SFM5s444 restoration is continuing

[doublemyv]

Oct. 1 2026 Firewall sealer/sound-deadener spray sample.  Using the spray can with straw and spray-handle from cangun1.com I was able to vary the pressure of the product coming out of the straw.  The photos show a light pressure on the trigger on the 2 simulated heater screws on the far left, then moderate pressure connecting the other screws and simulated heater hoses, and finally light pressure crossing the up arrow to the final 2 screws on the right.  Overall, I think this method will replicate the factory spray process pretty well.  Does any of the brain trust on the forum have a better recommendation for this process ?  Thanks, Mark 

[CharlesTurner]

Here's a '65 close in production to yours as a reference.

[J_Speegle]

Should do a fairly good job. Nothing currently seems to produce all the looks since depending on distance, speed and product it often looks like spider webs in some areas while in other (closer and heavier) or rough and bumpy like truck bed liner. Like that you remember the "connect a dot" pattern practiced by the couple of workers who typically applied the product. Might play/test with a greater distance from the surface and a slower speed to get a wider look. You'll have to be the judge since your there in person as you compare to the pictures provided.

Here is just another half dozen original examples from 65 San Jose cars built around the same time as your car. Also check and make sure that the seam on the passenger side, firewall to inner fender panel, has the bead of sealant from top downward but not all the way like the factory did.

Pictures and a few comments. Passenger to driver side





Center main wire loom has been off and replaced. It would have typically - if the pattern connected and the guy was doing his job - had more sealant like below




This cars master cylinder would typically have more sealant around the base but we can see its been removed and replaced at some point. Base can't be seen well from this angle



In this picture we can see that the other wire loom has been replaced and removed from the firewall so it does not have the amount of sealant that there shows on the firewall directly around its base.


Hope this helps.


 

[doublemyv]

Thanks Charles and Jeff,  as always, the pros provide the examples for us to follow.  I will use the photos as a guideline, and play with distance, pressure, and speed to get a wider and maybe spidery look on my test cardboard before application on the firewall.   And yes, I did apply the sealant on the firewall/innerfender junction as you advised and made sure it only went part way down as your photo shows.  Thanks a million,  Mark

[doublemyv]

Well, after several more tests, I think # 5 looks pretty good to replicate the Ford firewall sealer.  It's harder than it looks, and it seems to work the best with very low pressure from the can trigger gun mentioned above in my prior post.    With very low pressure on the trigger, and about 8" away from the test cardboard, and moving faster than I thought was necessary, you end up with the splatter spread out, and minimal actual sealing of the various nuts, firewall pins, wiring, and master cylinder mount.  So I guess the Ford tech that applied the sealer, wasn't too concerned with thorough sealing of every firewall penetration.  What do you guys think of the tests ?  Thanks, Mark

[sg66]

I played around with this a while ago and never landed on something I liked. Did you try a test after cooling the product in a refrigerator? I think that's where I left off on this science project but your heading in the right direction with low pressure and great idea with the cardboard!

[Bob Gaines]

Well, after several more tests, I think # 5 looks pretty good to replicate the Ford firewall sealer.  It's harder than it looks, and it seems to work the best with very low pressure from the can trigger gun mentioned above in my prior post.    With very low pressure on the trigger, and about 8" away from the test cardboard, and moving faster than I thought was necessary, you end up with the splatter spread out, and minimal actual sealing of the various nuts, firewall pins, wiring, and master cylinder mount.  So I guess the Ford tech that applied the sealer, wasn't too concerned with thorough sealing of every firewall penetration.  What do you guys think of the tests ?  Thanks, Mark

I would try using a combination of your undercoat product and some aerosol can 3M spray adhesive. That product typically sprays out in the string look texture.Those two in combination and maybe going back over the two products with some appropriate sheen black paint to color the whitish string looking adhesive may give the desired effect.