully dry.
UV primers are formulated to remain in a fully liquid state unless and until they are exposed to ultraviolet radiation, but when this happens it happens very quickly. The time required for the liquids to evaporate will depend on the strength of the UV light source, but curing will be complete after about 60 seconds, after which it is ready for sanding or painting.
While UV primers require a UV light source to cure them, this is a worthwhile investment that will soon be repaid in improved productivity and results.
Added to that, UV primers bring many more benefits to the Paintshop.
As we have already mentioned, UV primer requires ultraviolet radiation to trigger the curing process. It will therefore be more stable in the tin, where it won’t dry out or need to be strained to remove partly-cured lumps before use.
Providing a black or opaque spray cup is used while applying the primer, no UV light will reach the primer until it is sprayed and the contents of the cup can be poured back into the tin, minimising waste.
As UV primer is a single component (1K) primer it doesn’t need to be mixed with a hardener before use and it rarely requires reducing. This means that priming can begin with minimal preparation beyond the usual surface preparation and masking. Excellent adhesion directly onto almost any surface also means that etch primer is for the most part not required before applying UV primer.
UV primer has a higher solids content than other primers – 99%, compared with 60% for 2K high build primers and a mere 20% for HB aerosol primers. This means it typically has coverage 3-4 times greater and therefore less primer is required.
It also offers higher build characteristics than those of other 1K primers and is equal to that of a 2K primer.
This is another advantage of the higher solids content of UV primer. As solids constitute a greater percentage of the ‘wet’ primer, there is less evaporation and therefore less shrinkage. The rapid, 100% cure also reduces this risk and means that if any shrinkage does occur this will become obvious within the 60-second cure time and can be rectified immediately.
As a 1K primer, UV primer contains none of the isocyanates found in the hardeners of 2K primers. This makes them better for human health and the environment.
At a time when we are all focussing on reducing our energy bills, UV primer offers a more energy-efficient alternative to running a heated booth, where a 30-minute bake cycle at 60 degrees C can cost up to £50. UV light sources do use some electricity, but the power is directed at and restricted to the primed surface, so for a repair that’s approximately the size of a sheet of A4 paper the energy cost is approximately £0.05. Even an aerosol HB primer would use about five times that amount of electricity for infrared curing.
This UV-curing technology is now even more convenient with the launch of ProXL UV Primer Aerosol. Known for their professional-grade aerosol refinishing products, ProXL has introduced this product into the range to assist faster, more cost-efficient automotive refinishing.
Recommended for use with a UV light source that delivers a UV wavelength of 395 nm at a minimum of 50W, this grey, epoxy resin-based primer offers a super-fast curing time of 60 seconds, meaning that sanding and topcoat application can continue almost immediately.
High build characteristics and excellent adhesion to many substrates including bare steel, aluminium, painted surfaces and most plastics are other features of this technologically-advanced primer.
Is ProXL UV Primer the only UV-curable aerosol primer available on the market? Not at all, but the ProXL product has been proven to offer faster cure times and better film build than its rivals, making it a truly professional product for true professionals.
If you would like further information, advice or details on stockists of ProXL UV Primer Aerosol and our other automotive refinishing products, contact us on 01634 823900 or via our online contact form.
