Best Weld Through Primer (Best Choices For Self Etching Weld-thru Primer)

When it comes to welding, you need to know a few things. One of those is the type of primer you use. Welding through primer is a great way to maintain your welds while avoiding the need for a separate sealant. It’s also a great option if you’re working with difficult-to-weld metals or if you don’t have time to preheat your joint.

Each of the weld through primers has its benefits. After comprehensive research and considering its benefits and drawbacks, I’ve walked you through the list of best weld-thru primer.

Check out my entire list as any of them can be your cup of tea!

So, let’s get straight into it!

Best Weld Thru Primer
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What Is Weld Through Primer

Weld through primer is a coating that penetrates the painted surface. It is known as a filler metal primer. Because it fills in the gaps between the pieces of metal so that they can weld together. It’s a sealant that blocks water and other substances that may corrode the surface.

Functions Of Weld Through Primer

The presence of weld-through primer saves on paint because it can protect an entire panel before needing to be applied again.

Firstly, it helps prevent paint from being chipped or damaged by an external source and helps make the surfaces more resistant to water.

It also acts as a sealant like paint would protect the surface from corrosion, moisture, and other sources. The primer can save time and money when you weld.

How Does Weld-through Primer Work?

When you make a welded joint, you may find exposed areas where the metal is not touching any other metal. It would be best to protect those areas from the corrosive effects of water and other substances.

Before welding, you can use the primer to penetrate and semi-permeate these problem areas. When the primer dries on the metal, it becomes an integral part of the surface. It is then ready to accept paint adhesion. You can use a weld-through primer to build your object, which is popular as a special primer to people.

It comes with a paint base coat. The primer has to work together with regular paint to provide a protective layer that you don’t have to reapply.

As a result, welding through primer enables industrial metalwork to be painted more quickly and cheaply.

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Lets Read Reviews Of Some Best Weld through Primers

Here I’ve come up with the best weld through primers with their features, special quality, with good and bad sides, so that you may make your own decision.

Keep continuing to know the details.

1. Seymour 20-1675 PBE Professional Primer

I have chosen Seymour’s 20-1675 PBE Primer because it contains a high-performance Grade. It is an innovative water-based primer that provides adhesion and corrosion resistance in commercial or industrial environments.

Seymour 20-1675 PBE Professional Primer
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You do not get any volatile compounds in Seymour primer. Shield metal offers protection from exterior environmental elements while Seymour provides a variety of substrates, including concrete, wood, metal, and masonry.

Specialty of This Product

The specialty of this product is penetration, and heat resistance capacity is up to 250˚F. The presence of Phosphorus in this product makes it more advantageous for coating epoxy.


  • Easy to apply.
  • Excellent corrosion resistance.
  • Comes with water-based pigment.
  • Needs the least amount of usage time
  • Dries up in about an hour and is completely dry after 24 hours.


  • The primary purpose of this product is only as a sealant for prepping the surface for further painting.

Reason to Buy

I recommend it because it contains no CFCs, and it comes with a patented valve that gives accurate atomization to give good coverage while spraying.

2. 3M Weld-Thru Coating

Now, I’d love to share the details of 3M Weld-Thru Primer. It offers you an extremely durable zinc-based aerosol coating that resists weld spatter.

3M Weld-Thru Coating
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The primer is a corrosion-resistant and chip-resistant zinc-based coating that provides excellent resistance against abrasive or alkaline cleaning compounds. It is ideal for use on metal surfaces for protection against weld spatter under various field conditions.

This primer works by coating parts with an electrochemically active compound which reacts to produce a barrier.

Specialty of This Product

This 3M Weld-Thru II comes with a coating that prevents corrosion between untreated bare metal substrates when they are welded. I love it because it is unique in its resistance to weld spattering and abrasive cleaning compounds.


  • Comes with good corrosion capacity
  • Very good weld coating application, brush or spray equipment
  • Excellent chip resistance
  • Good tack after drying
  • Excellent weathering characteristics
  • Resists weld spatter


  • It is expensive due to the highly corrosion-resistant nature of the product.

Reason to Buy

You can use this product with professional and amateur welders who will be outdoors or in rough areas where spatter is a concern. While welding, this primer provides you with high durability.

3. U-Pol Weld Through

If you ask me to give you a product recommendation for welding, I immediately think of U-Pol.

It penetrates the surface of metals to get good penetration and release. The U- Pol primer is also free from solvents and dispersing agents, which reduces the risk of reacting with other materials.

U-POL Weld thru primer
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I personally liked it as it is weather-resistant, providing a tough barrier against wind, rain and sun. Though it is a bit expensive, it ensures durability. It offers excellent corrosion protection for the weld bead, making it effective in all corrosive environments.

Specialty of This Product

This primer has thick technical specifications that enable you to apply it very precisely and easily. You can apply this primer to different types of metals like cast iron, steel, or others.


