Overview
Built for the job.
High-Build Primer Surfacer is an elastomeric acrylic coating for priming automotive metal, aluminum, urethane, and plastics.
SEM 42013 High‑Build Primer Surfacer is a 20 oz gray coating designed for high‑build sanding and filling on a variety of automotive substrates. It provides a smooth, uniform base for subsequent basecoat and clearcoat layers, making it ideal for panel repair and full‑body refinishing.
Key technical features include a rapid sandable time of 15 minutes and a work window of 60 minutes, allowing efficient build‑up before sanding. The primer delivers approximately 11 sq‑ft of coverage at 2 mil dry film thickness (DFT) and reaches full cure in 48 hours. It is compatible with aluminum, bare metal, e‑coat, fiberglass, OEM plastics, SMC, and steel, ensuring broad applicability across body shop projects.
Safety handling requires appropriate personal protective equipment: eye protection, chemical‑resistant gloves, protective clothing, and a respirator in well‑ventilated areas. The formulation is classified with acute toxicity, skin corrosion, and eye damage hazards, and must be used in accordance with the listed H‑statements (H222, H280, H315, H319, H336, H350, H361, H371).
Why Pros Choose SEM SEM
- Provides superior adhesion
- Excellent filling properties
- Works on multiple substrates, including metal and plastic
- Easy to sand
- Topcoat with most refinish material
How to Use
For use on steel, aluminum, plastic, SMC and fiberglass
- Clean and degrease the substrate. Ensure the surface is free of oil, rust, and loose material before applying primer.
- Apply the primer surfacer at 2 mil dry film thickness (DFT) using a spray gun, roller, or brush. Work within the 60‑minute work time.
- Allow the coating to become sandable after approximately 15 minutes. Lightly sand the surface to achieve the desired smoothness.
- Re‑coat if additional coverage is required, maintaining the 2 mil DFT per coat. Observe the 1‑hour dry time before handling.
- After the final coat, allow the primer to cure for 48 hours before applying subsequent topcoats or performing finish work.
Compatibility
Compatible substrates: Aluminum, Plastic.
Compatible paint systems: Urethane, Acrylic.
Specifications
| Part No. | 42013 |
|---|---|
| Product Line | SEM |
| MFR Model | 42013 |
| Standard/Approvals | California PROP65 Warning: Cancer and Reproductive Harm | GHS02 | GHS04 | GHS07,GHS08 | OSHA HCS Hazard |
| Application | For use on steel, aluminum, plastic, SMC and fiberglass |
| Manufacturer | SEM |
| UPC | 646786420139 |
| Brand | SEM® |
| Maximum Sale Quantity | 12 |
| Maximum Sale Day | 7 |
| Color | Gray |
| Container Size (oz) | 20 |
| Curing Time | 1 hr Dry |
| Coverage (sq-ft) | 11 |
- Cure Time
- 48 hr
- Sandable Time
- 15 min
- Work Time
- 60 min
- VOC
- Zero
- Coverage
- 11 sq‑ft at 2 mil DFT
About SEM
SEM Products specializes in paint adhesion systems, flexible coatings, and plastic repair — the go-to choice for interior and trim refinishing.
Frequently Asked Questions
What substrates are compatible with SEM 42013 High‑Build Primer Surfacer?
It can be applied to aluminum, bare metal, e‑coat, fiberglass, OEM plastics, primer, SMC, and steel surfaces.
How long does the primer need to cure before final coating?
Full cure is achieved in 48 hours at ambient conditions.
What personal protective equipment is required when using this product?
Wear eye protection, chemical‑resistant gloves, protective clothing, and a respirator as indicated on the SDS.
Can the primer be sanded and overcoated?
Yes. It becomes sandable after 15 minutes and can be overcoated after the 1‑hour work window, provided the full 48‑hour cure is completed before final topcoat.
What is the coverage rate for the 20 oz can?
Approximately 11 sq ft at a 2 mil dry film thickness.
Documents & Safety
- Safety Data Sheet (SDS)
- sem_42003_catalog.pdf
- dualmix_39337_service_manual.pdf
- 42013%20HIgh%20Build%20Primer%20GrayUSA.pdf
Danger. Wear safety glasses or goggles, chemical‑resistant gloves, protective clothing, and a suitable respirator when handling. This primer is highly flammable, can cause severe eye damage and skin burns, is toxic if inhaled or swallowed, and is classified as a carcinogen and aquatic toxin. Use only in well‑ventilated areas and avoid skin or eye contact. Always refer to the full SDS before use.
Why Buy from autofxmart
- Authorized distributor — authentic, factory-fresh stock.
- Fast US shipping — most orders ship within 1 business day.
- 30-day returns — buy with confidence.
- Pro-shop pricing — bulk discounts available on request.
- Expert support — questions? Email us at support@autofxmart.com.
Specifications
Full data
Frequently asked
Good to know
SEM is compatible with Aluminum, Plastic. Always ensure the surface is properly cleaned, degreased, and sanded before application to achieve the strongest adhesion and a professional finish.
The curing time for SEM is 1 hr Dry. Drying and curing times may vary with temperature, humidity, and film thickness — always consult the Technical Data Sheet (TDS) for exact cycle conditions.
This listing ships SEM in a 20 (CN) container. Check the autofxmart catalog for other sizes and bulk pricing.
Most in-stock orders for SEM ship the same or next business day from our US warehouse. Expedited options are available at checkout. Freight-class items may require an additional 1–2 days for carrier pickup.
Yes. autofxmart is an authorized distributor of SEM products. Every unit is factory-fresh, sealed, and backed by the manufacturer's standard warranty. If you have a concern, contact support@autofxmart.com and we will make it right.
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