Overview
Built for the job.
Copperweld™ is a zinc based and copper enriched weld through primer that provides superior corrosion protection between welded substrates while minimizing heat affected zones and welding spatter.
Copperweld™ 40793 Primer is a 16 oz gold-colored epoxy primer designed for professional auto body and collision repair applications. It provides a high-build, corrosion-resistant base coat on bare metal, OEM panels, or previously primed surfaces, delivering reliable adhesion before topcoat application.
Each can covers approximately 15 sq-ft, allowing efficient coverage with a single coat as specified for the product. The formulation is compatible with a range of substrates including untreated steel and existing primer layers, ensuring consistent film formation across typical shop workflows. With a VOC content of 545 g/L, it meets regulatory requirements while delivering the performance expected from an SEM-approved system.
Due to its acute toxicity, flammability, and skin corrosivity, use requires full personal protective equipment: eye protection, chemical-resistant gloves, protective clothing, and a respirator. Operate in a well-ventilated area and follow the H-statements (H222, H280, H315, H319, H336, H351, H373) for safe handling.
Why Pros Choose SEM SEM
- OEM recommended
- Zinc based formula for superior corrosion protection
- Copper enriched for improved conductivity while welding
- Minimizes the heat affected zone while welding
- Low weld spatter formula
- Smooth spraying and easy covering
How to Use
For MIG and STRSW welding
Compatibility
Compatible substrates: Copper.
Specifications
| Part No. | 40793 |
|---|---|
| Product Line | SEM |
| MFR Model | 40793 |
| Standard/Approvals | California Pro65 Warning: Cancer | OSHA and GHS Hazard |
| Application | For MIG and STRSW welding |
| Manufacturer | SEM |
| UPC | 646786407932 |
| Brand | Copperweld™ |
| Maximum Sale Quantity | 6 |
| Maximum Sale Day | 7 |
| Solids Content | 17.3% |
| Color | Gold |
| Container Size (oz) | 16 |
| Coverage (sq-ft) | 15 |
- VOC
- 545 g/l
- Shelf Life
- Store in a cool, dry place with adequate ventilation away
- Compatible Substrates
- bare metal, oem, primer
- Number of Coats
- 40793
- Coverage
- 15 sq-ft per can
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 can Copperweld™ 40793 Primer be applied to?
It is compatible with bare metal, OEM finishes, and existing primers.
How much area does one 16 oz can cover?
The product provides approximately 15 sq-ft of coverage per can when applied at the recommended film thickness.
What personal protective equipment is required when handling this primer?
Use eye protection, chemical-resistant gloves, protective clothing, and a respirator as specified in the SDS.
Are there any special safety considerations for Copperweld™ 40793 Primer?
The primer has a flash point of -103 °C and is classified with multiple GHS hazards, including acute toxicity, skin corrosion, eye damage, flammability, and carcinogenicity. Follow all H-statements (H222, H280, H315, H319, H336, H351, H373) on the label.
Documents & Safety
- Safety Data Sheet (SDS)
- copperweld_40786_specification_sheet.pdf
- 40793%20Copperweld%20Weld%20Thru%20PrimerUSA.pdf
Signal Word: Danger. Wear chemical-resistant gloves, safety goggles or face shield, protective clothing (coveralls), and a suitable respirator when handling this primer. The product is extremely flammable with a flash point of -103 °C, can cause severe skin burns and eye damage, is toxic if inhaled or swallowed, and poses long-term health risks including carcinogenicity and reproductive effects. It is also hazardous to aquatic life. 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.
How to apply
Steps
1Clean and degrease the surface, then scuff as needed.
2Mask off surrounding panels and trim.
3Mix to the product's ratio and strain.
4Apply 2–3 even coats, flashing between each.
5Let cure fully before sanding, buffing, or assembly.
Specifications
Full data
Frequently asked
Good to know
SEM is compatible with Copper. Always ensure the surface is properly cleaned, degreased, and sanded before application to achieve the strongest adhesion and a professional finish.
This listing ships SEM in a 16 (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.
The MPN for SEM is 40793. Use this number when cross-referencing against TDS, SDS, or legacy supplier catalogs.
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