  • Can apply to all types of raw steel surfaces.
  • Easy to utilize and contain a good attachment capacity.
  • Excellent primer for weld strength
  • Can apply on a suitable condition.
  • Does not cause any damage to the metal


  • Not applicable for high-temperature applications

Reason to Buy

I suggest the primer because it is a heavy-duty primer that enables the finishing of welding work. It is the perfect choice for you if you like a durable paint job.

4. Spray MAX Self Etch Weld-Thru Primer

If you are looking for a high-flowing acrylic base or an alkyd topcoat for durability, the Spray Max will meet your needs.

Spray MAX Self Etch Weld-Thru Primer
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Because it has become one of the standard primers for welded frame repair work. It also works great as a preparation for sanding and gives you more control over the final quality of the welded joint.

On account of its excellent characteristics of flowing, you can use this primer on any type of surface easily. You can apply multiple coats on top of each other with dry periods without sanding between coats.

Specialty of This Product

The Spray Max Primer provides quick penetration on metal, carpet & vinyl for a high strength bond. It attracts me as it is great for damaged bodywork or welding seams in cars when you want to skip the primer steps.


  • Fast drying
  • Holds up well against rust and corrosion
  • Dries to a very flat surface
  • Matches OEM colors
  • Great for spraying in bed liners and truck caps


  • Make sure you shake the can thoroughly, or it will become runny.

Reason to Buy

You can cover many areas, and it is also easy to use and control. The price is good for the quality of the product, and it is an excellent bang for your buck.

5. Sem 40773 Zinc Based Weld Thru Primer

Now I’m talking about the last item, and it is Sem 40773 Primer. The manufacturer produced many types of products over the years, but Sem 40773 primer is the most popular one.

Sem zinc Based Weld Thru Primer
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It also comes with a self-etching zinc-based rust inhibitor that will keep your welds from rusting or corroding. 

The primer is truly amazing and works well.  It is also resistant to chipping, peeling, rust corrosion, and cracking. After drying, you can use it to prime and weld through with a layer of resin coating or paint.

Specialty of This Product

Sem 40773 comes with a self-etching zinc-based rust inhibitor that will prevent your welds from rusting or corroding. You do not need grinding or sanding.

Sem Weld Thru Primer feature
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  • Adhesion capacity is pretty good.
  • Good capacity for adhering to other superficial levels
  • Not affected by abrasion and extreme weather conditions such as rain, sun, and snow
  • Perfect for different applications like shields, drain grates or more.
  • Promotes good paint attachment


  • The use of this product has restrictions in some areas.

Reason to Buy

I like how this item creates a barrier that prevents the surface from breaking or chipping. It is ideal for construction, transportation, and manufacturing industries.

When to Use Weld Through Primer

For up to 3 hours, you can operate this welding primer with no rust until you’re ready to weld. Once your project is completed, you need to spray it onto the metal in order to avoid rusting it.

It makes a waterproof blockage by sealing off dirt, moisture, or dust from adjoining surfaces.

How to Apply the Primer

Prior to the starting of the welding system, you can brush the primer to the bare metal area. As the welding completed, the primer galvanized the metal that was welded, which protected it from further corrosion. It keeps corrosion off the inner edges of the welded metal pieces.

Here is the step-by-step process of using the primer:


You should clean the surface thoroughly before welding, and bare metal is necessary.


Remove the paint coating or priming material. You’re allowed to clean the entire surface using sand.


Then apply the weld-through primer to the bare metal prior to welding. Allow it to cure until you have a suitable layer of zinc connected to the metal.


After welding is complete, remove the primer from any remaining weld-through surfaces to ensure the paint will stick to them after painting.

Frequently Asked Questions (FAQ’s)

1. Does Weld-Through Primer Work?

Weld-through primer ensures a good connection between the weldment and the underlying substrate. It can help prevent cracking and other problems that can occur after welding.

2. Is Cold Gal A Weld-Through Primer?

1. Does Weld-Through Primer Work?
Weld-through primer ensures a good connection between the weldment and the underlying substrate. It can help prevent cracking and other problems that can occur after welding.

3. Does Welding Primer Stop Rust?

Yes, the Welding primer comes with reducing rusting and corrosion of metal joints. Make sure to prevent them from experiencing corrosion.

4. Is All Zinc Primer Weld Through?

All zinc primer welds are through, but there is always a small chance of a missed weld. If you have any concerns about your welds, it is always best to have them checked by a professional.

5. Is Self Etching Primer Weldable?

It depends on the composition of the self-etching primer. Some primers are weldable, while others may not. It is always best to consult with a welding expert to determine if a primer is weldable.

Last Words

Overall of all the best weld through primers, I personally recommend Seymour 20-1675 PBE Primer for use on welds that require a high-quality finish. It’s a great choice for priming both thin and thick metals, and the quick-drying formula makes it easy to apply.

That said, if you’re looking for a great way to improve your welding skills and protect your equipment, feel free to try any of my selected or recommended primers.

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