If corrosion resistance and long-term foundation matter most, epoxy primer is usually one of the strongest choices. If you mainly need a thin adhesion-promoting coat on properly prepared bare metal, self-etching primer is a common choice.

A high-build primer surfacer is usually the right choice. If the panel needs especially heavy filling and leveling, a polyester primer surfacer may be the better option.

A non-sanding primer sealer is often chosen when the surface is already properly repaired and sanded and you mainly want a fast, uniform coat before topcoat.

Epoxy primer is often preferred as a first major corrosion-resistant foundation over large areas of bare or blasted metal. A high-build surfacer may then be used over that when blocking and straightening are needed.

A high-build urethane primer surfacer is often a strong choice when you need to bridge repair areas, fill sanding marks, and create a uniform surface for sanding and topcoat prep.

Self-etching primer is a thin adhesion-promoting primer designed mainly for properly prepared bare metal and similar substrates.

You use self-etching primer when your main goal is to promote adhesion on bare metal, steel, aluminum, and similar properly prepared surfaces. It is especially useful when you want a simple, thin first coat that bites into the substrate well.

Its main strength is substrate bite and initial adhesion on metal.

It is not mainly a high-build product. It is not the primer you choose when your main need is filling scratches, blocking waves, or building a thick sandable film.

It can be attractive for that reason. The Custom Shop self-etch line is positioned as ready to spray, with good coverage, smooth flow, and no thinning required.

Not always. This is one of the most important cautions in primer selection. Many topcoat systems explicitly say do not apply over self-etching primer. In practical terms, many workflows use self-etch as an early foundation coat and then follow it with a compatible surfacer or sealer before color.

It is a good choice when you have properly prepared bare metal and want a thin adhesion-promoting coat rather than a corrosion-focused sealer or a heavy-build sanding primer.

It is usually the wrong first answer when the job needs heavy filling, block sanding, major straightening, or a more protective sealed foundation across a large restoration panel.

Epoxy primer is a durable, anti-corrosive foundation primer commonly used over properly prepared bare metal and other suitable substrates.

You use epoxy primer when you want strong adhesion, corrosion resistance, chemical resistance, and a stable sealed foundation for the rest of the paint system.

Epoxy primer is best known for corrosion protection and for serving as a durable foundation coat over bare metal and mixed restoration surfaces.

It is often the best choice on restoration work, bare metal panels, sandblasted sections, and jobs where long-term sealing and anti-corrosion performance matter more than fast filling.

Because it gives them a solid sealed base before surfacer work begins. Epoxy primers are often recommended over large areas of sandblasted metal, with high-build primer then used over the epoxy where needed.

Yes. That is one of the major reasons people choose it. Epoxy primer may also be used as an excellent sealer over substrates and old finishes.

It is not usually chosen as the fastest route for heavy filling and block sanding. While some epoxy systems build decently, that is usually not the main reason you choose them.

Usually no. If your main need is filling and easy sanding, a high-build surfacer or polyester primer may be more efficient.

It is a direct-to-metal primer surfacer designed to combine strong adhesion with build, filling, sanding, and surfacing capability.

You use it when you want more than simple adhesion. It is a strong option when you need a primer that can go direct to metal on approved substrates while also building enough film to fill scratches and refine repair areas.

Its main strengths are filling, build, easy sanding, direct-to-metal adhesion, and improved productivity.

They would usually choose it when they want more fill, faster sanding, and a more surfacer-like workflow. Epoxy is usually the stronger foundation and corrosion choice, while DTM high-build is often chosen when the job needs both adhesion and sanding/build efficiency.

Because DTM high-build can do far more surfacing work. Self-etch is thin and adhesion-focused, while DTM high-build is chosen when you need bodywork refinement, build, and sandability.

Yes. The DTM high-build technical sheet specifically says it may be used as a sealer when reduced appropriately.

It is especially useful on repair work where you need to prime bare spots, build over repairs, block the panel, and move toward topcoat prep without jumping between too many product types.

Yes. The DTM technical sheet specifically says not to use it over galvanized steel, and also notes that certain plastics like polyethylene and polypropylene are not appropriate.

It is a catalyzed primer surfacer designed to provide build, filling, sanding ease, and a smoother, more uniform repair surface before topcoat or sealer.

You use it when the panel needs to be straightened visually and mechanically after bodywork. It is a strong choice for filling medium to deeper sanding marks and providing a surface that blocks and sands easily.

