Technical Butyl Tape for Windshield Install - Round or Square?

Wondering if there was any experience/opinions to be offered...round or square? I like the idea of square but not sure it would provide the same compress-ability as round which seems would allow easier setting for height and adhesion. It's already getting cooler here so with either I'll likely be using a little supplemental heat to get the gl*** to settle-in.

I will be using urethane but simply to frost the edges, I'm wed to tape for the stick-it-to-it duties.

 

If this is a glue in windshield I always use a calk tube of urethane.

 

I've always used round, I like being able to "set" the gl*** down into it and seeing the contact area widen as I gently pushed the gl*** down into it.

It's just my preference.....

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Appreciate the replies!

@BJR - I contemplated my first urethane-only install but figured I'd stick with the tried and true method and possibly byp*** any mess and/or regret (frustrations).

@lostone - My exact thoughts and sentiment. Round has always offered a great visual gauge of adhesion. Square might be as user friendly but for me it's an unknown.

 

Round, I think 3m makes two or three diameters.

 

Thanks for the reply and...how ironic. The windshield in question is for a '65 Impala SS Coupe and I spy your '65 wagon avatar!

I'm installing the original gl*** so 5/16" should be the required size.

 

The thing with round butyl is after it’s placed in the windshield channel you can fine tune it. I take a piece of the wax paper that separates the butyl and use that on my finger and roll it to make final adjustments to get the butyl positioned where I want it.

 

learned something today, - never knew there was a ‘round’ tape.

 

The glued in windshield adds structure to the body/roof. I know you say b/s. But I worked in the factory. They proved it when we said BS.

 

I believe it. I used to autocross an o/t 60's car. One morning after track day I came out to see it had cracked it's windshield overnight. I'm sure the body twist did it.

 

Don't think anyone is going to call b/s as to it adding structural strength. Thing is - to the best of my knowledge these windows were not originally installed using today's version of glue-in urethane, the need was not there for body-on-frame vehicles. Come the advent of unibody (or even subframe) designs there became a need for using the windshield as an active structural member therefore the birth of hard affixing. I'm also pretty sure butyl tape was not actually used by OEM for front or rear gl*** installations. It instead was a similarly designed adhesive but made of different material, butyl is just a more modern aftermarket version of the original.

 

In my experience, the bonded in gl*** seals much better then gl*** installed with rubber gaskets. The rubber seals available today are not nearly as good as they used to be.
Given the choice of bonding the gl*** in with butyl, or installing it with a rubber gasket, the butyl wins.
As a casual observer, the calk tube butyl seems to be a better seal then the butyl roll, but it takes a steady hand to apply the calk tube stuff.

 

Appreciate the reply Gene.

Rubber gaskets aren't an option for this vehicle ('65 Impala). It's either butyl tape or Urethane from a tube. I just ordered two rolls of 5/16" round butyl (front and rear gl***). I'm out of town for a few days, let's hope time doesn't change my decision.

 

Don't you generally use what the factory used to set a window for the time it was built.

 

Yep, I do.


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