What caulk/adhesive for front spoiler
 

Hey guys I purchased this front spoiler lip for my 996 C4 . It installs onto the factory bumper with 3M tape and screws . Once I have it installed I would like to fill in the seams where the lip meets the front and sides of the bumper . I am thinking an adhesive caulk is the right product .

My car is black and I will have a pro shop prep and paint the bumper. Is Sikaflex 221 a good match for this application ? I basically just want to run a thin bead to transition between the two surfaces . So it needs to be sandable and printable . Is there a better product to use ?

Here is the spoiler.
https://images.app.goo.gl/PrW6mBrdCX6Qx2AaA

I'm thinking a 2-part urethane would be best.

I'd consider some sort of rubber automotive seam filler kinda like weather stripping installed after paint. any vibration or flex will crack anything like caulk over time and compromise the painted spoiler lip.

I hear greatstuff expanding foam is what Ferrari uses.

https://i0.wp.com/cdn.makezine.com/u...00%2C376&ssl=1

^^^^ Haha that's funny 😋

Maybe I should just install the spoiler lip and leave all the finish work to the body shop . That way if any paint adhesion issues I can't be blamed . Hmmm ?

I would leave the entire installation to the body shop, let them pick the product they want to stand behind.

Having now looked at the spoiler you plan to use, I would paint it, then install it, and skip entirely trying to blend it into the bumper.

Spoilers like that are meant to be replaceable. Having them painted makes that a much more expensive proposition.

I replaced the one on my 996TT once during my ownership when it got scratched and have a new spoiler in the box from Porsche for my 997.

Like Java, I would not paint it. Once they get scratched, which they will, it will not look good.

I have considered this . One body shop that gave me a quote suggested to paint the bumper and the spoiler and then assemble .

That’s exactly what I would do and I ran a body shop, years ago.

Good advice thank you 👍

Does your 996 have the painted side skirts or are they black?

No side skirts , I may or may not add in the future . I also added what was called a " Singer style " mini ducktail spoiler to the OEM rear spoiler . My theme is a sleeper C4 . She is black and I am going to add red exterior mirrors .

Then some red graphics and paint the brake calipers red. That's the extent of my vision so far.

i would seal it with some double sided foam tape.

caulk is going to age absolutely atrociously.

I'd use 3M Strip Calk. That's how it's, spelled; it's a sticky rubbery substance that doesn't dry out. It comes in a package of strips about a foot long and about 3/16 in diameter. You'd put it on one side, bolt the parts together and then use a plastic scraper to remove the squeezeout for a perfect seal and perfectly flush.

So it has the normal black matte rockers then? I always thought the black spoiler matched the side sills nicely.

I have red mirrors on my blue car.

My rockers are painted gloss black like the rest of the car . If I decide to add aftermarket rockers they will be GT3 style . But I also like the narrow body look that I currently have .

Do you want to ever remove it? If not, look at two part panel adhesives used in automotive body. Come in a gun with both tubes. But you will not ever take it off. But it will never fall off....

Just my own $.02 since you asked: I would follow Java's suggestion, and then use the tape or have some way for the spoiler to detach in the event of a severe hit, say running into a parking lot concrete bumper or some such. I know you say "I'll never do that", but the chance is there that you will. This will allow you to simply re-attach the spoiler or repaint and then re-attach. It'll save a lot of pain and anguish down the road.

And as for filling the seam, I think it looks much better with the seam not filled. That's why you paint the bumper and spoiler separately.