Epoxy primer has got a wide array of uses. It can be used as a sealer over bare metal and other types of surfaces.
If you are using epoxy primer on your car, you are assured of its ability to seal moisture from coming into contact with the metal and corroding it. Like other products, you need to be careful handling epoxy primer.
For instance, most primers need to be sanded to get a refined and polished finish. Should epoxy primer be sanded? Keep on reading to find out.
Is It Okay to Sand Epoxy Primer?
There are many contradicting statements regarding the sanding of epoxy primers on the internet. Some detailers recommend sanding of epoxy primers, and others are completely against this.
As a car owner interested in using epoxy primer, this information can leave you confused and wondering what you should do.
Epoxy primer doesn’t sand very well. This is because it is not meant to be sanded. If you are confusing primer with epoxy primer, one of the key differences is that the latter doesn’t require sanding.
If you must sand over epoxy primer, we advise you to give it time to dry, apply regular primer, and then sand it to get your desired finish. However, sanding epoxy primer directly will be challenging.
What Will Happen If You Sand Epoxy?
Sanding over epoxy primer doesn’t often lead to adverse outcomes. But this practice is discouraged. Sanding over epoxy primer often affects its adhesive properties, and filler or paint applied over it may not hold well.
Why Should I Sand Over Epoxy Primer?
The only reason you may be tempted to sand over epoxy primer is if there are a lot of imperfections on it. Imperfections are caused by not preparing the surface adequately before spraying the epoxy.
Also, if you don’t give the epoxy enough time to cure, it may have many imperfections. Knowing that epoxy primer isn’t sandable will save you a lot of problems during the paint job. That’s because you will be very keen on preparation and application.
Before we can move on, it’s worth mentioning the duration epoxy primers take to cure. An epoxy primer can cure within one or two hours.
That’s on a day when the weather is dry and sunny. But if it’s humid, you should add one more hour. However, if you have a car oven, it can dry within a few minutes.
It would be best to let the epoxy primer dry before you can do anything over it. There won’t be a need to sand over it when you do this.
Is Epoxy Primer Sandable?
Even if you wanted to sand over epoxy primer, you would have difficulty doing it because it’s super hard. The thing is, epoxy primer isn’t sandable.
It was formulated to be used without needing to be sanded. It won’t be easy if you introduce your techniques and decide to sand it.
If you must sand the epoxy primer, we would recommend wet sanding it since this will be much easier. Dry sanding epoxy will cause the sandpaper to be clogged within a short duration.
Wet sanding, however, minimizes the time taken for sandpaper to be clogged. Also, if you are going to sand epoxy, make sure that it is fully cured.
Sanding it when it’s still damp can affect its ability to seal moisture and adhere to other coatings.
What are the Risks of Sanding Epoxy Primer?
On the epoxy itself, sanding it can weaken its adhesive properties. It can also affect its ability to seal other substances from making contact with bare metal.
To the individual doing the sanding, fine pieces of epoxy primer can be very harmful to your respiratory health. You must wear adequate protective gear such as a mask as you engage in this. This doesn’t only apply to epoxy primers but all types of primers.
What Grit Sandpaper Should Be Used on Epoxy Primer?
We have mentioned earlier that epoxy shouldn’t be sanded. However, if you need to get rid of imperfections, you can engage in some light-wet sanding.
It is advisable to use fine sandpaper so that you don’t interfere with the structure of the epoxy primer. You can use 80-grit sandpaper. It should be fine enough to remove any imperfections on the surface without harming the structure of the epoxy primer.
You may be wondering, what will happen if I use abrasive sandpaper such as 180 or 220 grit? No matter what grit sandpaper you use, be prepared to break a sweat when you decide to sand epoxy primer.
Anyway, with more abrasive sandpaper, you will be able to scuff out most of the epoxy. In the process, you could be damaging its structure.
If you are careful enough, you can get rid of the surface imperfections. But if you happen to scoop off a significant amount of epoxy primer, apply more, and this time around, do it carefully to avoid causing imperfections.
How to Clear Epoxy Primer?
After application, if the epoxy primer looks cloudy, you may be looking for ways to clear it up. The first thing that will come to your mind is sanding.
But as we have already seen, it’s not necessary. Even if it were, epoxy primer is quite tricky, and sanding it would need a lot of elbow grease.
If you want to clear epoxy primer, the best way is to polish it with a microfiber towel. Alternatively, you can spray some acrylic that will add a sparkly appearance. If there are scratches on the surface, you can polish it with some paste.
Does Epoxy Sand Better If It Has Cured?
Epoxy will be much easier to sand if it has already been cured. This should be after a few days or within a week. Freshly cured epoxy is the one that’s harder to sand once it has been cured.
How Can I Avoid Sanding Over Epoxy Primer?
To avoid sanding over epoxy primer, you should avoid making any mistakes during preparation and application. During preparation, the surface needs to be thoroughly cleaned.
The presence of wax or grease on the surface can lead to issues later on that may require sanding. Secondly, as you apply the epoxy primer, make sure that it has been mixed up.
When you shoot the primer without mixing it, the epoxy can dry with nibs on the surface. It’s also advisable to follow the manufacturer’s instructions when spraying the epoxy primer. Different brands will have varying requirements.
Dry vs. Wet Sanding Epoxy Primer
When it comes to sanding a surface, there are usually two main options; dry and wet sanding. Each has its benefits, but we will be focusing more on the sanding of epoxy primer.
As mentioned earlier, the dry sanding epoxy primer will result in the sandpaper clogging up pretty fast. On the other hand, Wet sanding seems like a much better option since the sandpaper doesn’t clog very fast.
First things first, epoxy primer shouldn’t be sanded using either option. You should only sand if you made a mistake during the preparation and application.
Out of these two, wet sanding seems like the best option. But as you sand through the epoxy, you need to be smart enough to avoid contaminating the metal beneath with moisture.
As you wet sand, some water can creep into the structures and reach the metal. If you persist, the moisture will reach the metal, and if sealed, that will be a recipe for corrosion.
The bottom line is that even though wet sanding is more effective, it poses a threat to the metal beneath the filler. It’s up to you to evaluate whether it’s worth risking corroding your car parts.
Are All Epoxies Sandable?
Knowing that there are tons of different manufacturers in the market these days, you can’t be very sure about which epoxies are sandable or not. Research can help you find an answer. Anyway, certain epoxies can be sanded. But most of them can’t.
Before sanding epoxy, you must figure out which category it falls under. Knowing this can help you avoid wasting time engaging in unnecessary sanding.
You should also check the label and see whether the epoxy manufacturer recommends sanding the epoxy. Certain brands allow their epoxies to be sanded after it cures.
Can You Apply More Epoxy After Sanding?
If you realize that you have over-sanded the epoxy, you can fix this mess by applying more epoxy. Despite this being a DIY solution that may sometimes work, it can get to the metal and wreak havoc if you trap any moisture under the epoxy.
Will Sanded Epoxy Show Scratches?
Sanded epoxy will have scratches on it. The sandpaper will cause scratch marks, which can’t be prevented.
If you want to deal with the scratch marks on sanded epoxy, the best solution would be to recoat it with a fresh layer. That would conceal the scratches and ensure proper adhesion of other topcoats to the epoxy primer.