If you’ve been involved in a job involving the powder coating of steel, you’ll more than likely know that for something that seems so simple on the surface, there sure is an impressive amount of pitfalls and rules to adhere to. Ignore them and you just might be looking at reworking components. And if they happen to be already installed on a building or incorporated into a finished piece of equipment, costs can quickly skyrocket. But not if you know what to look out for.
So to help your next steel and powder job be right first time, we’ve complied a short list of common issues that the process can encounter. And with over three decades experience in the field, we’re pretty sure we’ve got a good grip on what can go right and wrong.
This is usually caused by poor pretreatment or a failure to remove the pretreatment chemicals after application. As you can probably tell, pretreatment is a double-edged sword; you need it to get good adhesion but it can also cause bad adhesion, too. The requirmenet here is the need to monitor your pretreatment process very closely. It takes no time at all for hundreds of components to be passed through a faulty pret-treatment stage and powder coated. This monitoring process, something that Impreglon Australia has been doing for many years, is something you’ll seldom find with less experienced powder coaters. Of course, you’ll need to start with good adhesion promoter, like a blast or a chemical etch. As always, make sure you aren’t building your house on poor foundations.
This is where either your chosen pretreatment or blasting hasn’t done its job. It’s often caused by silicon contamination and/or poor pretreatment. As you’ve probably guessed, it looks like small holes caused by contamination or ‘un-degassed’ zinc materials. The cure is simple – only go with experts like Impreglon who know what makes a good pretreatment, how to de-gas zinc materials and what will lead to disaster.
This one’s pretty self explanatory. If you’re doing large batches of work that need to be installed side-by-side or to match a similar colour somewhere down the line, it’s crucial to get the colour right. The most common cause of mismatched powder issues is over baking and under baking. Over baked powder can result in discolouration and under baked powder can experience issues with inconsistent gloss levels. Bad ovens, hotspots and a lack of temp control during the curing process are all common causes of colour mismatching. Impreglon checks its ovens weekly and uses an oven data logger constantly to ensure world-class temperature accuracy and perfectly even oven heating.
No matter how good your powder coating job may be, if the components are badly handled post processing, they will always look scrappy and their ‘full envelope’ protecting coating will be seriously compromised. The answer here is professional packing immediately after the components have been coated. Spray paint touch-up cans are all good and well, but touch-up paint offers nowhere near the same protection as powder, and it will quickly go chalky under the tough Australian sun. As always, Impreglon Australia’s process packers are amongst the best in the business.
Experience tells us that once a piece of steel has been blasted, it will need to be powder coated within 12 hours to prevent flash rusting. Ignore this and you’ll get flash rusting that can cause ‘mapping’ and delamination later on. If you trap rust under a powder coated finish on steel components, it will then spread even though the surface is sealed by the powder. Added to this, a simple crosshatch test will more than likely show poor adhesion. The answer is simple – reduce the timespan between the two process to a minimum. It’s something that Impreglon, with its ‘all under one roof’ operation has beaten, due to the fact that components don’t have to be transported between steps.
So if you’d like to discuss more on powder coating steel or any of our other services, why not get in touch?