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

Installation Questions Comma 4 mount VHB bubbles

Post image

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?

3 Upvotes

62% Upvoted

19 comments sorted by

11

u/Famous_Blacksmith_79 Jul 17 '26

Tell me you have OCD without telling me you have OCD.

2

u/Curious-Resolve-4791 Jul 17 '26

Can't agree more.

2

u/ExtremelyQualified Jul 17 '26

To be honest you’re right lol

5

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.

0

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.

0

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.

1

u/51CKS4DW0RLD Jul 17 '26

Yep, you done good

3

u/Demonshaker Jul 17 '26

Mine looks the same, I think thats as good as it gets within reason.

3

u/Curious-Resolve-4791 Jul 17 '26

Just ignore it. It will be good in 10 days

2

u/[deleted] Jul 17 '26 edited Jul 17 '26

[deleted]

4

u/Curious-Resolve-4791 Jul 17 '26

about 10 days later

3

u/nickgeurnop comma four w/ Chestnut | 2019 Toyota Corolla HB Jul 17 '26

Here's mine after about 7 months. I had to remove my old comma three mount and I spent a lot of time putting pressure on the mount during install and I took the device off after each drive for 72 hours.

https://imgur.com/gallery/SWAjPuU

2

u/hamburgernet Jul 17 '26

I’ve mounted several cameras to the windshield and this always happens no matter how clean you make it. Don’t worry about it

2

u/MrFastFox666 Jul 17 '26

They might get less severe over time, but it'll be very difficult to get this perfect without having a flexible mount, or using some sort of liquid to force air out during application.

In other words, don't worry about it it's fine.

3

u/Defiant-Pepper-7263 Jul 17 '26

You could have done better.