Grinding - Pressure

Being somewhat new to this metalworking stuff I was wondering how hard should I push down while grinding welds with a 4" angle grinder.

In woodworking sometimes it is better to let the tool do the work but in other instances you can speed the process along.

I was working on some medium thick metal tonight and my main concern was burning up the grinder or an exploding disk. I am not sure how much abuse the disks will take before they give out.

The answer may be that if my welding was better the grinding would be less.

On thick metal you can push as firm as the grinder will allow but on thin you will heat up and destort the metal causing warping.

More pressure will burn up wheels faster. Better to let the tool do the work.

I would use a flapper wheel, it will remove metal faster than a grinding disc.

Push hard enough to remove metal but don't turn what you are grinding blue or red hot, may warp your panel. Move around so one side cools while grinding the other side.

lungs

You need to pay close attention when grinding welds not to go too wide. The welds can be a lot harder than the material in either side.

You can quickly make yourself a lot of work leveling out body pannels if you dont pay close attention to what your doing. The softer material on either side of the weld will cut faster than the hard welds. I would be more interested in control than preasure. My .02

Dirtyrat said:

I would use a flapper wheel, it will remove metal faster than a grinding disc.

Click to expand...

Agreed, and leave a nicer finish.

Grinding is a bit of an art when done right. Using the right disk is very important as well. Use a hard disck to remove lots of metal first (like a weld) a Pearl DCRED45 disk is the best I've found. For light metal removing and blending switch to a flexable hard disk get down to just above the level you want and switch to a flap wheel. 40 grit is good for stuff like frames but body work you may use a 80 or 120 grit.
Generally it's more about the wheel than pressure. You should not have to push that hard... you'll just make stuff ugly. I tend to use a bit of a circular motion once into the blending stage. Round tubing is a little tricky... grind parallel to the tube not across it.
Hope that helps.