Filling, build, repair refinement, and easy sanding.

Because the main reason to choose it is surfacing performance, not primarily corrosion sealing. If the job is already on a good foundation and now needs leveling, build, and sanding, high-build urethane is often the better answer.

Because self-etch is not a heavy-build product. A 2K high-build urethane primer is used when you actually need to shape and smooth the surface before paint.

Think high-build primer when the bodywork is basically complete but the surface still needs refinement, filling, sanding, and blocking before paint.

Polyester primer surfacer is a high-solids, maximum-fill primer surfacer designed for heavy-build applications and aggressive surface leveling.

You use polyester primer when you need maximum fill. It is the primer to think about when the panel is rougher, wavier, or more heavily repaired and you want a thicker surfacing material that helps straighten the panel.

Maximum build, excellent filling, reduced shrinkage, and creating a surface that can be blocked smooth.

Because polyester primer is usually the stronger choice when the surface needs more serious filling and leveling than a standard high-build urethane primer can efficiently provide.

Polyester primer is said to work over fiberglass, metal, plastic, and wood when properly prepared.

It is not mainly the quick final sealer before color. It is a heavy surfacing and blocking product, not a spray this and go straight to color shortcut.

When the panel still needs real leveling work and the priority is maximum fill rather than just mild scratch filling.

Acrylic lacquer primer surfacer is a high-build sanding primer commonly associated with older restoration-style workflows and users who want a primer that fills and sands easily.

You would use it when your main priority is a primer that builds quickly, fills well, and sands easily, especially in restoration-style workflows or where a lacquer-compatible system is being used.

Because the reason to choose lacquer primer surfacer is usually sandability and filling workflow, not corrosion-focused sealing.

Usually because they prefer that specific restoration-style workflow, or they want a product known for straightforward sanding and traditional primer-surfacer behavior.

It is a reasonable choice when the system and job support it, especially in restoration contexts where build-and-sand behavior matters more than using epoxy or 2K urethane as the main foundation.

It is a one-component sealer designed to provide a smooth, uniform surface before topcoat without requiring a separate sanding step after application in normal use.

You use it when the panel is already properly repaired and sanded and you want a fast, clean, uniform final coat before color.

Speed, simplicity, smooth flow, color holdout, and final uniformity before topcoat.

Because surfacers are for building and sanding. A non-sanding sealer is for finishing the prep stage once the surface is already where it needs to be.

It is especially useful before topcoat when you want better color holdout, one uniform substrate, and a faster, simpler final prep step.

No. That is not its job. If the panel still has sanding marks or waves, use a surfacer first.

Yes. In fact, many of the best workflows use more than one primer type because each one solves a different problem.

A common workflow is: Epoxy or self-etch on bare metal, high-build surfacer over repairs, and final sealer before topcoat.

Not always, but it is a common and often preferred approach on bare-metal or restoration work because it combines corrosion protection with later surfacing ability.

Yes. Technical guidance explicitly says DTM high-build is great to use over epoxy primers in restoration applications.

No. This is important enough to repeat. Some topcoat systems explicitly say not to apply over self-etching primer. Always check the topcoat technical sheet and system compatibility.

Use a sealer when you want one uniform surface color, better holdout, and a cleaner, more predictable topcoat foundation.

Epoxy primer is often the strongest answer when the job involves a lot of bare or blasted metal and long-term corrosion resistance matters.

A high-build urethane primer surfacer or polyester primer surfacer is usually the better choice, depending on how much filling and leveling is still needed.

A non-sanding primer sealer is often the best answer.

Self-etching primer is one of the most common answers for that job.

High-build surfacers and lacquer-style primer surfacers are typically chosen in part because they sand well. Product language for the high-build primers repeatedly emphasizes easy sanding.

High-build urethane surfacers and polyester primer surfacers are the main block it smooth categories.

Self-etching primer and non-sanding sealer are not mainly build products.

A non-sanding sealer is normally chosen so you can go straight to topcoat in the proper window rather than sanding it as a build coat.

Use it for metal adhesion, not for heavy filling.

Use it for corrosion-resistant foundation and sealing, especially on bare metal and restoration work.

Use it when you need to fill, sand, and smooth repairs.

Use it when you need maximum fill and panel straightening help.

Use it as a final uniform coat before color, not as a filler.

Use it when you want a traditional build-and-sand primer surfacer, especially in certain restoration workflows.