Fixing a Rust Hole, how dumb am I?

[Regal_Six]

Alright, so I've got the ol burb parked in the garage waiting for a free weekend to do the front ball joints - and I decided to take a look at a little brown spot I had by the fender. Started standing and sure enough it's a little rust spot that's gone all the way though.

I scraped out whatever I could with a dull knife, and drilled the hole out with a 3/8" bit to make sure I have clean metal. I have two questions for literally anyone who's done body work because I've never patched sheet metal before.

There's no way I'm going to get that hole patched with just welding, so I was planning on putting a steel bolt in just a little past the thickness of the metal, putting two good tacks on either side of the bolt and cutting/grinding it smooth before going over with body putty. Any issues with this?

The area with the hole has no rear access, there a little void back there between the fender and the body. There's definitely some dirt and stuff in there - is there anything I can do to slow any rust in there without pulling the fender off?

Any tips appreciated - you can assume I'm a complete moron - I won't mind!

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[strikk]

There are a hundred ways to do this, do what you find to be most comfortable with.

Find some 16 or 18 gauge sheet metal, any clean scrap is fine. Cut out a 3/8th circle to nicely fit in the hole. Coat both sides of this little coin in weld through primer and burn it. grind it smooth and onto some paint.

Or just paint up what is there and find a 3/8 rubber plug to keep the water out

 

[andy396]

Could just use a washer.

As far as preventing further rust, it'll be hard to do anything close to right without pulling the fender.

 

[thegawd]

The access hole is a body drain. There are quite a few and they have rubber grommets closing them off. Around the fender fills up with sand, dirt, salt and whatever else can get in there. Wash these holes out once a year and these probably wont rust at all. My sierra was full on all 4 corners of the truck with sand. These panels were welded over in the passed but no one cleaned them out. What a mess. Simply run a garden hose in every body drain until only water comes out.

My body work is not the best so I wont comment there.... my sierra is a 20 foot truck. LOL however I have and or am replacing a bunch of these panels with the actual complete part, all of the old has to be removed first. I am not an expert LOL.

Al

 

[Regal_Six]

The access hole is a body drain. There are quite a few and they have rubber grommets closing them off. Around the fender fills up with sand, dirt, salt and whatever else can get in there. Wash these holes out once a year and these probably wont rust at all. My sierra was full on all 4 corners of the truck with sand. These panels were welded over in the passed but no one cleaned them out. What a mess. Simply run a garden hose in every body drain until only water comes out.

My body work is not the best so I wont comment there.... my sierra is a 20 foot truck. LOL however I have and or am replacing a bunch of these panels with the actual complete part, all of the old has to be removed first. I am not an expert LOL.

Al

That's actually really helpful, I had no idea there were drain holes to look for. I'm going to fish around and look for it as soon as I get home - if I can get that area cleaned out maybe I can launch some rust converter up into it and that'd be good enough for me to sleep soundly.

Mines hardly even a 20 footer, but I like the thing so much I'm doing whatever I can to keep it alive. I'm gonna be rattle-canning the touch ups and throwing some ebay clear film over it. As long as I can keep the cancer at bay I don't really care if the paint is spotty.

 

[Bone Shaker]

I always weld solid Easy with the heat Take you time. Never thought about the bolt trick. Whatever you use grind down after Welding. Small spots get bigger when you are working on them. Good luck and you got this

 

[letitsnow]

If you don't want to weld, adding a small fiberglass patch works too.

 

[Eveready]

Dunno if any of you guys have done this and it could possibly be a fire hazard so you are on your own. After you clean those voids with water, unless you get them very dry they could rust. Denatured alcohol (shellac thinner) is anhydrous (it soaks up water) and quickly evaporates.

If I were doing this my last flush would be some of that stuff, and then leave it open a while to evaporate, being sure too that it is gone before welding because alcohol will burn. A heat gun or hair dryer might hasten the process.

The alcohol will definitely remove the stray moisture and possibly reduce the potential for rust. I haven't heard of this being done, but I know about these properties of denatured alcohol from other processes I am familiar with. Again YMMV and this is theoretical.

 

[1989GMCSIERRA]

Weld a washer on there grind down weld sand it , filler and repaint. You can also back it with a brass or copper plate then weld to fill. Ty make a special tool for this purpose

 

[Hipster]

Cut a piece of sheet metal to fit the hole, hold it in place with a magnet until you get a couple tacks on it. Grab a couple magnets off the fridge. Grind the paint back from the hole so you get decent welds. I wouldn't use a washer as most are coated with a cad or galv. type coating that body fillers and paint don't like to adhere to. Fiberglass and metal expand and contract at different rates so any repairs done that way can be short lived and if and when it lets loose it wiil be the whole sheet you put on. While weld-thru primers help but they still burn off during welding so if you can get something on the backside when done it helps. paint, undercoating, something to protect it on the back. 3M makes body cavity wax for corrosion protection in a spay can with a tubular wand you can fish up through cracks and crevices to get some protection on the back. You can always unbolt the fender from the wheelhouse and the rear edge and pull it out a touch to get all the crap out and get in there. At the bottom of the fender is that road schmegma or surface rust coming though?