How should I fill firewall holes

[gigamanx]

Did a little searching and can't seem to find a good answer. I'd like to start filling some of the firewall holes I know I won't need on the cab. I've started marking the ones that can go. What is a good method of getting pieces to fill the holes? For the smaller screw type holes, I tried welding one and just made it bigger by melting the edge of the hole, so that's obviously not the way to do it haha. I don't want to replace the metal with a single sheet since I like the curves and bumps of the original one.

Would love to hear experiences and tips on smoothing things out!

[dsraven]

try

https://www.welderseries.com/

on line for some sheet metal plugs for cheap, or shop locally. clean the area well first, then if you grab a cheap stepped drill from harbor freight or whatever you can get a bunch of plugs the same size then drill the cab hole to fit the plug. that way the hole is nice and clean for welding. you can use a copper plate behind so if you have a little burn through it will stay put (weld doesn't stick to the copper). do a series of tacks around the plug, say 2 or 3, then carry on to the next plug because if you weld the whole thing at once you will warp the firewall or wherever you are welding. tack then move on, come back and extend the tack, then move on to allow cooling. soon the plug will be done. you can wipe with a wet rag to help cool and shrink the area so it doesn't warp too bad.

[bowt1ed]

I just cut out slightly over-sized sheet metal circles, cleaned surfaces/edges, placed on the inside of firewall (helper to hold tight against), and welded from outside. With that thin a gauge, not too much filler required. As I recall, filled around 45 of them.

Cheers, Jim

[Dan in Pasadena]

Originally Posted by bowt1ed

I just cut out slightly over-sized sheet metal circles, cleaned surfaces/edges, placed on the inside of firewall (helper to hold tight against), and welded from outside. With that thin a gauge, not too much filler required. As I recall, filled around 45 of them.

Cheers, Jim

^^^This^^^ is what was done with my firewall too. We stopped counting at 50 holes!

Came out good and I had wondered if it would repair decently.

[bennylava]

Originally Posted by bowt1ed

As I recall, I filled around 45 of them.

I can only imagine the massive cost of having a shop do that. Any idea what it would cost?

[Dave0]

I filled over 65 in mine and almost every one was a factory hole!

[b-mac]

I'd recommend one of these.

http://www.eastwood.com/magnetic-hol...8aAkpwEALw_wcB

[gigamanx]

Originally Posted by dsraven

try

https://www.welderseries.com/

on line for some sheet metal plugs for cheap, or shop locally. clean the area well first, then if you grab a cheap stepped drill from harbor freight or whatever you can get a bunch of plugs the same size then drill the cab hole to fit the plug. that way the hole is nice and clean for welding. you can use a copper plate behind so if you have a little burn through it will stay put (weld doesn't stick to the copper). do a series of tacks around the plug, say 2 or 3, then carry on to the next plug because if you weld the whole thing at once you will warp the firewall or wherever you are welding. tack then move on, come back and extend the tack, then move on to allow cooling. soon the plug will be done. you can wipe with a wet rag to help cool and shrink the area so it doesn't warp too bad.

See now this is why I asked all you fine smart people... Funny they are called unholes. Here I was thinking I need to cut perfectly shaped pieces to fit in all manner of crazy spots on the firewall. I did not think of my step drill bits.

Originally Posted by bowt1ed

I just cut out slightly over-sized sheet metal circles, cleaned surfaces/edges, placed on the inside of firewall (helper to hold tight against), and welded from outside. With that thin a gauge, not too much filler required. As I recall, filled around 45 of them.

Cheers, Jim

That is a ridiculously smooth firewall. Nice job!

https://www.welderseries.com/Unholes-p50202282

[dsraven]

if you need a hand to hold the plug, and you have a few extra minutes to spare for fabbing up a quick tool, you can make a magnetic plug holder from a C clamp. just get a cheap steel C clamp and cut the very bottom off, like the bottom of the C part, so you have a vertical portion left there plus the top part of the C with the screw down part still intact. now drill up into the vertical section and run some threads into it. find a round magnet that sticks well and has a hole in the middle and is also smaller in diameter than the distance over to the threaded part of the C clamp. some dollar stores will have everything you need, the clamp and the magnet. the magnets sometimes are sold with a hook on them that is bolted on through a hole in the middle, perfect. toss the hook in the junk bin. bolt the magnet onto the bottom of the C clamp so it will hold the clamp vertical. now you can magnet the clamp onto the back side of the firewall and then screw the threaded part down so it sits level with the sheet metal and holds the plug in place. the clamp comes in handy for other stuff too.

or just use a magnet to hold the plug but then the magnetics will deform the mig welder and cause spatter. of you are torch welding then it won't matter, haha.

