Linear L-411, L-417, L-418 High Build DTM Epoxy Primer kit
Linear L-411, L-417, L-418 High Build DTM Epoxy Primer kit
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Linear High Build Epoxy Primer Kit (includes activator 5 Quarts Sprayable)
Before purchasing, please download and read the TDS.
Linear High Build Epoxy Primer has outperformed all of the 11 other primers we have put it up against in nearly every category! This 4:1 true epoxy (not a hybrid) is designed to be used over bare metal, body worked over, and then used again as a high build primer over filler work. Using one bulletproof product throughout the body work process will provide excellent uniformity, meaning that everything will expand and contract at the same rate in environmental changes such as temperature. Back in the day the common practice was to use epoxy over metal, then a spray poly, and then a 2k urethane before paint. You no longer have to do this! All those products will shrink, expand and contract at different rates and can cause issues such as cracking or "phantom waves" in temperature changes. All color variations are gravimetrically identical meaning they can be mixed together any way you like to get any shade of the 3 colors. Using one primer from metal up combined with weighing your filler mixes will lead to no shrink back and excellent uniformity for a job that will last many years to come!
- Done shrinking in 24-48 hrs
- Highest dry film build
- True 76% solid content (what's left on the panel not solids by weight!) 4-6 mils dry film build per coat (1.7 TIP)
- Semi Gloss finish allows for a built-in guide coat to easily identify pinholes and imperfections
- Very easy sanding
- Excellent adhesion to bare metal DTM primer
- Excellent corrosion resistance with rust encapsulation and moisture scavenger properties
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Understanding L-Series Epoxy
What's the difference between primer, surfacer, and epoxy?
Primer is a DTM (Direct to Metal) product — it bonds to bare metal and protects it. Acid etch and epoxy are both primers.
2K urethane is technically a surfacer, not a primer. It's breathable and offers zero metal protection — it can actually wick moisture straight down to bare metal. Never spray 2K urethane directly over bare metal.
L-Series epoxy is a true DTM primer. It goes on bare metal first and provides real corrosion protection, high build, and a sandable surface — all in one product, from metal up.
Why use L-Series instead of stacking epoxy + spray poly + 2K urethane?
The traditional stack — epoxy, then spray poly, then 2K urethane — requires careful timing between coats. Spray poly kicks fast and can trap solvents from the epoxy underneath if you don't wait at least 24 hours. If you burn through to that layer later, the epoxy may still be soft underneath.
L-Series eliminates that stack. It's a high-build DTM epoxy that goes from bare metal through final block sanding — one product, no timing headaches, no trapped solvents between incompatible layers.
Can L-Series go over rust or just clean bare metal?
L-Series is formulated with an inorganic-organic corrosion inhibitor and anti-corrosive pigment designed to encapsulate and neutralize rust. It also contains moisture scavenger properties that actively draw moisture away from the substrate.
That said, you still need proper surface prep: thoroughly sand bare metal with no finer than 80 grit, or sandblast (no soda blast). Clean with a quality acetone cleaner before coating. Do not use an etch primer underneath L-Series — it's a DTM product that bonds directly to metal.
What temperature does L-Series need to cure properly?
65°F minimum panel temperature for at least 48 hours after application. This is non-negotiable — if you can't keep the panel above 65°F for two full days, don't spray L-Series until you can.
The slow cure is by design (solvents need time to escape), but it only works if the environment cooperates. Don't epoxy something and shut the heat off overnight — you're asking for problems. Spray in a warm environment and keep it warm.
Why does L-Series take 48 hours to cure? Isn't faster better?
No — faster is actually worse. Fast-curing primers skin over before the solvents underneath have fully escaped. Those trapped solvents continue to evaporate slowly, causing the primer to shrink over time. That shrinkage telegraphs scratches and imperfections up through your paint weeks or months after the job is done.
L-Series cures slowly by design. The 48-hour window lets all solvents escape before the surface seals, so what you block is what stays. No late shrinkage, no ghost scratches appearing after paint.
Why do high solids matter?
Every sprayable product contains solvents that evaporate as it cures. More solvent = more mass loss = more shrinkage.
L-Series measures 65% solids by volume and 76% solids by weight. Volume is what determines how much build stays on the panel after solvents flash off — 65% by volume is exceptionally high for an epoxy primer. Less shrinkage means the surface you block stays true, and the finish you see after clear is the finish you keep.
Why does L-Series sand so differently from other epoxies?
Most epoxies are loaded with vinyl to make them flexible, but vinyl makes the product gummy when you sand it. Paper clogs almost immediately and you spend more time cleaning or replacing sandpaper than actually blocking.
L-Series sands to a fine, dry powder. The paper stays clean, the block glides, and you can actually feel what the surface is doing. It also acts as its own guide coat — the color and sheen difference between high and low spots is visible without spraying a separate guide coat.
Can I apply body filler over L-Series?
Yes, but L-Series must be thoroughly sanded with 80–180 grit before applying filler or glazing putty. The epoxy needs mechanical tooth for the filler to grip.
This makes L-Series ideal for the common workflow: bare metal → L-Series epoxy → sand → body filler → re-prime with L-Series → block sand → topcoat. One product handles both the initial metal seal and the final surfacing.
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Shipping Policy
We ship from our warehouse in Antigo, Wisconsin. Processing under normal circumstances (not backordered or during sale / high order times) is 1-2 business days.
We ship using UPS or USPS (selected by customers at checkout).
For shipping-related issues, start with our Claims & Returns form. If your order included Order Protection and the issue is loss, theft, carrier damage, or misdelivery in transit, use the Order Protection claims portal from your confirmation email first.
Returns / Refunds
Returns are accepted within 30 days of delivery for unused items in original condition with original packaging and proof of purchase.
Custom Color Basecoats, OEMatch Basecoats, mixed paints, opened or used items, final-sale items, digital products, and gift cards are not returnable.
Please review our Return & Refund Policy for full details. To request a return or report a wrong or missing item, use our Claims & Returns form.
Warranty
All Linear Blocking Tools are backed by a Limited Lifetime Warranty. Coverage includes product failures caused by normal use and normal operating conditions. Damage caused by misuse, abuse, accidents, unauthorized modification, improper storage, or cosmetic wear is not covered.
Please review our Warranty Policy for full coverage details. To start a warranty claim, use our Claims & Returns form.
Financing

That's right! Linear now offers 0% Financing to most applications! Zero hit on your credit score and no risk! Buy Now...Pay later!
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100% Unequivocally the single best high build, true epoxy that I have ever used, I love spraying it, the adhesion to bare metal rivals anything on the market, ease of sanding makes body work and blocking actually enjoyable, not to mention only having to use one product from start to finish simplifies the entire process and saves money in my opinion. I will always recommend this product to anyone who specializes in restorations or custom paint, but even to the hobbyist this product is well worth every penny! Hands down my New favorite product!
1st time using this product. I sprayed alot of primers over the years. Being a epoxy primer, I expected it to spray on thick but it wasn't. It was a nice thin smooth film. Would buy again.
Really like Linear Blocking Tools DTM primer. One kit got damaged in shipping. Colten and crew sent out another quart of L - 421 ASAP. The best DTM we have tried. Five Stars
May want to use a different shipping method. UPS just dropped the boxes at our door , upside down and all the cans were dented. Thankfully, none were leaking .