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Adhering stainless firewall to fiberglass body?


Active Member
Those who have done it, what would you suggest I use to stick my firewall to the body? I'm thinking silicone.
Lee, I suggest that you use Loctite Power Grip Instant Grab Heavy Duty Construction Adhesive. It is available at Lowes and I imagine that Home depot will have it also. I used it to adhere some aluminum to ceramic tile and it worked great. Read the label and you'll see that it will glue just about anything to anything.

Thanks Jim. That "Instant Grab," is it like contact cement? If it is, I can't use it, as I have to be able to move the firewall around a little to get everything lined up (I had the stainless water-jetted and it has holes for the steering column, throttle cable and coil wire). The reason I was thinking silicone is it would give me some working time and also might allow me to peel the firewall off in the future if I need to (altough I can't think of any reason I would need to do that).
My advice is to look for something that will take the heat. Most, not all, but most cements/glues will release with heat. Your car will get heat from the motor, and sitting in the sun at a show. I would look for something that is good to at least 250 degrees F.

I think your silicone idea is good. There are lots of silicone adhesives that are rated to some pretty high temps. You might also think about scratching up the surfaces to be glued together for a little more grip.

Lee, the product that I referred to has 24 hours for a full cure. You have plenty of time to work with it then hold it in place with tape or a couple of clamps. I advise you to look at the directions on the tube while in the store, then make up your own mind.


P.S. It is NOT like contact cement. Only one surface needs to have the adhesive applied to it. You are then able to move the piece for precise location.
Lee, i use pins or dowels in the holes to line up SS firewall covers with the loc-tite.

We used liquid nails on dad's. It's been a few years and it's holding up nicely.
Lee_in_KC said:
Those who have done it, what would you suggest I use to stick my firewall to the body? I'm thinking silicone.

I used button head bolts around the edge.
There is an epoxy available that was designed to adhere body patch panels to the body. Although I forget what it's called any good body supply shop should have it. I have used it before with good results as with and type of "glue" the surfaces need to be clean and skuffed up doesn't hurt
Lee, it looks like there are several adhesives out there that will do the job nicely if you do not like to have any fasteners showing. If I were you, I would check each one out by reading the labels to see which one best suits your needs. Then again, if you don't mind fasteners showing there are many different types available from which to choose. It all depends on the look that you want to achieve.

The deed is done. I ended up using silicone adhesive. I scuffed the back of the stainless with a Scotchbrite pad, cleaned it with lacquer thinner, wiped down the 'glass firewall with lacquer thinner (it's mostly primer, with some color around the edges), and stuck it on. I kept the bead of silicone about an inch away from the edges of the stainless, within reach of a putty knife, in case I want to remove it. The center is held on by the throttle cable and the grommet for the coil wire. We'll see how it holds up. I can re-do it with a stronger adhesive if necessary.

I didn't want to use mechanical fasteners. I like the clean look of the stuck-on cover. I'll post pictures after I peel off the protective skin on the shiny side of the stainless. Gonna wait a good 24 hours to make sure the silicone is cured.
Here are some pix...



Lookin' good Lee!

Wasn't tough at all to install with the motor in place. Just slid it in from above and pressed it back. The coil wire grommet, throttle cable and steering column were installed after the stainless was in position and helped hold it in place while the silicone cured. Also used lots of tape around the edges and a couple of wood sticks from the back of the heads to the stainless.

Material is 18 gage mirror-polished stainless ordered from Buy Polished Stainless Steel. I made a template from foam board by sticking it to the firewall with double-sided tape and tracing the edges of the firewall with a pencil onto the foam board. I then drew a 1"x1" grid over all the lines on the foam board (edge of firewall, coil wire hole, throttle cable hole, steering column hole), and used the measurements to do an AutoCAD drawing. I printed that out full size (we have a 42" plotter at my office!) and cut it out very carefully. I then taped that to the firewall to check fit. I made a few small adjustments to some of the lines to get them dead-on, then e-mailed the CAD file to the water jet shop. They converted it to a CNC-compatible file and cut out the piece. It came out damn-near perfect. I misadjusted one of the lines and the piece came out about an 1/8" short on the passenger-side radius where it swings from the vertical to the horizontal. Not really noticeable to the casual observer, but I won't be winning any Ridlers or AMBRs. :cry:

By the way, the body was not on the chassis when I made the template!! Would have been impossible to get the bottom configuration traced with the body on the chassis.
BUTCH!!! Quit worring about firewalls and get your but in the garage and finish your car.The big cruise is this weekend.There will be (going by last year)about 750 cars and 750,000 people lining the streets.NOW GET MOVING!!! BBQ's everywhere

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