So today i was trying to mount my roof spoiler and the double sided tape they had on it is ****.. it wont stick at all....can anyone give advice on what to use to make sure it is really stuck down? I tried using a window sealant also but that didnt help at all... Thanks in advance for any and all advice

 

First, the surface you are adhering to must be clean. Wipe the area down with rubbing alcohol to prep it for the double sided tape.
Some roof spoilers have fitment issues. If it's not perfect, it's basically trying to pull itself off as you're trying to install it. Whether it's tape or silicon as an adhesive, you may need to tape it down in place until the adhesive has had time to set.

Just curious... What spoiler are you installing?

 

I am guess it's a Ravspec as a lot of people, myself included, have issues to adherence, particularly at the two ends. I bought extra double sided tape and taped the spoiler to death. The ends still pop up a bit, but not noticeably. I didn't have to use sealant. I would give that a try. Oh, and as Aeson said, clean surface a must.

 

the key for me was to help the adhesion by laying many layers of blue painters tape on the side for proper grip. Worked like a charm, 1.5yrs in and no adhesion issues, btw i did use windshield silicone adhesive.

 

3M exterior double side tape with properly cleaned mounting surface as mentioned above and make sure to apply the tape to the entire footprint of the roof spoiler. My bf has 2 CF lip spoilers on his supra that are installed in this same fashion and they have been on the car for well over 2 years now with no issues.

 

Exactly... that was where I was going with my question

 

I actually went with the Stillen... picked up the 3M tape since the original tape got destroyed....now im just waiting till my friend brings over his heat gun... thanks all for your advice i really appreciate it! will post pics when it is installed...hopefully sometime this weekend

 

^ that could be the problem, there are various adhesion strength 3M tapes, the original one from Stillen is the Heavy-duty 3M which i believe is the strongest double sided foam tape they make. Check to make sure that the 3M you got it also a high grade high adhesion one... Plus the heat gun should be a big plus.