I use a MAC mini grinder with a 4 inch stone.Big differents between a low end grinders and high end grinders.I finsh with the low end air grinder I have with a 24 grit disk. I only use electic for cutting
I think air would work better because they are easier to handle IMO. Many of the electric ones dont even have variable speed its just on and off.
On sheetmetal I use the edge of a 3" cutoff wheel in my angle grinder to knock em down and a 3" roloc disk to finish.
I tried using flap wheels but don`t have much use for them. I find there great for buffing!! and are costly. But to each there own.
There great for just about anything.I grind alot and found that after killing 6 or 7 electic grinders I tend to just keep them for cutting. Nice work all the same.
Ron Covell spoke of grinding mig welds in his column in Street Rodder a while back. he suggested using the edge of a thin cut-off wheel on a die grinder. this way you only grind the weld and not the surrounding sheetmetal. this keeps the heat down, and you don't make the sheetmetal thinner in your weld area. I buy the really thin wheels, so I stack 2 together giving me about 1/8 thickness. sometimes I might use the edge of my 4" electric grinder, but you have better control with the air die grinder. it takes a little longer but I feel it is worth the end result.
i used an air grinder at work all the time, i prefer my electric, so i took it to work then they bought me one for there.. All my tools are home now, 3 boxes full of all my heavy truck tools/air tools/etc but no air in the garage or room.. I have mastered my grinder, and will always use it..
I always used my pistol gripped high speed air grinder (snapon at425e) and fiber disc's. I don't care for stones. the fiber discs are very aggressive and work quick. but will tear the hell out of sheet metal if you use 24 grit and are not paying attention. ( not that I have ever done that or anything)
I knock em down with a stone on my 4 1/2 angle grinder, then finish with a 60 grit flapper, I like flappers because they tend to knock bumps down to the surface but don't dig into it like a stone does. You can get flappers for around $2 each on ebay.
i do a bunch of metal finishing at my full time...i use a variety of methods, most times ending with a DA and 80 grit or finer....sanding discs on my 4.5 grinder is one option... I have a 90 degree air grinder i use with roloc discs, but i also have different "grit" scotchbrite wheels i use... then the old cutoff wheel that been mentioned here..that works well as long as you dont slip...haha My favorite way is to tig weld the panel and DA it smooth...weld disappears, and theres minimal cleaning...I NEVER use stones (unless im cleaning a tubing notch)...and only as a last resort do i use anything courser than 80 grit.
Quality ones last, ****py ones don't. Buy a single good brand one and give it a go and you will be suprised at the difference.
I use a big electric Blakndeker grinder with a varible trigger with an 8 inch grinding stone. I don't use shields as they get in the way. I turn the grinder straight up where the wheel spins and only touches the weld itself and not any surrounding metal. Then I clean up with a cutoff wheel mounted on a straight cut off tool or on an angle grinder to flush up the welded surface. Some times I place a copper square over the area to be welded and weld from the backside which results in a very flat welded outside surface. I'm like most old guys here as I strive to not use filler. The mig adjusted just right will be the filler. Oh I forgot,,,3 years ago I bought some "boxes of thin rigid fabric discs or washers",,,they were on ebay and local. I bought them because they were priced right!!! The guy didn't know what they were, so I got around a thousand "washers" for 20 bucks. They're the nice thin Cut Off Wheels!!! I put em on an electric angle grinder and cut quickly thru metal. I've used about 1/4 of 'em so far.
BAD IDEA. I had a 9" wheel implode on me a few years back. I had taken the sheild/guard off. I now have a scar that goes from my left ****** to my right hip bone to show everyone why this is a BAD IDEA.
Have you ever been bit? I have a big grinder too but have alot or respect for it,no tight places and no edges. I been bit before and it don`t feel good. I only use it for large flat p****s. Man I can remember using 10 inch cutting wheels with this grinder.Don`t know what I was thinking back then.
I remember paying over $10 a peice for them and found for the money they were not worth it to me. I know they are good but I find they take too long to do the job.
Here is how I was hit. I have a 9" grinder. I found that when your 14" chop saw wheels wear down, the collet hole is the same size as my grinder. So basicly you now have a 9" cut off blade. These work great for double panel straight lines like ****er (like when chopping tops). Anyway, I had one that was about 1/4" too big for the guard, so being a MAN (insert Tim Allens grunt here), I removed the guard. I had 2 brackets to cut. I sliced through the first bracket like ****er. As I pulled the grinder over to the other one, still spinning, it imploded. It didnt even cut my shirt. It felt like I had been run over by a semi truck. I looked inside my shirt on my gut and there was a PURE white line across my chest/stomach. Within a few minutes that white line started pouring blood. I probably should have went to the ER,,, but remember "the man" part above? Well within a day or so, I was bruised (yellow/black/blue/purple) from my neck to my knees, both front and back sides. I now have a 24" scar 10 years later. Might want to rethink removing the guard.
Ouch!! I had mine kick back and hit my arm. lucky for me I was only using a 8 inch 24 grit disk....without a guard!!! left a mark.
the day i got my finger tip almost cut off when it was pulled in between the gard and the cut-off disk was the last day i had a shield, i know the risks of disks flying apart, that happens mostly if you drop of hit the disks and crack them, i grind my welds with a 1/4" disk and then finish with a sanding disk in my die grinder and maybe even a file. i try and keep my mouth shut when i'm grinding to.
The company I was working for bought the six (6) inch suicide wheels to use on the four and 1/2 (4.5) inch grinders. Guards were removed. Cutting expanded metal the wheel exploded. Neatly laying my little finger in the palm of my hand. I will not pickup a grinder with out the second handle or guard.
4 inch makita grinder .They are the best in my opinion First one lasted 20 years ,Im on nunber 2 now ,
I tig or mig sheetmetal and grind with a 50 grit disc that's best suited for the job. Small jobs I use a roloc, bigger jobs I use a 5" on a Dotco. I use 50 because it cuts very fast and leaves a smoother surface to true out or polish if it's required. Yes you want to stay off the sheetmetal as long as possible. The smaller and cooler the weld the easier it is to finish. Good welds will disappear almost completely. 24 and 36 grit grinding just digs big grooves in the work area. I have finished with 80 on a direct drive DA that has no orbital head (it's a National Detroit part that replaces the DA head). Mostly that's for photo ops or prep for chroming. Logic rules here. The better you start out the finer the finished product, less need for fill. FIller ****s.
I agree with Zman, take down the biggest part with a hard disc or a zizz wheel being careful not to undercut it, then a flap wheel will smooth out the rest. Remember to NOT build to much heat while grinding or you do more damage than good.
I use a thick cut off wheel to grind down the proud of the weld. I turn the air down on the die grinder so that it is running fairly slow. I then clean that up with 80 grit on a orbital sander. Here are some pictures to prove that it does work. These panels were MIG welded because I did not own a tig welder or even know how to use one at the time. Grinding the weld is the easy part. Welding your panel with out a ton of distortion is another story.
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