How do I fix my grinding errors?

I'm a real beginner at this stuff so I make lots of mistakes and hopefully I learn from them. My latest has been to weld the holes for the reveal moldings on my 49 Chevy. I posted a thread a few days ago and got valuable info so yesterday I welded up one side of the car. The welding got better so it was time to grind the welds. I first ground the weld using the edge of the grind wheel and then finished it off with the flat.

With my lack of knowledge and my desire to get the welds real smooth I took too much off in places. I sprayed some primer on to protect against rust until I can get back to it. Here is what I have:



What do I use to fill this back up? What is the best product? After filling, how do I get the shape the same as the rest of the piece as I realize now it is somewhat rounded?

Thanks for the help. Bill

 

Looks like its time to learn lead work.

 

Don't be so down on yourself. Weld filler metal is much harder than sheet metal therefore, over grinding is very easy to do.

I'm a hack when it comes to body work. I would plastic fill it, sand and go on to the next project. Sorry, that's the way I roll.

 

Have you tried using a abrasive flapper wheel? I cut the top off with the standard grinding disc then smooth it with the flapper.

 

I'm not down on myself...hell my welding improved considerably as I went from hole to hole so if nothing else the other side should go much easier.

I'm just trying to find out how to fix it now that I have done what I did.

And I appreciate any advice on how not to do it with the rest of my holes.

 

Yeah, good place to start to learn the skill of leading. Failing that good old bog 'Filler' will do the job.
Doc.

 

I would use plastic filler because I have not used lead, but I would guess that either works.

One question though. Is there enough metal left where you did the grinding? When you were grinding, did you get "blue" spots easily? If it is thin, maybe you are going to need to do some welding again.

Neal

 

I don't know what kind of tools you have but when I weld a hole I use the edge of a 4" grinder, or a thicker 3" on my air die grinder.

use just the edge of whichever you use, and grind only the weld, NOT the surrounding metal. you do not want to make the sheetmetal any thinner than it already is . when you get it near flush then use the flat side of a 3" sanding disc to perfect it. watch your heat. heat can mess some stuff up... not so much on that panel, but on a hole filled on a flat panel you can warp it easily with too much heat from the grinder.

to fix that just use some mud... doesn't look it would be too thick

 

Your well within "mud range" provided (as mentioned above) that you haven't ground the base metal too thin; If so, it's probably patch time.
If your inexperienced with lead as you point out, I'd stay away from it. At least on this one.... It's much easier to learn one thing at at a time. Follow 49ratfink's advice on the rest of the car as far as grinding is concerned and you shouldn't have any problems.

Rich

 

SOCAL Pete's suggestion is well taken . Use a flexible grinder disc or my favorite - a belt sander which distributes force evenly over a wide area . There are plastic body fillers that use metal filler instead of chalk like the traditional Bondo . Use those , they are way better . AllMetal , Aluma-lead , and Bondo has one now too .

 

You've learned a hard lesson- Good grinding skills are harder to pick up than good welding skills. Unfortunately it's something that can really only be learned by practice, not really something that you can pick up from reading.
Since there is no depth perception in pictures I'm hard pressed to tell you what to do next. I'm leaning towards a GOOD polyester filler- it doesn't look like it's that deep, and filler on molding such as this is a good application.
It looks like you went at it with a hard disk- in the future, as others have stated you need to use the hard disk to top the weld, then use a soft pack to bring it down level with the parent metal. Even that requires practice though- if you hog on it you will end up with a gentle crater surrounding a rounded top. You want to put the soft pack to it so it JUST throws a spark off the weld. Patients and a steady hand will save you a ton of work later on.
Like I said, it's hard to explain and harder to learn, it took me years. If you want to keep at it you might should put down a few welds on a scrap piece of fender or something and practice topping/blending it.

 

A real thin swipe with some finish filler and a little block sanding will fix that right up. Lead would be a huge pain in the ass to use to fix that. (I know it's "traditional" but lead is not a superior filler to a good plastic product like Rage. Lead has it's applications but I don't think this is it)

When you're all done doing your bodywork you should spray the whole car out in fill primer (I like Ultimate 2K but everyone has their favorites) and then block the car out one final time, so your mud work doesn't have to be flawless.

In the future, try grinding your welds with a flap disk. So much cleaner, and I find it's easier to control than a grinding stone. Cost a little more (they don't last like a stone does) but worth every penny.

 

Agreed with the flap disc....I pretty much dont use a stone disk anymore...dont cheap out on the flap disks (IE H.F.) as they dont last worth a shit and you end up spending more money to buy more disks....I use a flap disk that I get at the local hardware store, Blue package (cant remember the brand name) but the product name is 20x...(supposed to last 20 times longer than others) I must say they do last a long time....

