Overview
Built for the job.
Self etching primer provides excellent adhesion and corrosion resistance to properly prepped steel, aluminum and stainless steel.?
SEM 39683 Self‑Etching Primer is a gray, aerosol‑delivered primer formulated for fast, reliable adhesion on aluminum, steel and previously primed surfaces. It is designed for professional body shop applications where a consistent, corrosion‑resistant base is required before topcoat application.
The aerosol provides a uniform film that cures in 5–10 minutes between coats, allowing a full four‑coat system to be completed efficiently. The primer’s low flash point of –103 °C and VOC content of 648 g/L (59.53 % VOC) deliver rapid flash time while meeting typical shop ventilation requirements. Compatibility with aluminum, steel and existing primer substrates ensures versatility across most repair projects.
Due to its acute toxicity and classification as a flammable aerosol, proper personal protective equipment is mandatory: eye protection, chemical‑resistant gloves, protective clothing, and a respirator suitable for organic vapors. Application should be performed in a well‑ventilated area, and cleanup must follow local VOC regulations.
Why Pros Choose SEM SEM
- Excellent adhesion to steel, aluminum and stainless steel
- Quick drying
How to Use
For bare steel, bare aluminum
- Clean the substrate (aluminum, steel, or previously primed surface) to remove dirt, grease, and loose material; ensure the surface is dry.
- Apply the first coat of SEM® 39683 Self‑Etching Primer using a spray gun or compatible aerosol technique.
- Allow 5–10 minutes flash time before applying the next coat.
- Repeat application until a total of four coats are built up, maintaining the 5–10 minute flash interval between each coat.
- After the final coat, allow the primer to fully cure according to the manufacturer's recommended cure time before proceeding with topcoat application.
- Clean equipment and any spills with cleaning materials that comply with VOC regulations.
Compatibility
Compatible substrates: Steel, Aluminum, Stainless.
Specifications
| Part No. | 39683 |
|---|---|
| Product Line | SEM |
| MFR Model | 39683 |
| Standard/Approvals | California Prop65 Warning: Cancer and Reproductive Harm | GHS02 | GHS04 | GHS07 | GHS08 | OSHA HCS Hazard | VOC Compliant |
| Application | For bare steel, bare aluminum |
| Manufacturer | SEM |
| UPC | 646786396830 |
| Brand | SEM® |
| Maximum Sale Quantity | 12 |
| Maximum Sale Day | 7 |
| Solids Content | 14.60% |
| Color | Gray |
| Container Size (oz) | 20 |
- Flash Time
- 5–10 min between coats
- VOC
- 648 g/L
- Substrates
- Aluminum, primer, steel
- Coats
- 4
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® 39683 Self‑Etching Primer?
It can be applied to aluminum, steel, and previously primed surfaces.
How long should I wait between coats?
The recommended flash time is 5 – 10 minutes between coats.
What personal protective equipment is required when spraying this primer?
Use eye protection, chemical‑resistant gloves, protective clothing, and a respirator approved for aerosolized chemicals.
Can the primer be sanded and painted over?
After the recommended number of coats (four) and proper flash time, the primer can be sanded and top‑coated with compatible paints.
What safety hazards should I be aware of?
The product is classified for acute toxicity, eye damage, skin corrosion, aspiration hazard, carcinogenicity, flammability, and aquatic toxicity. It has a flash point of –103 °C and is supplied as a compressed gas aerosol.
Documents & Safety
- Safety Data Sheet (SDS)
- sem_39671_specification_sheet.pdf
- 39683%20Self%20Etching%20Primer%20GrayUSA.pdf
Danger: This aerosol primer is toxic if inhaled or swallowed, can cause serious eye damage and skin burns, is flammable, and is classified as a carcinogen and aquatic toxin. Use safety glasses, chemical‑resistant gloves, protective clothing, and a suitable respirator when applying. 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 Steel, Aluminum, Stainless. 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 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.
The MPN for SEM is 39683. Use this number when cross-referencing against TDS, SDS, or legacy supplier catalogs.
What Our Customers Say
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5.0 / 5.0
(1 review)
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As described and fast shipping. The best primer in the world for aluminum. Thank you!
