| There are two primary ways for steel fabricators | | | | disasters from this level of surface preparation when |
| and industrial facilities to perform surface preparation | | | | high performance coatings have been applied. The |
| before painting. These two most common ways are | | | | most specific problem I've seen is when an epoxy |
| SP2/SP3 (hand & power tool clean) and SP6 | | | | with a good adhesion rating has literally pulled off the |
| (Commercial Blast or Sand Blast). I will go through | | | | existing mil scale on the steel like it was a magnet. |
| each one in regards to their relation to the coating | | | | The trick here is that even though some data sheets |
| that will be applied. | | | | on high performance coatings say you can perform a |
| Hand & power tool cleaning (SP2/SP3) is usually | | | | hand & power tool clean surface preparation, it |
| fine for single component products. These products | | | | will also state the existing mil scale on the steel |
| would include metal shop primers, universal metal | | | | needs to be removed. How long does this take with |
| primers, alkyd/oil topcoats, acrylic topcoats, and | | | | a hand & power tool clean surface preparation |
| silicone-alkyds. However, the performance of these | | | | (if it is even possible) and are your employees going |
| coatings over time is always dependent on the level | | | | to work that hard to get it done? |
| of surface preparation. Even though this method of | | | | Another item you need to keep in mind is the level |
| surface preparation might be sufficient, the coatings | | | | of profile that is exists after your commercial/sand |
| that are applied will almost always perform better if a | | | | blast (SP6) has been completed. Having a profile on |
| commercial/sand blast (SP6) was performed. | | | | the surface of the steel is important because it gives |
| For epoxies, urethanes, zincs, or other | | | | the coating a tooth to grab onto. However, too |
| multi-component products, a commercial/sand blast | | | | much of a surface profile can be a problem |
| (SP6) should be performed. Yes, I know what you | | | | depending on your paint system because there might |
| are saying already. I lot of data sheets from different | | | | not be enough coating being applied to cover up the |
| paint suppliers say that SP2/SP3 is the minimum | | | | depth of the profile. For each project, make sure you |
| surface preparation for many of these products. I | | | | contact your paint supplier to find out exactly how |
| can only tell you from my experience, I have seen | | | | much profile you need. |