What’s Soft Butyl And Permanent Sealant

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In headlight projector lens retrofit, you need to open the headlight cover. It is a hard job to open it because it is tightly sealed to the headlamp bottom. But you must open it or you can not change the projector lens inside.

Usually, there are two kinds of adhesive in the headlight. One is soft butyl which called hot glue in China and another is a permanent sealant which called cold glue in China.

1. What is the difference in this two adhesive?

The permanent sealant is more stable, better sealing. of course the cost is higher than the soft butyl. So if it is a soft butyl headlamp then it is easy to open it while if it is a permanent sealant headlamp please be patient and don’t go crazy. Choose ROYALIN headlight retrofit tools and make it easier to do that.

Hot glue is reversible, just as the water can change into the ice, and the ice can back to the water. Put the soft butyl headlamp in the oven at 120 degrees and bake it, the glue will soon soften. While the cold glue is irreversible, just like a boiled egg that never changes back. That means as for resealing, you will have to remove all the old permaseal from the headlamp channel and use some new butyl to resealing it.

headlight sealant

2. Why some headlamps sealing with butyl and some headlamps sealing with permanent?

The structure of each headlamp is different, the power of the bulb is not quite the same, and high wattage and high temperature. The temperature of the headlamp determines whether the car manufacturer uses hot glue or cold glue to seal the headlights.

On the other hand, Different car brands generally use different types of sealant. German car, European car is commonly used cold glue; And Japanese car, Korean car, Chinese car commonly used hot glue seal. But in recent years, Japanese car also has more and more models choose cold glue.

3. How to open soft butyl headlamp?

It is easy to open the soft butyl headlamp. Royalin headlight oven is the best choice. You just need to put the headlight in your oven, set the time to about 10 mins with 150-200 degrees. Once time is up, you can take it out with the oven glove carefully because the headlamp is so hot and you can see silicone sealant around the headlight will be softened. You can use your hand to pry the lens from the corner of the headlight, if still hard to pry you can choose ROYALIN headlight retrofit tools RY-RT001 (7pcs headlight sealant knife), it will help you to pry the headlight lens much easy.

Well, if you do not have the ROYALIN headlight oven, a heat gun is also available to open the soft butyl headlamp. Using the heat gun to heat the edge of the headlights directly, and then use our tools RY-RT001 to pry the edge of the headlights apart slowly while heating. This method may take a longer time. So if possible one set headlight oven is necessary.

4. How to open permanent sealant headlamp?

The same to open soft butyl headlamp, but now headlight oven must necessary. Because the permanent is harder than soft butyl, you need to put the headlamp into the oven to heat several times. Pry, bake, pry, bake…repeat method. Just choose a spot to pry with a screwdriver and keep working it until you’ve gotten under the lens and into the headlight. Then work your way around. It usually gets easier after the initial “breakthrough”. But the whole process is arduous, maybe 2-3 hours are needed.

headlight open tools


There still have another work need to do after you’ve opened the headlights. You must clean up all the sealants from both the lens and housing. While this process can be time-consuming, thoroughly cleaning out the old sealant from the channel helps ensure a weather-tight seal that doesn’t allow any condensation or leaking. This time you can choose ROYALIN headlight tools RY-RT002 and RY-RT019. This two kinds of headlight sealant knives help you clean the old sealant much easy.

Levi Chou

Levi Chou

Hi, I’m Levi Zhou, the founder of royalincarparts.com, I’ve been engaged in auto parts aftermarket for decades, and the purpose of this article is to share with you the knowledge relating to car lighting retrofit from a Chinese supplier’s perspective.

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