proper weld grinding?

[flcobra]

hello, i've only done a few repairs before and i'm not sure that what my dad taught me is correct. after welding i've always ground the weld down with a medium size electric angle grinder with just a regular old grinding disc on it then filled with filler. now i'm working on a hood that need's to be right and i'm not sure this is the right way to do it.
do i need to use a air angle grinder and if so what grit discs? or will the way dad taught me work ok?:confused:
thanks, rob

[Roch_Greg]

The type of tool isn't as important as the grit or abrasiveness of the disk/stone being used although some will say that grinding can produce heat which can warp metal if not careful.

That said whether it's electric or air powered your going to be needing a grinder to take the weld down. Some will use grinding disks and others will use flap wheels. Some folks even using cutting disks to knock the bead down till it's almost flush then use one of the other means to finish off the metal.

Now some will say they don't grind the beads down till it's flush with the surrounding metal so as to not take off too much of the surrounding sheet metal.

There are welding wire products out there that are suppose to be easier to grind down "Twenty Gauge" and "Easy Grind" but the best way to avoid a lot of grinding is to not have a weld that needs it.

Your dad did show you right you'll just need to work on your technique.

Greg

[56Ford]

I use a 60 grit-sometimes 40grit disc in an air grinder. It's more gentle than a regular hard grinding disc.

when I worked at a large fab shop. the grinders used nothing but flap wheels on parts prior to me painting them.

I'd just use what you're comfortable with, but on a highly visible surface like the hood panel, take it a little at a time.

[flcobra]

thanks Greg. i'll keep after it the way i learned.
rob

[flcobra]

thank u 56ford i'll just take my time and skip around so i dont cause to much heat
thanks everyone this forum is the best

[Roch_Greg]

Try using the "push" method wend welding. This is where the tip of the gun is angled slightly in the direction your welding and you sort of "push" the puddle along.

It will give a little less penetration but you should be able to lay a bead that's not so high and use less heat.

I just got my welder a few months ago and finally got the balls up to start my projects on the Regal. First off the bat I had to pick a high on the body and obvious panel to work on, the roof. Right below a body line yet.

Managed not to warp or mangle anything but brother there was some grinding to do and I'm filling w/USC's All Metal.

Just watch what your doing and keep practicing you'll be fine.

[SHOWCAR FINISH]

I agree.

When the weld needs to be ground absolutely flush with no comprimises I was taught to drag for a better penetration. Could always move slower to but that's not a good thing when welding.

[Lost in NJ]

I have found that the flap disks on a 4" grinders to be the most effective way to grind down welds. The flap disk will just polish once you hit flat metal. I also use a bunch of other grinding wheels when needed for detail. Do not over look a Dremel and the fiber cut off wheel for detail grinding.

Since you are grinding welds heat is not an issue.

First you must understand that every weld is a shrink point.

You have to grind down the weld blob before you correct the shrinkage from welding. You must grind down both side of the weld. Then you need to correct the shrinkage with hammer on dolly hits.

[SHOWCAR FINISH]

grind down both sides of the weld?:confused: Never heard of that.

I do think the fiber wheel works well though. He's right about welds shrinking the metal. Hammer on dolly works great with light overlapping blows.

[56Ford]

I grind both sides of the weld all the time especially on restorations.

[SHOWCAR FINISH]

So I imagine these are FULL restores where the picky guy will actually inspect behind panels and all. Sounds like something for looks. Pretty interesting.

[56Ford]

So I imagine these are FULL restores where the picky guy will actually inspect behind panels and all. Sounds like something for looks. Pretty interesting.

Even partial restorations I grind both sides. The object is to make the car look as if it has never had any metal work done. Obvious place like fenders, firewalls etc are under the eye of the judge and points will be deducted if obvious repair work is present.
I buttweld 95% of the time and the other 5 % is spotwelding.

When a customer is paying $20-30K to get a car restored, I aim to please. And that includes things they don't know about!

[SHOWCAR FINISH]

That's awesome!

I hope to one day work at a place that cares about doing it thoroughly like that.

[56Ford]

That's awesome!

I hope to one day work at a place that cares about doing it thoroughly like that.

Most of the resto shops- at least down here try to cut corners. I interviewed for a position at a couple of these shops and didn't like the way they did things, so I started my own shop!
This August will mark 6 years in business.

There's plenty of work to go around. Just start small!

[SHOWCAR FINISH]

Lots of corner cutters out here too. There's a few restore places out here and I should probably check them out. In fact, I'm gonna get some addresses and pay them a visit today. I think my schooling has prepared me more towards restores anyways. Sometimes I'll be rushed by my boss
but I still do the same job regardless of how mad he gets. If he felt the junk I was basically finalizing then I think he'd understand.

However, if I was on commision I can imagine I can care a little less about perfection.

btw, I'll post up some pics of some of the stuff I did at this last place. I was only there for a month and helped with a few hotrods. Didn't bother taking pics of the newer cars.