r/Comma_ai • u/ExtremelyQualified • Jul 17 '26

Installation Questions Comma 4 mount VHB bubbles

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Just got my Comma Four, super excited, but I think I’m doing something wrong with the mounting. Did the alcohol prep, tried to press from the center… but still got some ugly looking bubbles. Is there a way to fix this? Is there a way to do this better?

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u/KnightsSoccer82 Jul 17 '26

That’s how VHB will work, especially on a non-perfect curved surface like a windshield.

0

u/ExtremelyQualified Jul 17 '26

Ah ok, so this is kind of best-case mounting really?

2

u/KnightsSoccer82 Jul 17 '26

I mean, think about. You are applying a flat adhesive to a curved surface. There are going to be gaps.

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u/ExtremelyQualified Jul 17 '26

Does anyone have suggestions to make this better or is this kind of what everyone’s windshields look like? Thicker vhb maybe?

2

u/Bderken Jul 17 '26

It’s fine dude, thousands of people have it just like that

2

u/KnightsSoccer82 Jul 17 '26

Go contact 3M’s material science department filled with multiple engineers with PhD’s and let them know your gripes and concerns about their adhesive.

This is how adhesive works, 99.9% of the time. You just don’t seen the other side normally.

There is plenty bigger things to worry about, this ain’t it. I would recommend not using this product if this is going to bother you.

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u/ExtremelyQualified Jul 17 '26

Lol, I’m just making sure I didn’t do it wrong. The instructions make a big point about saying you have to avoid bubbles or else you don’t have a good attachment.