question Using an Angle Grinder and Grit Flap Disc to remove paint

[LarryH57]

I bought an Angle Grinder and Grit Flap Discs to remove paint on my MV in order to take off a few coats of paint before repainting, as I prefer to do this rather than use paint stripper. As I'll be wearing coveralls, gloves, eye protection and a mask, I'm wondering if it is in order to remove the guard on the Grinder, so that all of the disc can be in contact with the paint rather than just half. I appreciate that a guard is needed for more serious work such as cutting with a grindstone, but would it matter to remove the guard with a Grit Flap Disc?

[Rover8FFR]

I bought an Angle Grinder and Grit Flap Discs to remove paint on my MV in order to take off a few coats of paint before repainting, as I prefer to do this rather than use paint stripper. As I'll be wearing coveralls, gloves, eye protection and a mask, I'm wondering if it is in order to remove the guard on the Grinder, so that all of the disc can be in contact with the paint rather than just half. I appreciate that a guard is needed for more serious work such as cutting with a grindstone, but would it matter to remove the guard with a Grit Flap Disc?

 

I removed mine as it gets in the way doing some cutting.

 

Also much better using a Flapper disc with it off too. You wont get full disc down as the centre ring can damage the surface easily, but you get more area of disc.

 

As with all these things, wearing the right PPE and going steady is the key.

 

Good Hunting

[G506]

Just my opinion, but I would leave the guard on if you can. I know there's a lot less risk from flying debris with a flappy wheel that an abrasive wheel, but even so the periferal speed is still high. Also stops your fingers ending up touching the disc inadvertently. Gloves will only protect you so much.

I have a few scars on fingers from discs rotating at high speed; your choice, but I know what I do now I've learnt lessons the hard way.

 

Hope this helps!

[Sean N]

Don't remove the guard.

 

As G506 says, it's very easy to slip onto the rotating disc without realising it, and it will go through even fairly heavy gloves in a flash. If the disc explodes there's nothing to keep the bits away from you. When cutting, you won't be able to direct the spark stream away from you / critical areas. You should be using the flapwheel at a shallow angle to the job anyway, so there should be no need to remove the guard. You certainly won't be able to put the whole face of the flapwheel against the job, as it'll mark the job badly and jump around like a wild thing.

 

Possibly a bit late now, but I would recommend buying a grinder such as the Bosch where the guard can be set to different positions. That way you can work in all directions without the guard getting in the way.

[fv1609]

Larry if this is your LightWeight then IRR paint is not meant to be removed unless the area has been damaged in which case two coats of IRR are needed.

 

This explains why the paint finish on many vehicles looked so atrocious, my Carawagon had seven layers of paint. But that is the authentic look unless you are depicting it as a just been issued vehicle that has yet to see much service.

[Lauren Child]

IRR paint does come off reasonably easily, but remember its got some chemicals in it that can be very bad for you. Either way you should wear PPE.

 

Back to the original point, i wouldn't remove the guard. If you need to sand more effectively, get the right tool for the job and pick up a sander.

[Richard Farrant]

I caught my knuckle of the edge of the disc, holding normally, but guard removed only to get in to a corner, would not have done it otherwise, or again. With a 4.5" grinder there is little room between hand and disc and you are concentrating on the disc cutting. As others had said the debris is hurled at you as well. I always use a full face visor and glasses, having had to go to hospital once to have my eye scraped, I do not intend to go there again and that was wearing goggles, where it shot under it. If you have not tried using a flap disc before, you may find it to harsh and through to the metal before you know it. Better to use normal sanding discs and flat off rather than remove.

Warning if using wire wheels on a hand grinder too, use full face visor as those bits of wire are bloody deadly.

[saxmanguy]

Not really recommended in any situation, but if you think you need to ask, Definate no no

[ruxy]

Angle grinder Flapdisc - even to try and rough off - NEVER !! Even in expert hands a DA sander would be no use on your biggest panel area. You need to miss the fine details like pop-rivet heads . I only use two power tools , then lots of hand-work to prep LoL

 

Power tools on intricate panels you need :-

 

http://www.rupes.com/p/us/en/0271452533686

 

and

 

http://www.fein-uk.co.uk/en_uk/multimaster/

Edited January 5, 2015 by ruxy
spelin

[paulbrook]

There is a lot to be said for a decent hot air gun and a scraper, at least to get the worst off. Even the flap disc will quickly clog otherwise.

[ruxy]

There is a lot to be said for a decent hot air gun and a scraper, at least to get the worst off. Even the flap disc will quickly clog otherwise.

 

He is asking for a abrasives short cut , no graft , desk-walla LoL , I have a mini DA sander - not impressed , flat panels sanding , you work flat , P40 , P80 , P220 & then 400/500 grit wet with the good old 3M rubber blocking , the only thing that has changed was when Scotchbrite came along IIRC abt. 1970 , rope cleats & other finger blades - forget green - start with red / finish with grey ..

[paulbrook]

Mmmm

 

I was trying to be helpful based on what bit of experience I have. I think people post here because they want folks advice and opinions, and having spent a lifetime of sticking paint on and getting it off again I just thought that I would try and be helpful.

 

I hope that no-one assumes that I take the somewhat haughty position of the previous poster. If that came across in my own post I apologise.

 

IRR paint was/is carcinogenic by the way, and long gone are the days where it was put on with a yardbrush and removed with copious quantities of OX8. That said OX8 was very very effective!

[Grey area]

I've recently entered the wonderful world of soda blasting and bought a soda conversion manifold for my sand hopper. Won't affect the alloy and will get in and around rivets and seams. will also clean up the galvanised steel. Didn't know the dangers of IRR paint - glad I read this!

