After 51 years; my firewall in my 56 looks like Swiss cheese that rats have knawed on! Also some dents; so I decided to get left and right replacement panels from John's F-fun hundred....ordered yesterday. Anybody have any suggestions or tips about installing these? (Yes, I have a mig welder)

 

The main things when welding in replacement panels and patches:
1. Butt the panels, do not overlap. There will always be some shrinkage along the weld seam that will need to be stretched back out, overlapped seams cannot be stretched successfully.
2. Have a great deal of patience! Use 1/4" tacks placed no closer than 6 " apart first go round. Allow to air cool. grind the bead nearly flat and on dolly hammer stretch the tacks and "heat affected zone" (the heat discolored area around the weld) until the panel lies perfectly flat between the tacks once again, should require no more than 3 or 4 taps on each tack but be sure the panels perfectly realign before continuing. Dealing with the shrinkage while it is minor is a lot easier than waiting until the end when warps and oilcans are locked in. Retack any tacks that cracked. If you are getting a lot of cracked tacks, go to your local ESAB welding supply house and have them order you a spool of .025 ESAB "Easy Grind" wire (assuming your MIG will accept 8" spools and .025 wire), it is softer and less likely to crack from hammer welding than any other wire so do NOT accept any substitutes! It will say "Easy Grind" on the spool and it does not have a number designation, have them call ESAB if they claim there is no such thing or something else is equivilent even if it's from ESAB or it's "what all the body shops use". Now make a second series of tacks 1/2 way between the first and repeat all the above (except ordering another spool of wire! ). Continue this way, never welding closer than 6" apart and stretching the shrinkage out until the panel is completely welded in. Trick: pressing a piece of copper sheet tightly against the joint behind where are welding will reduce the chance of blowout and reduce the size of the heat affected zone, hence amount of shrinkage.

 

hey cuz...

unless you got arms like an orangutan this sounds like a two man job... gonna be hard to hammer on one side while reaching thru door or windshield with other to hold dolly.... I have seen some shiny (we like shiny) stainless steel firewall covers that hide all your blems... wiring is run out of site under firewall cover... just another option

BTW ... that "easy grind" wire is better than ice in your beer... well almost , but it does decrease your grinding quite a bit... I use it exclusively

cuz john

 

If you can't find a helper, a porta power can be rigged to back up your hammering. Doesn't need much pressure, the metal being squeezed between the hammer and dolly does the stretching. Taking the doors off also makes it a lot less of a reach. I cut out the cut up metal and replaced it with flat 14 ga. See my gallery.

 

Consider doing the welding from inside the cab. If there's the correct amount of penetration, there will be very little to grind from the engine side. It will grind smoother with less to remove. Who cares about the inside of the cab that will be covered by sound deadener and carpet.?

 

Ah, thanks for all of the good advise....I can't wait to get the panels to see what it is all gonna be involved. The Vendor said that the panels will reach and install where the original ones are spot welded......sounds like no fun de-spotwelding the old ones. It'll be a couple weeks before I get the new panels...... We'll see.

I had actually considered just plugging the holes in the original and making a custom louvered firewall cover....have never seen that done but I think may look cool.

 

There are a number of products on the market to drill out the spot welds. Its a lot cleaner and faster than anything else. Far less destructive too.

When I saw a worker on American Hotrod using an air chisel I thought I was gonna croak. Then again, other guys in the shop walked around while he did it and laughed at him. You get what you pay for Boyd.

 

Spotweld drills are a bit pricey but worth it. drill the new panel in between the original spot welds and plug weld in the new panel. still avoid welding closer than 6" to a warm weld. run some seam sealer around the edge and you're done. I like a heavy duty paint scraper for separating spot welded panels after drilling.

 

I tried the spot weld cutters, but still think that a 3/8" Black & Decker Bullet drill bit works faster and will last much longer.

 

When I drilled out the spotwelds to replace my cab cowl, I used a 3/8 step drill I had from an old set. Worked really well. The 3/8 dia was in the scrap piece and only a pilot hole in the panel I kept. The work went pretty fast. I separated the panels after drilling with a putty knife and hammer. A picture of it:
https://www.ford-trucks.com/user_gal...124605&width=0

 

Sonic, it most likely too late now that you have ordered the parts, but I have done it both ways, and the cover of which J.Niolon speaks is really the way to go for you others thinking of it. The swiss cheese will make for great routing holes for wires and the covers keep everything clean. It is a real simple way to deal. It is also quieter and even keeps more engine heat out of the cab. If a firewall is solid and the objective is the hide holes, this is a great way. J