The Sikaflex 291 is a gel adhesive that dries faster and is less expensive. The 3M 4200 is more expensive but offers a stronger and more durable bond.
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Key Takeaways
- The Sikaflex 291 is a 1-component polyurethane adhesive that is permanent and can be used for multiple purposes.
- The 3M 4200 is also a permanent adhesive but stronger and more expensive.
- The Sikaflex 291 has a better temperature resistance than the 3M 4200.
Among all the marine sealants I used so far, the Sikaflex 291 and 3M 4200 seemed worth comparing as they are both strong, durable, and reliable for creating a permanent bond.
That’s why I prepared this Sikaflex 291 vs. 3M 4200 comparison article. Hope it will be helpful for you!
Sikaflex 291 vs. 3M 4200
Overview of Sikaflex 291 Sealant
The Sikaflex 291 is a permanent marine adhesive made of 1-component polyurethane.
This sealant works well on various environments and various surfaces.
Due to its formula, this sealant flexes easily and dries super fast.
On top of that, you can apply it on painted surfaces without worrying about damage or corrosion issues.
Overview of 3M 4200 Sealant
When it comes to marine sealants from popular brands, the 3M 4200 is certainly one of the top-notch ones.
This multi-purpose adhesive is made of polyurethane and has a fast-drying formula.
It is much stronger and suitable for all weather conditions.
On top of that, you can use the 3M 4200 sealant to seal a variety of materials for multiple purposes.
Detailed Comparison Between Sikaflex 291 And 3M 4200
Adhesive Base
The Sikaflex 291 contains a 1-component polyurethane formula as its base material.
This type of adhesive is 100% solid and uses moisture to cure properly.
And the 3M 4200 sealants are made of polyurethane, which is similarly high-performing and cures faster.
Adhesive Type
The Sikaflex 291 is a gel-like adhesive, and it is not very runny.
On the other hand, the 3M 4200 comes in a more liquid form and is a bit runny.
However, they both come in tubes with long nozzles, which makes the application process simple and easier.
Color
Both Sikaflex 291 and 3M 4200 come in two different colors: black and white.
These options are handy for applying sealants on various surfaces or materials without being too visible.
So you can choose either black or white or you can just both depending on your requirements.
Applicable Materials
I found the Sikaflex 291 more versatile than most adhesives as it can be used for both general purposes and as a marine adhesive.
You can use it on metal, fiberglass, wood, metal primers, painted coatings, etc.
Additionally, you can use this sealant on hardboards, ceramics, and certain other materials as well.
The 3M 4200 is also suitable for use on a range of materials, including wood, fiberglass, metal, and certain plastics.
Water Resistance
When it comes to water and weather resistance, both Sikaflex 291 and 3M 4200 are highly reliable.
They are both reliable and waterproof and can even withstand salty water conditions.
Temperature Resistance
The Sikaflex 291 can resist temperatures between -58°F to 194 °F. The application temperature of the sealant is 41°F to 104°F.
The application temperature of the 3M 4200 is 40°F to 100°F. And it can resist temperatures as low as -40°F and as high as 190°F.
Though there is a slight difference between their temperature resistance, I don’t think it will make much of a difference.
Bonding Strength
As for bonding strength, the 3M 4200 is definitely stronger than the Sikaflex 291.
While the Sikaflex adhesive has a 260 psi strength, the 3M one offers an excellent strength of 300 psi.
It also means the 3M 4200 is more rigid than the Sikaflex 291 sealant.
Drying Time
If you are looking for adhesives that allow you to make adjustments, both Sikaflex 291 and 3M 4200 are ideal for you.
The Sikaflex 291 has an open time of 40 minutes and starts hardening or skinning within an hour.
As for the 3M 4200, it gives you a longer time to make adjustments.
It stays open for 60 minutes and starts skinning after 90 minutes.
Cure Time
My patience was tested with the Sikaflex 291, as it took more than 3 days to cure. In some cases, it can take even longer.
Thankfully, the 3M 4200 cured within 24 hours.
Cost
If you are looking for a budget-friendly sealant, the Sikaflex 291 would be a good choice.
Depending on the tube size, seller, and availability, it costs around $1.69 to $5.76 per fl/oz.
On the other hand, the 3M 4200 is more expensive and can cost between $2.39 to $6.96 per fl/oz.
Which One Is Better?
From my experience, I would say both of these adhesives are good in their own way. They both create a strong bond and are permanent.
On top of that, the nozzles are pretty lengthy, which means you can easily reach narrow and furthest corners without much trouble.
Moreover, as these are one-part adhesives, you won’t have to go through the trouble of mixing them. Just use the sealants as they come.
You can paint over both of them once they dry or leave them as they are because these adhesives don’t turn yellow over time.
Editor’s Opinion
As you noticed in today’s Sikaflex 291 vs. 3M 4200 comparison, there is a huge difference between the cure time of these sealants.
So, if you want to get the job done faster, you should pick the 3M 4200 because the adhesives that cure faster are usually stronger.
However, if you don’t mind waiting for the adhesive to take time to cure and also want something less expensive, the Sikaflex 291 is a better option.
One more tip before I finish this: make sure to prep up the surface well before applying the adhesives to get the best result.
