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Post by Clinton Cool on Apr 13, 2017 20:27:08 GMT
I've got some rusty areas on my roof, I only painted it last year. I'd scraped and used Kurust before painting over it. It's only small areas that are affected by the rust. I'm going to order an angle grinder to do a better job, take it back to bare metal in the affected areas, then prime. I've never used and angle grinder before. What type of disk would you recommend for this job? |
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Post by faffer on Apr 13, 2017 20:34:34 GMT
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Post by Deleted on Apr 13, 2017 20:38:05 GMT
I like flap discs. The wire brushes polish the metal and the abrasive something-or-other that looks like a kitchen scourer seem to wear out too quickly if you put pressure on. I guess there is a technique to it. I tend to go at things like a bull in a china shop.
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Post by Telemachus on Apr 13, 2017 20:43:43 GMT
I've got some rusty areas on my roof, I only painted it last year. I'd scraped and used Kurust before painting over it. It's only small areas that are affected by the rust. I'm going to order an angle grinder to do a better job, take it back to bare metal in the affected areas, then prime. I've never used and angle grinder before. What type of disk would you recommend for this job? Discs come for use on stone or steel, obviously you want steel. Discs come thin, for cutting, or thick, for grinding. You want thick for grinding. However they are fairly brutal on mild steel, likely to leave gouge marks, I suggest a sanding disc or flap wheel would be better. |
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Post by Deleted on Apr 13, 2017 20:44:24 GMT
Faffer is right. Knock it back with those wire wheels
You will end up with a swirly mess if you go gung ho with a grinder and not a lot of skill or experience.
Fibre discs and backing pads are good if you are not too heavy handed.
Good gloves, overalls and a full face shield are a must. Start the job with all your digits and eyes working and finish in the same condition.
I wish I'd worn ear protection more often when using a grinder, the one upside of less sharp hearing is Mrs Gazza's bollockings seem less severe these days 👍
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Post by lollygagger on Apr 13, 2017 20:51:13 GMT
I did this for years. Knotted brush discs melt and smear the paint, flappy discs clog with paint, grinding discs leave marks. The answer is a poly abrasive disc which easily strip paint and rust leaving shiney unmarked steel. There will be a lot of dust.  |
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Post by tadworth on Apr 13, 2017 20:58:40 GMT
As above.
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Post by Deleted on Apr 13, 2017 20:59:09 GMT
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Post by Clinton Cool on Apr 13, 2017 21:02:46 GMT
Thanks for the replies. Seems a wire wheel might be best for this job. Do they only last 5 minutes, or are they fairly robust?
The other job I need to do is my cruiser deck. There's quite a lot of rust coming through. Next time I do it, I want to do it right. There's probably 2 square metres of paint to remove. 3 or 4 coats probably, plus lots of rust. It doesn't matter if the deck ends up slightly uneven, scoured etc. Would I be right in thinking that a standard (thick) disk would be best for this? If so, do I need to buy a dozen to do this job, or will 1 do?
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Post by Deleted on Apr 13, 2017 21:04:11 GMT
I did this for years. Knotted brush discs melt and smear the paint, flappy discs clog with paint, grinding discs leave marks. The answer is a poly abrasive disc which easily strip paint and rust leaving shiney unmarked steel. There will be a lot of dust. I went through one of those in about 3 minutes. Very effective but it would get rather expensive! I guess I pushed too hard. I've also been known to rapidly blunt large drill bits by not going slowly. I guess there is a technique to it. And patience is a virtue. |
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Post by faffer on Apr 13, 2017 21:08:54 GMT
Another thing hold the grindr at around 20 deg not 40-45 as some folk do. get a better job done.
For the 2sqm i would use poly and they will last. get half a dozen. Dont rush it and the grinder will do the job. Dont push on as it will not do any better but ware the disc and grinde itself.
As said above by lollygagger others will clog. poly or knotted.
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Post by Telemachus on Apr 13, 2017 21:09:42 GMT
Thanks for the replies. Seems a wire wheel might be best for this job. Do they only last 5 minutes, or are they fairly robust? The other job I need to do is my cruiser deck. There's quite a lot of rust coming through. Next time I do it, I want to do it right. There's probably 2 square metres of paint to remove. 3 or 4 coats probably, plus lots of rust. It doesn't matter if the deck ends up slightly uneven, scoured etc. Would I be right in thinking that a standard (thick) disk would be best for this? If so, do I need to buy a dozen to do this job, or will 1 do? Wire wheels tend to polish the corroded bits rather than remove them. We used a flap disc from Screwfix to strip the well deck and remove some rusty bits, only used one and it wasn't worn out at the end. www.screwfix.com/p/bosch-flap-discs-115mm-40-grit/26022If you are determined to use a grinding disc, you will only need one or maybe two. |
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Post by faffer on Apr 13, 2017 21:12:47 GMT
Faffer is right. Knock it back with those wire wheels You will end up with a swirly mess if you go gung ho with a grinder and not a lot of skill or experience. Fibre discs and backing pads are good if you are not too heavy handed. Good gloves, overalls and a full face shield are a must. Start the job with all your digits and eyes working and finish in the same condition. I wish I'd worn ear protection more often when using a grinder, the one upside of less sharp hearing is Mrs Gazza's bollockings seem less severe these days 👍 maybe why i have Tinnitus lol |
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Post by lollygagger on Apr 13, 2017 21:26:02 GMT
I did this for years. Knotted brush discs melt and smear the paint, flappy discs clog with paint, grinding discs leave marks. The answer is a poly abrasive disc which easily strip paint and rust leaving shiney unmarked steel. There will be a lot of dust. I went through one of those in about 3 minutes. Very effective but it would get rather expensive! I guess I pushed too hard. I've also been known to rapidly blunt large drill bits by not going slowly. I guess there is a technique to it. And patience is a virtue. I can bare metal a whole VW camper with one disc. Sharp edges kill them. Use almost flat, always go "off" edges. Leave fiddly bits to last.  |
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Post by Deleted on Apr 13, 2017 21:27:59 GMT
Angle of attack was where I went wrong. I hate VW vehicles but anyway thanks for the advice |
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