Best way to grind down welds?

[skokie]

Whats the best or most efficent way to grind down welds? Total noobie question to

[Frizzle Fry]

Grinding disc followed by a flap sand disc on an angle grinder. 4.5" angle grinders are cheap and work fine for body/small jobs.

[cdowns]

i like using a die grinder with a 3" cutoff wheel i feel they do a faster job and generate less heat on sheetmetal// on frame work and things like motor mounts made out of 3/16 thru 3/8 metal i'll normally use an angle grinder

[jbon64]

Originally Posted by Frizzle Fry

Grinding disc followed by a flap sand disc on an angle grinder. 4.5" angle grinders are cheap and work fine for body/small jobs.

much agreed with the above , if you want the grind marks to disappear use a DA with a 120 disc after using the flap wheel

[Rokcrln]

I agree with all three post above and I have 3 4.5" grinders set up at all times!
1) 4.5" hard grinding disk
2) 4" .040 thick cut off wheel
3)4" flapers (grits per job)

Then for smaller spots I have 3 small right angle air grinders set up with~
1) 3" .040 cut off wheels
2) 2.5" 3m style spin on sanding disks
3) die grinding bits for real tight corners

and yes the DA trick for the real smooth look.

But the best trick short of TIG welding it (almost no raised weld) is to make sure you are using the right wire! For body panels I like to use .023 solid core wire with a 25/75% gas mix. Then adjust it for just enough weld for full penitration with out creating to large of a bead above the surface.

Oh ya and PRACTICE, PRACTICE, PRACTICE!!

Have fun learning and I highly recomend buying a few books on welding. Even if you know how to weld you can always learn a few more tricks. I have been welding for over 20yrs now (certified for almost 14 of that) and I just bought my first two welding books and so far (half way done with the first) they are great. I would have been so much farther ahead if I had done this 20yrs ago.

I know people will ask so here it is~

Both are by Richard Finch, (eastwoods)
1) welders handbook
2)Performance welding handbook

If you buy them read it front to back and do not skip over what you think you already know, you just may learn what you don't.

Good luck,

Kevin
LFD Inc.

[badpeanut]

What is the purpose of the flap sand disc?

[special-K]

A:getting rid of scars.
I use a cutting wheel.The rest is dress.

[Dano69c10]

I have a stupid question, what is a DA?

[BrianJordan]

a good welder doesn't need a grinder.

i'm just kidding guys. i would be lost with out my grinder.

[dirtball]

Originally Posted by Dano69c10

I have a stupid question, what is a DA?

D ual A ction sander.

[wolfthing2000]

For minimum grind and a flat weld: GAS WELD ( oxy-acetylene that is)

[mbgmike]

Originally Posted by Frizzle Fry

Grinding disc followed by a flap sand disc on an angle grinder. 4.5" angle grinders are cheap and work fine for body/small jobs.

Yeah i agree but don't grind too much. I use only Ingersoll- Rand because i got tired of burning up the cheap grinders. I can burn up 5 to 6 cheap ones a year. The I-R ones I have had for years now. Frizzle Fry knows how to do it. If you don't do it much a cheap tool will work fine.
Mike

[mbgmike]

If you are a production shop you do not use a DA to grind down welds.

[skokie]

Thanks for all the info guys. I appreciate it.

[badpeanut]

What is the best grit flap sand disc to get?

[BigMike]

Originally Posted by wolfthing2000

For minimum grind and a flat weld: GAS WELD ( oxy-acetylene that is)

Yep, then you'll have a nice flat welded piece that resembles a Pringles potato chip after it warps

Sorry, had to...

Mike

[wolfthing2000]

IF you get it too hot youwill warp it............ How do you think the old school did it befor MIG??? OXY CETLIN!!!!

[67chevy2wd]

So what do you guys think of 0.30 wire? Is it better to weld short beeds or just to keep tacking until it is all welded up. It seems like just tacks would leave small pin holes.

[BigMike]

Originally Posted by wolfthing2000

IF you get it too hot youwill warp it............ How do you think the old school did it befor MIG??? OXY CETLIN!!!!

True, but time changes and so does technology. For what we do to our trucks as hobbiests, there is no question that a MIG welder is far superior to Oxy-Acetylene. Kinda like cutting down the trees on your property using an axe instead of a chainsaw: lol:

Just razzin ya anyways, thought it was funny

Anyways, sorry for getting off topic.

I use a 60 grit and an 80 grit flap wheel. Never heard of one or thought it would do as good as it does, but they'll bust down welds pretty quick. I got mine at Home Depot, I think for like $6.00. They just thread right on to your grinder like the large grinding disks.

Mike

[BigMike]

Originally Posted by 67chevy2wd

So what do you guys think of 0.30 wire? Is it better to weld short beeds or just to keep tacking until it is all welded up. It seems like just tacks would leave small pin holes.

For the large stuff I use the .030, for sheet metal I use the smaller .025. You can turn the heat down a bit for the .025 so you get less burn throughs. You'll need to swap out for the smaller .025 tip too.

Mike