Question about firewall.

David Lee · 06-11-2017, 08:55 PM

Today i pulled the dash out of my project. As you can see in the photo below, there are a few holes to fill. Would it better to fill the holes from the interior firewall or fill it from the engine side? Or is either side a viable option?

Thanks

Larry Hill · 06-12-2017, 07:52 AM

The side that is the easiest to weld, grind and metal finish from.

MAURICE BLENDHEIM · 06-12-2017, 11:52 AM

David…A method I have used for years to fill the holes in the firewall is with nails with a large diameter head (un-galvanized). Insert them in the hole from inside the car, standing in the engine bay hold them in place with Visegrips, then tack into place after preparing area around hole. Turn wire speed lower and continue to tack to fill hole using the nail as the filler, 9 times out of 10 the shank of the nail falls to the floor. You then dress it back with 50 Grit. An old body guy showed me that trick to fill moulding holes on a set of doors back in the oxy-acetylene days (40+ years ago). Good Luck…Maurice.

Mark Yacavone · 06-12-2017, 12:12 PM

David, It really depends on what kind of finish and look you are trying to achieve.
As Larry said, you'd probably want to fill and grind from the engine side.
For a quickie, you could make one patch panel that would cover the heater hole and surrounding small holes, all in one shot. Pop rivet it on from the front. A couple of 1/4 -20 bolts and flat washers for the remaining holes , a can of Krylon semi, and you could be done in an hour. All up to you.

Coleydog · 06-12-2017, 01:48 PM

I maybe want to return my car back to stock one day and have basically same question, can I just pop rivet or bolt a piece of aluminum over the whole heater fan opening using existing holes?
I like the idea of using nails, I have other projects to use that idea on.
Just had to return, after thinking of the nails, just had to say that's one heck of an idea, my mind is racing now.

Wayne W · 06-12-2017, 06:00 PM

I am lazy, so, I would use some body panel adhesive on a piece of metal and put it on the inside of the firewall. When it is cured you can finish the engine side smooth and paint. No warpage of the metal and no fires. If it hold quarter panels on cars it will hold those small pieces. In the old days I did it with bondo and they stayed. Mickey Mouse but it works

06-11-2017, 08:55 PM	#1
David Lee VIP Member Join Date: Oct 2007 Posts: 1,168 Likes: 487 Liked 346 Times in 126 Posts	Question about firewall. Today i pulled the dash out of my project. As you can see in the photo below, there are a few holes to fill. Would it better to fill the holes from the interior firewall or fill it from the engine side? Or is either side a viable option? Thanks

06-12-2017, 07:52 AM	#2
Larry Hill Live Reporter Join Date: Oct 2004 Location: Hickory, Ky Posts: 10,629 Likes: 1,922 Liked 10,681 Times in 2,222 Posts	Re: Question about firewall. The side that is the easiest to weld, grind and metal finish from. __________________ IHM Used Parts https://ihmusedparts.com 888-821-1817

06-12-2017, 11:52 AM	#3
MAURICE BLENDHEIM Senior Member Join Date: Jun 2011 Location: Langley (no igloos), British Columbia, Canada Posts: 569 Likes: 307 Liked 284 Times in 87 Posts	Re: Question about firewall. David…A method I have used for years to fill the holes in the firewall is with nails with a large diameter head (un-galvanized). Insert them in the hole from inside the car, standing in the engine bay hold them in place with Visegrips, then tack into place after preparing area around hole. Turn wire speed lower and continue to tack to fill hole using the nail as the filler, 9 times out of 10 the shank of the nail falls to the floor. You then dress it back with 50 Grit. An old body guy showed me that trick to fill moulding holes on a set of doors back in the oxy-acetylene days (40+ years ago). Good Luck…Maurice.

06-12-2017, 12:12 PM	#4
Mark Yacavone Veteran Member Join Date: Mar 2002 Location: Miles From Nowhere Posts: 7,809 Likes: 2,900 Liked 5,114 Times in 1,948 Posts	Re: Question about firewall. David, It really depends on what kind of finish and look you are trying to achieve. As Larry said, you'd probably want to fill and grind from the engine side. For a quickie, you could make one patch panel that would cover the heater hole and surrounding small holes, all in one shot. Pop rivet it on from the front. A couple of 1/4 -20 bolts and flat washers for the remaining holes , a can of Krylon semi, and you could be done in an hour. All up to you. __________________ "We are lucky we don't get as much Government as we pay for." Will Rogers

06-12-2017, 01:48 PM	#5
Coleydog Senior Member Join Date: Jul 2014 Posts: 569 Likes: 36 Liked 53 Times in 38 Posts	Re: Question about firewall. I maybe want to return my car back to stock one day and have basically same question, can I just pop rivet or bolt a piece of aluminum over the whole heater fan opening using existing holes? I like the idea of using nails, I have other projects to use that idea on. Just had to return, after thinking of the nails, just had to say that's one heck of an idea, my mind is racing now. Last edited by Coleydog; 06-12-2017 at 01:51 PM.

06-12-2017, 06:00 PM	#6
Wayne W Junior Member Join Date: Aug 2010 Posts: 91 Likes: 8 Liked 3 Times in 1 Post	Re: Question about firewall. I am lazy, so, I would use some body panel adhesive on a piece of metal and put it on the inside of the firewall. When it is cured you can finish the engine side smooth and paint. No warpage of the metal and no fires. If it hold quarter panels on cars it will hold those small pieces. In the old days I did it with bondo and they stayed. Mickey Mouse but it works