I've got by with a 4 inch grinder till now but it can't handle the heavy cutting & stuff so I'm looking at a 9 inch. The electric ones are expensive & heavy so I'm thinking of air operated. But, I'm suspicious that they haven't got as much power although they (air) would be great for buffing etc. My compressor is a 2cyl 15cfm model. Comments?

What are you cutting?

I may be wrong but an angle grinder will spin far too fast to be useful for buffing. At the speeds they spin at, the cutting compound or whatever you are using will be sprayed all around the garage rather than staying on the pad. I use a variable speed sander/polisher for buffing and have it cranked right down low for best results. I use a 9in electric angle grinder for cutting and would hate to use if for anything other than cutting.

Your compressor will handle most tools - anything over 12cfm is generally enough I think. Unfortunately you can't always kill two birds with one stone so since your primary concern is cutting - go with a cutter (haven't used an air powered one before myself sorry) and save up for a variable speed sander/polisher later for buffing. This is just my two cents though!!

I'll be mainly cutting steel- square round angle etc. The comment re variable speed is very valuable. Thanks all.

I bought a 180mm Ryobi polisher/sander/grinder/cutter not that long ago for $119. Has 6 speeds, works a treat for the big jobs in the open, but still use the 100mm Makita for the tighter jobs.

Why don't you get a drop saw for cutting the tube and angle sections, and a 5" (125mm) grinder for the sheet. Those 1mm wide cutting discs cut through sheetmetal like a hot knife through butter. I won't use a 9" grinder unless I absolutely have to.

The scales are falling from my eyes! I HAVE an 8 inch electric saw! I've only ever associated it with cutting timber so I tried a steel cutting disc & it works a treat.
I'll go for an air driven grinder now for wire brushing & buffing.
Nothing like a good discussion to broaden one's scope!
Thanks all!

Don't use a grinder for buffing. The higher speeds create too much heat and will burn the paint. Stick with purpose-built buffers, or use a multi-speed job like 56astro mentioned (I'd still go with the purpose built buffer, but economically the multi-purpose tool makes sense).

I have been doing steelwork for about ten years now, and I still don't have a 9" grinder. Sure there are times when I probably would have liked one, and I have even borrowed one once or twice, but I find I can cut most things comfortably with my 5" grinder and 9" power saw (with abrasive blade). If I was going to buy anything else right now, it would be a drop saw before I bothered with a 9" grinder. They are excessively dangerous - I knew a guy who cut his hand off (through the wrist) with one. I guess the same goes for all power tools though, but the big ones kick and bite harder than the little ones.

Sure'nuff! The only thing that has hurt me in 30+ years has ALWAYS been the angle grinder! I'm currently nursing a a graze under my left armpit- I still can't work out how it happened! From now on I only use it with the right-angle brace attached.

I'm a maintenance engineer at an oil refinery, and we have banned 9 inch grinders (cutting discs only) due to the safety issues associated with kickback.

Personally I think a drop saw is hard to go past for cutting tube and angle etc etc. Definetely use a buffer when buffing - you only have to burn your paint once to work that one out.....:cry

9 inch grinders have their uses though.... like cutting up cars or if you are a bigger stronger bloke than I am....

Doug - you dont work at kwinana do you ?

Yep, sure do. You sound like you know some people here ?

Couple of years ago I did a review of your computer systems (COE3 -Thin Clients)(Assuming your with BP?) -
Had to stay over there for about 8 weeks.
Are they all still stuffed up ? - I recomened a partial rollback but never got to here if they did

Couple of years ago I did a review of your computer systems (COE3 -Thin Clients)(Assuming your with BP?) -
Had to stay over there for about 8 weeks.
Are they all still stuffed up ? - I recomened a partial rollback but never got to here if they did.

???


Theres an echo in here

Oh, the joys of the WTS system and thin clients....:repuke:puke:repuke

We have now (about 12 months ago I guess) gotten rid of 99% of the thin clients in the refinery. Everyones gripes got too much, and basically the system was slow, unreliable and did not supprt many of the more specialised apps. So we got rid of it. Most of the ppl are now running either P3 850s, or the lucky ones (like me) P4 1600's.

Small world eh ? :bounce :bounce :bounce

It sure is a small world (But I wouldn't want to paint it).

Glad to here things eventually sorted themselves out.

(How popular was I when I suggested using the Thin clients to build a retaining wall in my garden - They do have nice drainage holes in the side).

Nice to hear from you.

Now, Doug: a few years ago a friend of mine borrowed a 9" to trim the nails from some posts where we were putting in a pergola - not only did I get a chance to practise my first-aid skills, the doctor let me watch while he rebuilt his wrist! The wounds were wonderfully cauterised (the doctor had to cut away the burnt flesh,) and he managed to notch a bone without causing permanent tendon damage (lucky bastard!)

How can you scare people like that?