Another smoothed firewall question

[69Myway]

I welded and filled my firewall earlier this year before I put the car on the rotisserie.

I don't like leaving the seam, and opted for a full smooth look.

The problem is it took a lot of filler to get it all flush and smooth.

I am now back on the firewall and as you would guess it, noticed a crack starting in a spot.

So...I am digging it all out now.

All the large holes are filled with metal. The wall is just so wavy and imperfect that it will be impossible to make flat without lots of filler.


So...is it possible to cut one large flat piece and weld it from edge to edge, grind it, then only apply filler as needed at the seam?

I also want to get rid of the indention just behind the motor. I am running an LT1 so I don't need any indention for a distributor.


?????

[OHCbird]

Did you do something like DSE's plate?

[TonyL]

to answer your question. yes. you should remove with a cutting wheel any "raised" areas that would cause your new fabbed peice of metal plate not to sit flat on the panel. weld around the perimiter and plug weld in places so you dont get rattles. (dont forget weld through primer) Far less filler would be required this way, and you'll be far happier with the results.

[69Myway]

DSE uses the one plate to reach across the blower opening and core opening. I did seperate plates and plugged up all the holes.

I have all low areas that require 1/8" or more filler to bring them up level with the top and bottom of the firewall.

It seems as if a new plate of metal should be stretched over the majority of it and welded in place (thanks for the reminder on the weld through primer...that is good stuff).

If I am going to that extreme, I am wondering if I can weld a panel with some style on there (like the scoops that are in front of the rear tire on the 69 etc) for some extra kick, instead of a dead flat space.

[69Myway]

BTW...what would you guys think if I could get a roof panel from a van or SUV, and or floor panel from the bed of a truck (ribs), and weld that across the firewall to give me the smooth look, and add some style with the ribs??????

[69Myway]

Or...what if I cut out the rear panel from a CHEVROLET pick up truck tail gate and fused that into the firewall. It would then have the embossed raised letters. They have large and small versions. Now...getting one that is not all smashed up already would be a trick.

[David Sloan]

I think i would like to see that !! Might just look good !! Get to work!!!

[Steve1968LS2]

We used two pieces of plate steel for the new firewall.. you can see in this this pic the where the center seem was ground down... I think if you use the right thickness of steel then you won't have the wavy problem. They used very little filler to finish up the firewall.



Trust me.. you DO NOT want to skimp on the firewall.. I can attest to the pain of having to pull the whole driveline back out of the car to fix a badly done one :(

[69Myway]

Steve,

When I went to your site and saw the problems you had with yours...it made me start to think about mine. I had basically welded it closed and filled it up with the plastic stuff.

I felt very confident about my work...but, it is a recipe for problems later.

Been doing research today. Been checking out the roof lines on different vehicles with an eye towards making it fit the Camaro.

I have guy getting a sheet of 20 gauge for me this week in case I go back with the dead flat look.

[69Myway]

Quick question.

I have the opportunity to get either 20 gauge or 16 gauge sheet steel to do the firewall cover.


I am not concerned about adding extra weight to the car.

Which one do you think I should get?

[69Myway]

It looks like I am going with 20 gauge as that is what the race shop has for me right now.


What I did was dig all the filler out.

I made a cardboard template of a panel that covers everything.

We are making one out of steel and I will upload the pics as I go.

[next69]

When you guys smoothed your firewalls did you remove the original firewall first, or just put new metal over the existing firewall and plug weld from behind to prevent rattles. It seems like it would be easier to remove the old firewall because you are trying to lay a smooth panel over a panel that is not smooth.

[J68Bird]

I just finished mine. I did cut out the heater section so the panel would lay flat. I wanted to keep the seam, but it took alot of welding to fill it. Even though I took my time there was still some distortion from the heat. I've worked the panel with a hammer & dolly and a shrinking disk and it's almost flat now.


J .Clear
68 Firebird Conv.

[69Myway]

I am very happy with this so far. I want to thank all of you guys for pushing, challenging, and setting the bar higher with each new project. It helps me aim for more excellent work. I never strive for perfection, but I do strive to do it right and make it last.


I don't have a pic yet with the first filler, but it is MINIMAL and only around the edges. This is going to be great.

Notice I also filled the cage nut windows.

After this Hurricane passes, I can make some more progress.

[Andrew McBride]

looks great

Andrew

[next69]

Hey, your firewall looks great. I was wondering if you removed the original firewall, or did you just lay new sheetmetal over the old?

[69Myway]

I cleaned, prepped, re-seam sealed, zinc primed....then installed the new one over the original. So, it is more or less a simple skin.


If you notice, I also dropped it a bit over the trans. The LT1 does not require the same room in the rear so I brought it down smooth.

[69Myway]

Yes!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !

How do you like me now?

I ground down the spot welds then used the fiberglass reinforced filler to slick the plate into the old firewall surface. I topped that off with some light weight filler as needed. I used a 17" hand board and worked the entire panel to remedy some minor warp from the heat/welding process.

It required some skim coating to get it just right.

Notice how nice the new trans hump hole opening came out. I dropped and filled it so there is nothing on the wall until the trans hole opens.

You can also see where I filled in the windows to the sub frame mounting cage nut holes.

The first pic is the metal etch primer. I also wire wheeled the windshield chanel and whiz wheeled it to bare metal so I could get a good solid bite from the etching primer in that chanel.



Finally, I nibbed out som small problems and shot it with erothane primer/sealer. Now, I will guide coat and minor fill as needed. My thought at this time is to bring the racing stripes right off the cowl and down the wall since it should be able to work well considering how smooth it is now. Also, I am going to pick up from the tape line in the tunnel and bring the truck bed liner coating back up and around the steering column hole area and down around the bottom edge of the wall.

[nitrovette]

WOW ,chris that is looking sharp,nice job.They look so much better smoothed.