I think I spend more time making tools than I do working on the truck. dough head alert.

[fourspeedwagon]

Well, Yesterday I would’ve said to do exactly what dsraven said.. but now I’m wondering if Jim and Dan’s method isn’t the way to go.
I may be picking up a new-to-me ‘51, and noticed it has quite the shotgun scatter of holes. Only thing different I was thinking was to zap a mig wire to it as a handle so I wouldn’t need magnets and cut off C clamps etc.

[dsraven]

this is what I did. 16ga. totally flat now.

[dsraven]

the rest of the story. cut it out so it will fit over the envoy donor

[dsraven]

the rest of the story. it became a donor for the envoy frame swap. really not that much more work to replace the whole thing though compared to plugging and finishing all the holes. especially if the floor is also rotten. the point is not my swap, it is the work involved to just replace the whole thing. wasn't that much really once I figured out how big to make the recess. need to remember to leave room for the gas pedal though. some guys just do a square recess so that would be easier.

[bennylava]

Originally Posted by dsraven

the rest of the story. cut it out so it will fit over the envoy donor

Do you have a build thread on the truck? I'd like to see how far along it is.

[dsraven]

sorry bennylava, no build thread. I tried a couple times and it said I have a thread started but I can't ever seem to find it again. the project has taken so many turns it would prolly crash the server anyway if I started a thread now and added all the stuff from start to where it is now, haha.
the good thing is I have a fully boxed frame with a MII out front and ford 8.8 with 4 link in rear with air ride set up and LS 4.8 4l60 sitting between the rails. it is sitting in my daughters garage while my old 57 gmc body sits on an 04 envoy frame presently. not done by a long shot, but sitting on the frame at least.

[greg_h]

The advice I was given was to find a flat washer that fit the hole, weld it in, and the weld up the small hole in the washer.

[fourspeedwagon]

Wow! Dsraven that extended cab rig is amazing.
Now I’m off to see if there’s a build thread on that. Awesome truck

[iowaboynca]

With all the craftsmanship, i'm a bit embarrassed to say I used various sizes of fender washers. Used either screws or small magnets to hold on to firewall to tack weld.

For the big holes cut out filler out of 18g sheet metal and tack/stitch welded.

You can see the results below.
http://67-72chevytrucks.com/vboard/s...3&postcount=97

[Dave0]

I cut all mine the same size with a throatless shear and a disc grinder.

[hogfarm]

I went to the local machine shop and they gave me a coffee can full of the drops from there punch press,all different sizes

[gigamanx]

Originally Posted by hogfarm

I went to the local machine shop and they gave me a coffee can full of the drops from there punch press,all different sizes

That's a great idea!

[Dan in Pasadena]

Originally Posted by iowaboynca

With all the craftsmanship, i'm a bit embarrassed...

Psh....NO reason to be embarassed. You did the work and if you're pleased with it that's all that matters. Be proud!

[Bigt94550]

Not to hijack but it is on topic...there are 2 welded nuts on the drivers side firewall that hold the emergency brake bracket. Your pics ( Dan and Bowtie) have them gone. Did you weld a nut on the interior firewall or forgo the nut entirely?
Troy

[Scott2]

I used the Bob Drake solution:

https://www.bobdrake.com/FordItem.aspx?Item=HR-1580

Not cheap but I used my time saved from making them to fill in the holes. Just drill the holes to match a plug, use a magnet like the Eastwood already mentioned to hold it, and weld away.

[Dan in Pasadena]

Originally Posted by Bigt94550

Not to hijack but it is on topic...there are 2 welded nuts on the drivers side firewall that hold the emergency brake bracket. Your pics ( Dan and Bowtie) have them gone. Did you weld a nut on the interior firewall or forgo the nut entirely?
Troy

Yes, ground them off and welded studs on the interior side.