Im looking for a simple quick way that will fill the holes in my firewall without just welding in a sheet of steel in place of it, it has 15-20 holes in it some small like 3\8 up to some that are an inch or so. might have to zoom in a bit to see them all....
Depends on your skills and abilities, if you are half decent with a mig you can put a steel patch behind them and weld in from the front, then fill with plastic filler. holes less than about 3/8" you should be able to fill without the patch. some guys use a big chunk of copper to back up the hole when filling, it seems to help keep from burning thru so easily. tig or gas welding in a plug of sheet metal is the way to make it look nice from the back too....and would require hammer work as you go....
Small ones, carriage bolts if you're gonna paint em, chrome bumper bolts if you're gonna bling em. Large holes, maybe electric box knockout plugs? Not the prettiest, but not welded Or you could just glass & putty. Good luck.
use a copper backing like mentioned for the smaller ones..make sheetmetal plugs and weld them in on the larger ones..theres no need to not do things properly...
Only15-20 holes? Sheee-it... mine had 46! I cut plugs and gas welded them in. hammerwelding as I went to keep it flat. That firewall is going to get a lot of "cowl shake" and plastic will just crack out.
Find someone who works in a fab shop, like FoMoCo. Then, have them give you a bucket full of "slugs" to weld in behind said holes. Oh, wait, I just gave my "secret" away. Jay
I cut plugs for the larger holes and weleded them up. The smaller holes, I used a peice of Brass (Copper works the same) solid rod about 5 inches long and 2 inches in diamater. Hold it behind the hole, weld the hole from the engine side and grind it clean. Use a flapper wheel for the final grinding. Youll barely see it inside at all. For copper, you can just go to Local Home improvment store, get a peice of copper tubing, and hammer it flat on the end and bend to an "L" shape to hold against the firewall. Have the person holding the copper inside use vice grips and gloves!!!!!!!
Another way is to get a metal hole punch ala a paper hole punch. They make them with swapable different size 'hole punch' bits. Punch out a variety of said 'slugs' from 18g or 20g sheet. Then, use a step drill to drill out each hole to one you have a 'slug' to fit. Pop the slug in, hammer/dolly it which will stretch it and make it snug. Then O/A it and hammer it, or TIG it if you have more money than me. This takes longer and the punch is a bit pricey, but it's a true metal repair and once you have the tools, you can use them for and fix all kinds of messes that you wouldn't have previously messed with. If you do it right, it'll be VERY hard to tell they were ever there, even before painting...
guys are you kidding just smooth panel the firewall super clean, or if you want the factory look there are people repopping firewall skins
I will assume you are going to use a mig. For the small holes place a piece of flat copper which was stated earlier on the back side. Have a buddy hold it or I have used duct tape if I am alone. Pull the trigger and do it. Hit it with air immediately so it does not warp. The copper absorbs the heat and it holds up the puddle. For the bigger holes cut slugs that are slightly smaller so you get good welding penetration. Magnets are a tin smiths best friend. Use them to hold the slugs flush and tack them in. I prefer butt welds. I carefully knock down the welds with a die grinder until I can barely feel them with my fingernail. I then grind in an X pattern with a rolloc disc. I hope this helps.
before you start welding up the holes make sure you know what holes your not going to use .i wanted to hide as many wires as i could .battery is the trunk mounted the solenoid & control box on the inside of the firewall.all wires and cables run under motor .the cables come in on the pass side kick panel.the few wires that come off the motor go into the firewall behind the pass valve cover.
Small holes 5/16 and smaller i just fill with weld. larger holes i trace in cardboard and then cut them out of sheetmetal, then use a bit of tape to hold them FLUSH in the hole and tack in all around cooling your weld with air (no water) then slowly weld your way around it. try to weld even on each side so if it warps even slightly it doesnt all build up all around to a big buldge. Also make sure you grind away the paint around the hole on both sides and clean so your welds don't get porosity. I prefer TIG or gas welding because its easier to hammer flat. This is how we do it at my shop and i can't imagine doing it any other way especially using a gob of filler.
tip--Remove firewall if possible. Weld from back side. Use copper backing bar as stated above to fill small holes with weld. Use big assed magnet to hold sheet metal "plugs" in place for tacking on large holes. By doing all the welding from the backside, very litle grinding of weld and very little bondo work required on exposed side.---Or---cheat like Hell. as we did in the sixties---make a full sized cardboard template of the entire firewall and have it cut for you from polished stainless steel. Attach to old firewall with polished stainless bolts around perimeter.
i like the idea of the knock outs. i think i'm going to go with that. spot welded from the inside, then spray truck bed coating on the inside of the firewall and floor. in regards to the red paint...i can always rattle can it again.
hey man as you know i have the same cab as you, i did just like these guys are recommending, just weld up the smaller ones and you'll have to cut out like 8 patches max for those bigger holes, then weld em up, smooth them and you're good to go. I welded, ground, did filler and painted it all in one day it's not that hard, just go for it. before, just like yours after, in this pic the paint looks a little wack but that's just the picture, people ask me all the time where the aftermarket firewall came from, and can't believe it when i tell em "nope that's stock"
thanks man, i welded up the smaller ones and made patches that i just put behind the bigger holes and welded them up, then filled it.
When I bought my coupe, it had an aftermarket recessed firewall already installed. However, when I fabbed my motor mounts I inadvertantly put the motor an inch or so too far back and that firewall had to be moved back. I had a friend put two bends in a new sheet of 16ga. steel and a couple friendly HAMBers, (thanks Tim and Glenn!), came over and helped me tack into place. I spent another hour or so finishing the welding and then another six or eight smoothing it all out. After painting the checks, I'd have to say that all that time was well spend. I've gotten to the point after reading posts on here about other guys doing bad work that I plan things out so they're done right and done well. The last thing I want is to someone to buy this coupe later and then get on here and bad mouth my work and another HAMBer know it was my car and my work. I had an old graphic arts teacher who used to say if you got time to do something a second time, you had time to do it right the first time. Whether you plug the holes or repalce the whole firewall, do it right the first time and you'll be far happier in the end. Vance
I had 75-80ish holes in the firewall of my truck ranging from the size of a pencil tip to the size of a couple heater hoses put together. Most of them just got welded up while the bigger ones received some small patch panels. Lots of welding and grinding, but well worth the effort. Good luck.
Hey antihuman, go to this thread, it's like it was written with guys like you in mind! http://www.jalopyjournal.com/forum/showthread.php?t=199760 Vance
Here's mine on my 56 Ford pickup project. I think there were between 60 and 70 holes total. I filled them individually. Some of them I cut filler pieces and some of them I just welded up. I backed them up with a chunk of brass while I was welding. It acted as a heat sink and held the filler pieces in place. I used magnets, vicegrips and duct tape to hold the brass in place while I was welding. And I'm not finished, gotta figure out what I want to do with the brake booster. Larry T
Here is the punch press that I posted a link to on the above link... http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=91510 And it's only $25! Vance
Or you could just get a tube of Shoe-Goo, Weatherstrip glue, or some other kind of rubber in a tube to keep the rain out...
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