 

hard/stone disks have no place in hotrod fabrication. The only time I use em is if I am roughing out some heavy material and I stop WAY short of the final size.

Lots of softer disks with backers that you can use as have been mentioned. I am a new fan of the 80 grits with big holes in em on a small grinder.

 

I think I will stay away from the lead. The metal is not ground thin...it just is ground flat and shows the grind marks compared to the rest of the piece which has somewhat of a curve to it which I didn't notice until after grinding.

As for the plastic filler...what brand should I be looking for? I know there are several different grades or hardness or sand-ability (don't know if I'm using the right words here) so what do I need to look for?

Any tips on working with the filler will be appreciated. In my "tech" bookmarks I have a thread by Overspray called Body tech bondo 101 which gives lots of info so I have a place to start.

 

I'm all for flap discs, but would be interested in trying a little belt sander. Flap discs are more expensive than rock, but I get them bulk. I'm gonna use them. I still use hard discs to prep heavy material, bevels, etc.

 

This is what I use for small imperfections, works on bare metal or you can use it over primer as long as it is ruffed up first.

 

Not sure what you've got for tools, but I really like 3" Roloc-type sanding discs on an angle die grinder. These work great for tight or "sensitive" places like the reveal you pictured. Plus with the air tool, you can feather the throttle a it, as well as pressure.

And I agree with everyone who mentioned the "good" plastic filler for fixing what you got... stuff you get at the auto body supply, not at the major chain discount parts counter.

 

Those aren't grinding errors. They're body filler opportunities.

 

The plastic filler that I use is RAGE GOLD,... kinda expensive as far as filler goes but worth it, mix it , apply it, sand it down with a block and prime it with a quality primer.
Brian.

 

First of all, is that right at the door jam? If so, and you don't have the experience of applying lead...........don't. As for what else to use. I like All-Metal. You can get it from most automotive paint stores or even Eastwood. You might even try using Rage body filler. But which ever, be generous with it, you can take it off easier than you put it on, and you can do the All-Metal with a rasp, or the Rage with sandpaper.

I second you losing the hard/stone disc's unless you're grinding something that will still need work. I use the hell out of flap disc's. I have them to fit my 7 inch grinder, my 4 incher's, and I even found some with the Roloc back on them to use in my pneumatic grinders.....which I use the most. This is a good time to reflect on what you're doing and learn from it. Here's a good tip...... when grinding or sanding, the smaller the wheel or sanding block you use (even on it's edge), the smaller area that is actually being affected. Go with a larger wheel or block and use longer strokes so that you don't do as it shows in the pic. Hope this helps, and keep us up to date on how the fix goes.

Mott

 

I've ordered some Rage Gold and Some Metal Glaze so now I will attempt to learn another new skill.

 

To help cut down on the sanding time, cut the profile of the beltling into a platic spreader. Make it a hair larger than the actual profile. Use this to get the shape real close when you apply the filler.

 

I agree with Slide on this one, I use 3" 3M roloc disc, they come in various grades, very easy to control, makes it easier not to dig a ditch in the surface your grinding and as he say's, you can feather surface easily, pretty pricey, but well worth the money. Sometimes I use a cut-off wheel to knock down the high spot of the weld and then finish with the roloc, work's for me.

 

Some guys might disagree but this is what I use. Ansari 1/8 inch thick wheel on a die grinder. Very very steadily knock down the weld. Take your time. A die grinder should be used gingerly not balls to the walls. You are grinding the weld only. No metal around it should be touched. I prefer 2" 3M roloc dics as I have more control. Grind in an x pattern until it is finished. As you finish it you will learn metal almost has a grain to it just like wood. It will look better finished one direction versus the other. Hope this helps

 

This forum is one of the reasons I've learned so much with my project. Just like this tip...I never would have thought of it on my own.

 

As mentioned before I love the metal glaze for small areas because it is a little more on the runny side compared to rage gold and is easier to sand and feather edge out with no shrinkage. On larger areas I love the rage gold, it is good stuff and is easy to sand. Good luck with your project and keep us posted as your skills enhance. The most important things when it comes to this hobby is to have patience and don't be afriad to ask questions.

 

I've been known to go back and fill the gouges with more weld. It will take more time than a coat of mud but getting it right with steel can be rewarding. You have to be careful and dedicated but there is no reason that it can't be filled with weld. It will take longer and only you will know but that smug feeling can be nice as long as you don't have a holier than thou attitude about it. After a while you'll be more careful. Lots of people use plastic to dress their welds on frames. I go back and add metal where it is low and grind to get that perfect fillet. I'm not doing production work where time is money.

 

That works great and if its thin or low enough, I will do the same. Otherwise I will just use a GOOD QUALITY filler. But with a beginner welder, using weld to fill on already thin metal might be more destructive than constructive.