smoothing welds?

what is the best kind of disc to use?

will it fit on my 4.5" angle grinder, or do i need to use an air tool?

where can i get it?

advice on making this look good and not screwing it up?

thanks.

im assuming your asking for sheetmetal? or just any application?

Get a flap wheel. It's like multiple layers of sand paper on a disk. You can run them on your 4.5 grinder, just get the right arbor size. Home Depot or Lowes has them in a variety of grits. Harbor Freight carries them too, theirs just wear down much more quickly.

http://www.defusco.com/Abrasives-Flap-Discs/c64_258/index.html

^^^this place has pics.

Edited: 10/25/2008 1:36:39 AM by stockflooredsdime

Flap wheels are OK, but they wear out fast and are difficult to make the metal perfectly smooth without being wavy or gouged.

I use a flexible resin/fiber sanding disk with a plastic or hard rubber backing plate with my 4.5" angle grinder. Its the best way to knock down welds and smooth them out too. Try Home depot, lowes or any welding shop.

Here is an example of what I am talking about.

http://www.milwaukeeconnect.com/webapp/wcs/stores/servlet/category_27_40028_-1_192523_192327

Originally posted by stockflooredsdime

I use a flexible grinding disk with a plastic or hard rubber backing plate. Try Home depot, lowes or any welding shop.

This is what I use. Its a plastic backing plate with a nut that sits flush. You buy sandpaper discs in different grits that fasten onto it. I keep stocked up in 24 through 100 grit, and do damn near everything with them. And at about $1 each for nice ones they are cheaper than a flap wheel.

The trick to grinding with them also, is to keep them flat on your work. Don't try to use the edge, you will just create low spots. Use the flat until it starts grinding everything.

Sorry I got a little more specific, after you quoted me.

I doesnt make sence how a single peice of sand paper could wear out faster than multi layered pad. I have both the plastic backed pads and flap wheels. I think i depends on the situation. For frame work or larger welds, I go for the flap wheel and it you want to get it real smooth after hit it with a 90 degree air grinder with some 50 grit on a twist lock pad. I have never had a problem getting things smooth with a flap wheel though.

if you use proper technique you can use any 4&1/2" grinding disc. Just grind the weld only, without passing over into the surrounding metal. then when you get it down flush, use a roloc disc with 40 grit, then 50 grit then 870 grit.

This takes practice but works well when done correctly. Using a flap disc also takes practice to do correctly or you end up with waves. Dont buy cheap flap discs. They dont last and a good one will last longer per dollar than cheap ones.

body sanding discs are also a good way to go but like everything else they take practice. The key is to grind the weld ONLY at first.

I'm on the disc with a backer team mysely. I usually do the majority of my grinding with a hard wheel on my 4.5 inch grinder and then bring out the disc and backer for my finish work. a lot of your results come from how you hold the grinder so don't be afraid to experiment a bit to find what works best for you.

Originally posted by Dejavu



im assuming your asking for sheetmetal? or just any application?

mainly framework, suspension parts, etc.

thanks for all the advise guys.