How should I fill firewall holes

[Khaus]

How about bead rolled firewall filler panels from LS Fab? $140 and give a super clean and custom look to the engine bay. Instruction available on the website to help with the install and can be used a replacement panel or put over top the original firewall if wanted.

[dsraven]

If you want the stock look, and are not afraid of work,
Drill hole with step drill to get it round and a normal size you can buy filler plugs for
Clean area around hole to bare metal for a good weld
Buy some "unholes" from welders series online
Hold in with a magnet till tacked. Magnets distort weld so take them off asap
Weld plug in after racks completed in 4 spots around the circle
Beware of heat build up and distortion caused from that. If you have a helper have them hold a dolly on the backside while still smoking from the weld. Then hammer the weld a few times to help with the shrinkage caused from the weld heat/cool.

Or, glue a larger plug on the backside and then fill the void with bondo if you dont have a welder

[Dan in Pasadena]

I suppose someone should mention one other alternative:

Aftermarket suppliers use to make a fiberglas sheet that covered the stock firewall and it had a recess in the center too. It simply bolted in behind the hood hinges and the top was shaped exactly to fit under/up against the factory pinch weld.

I don't see it offered on the one site I knew used to sell them: No Limit Engineering

CORRECTION: Gibbons lists a part number CH523 Smooth Firewall Cover. Maybe it's this part. No pics on their site.

[MARTINSR]

This is only for the small holes up to a half inch but a great trick I learned years ago from a Ron Covell basic metal working VHS tape, yes a VHS tape, that's how long ago we are talking. It was shown in the first few minutes of the video and I remember stopping it and saying to my wife, "I could take this tape out and throw it in the garbage right now, that one trick was worth what I paid for it and more!"

What you use is the metal you punch out of a hole using a Roper Whitney punch like this, the XX.



Or this one, but the holes are much smaller, the "jr."



I have to say, if you are doing a fair amount of fab work, these tools are a MUST HAVE. But in this case, you are just punching a hole in a piece of scrap metal. The piece of metal you punch out has a big dent in the middle, the piece is stretched up a little bit. You then take a hole you want to fill and you open it up using a variable bit or step bit until the hole barely fits the piece you punched out of the scrap metal. You put that piece in the hole and then with a dolly on the back you tape the piece with a flat body hammer and the piece gets larger because of the dent sticking up is now pressing into that piece and spreading it. The piece now fills the hole and stays there! A tiny bead around the edge and wham, no more hole.

Oh, and that punch, you can get dies to punch square holes and oblong holes and many others, I use them all the time! Awesome tools to have in your box.

Brian

[gigamanx]

Originally Posted by bowt1ed

I just cut out slightly over-sized sheet metal circles

How did you cut them out?

So far, various sized washers or just going to the local metal shop for some scraps seems to be the way to go. I like all these genius little tools made from things laying around. I'm new to welding, so my mind doesn't wrap around the idea that I can build all manner of little dohickies for the garage.

[_Ogre]

for any hole .5'' or under i just welded them closed while holding a piece of brass on the back side
weld won't stick to the brass and the brass acts as a heat sink to prevent weld blow out
a piece of flattened copper pipe works well too, it just gets really hot quickly

for bigger holes i just welded scrap 16 ga squares, carpet covers them well

i shaved the firewall flange while i was at it

[Jesse Z]

Someone prior owner filled all the holes in my firewall, but I can't figure out how. There appear to be plugs inserted in every hole that fit so perfectly without ever being welded that it literally requires a magnifying glass to see them - primer would no doubt cover them completely. Anyone know how this was done?

[Donaldo]

I don't usually use the 'F'ord word, but Bob Drake in Oregon offers a graduated set of filler plugs. I cut my own, mig welded and ground flush.

[gigamanx]

I'm going to go nosey around HF and Lowes and see if I can't find a combination of bits that can make one of these. The tool is sweet, the price not so much.

[b-mac]

My original copper backing was a piece of pipe smashed flat at one end. But as someone mentioned, it get's hot quick, and you need a second hand for that or a spoon. Whatever you design, keep the magnet away from the weld. Heat will cause it to lose magnetism.

[MARTINSR]

I do think those are good proportions for sure.

Brian

[sevt_chevelle]

Yep, those Roper Whitney punches are awesome. I used mine all the time to punch holes on new metal for plug welding or spot welding. I don't think I've ever seen another body tech with one in their box. You can also make your own "backing plates" and use clecos for a nice tight no gap butt joint.

If it were me, I would make my own plugs or buy some drops from a local machine/welding shop, fit them up for a nice butt weld and weld them up. I just prefer to do a repair that is invisible from both sides.

[MARTINSR]

Originally Posted by sevt_chevelle

Yep, those Roper Whitney punches are awesome. I used mine all the time to punch holes on new metal for plug welding or spot welding. I don't think I've ever seen another body tech with one in their box. You can also make your own "backing plates" and use clecos for a nice tight no gap butt joint.

If it were me, I would make my own plugs or buy some drops from a local machine/welding shop, fit them up for a nice butt weld and weld them up. I just prefer to do a repair that is invisible from both sides.

You haven't personally seen my tool box but you have now met a tech with one, and only only one but two. I got the XX many years ago and was rocking and rolling with it and then at an estate sale I found an Jr for something crazy like $5 and got it. It's a real vintage one in a metal case, I love using it thinking about the old guy who once owned it. I got a number of nice tools from that estate sale including some knock out plugs, those are very useful too.

Brian

[Warrens69GMC]

Some good info here!!

[Black_Sheep]

I wanted an overall clean, smooth look so I did a steel overlay. As the pictures show, no welding was involved. I resisted "gluing" them on but a couple experienced bodymen convinced me that it was the way to go due to no warpage and minimal finishing associated with the process.

Fitting poster board templates



After prepping I used 3M panel bond adhesive to attach the 18 gauge sheet metal panels.



Edges beveled and blended with filler.



Primed and painted...



I'm really happy with the end result

[gigamanx]

Originally Posted by Black_Sheep

I wanted an overall clean, smooth look so I did a steel overlay. As the pictures show, no welding was involved. I resisted "gluing" them on but a couple experienced bodymen convinced me that it was the way to go due to no warpage and minimal finishing associated with the process.

Fitting poster board templates



After prepping I used 3M panel bond adhesive to attach the 18 gauge sheet metal panels.



Edges beveled and blended with filler.



Primed and painted...



I'm really happy with the end result

Very cool. I like the edge blending around the firewall cut out. I was planning on doing some work last weekend on mine and ended up slicing my hand open drilling some sheet metal.

Life lesson: Don't hold onto a stationary thing while using a spinning thing.

[ptc]

If you know an electrician with a toolbox, he probably has a whole bunch of 1/2", 3/4", and 1" KO punch outs from metal boxes. Those work good too for larger holes. or just buy a few metal boxes from HD or lowes and take em out yourself.

Also roofing nails work good for small holes - they have a BIG head....

[dsraven]

just try to get the knock outs that are plain metal, not zinc coated.

[gigamanx]

Originally Posted by dsraven

just try to get the knock outs that are plain metal, not zinc coated.

Haha, I had some outside and ran out to check...dang it zinc.

[gigamanx]

borrowed from another thread, just throwing the link in here for a future couch mechanic

Hole fill kit

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