Filler Primer

There’s always that moment with 3D prints, especially FDM, where you realize the print is only halfway done when it comes off the bed. The layer lines are still there, the surface still carries that stepped memory of how it was made. Used on prints, it’s less about color and more about erasing evidence. The filler part actually does something. It lays down a thicker coat than standard primer, settling into those micro gaps between layers. Not perfectly, not in one pass, but enough that after a couple coats and a light sanding, the surface begins to shift from “printed object” to something closer to finished. It’s incremental, but noticeable. The spray system is surprisingly useful. The adjustable patterns aren’t just a gimmick, you can go wider for coverage or tighter for detail, especially when you’re working on irregular shapes or smaller parts. And being able to spray at any angle is one of those things you don’t think about until you’re trying to hit an awkward underside and realize you’re not fighting the can. Dry time is fast enough to keep momentum. You’re not waiting hours between coats, which makes the whole sanding/priming cycle less tedious, because this process is already repetitive by nature. Deep layer lines or rough prints will still need sanding. But yeah, keep in mind this doesn’t replace prep, but it makes the finish stage more forgiving. And like most rattle cans, control is everything. Too close, too heavy, and you’ll get buildup or runs that set you back instead of forward and the last thing you know, you’re days behind because now you have to print a new slice. But at least this bridges the gap between raw print and something that has a better finish. It doesn’t transform the object on its own, but it gives you a surface you can work with. Disclosure: This review is part of Amazon’s Vine Program, which provides products at a reduced cost in exchange for honest reviews (taxed as income). I personally test all products, and my opinions are my own and uninfluenced. I hope this review helps with your purchase decision.

I've recent gotten into painting 3D printed parts, and the consensus online was to use rust-oleum automotive filler and primer. I've used Rust-Oleum automotive filler and primer to prime and smooth the prints. I gave it a go once before with a standard spray nozzle, and it worked well, but the coverage was too broad. When I saw this new adjustable nozzle was available on new bottles, I was excited to try it. The product comes in a standard well labeled spray can. Rather than a traditional cap, you have the new nozzle. It comes locked, and you rotate it to different settings (high output, standard output, low output, vertical fan, horizontal fan). Instructions tell you to set the nozzle, shake the can, spray in a back and forth motion over a target at about 12" away, and apply 2 (or more) coats a few minutes apart. It dries to the touch in about 10 minutes (ready to wet sand), and in a few hours (depending on the coat), you can dry sand. Overall, I was pleasantly surprised to find the nozzles really help in controlling coverage, and the product does a great job covering layer lines and the remains of support scars. It bonds well to PLA and PETG, and the color makes it easy to see imperfections that need to be sanded. At $15, it's about twice the price of the standard nozzle at my local hardware store, but the improvement in control results in better performance and minimized waste, and I'll be buying it again for smaller objects.

I have used Rust-Oleum products for decades, and with the old types of spray cans, the only way to alter the spray pattern was to twist the nozzle, and it would change it from a vertical and horizontal spray pattern, but that was not consistent and didn't provide the best results all the time. I saw this new can with the adjustable spray patterns and had to try it for a new auto project I was working on. When testing it out for the first time, I was really impressed with the consistency it provided with each spray pattern. The application was perfectly consistent, and there was no dripping or leakage at all. This primer provides great coverage with its coats, and the appearance of each coat looked great with no bare metal showing through the primer. After allowing the primer to dry, it was easily sandable and had good filling properties and hid the sanding marks from sanding between coats. I am super pleased with the ease of use of this spray primer, the quality of the results that it gives, and it is an exceptional value. There may be cheaper products out there, but this Rust-Oleum spray primer requires fewer coats and provides much better results than other similar products, which actually saves you money by needing fewer cans to do the same amount of work. Plus, you can always trust Rust-Oleum to provide consistent, high quality end results.

I'm painting the head of an expensive vintage brass floor lamp so I don't have room to play around with less established brands. Rust-Oleum Automotive Filler Primer went on nicely thick over a couple of coats of Rust-Oleum etching primer. This was no quick spray. There's a ten minute wait between coats and I went with twice the recommended two light coats since there will be sanding. There's a premium cost for the fancy spray top that allows for adjusting the spray pattern plus spraying upside down, both of which came in handy because I was painting inside a box with a clear plastic sheet front and no back, mounted in my apartment window. It kept the fumes to almost nothing but would have been too awkward for a classic spray can. It's unlikely that I would have bought the cans with the fancy top but now that I have used them I'm a convert and will gladly pay a little more for them when outfitting some jobs.

It's amazing stuff. This product is the first of its kind that I've used and I can say it's a bit miraculous. I used this to help with my mom's truck restoration project. We were indeed able to fill many small holes and repair many surfaces with the help of this spray. The truck is still not yet built - but, the parts we've worked on look great, feel stronger than before, and have no leaks! The value is also fantastic at the time I'm getting this can. It will definitely earn its keep! We haven't used the whole can yet and we've been able to treat maybe 15 square feet, some areas more heavily than others. We've already bought more and can recommend this for auto restoration!

This filler is great, it builds up pretty nicely and sands easily. The only thing is that the spray patterns don't make too much of a difference besides the 2 different fans. Since this primer and their normal spray can primer is about the same price, i won't complain for the thoughtful attempt. Good product, 10/10!

I've used several cans of this and other versions of the 5 in 1 primer and paints and am very happy with the results. The paint itself is excellent as RustOleum normally is for me. Adheres to just about everything, covers well, dries quick and looks good. The big change here is the nozzle and the versatile spray patterns. I really like the low out put and vertical fan options the most. The low output is great for doing a light dusting first coat. The vertical fan covers nice and evenly and is great for covering larger areas or panels on a car etc. I did have a couple tips that didn't spray great out of about 10 cans. Fortunately there are more tips on the can so it wasn't a deal killer and I still like the spray pattern options. Not sure I'll pay the extra for fancy nozzle for little stuff like paining parts, but I'll use it when I need to paint bigger stuff and want a great finish.

I'm a big fan of these 5 in 1 nozzles on the dial since they make the application easier. Basically any pattern you want to spray you can, or if you clog up you just switch to another. The choice of two fan directions or three output volumes will cover any situation or angle you need to spray at. The fill primer smooths and fills in smaller gaps and scratches in your material to help you get to a final finish faster. The finish is flat and it dried pretty quick, though that will depend on how much you lay down at once. It sanded up well and seems like a durable layer. Easy to use, works well, and durable means good value for money.