Custom Shop Gray Epoxy Primer/Sealer 2.1 VOC Quart Kit

In this review the Custom Shop KEP Series Gray Epoxy Primer/Sealer is evaluated as a practical, high-performance DTM primer for automotive and industrial projects; it is best for users who need strong adhesion to bare metal and corrosion resistance without chromates. The single biggest reason to consider this product is its 1 to 1 mixing simplicity combined with a formula designed for direct-to-metal use and excellent topcoat gloss holdout. The review focuses on how it handles, what surfaces it bonds to, and realistic expectations for drying and sprayability.

Key Features

• 1 to 1 Mix Ratio: Mixing one part primer to one part epoxy hardener makes measuring straightforward and reduces mixing errors on the job.
• DTM Performance: Formulated for direct-to-metal use, it offers superior adhesion to bare metal, steel and bare aluminum for corrosion-prone applications.
• Anti-corrosive Additives: Contains a rich blend of rust and corrosion inhibitors for improved salt spray resistance and long-term substrate protection.
• Sealer Capability: Can be used as a sealer under single-stage urethane or basecoat/clearcoat systems, promoting good topcoat gloss holdout.
• Fast Dry and 4-Hour Pot Life: Fast drying characteristics and a four-hour pot life after mixing give workable application time while limiting downtime.
• Wide Compatibility: Compatible with many automotive topcoat brands and accepts topcoats after a short flash with appropriate reducer.

Who It's For

This epoxy primer is aimed at automotive restorers, collision repair shops and industrial users who need a reliable DTM primer with anti-corrosive properties and easy mixing. The kit format and 1 to 1 mix ratio suit technicians who value accuracy and straightforward on-site mixing without induction time.

DIYers with experience in spraying primers can benefit from the product, but novices who require guaranteed sprayability or instant workability may want to test a small panel first. If you need a very thin, fast-spraying low-viscosity epoxy every time, some users report variable sprayability, so evaluate application equipment and thinning preferences before large jobs.

Pros & Cons

Pros

• Excellent adhesion to bare metal, aluminum, fiberglass and prepared OEM finishes.
• Anti-corrosive formulation and good salt spray resistance for rust-prone environments.
• Simple 1:1 mix ratio with a four-hour pot life keeps mixing precise and predictable.
• Works as both a DTM primer and a sealer for single-stage and basecoat/clearcoat systems.

Cons

• Sprayability and drying experience are mixed among users, so some prep and thinning trials may be needed for optimal results.
• Reported thickness concerns by a minority of users suggest attention to film build and application technique is required.

Specifications

Product Type	Anti-corrosive epoxy primer/sealer
Mix Ratio	1 to 1 (part A to part B)
Kit Size	1 quart kit (1 pint primer + 1 pint epoxy HDR)
VOC	2.1 lbs/gallon
Pot Life	Approximately 4 hours once mixed
Suitable Substrates	Bare metal, steel, bare aluminum, fiberglass, gelcoat, body filler, rigid plastics
Color Options	Gray (also available in black and white)

Our Verdict

The Custom Shop KEP Series Gray Epoxy Primer/Sealer is a practical, value-oriented option for professionals and experienced DIYers who need a DTM epoxy with anti-corrosive protection and simple 1:1 mixing. It delivers strong adhesion and sealer performance for topcoating, though application technique and thinning trials can be necessary to address mixed reports of sprayability and drying. For corrosion defense and ease of mixing, it represents solid value.

Frequently Asked Questions

Can this be topcoated immediately?
When used as a sealer, adding 1/2 part XR70 or UR70 reducer allows topcoat or basecoat application in about 30 minutes depending on conditions.

Is this safe for aluminum and fiberglass?
Yes, the formulation lists superior adhesion to bare aluminum and fiberglass when substrates are properly prepared.

Do I need special reducers or hardeners?
The kit includes the epoxy HDR and mixes 1 to 1; use XR70 or UR70 reducer when using it as a sealer before topcoating.