what 3M VHB tape do you use?

**ShrimpBurrito** · 09-08-2018, 09:50 PM

What 3M VHB tape is of highest regard here for attaching solar panels to the roof? I've seen numerous discussions on the topic, but since there are several, I am not sure if there is any one that specifically stands out.

I'm just looking to attach a license plate frame to the back, as the plastic ones I've had attached to the tail light have broken several times.

Thanks!
Dave

Craigrrr · 09-09-2018, 08:36 AM

I have used this on my first solar panel, 3M 4941 VHB tape
then on my others I have used 3M VHB Heavy Duty Mounting Tape 5952
both works well

**ShrimpBurrito** · 09-10-2018, 10:56 AM

Thanks, Craig. I see both of those tapes are foam, both are the same thickness, and both are used for a "wide range of materials", including metal. So I'll have to look into other differences.

Anyone else have any input?

Many thanks,
Dave

**rickst29** · 09-10-2018, 01:54 PM

On my 3 panels Solar Panels, the bond has been solid and unmoved for many years. It holds firm, but the adhesive tape did not strip TM paint when I used a putty knife to carefully lift the mounting feet and tape of two "solid" aluminum/glass panels from the roof. (I did that to move them and make lifting a bit more easy.) I have used with both 4x1" aluminum panel mounts (6 mounts per panel, rather than 4); and a flex (using 5" long strips, with 3" gaps letting water drain out between the taped segments.) I think that it would do very well in your license plate frame "horizontal mount", although that has the shear load of the license plate and frame dragging towards the ground, a bit more sheer stress than my flex panel faces from the wind while driving. As with my flex panel, there will be no "weight" pressing into the tape to assists with holding the bond.
This one is inexpensive, handles high heat very well, and it's inexpensive. 1" width is the one you want, RP25 is the optimal thickness for just a bit of flex (to handle shell flex during travel), without providing too much foam, weakening the bond. https://www.amazon.com/gp/product/B007Y7DV4E/

**ShrimpBurrito** · 09-10-2018, 02:48 PM

Thanks for the suggestions. I just talked with 3M tech support, and his recommendation, without my asking about any specific VHB tape, was to go with the 5952, given it would have the highest level of adhesion to both painted and bare metals. I thereafter specifically brought up the 4941 and RP25, and he still thought the 5952 would be the better option.

Given Rick's anecdote about removing paint in the process of removing the tape, I asked about that too, and he said the only good way to remove these tapes while minimizing damage to the mounting surface is to slice the tape lengthwise, as to divide the tape so that each resulting side would be half the thickness of the original tape. The remnant of that process is half the tape still stuck on the surface, but with one side no longer being adhesive. Then, he suggested using a solvent like MEK, acetone, etc. to remove/eat away at that remnant. The choice of solvent depends on which one doesn't also eat away at whatever the material the tape is stuck to, so in our application, I'd want to test in some place to see if the solvent eats away at the TM paint.

Thanks for the feedback!

Dave

**ShrimpBurrito** · 09-10-2018, 02:53 PM

Now that I think of it, I've used acetone on the roof before, so I know that is safe to use without removing paint.

Dave

Craigrrr · 09-10-2018, 03:11 PM

I used a piece of fishing line ran in between tape and solar panel to remove. then I used a chemical remover . It might have been MEK.

Larryjb · 09-10-2018, 05:31 PM

Quote:

Originally Posted by ShrimpBurrito

Now that I think of it, I've used acetone on the roof before, so I know that is safe to use without removing paint.

Dave

Acetone does soften the paint. I know from experience.

It will go to bare metal easily.

Acetone is about the only solvent that removes silicone sealant. This is why I don't use silicone anymore.

BrucePerens · 09-10-2018, 06:01 PM

Acetone strips paint to bare metal on my TM. The Kleer Kote is mostly gone due to UV.

You have the option to use 3m 5200 marine sealant and a caulking gun. Probably much better bond than tape. Takes a week to cure, or there is a faster version. It is holding the braces to my previously-sagging roof, plus a few screws mainly to hold pieces in place while curing and the two shafts that pull up the roof.

**ShrimpBurrito** · 09-10-2018, 06:31 PM

Interesting reports about the acetone. Maybe I just got lucky. I'll be sure to use caution if I choose to try it again.

And now, I just found a roll of 4941 tape in my garage.....the number of different types of tapes is mind boggling.

I forgot about the 5200.....

Dave