Filler Primer

Filler primer is one of the easiest finishing products to understand. It is a primer with more solids than ordinary paint, designed to fill small scratches, sanding marks, and minor surface texture.

Common Uses

Filler primer is useful for:

• Visual prototypes
• Display models
• Light layer-line filling
• Cosmetic parts
• Paint preparation
• Small models
• Final surfacing after heavier filler work

Advantages

Filler primer is popular because it is:

• Easy to apply
• Widely available
• Relatively inexpensive
• Sandable
• Fast compared with heavier coatings
• Good for cosmetic improvement
• Useful between sanding steps
• Compatible with many paint systems

For many PLA, PETG, ABS, ASA, or PVB parts, filler primer can make a printed model look much better with modest effort.

Disadvantages

Filler primer has limits:

• It does not fill deep layer lines quickly
• Multiple coats may be required
• It is not a structural coating
• It may chip or scratch
• Solvents may affect some plastics
• It can obscure fine detail if overapplied
• It does not seal as well as epoxy
• Durability is limited without a proper topcoat

Filler primer is best for light cosmetic surfacing, not heavy industrial protection.

JaegerTech View

Filler primer is a practical finishing step for prototypes and display parts. For foundry patterns, molds, or industrial tools, it is usually part of a larger coating system rather than the entire solution.

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High-Build Primer and Spray Putty

High-build primer and spray putty sit between ordinary filler primer and heavier body filler. These products build more material on the surface and can fill more visible layer lines and sanding marks.

Common Uses

High-build products are useful for:

• Large visual models
• Pattern surfacing
• Prototype finishing
• Print section cleanup
• Layer-line reduction
• Cosmetic parts before paint
• Automotive-style finishing workflows

Advantages

Benefits include:

• Higher build than normal primer
• Good sandability
• Faster surfacing of rough prints
• Useful for large parts
• Helps reduce repeated primer cycles
• Good intermediate step before paint

Disadvantages

Limitations include:

• Can obscure detail
• Can crack if applied too thick
• Solvent sensitivity
• Requires sanding
• Not a structural coating
• May need topcoat
• May not bond well to poorly prepared surfaces

JaegerTech View

High-build primer and spray putty are useful for making printed parts look better faster. They are especially helpful on large FDM parts where normal primer would take too many coats.

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Body Filler and Glazing Putty

Body filler and glazing putty are used to fill larger defects, seams, gaps, low spots, and layer-line texture that primer alone cannot handle.

Common Uses

These materials are useful for:

• Bonded section seams
• Large print layer lines
• Gaps and low spots
• Pattern repairs
• Cosmetic prototypes
• Mold master finishing
• Surface shaping
• Large-format print cleanup

Advantages

Body filler and glazing putty offer:

• Excellent filling ability
• Fast shaping
• Good sandability
• Familiar automotive workflow
• Useful for large parts
• Good seam correction
• Ability to reshape surfaces

Glazing putty is especially useful for small pinholes, scratches, and final correction before primer.

Disadvantages

Drawbacks include:

• Labor-intensive sanding
• Not structural by itself
• Can crack if applied too thick
• May shrink
• Can detach if surface prep is poor
• Strong odor and PPE requirements
• Can add weight
• Can hide dimensional details

JaegerTech View

For large-format prints, body filler and glazing putty are often unavoidable if the customer needs a smooth cosmetic or pattern-grade surface. They are powerful finishing tools, but they require skilled sanding and shaping.