[fesm_ndt]

I like those soft foamy heads you can fit on a grinder with bonded sanding discs. The Velcro ones tend to lose effectiveness all too quickly.

 

Flap discs do disintegrate as I have had a few shatter

 

As with what Adrian said wire wheels are deadly. The knotted type is best. I posted in the safety thread in here ages ago how a wire went into my thigh completely under the skin. It took the doctor around an hour the slice it out as it went in vertical. The more annoying part was it never healed and I had to keep going back to get it cut open. To this day it never really hardened into a scar. One interesting thing I did learn was if you get antibiotic capsules you can open them and pepper the wound when you put a new bandage on. Gets the goodies direct to the problem

[ruxy]

Most of us at some stage have tried a hot air gun on IRR (along with several other methods - read the forums , oft. discussed topic) , can't say I have had results worth pursuing , that is two better Bosch models and a industrial one. Aluminium is a cold metal , heat dissipates quick , you will local scorch harden on more than lift. Most IRR is going to be through hardened before you try and remove , fresh stuff you may get better results (but better using another methods & quicker too).

 

The idea of using a flap disc is totally barmpot , if I think so - then I will say so & you can think what you like , carry on with your own thing - you have no control against gouging in a uneven manner , L'wt the idea is to get a flat surface and keep improving on it , the curve on bonnet edge , fiddly bits like headlamp fairings are - dismantle & hand-work. In fact the whole lot is many hours of hand-work to do a good prep) - a bit of mental stamina comes in handy Lol.. . such as all the Lightweight body rope clips , tail-gate fittings - any contact & you will just shred the wheel & probably have the tool whipped out of your hands. Every flap-disc or flap-wheel I have come across has been a cloth backed ceramic / aluminium oxide type - in other words a linisher belt that is for metal dressing although it will remove loose paint along with rust . To remove sound paint then you need a open-coat paper , linisher belting is close coat that soon clogs. Yes, I do have a Vanco linisher , also worked on semi-auto linishers that buffed off aluminium castings , mop stage at the end using what to me was the same as Solvol Autosol .

 

Plenty of scope for discussion on best make / type of sanding sheets - I keep trying different ones but fall back on to chopping up standard sheets of Mirka white production papers.

 

Myself - I will sand to Solihull factory finish and no further , the alloy is coated with a few microns of alondising - I would not wish to harm this coating. Likewise - I use a Azenda pot blasting gun around the difficult parts for machine / hand sanding.

 

BUT , as I said pointless going OT on other paint removal methods as the OP has set his mind on using a flap-disc , so probably best to let him carry on , he will come to his own conclusions (probably without injury or silicosis) and report back in due course.

[paulbrook]

In a nutshell - the Rustytrucks approach to paint removal.

 

1. It is nasty. Take appropriate steps and wear the right gear.

 

2. Unless it is really old cellulose or similar "hard" finish paint tends to come off better if it has been "killed" first, ie the natural adhesive qualities have been disrupted. This can be done with heat or chemicals. We almost exclusively use as much heat as we can get away with without distorting anything. SOP in the Big Shed is to reach for a rosebud on the oxy-acetylene set (even on flat aluminium...) but there is a fine line here between success and disaster so I do not advise it! A heat gun is good - you don't need to take all the paint off with it you just need to harden the paint up so it comes off "dry" and does not clog whatever you are using. We even kill paint before sandblasting as it saves a lot of time and effort.

 

3. Small steps. Aim to do a section at a time.

 

4. Aim to use a variety of approaches, including old screwdrivers, bits of stick, passing small animals etc. There is no "one" way. We routinely use flap discs and wire brushes in our grinders, but only where they are the tools to use.

 

5. Did I mention it was nasty? Take appropriate steps, including sweeping/hovering all residue on completion of the task.

 

There is a whole chapter to be written on guards on grinders - my grinder is guardless as it happens, but my grinder is pretty much an extension of my right arm. That said we use the fantastic paddle-switched Makitas which have very slim bodies and can be switched on and off without getting anywhere near the spinny bit.

 

OX8 is brake fluid by the way and it is the sworn enemy of IRR paint. Used old-styleee brake fluid (probably not the silicone based modern stuff) is effective and cheap (free even from your local garage - ask for their used stuff). Paint it on and keep painting it on for a week. With luck the majority of the IRR paint will wash off with a pressure washer. I know this because it is how we used to do tank transporter trailer beds!

[RichardT10829]

If your going to remove paint with grinder you are better off fitting a wire wheel rather than paddle disc.

 

I did my entire carrier this way.

 

paper suit and a good respirator are a must.

 

you get a nice finish on the steel where upon you can spray your etch primer base.

[Rover8FFR]

OX8 is brake fluid by the way and it is the sworn enemy of IRR paint. Used old-styleee brake fluid (probably not the silicone based modern stuff) is effective and cheap (free even from your local garage - ask for their used stuff). Paint it on and keep painting it on for a week. With luck the majority of the IRR paint will wash off with a pressure washer. I know this because it is how we used to do tank transporter trailer beds!

 

Will this work on other paints or just IRR?

I have noticed on my LR Mk8 FFR that over time the two colours on top of the DBG are coming off in large layer chunks, which have been assisted by the pressure washer.

 

I wondered if the use of OX8 was a way of removing the layers on top of the DBG factory finish.

 

Will it hard the DBG finish?

Will it remove the paint from Galv parts effectively and not affect the properties of the Galv?

 

Cheers to the experienced guys out there!

[ruxy]

If your going to remove paint with grinder you are better off fitting a wire wheel rather than paddle disc.

 

I did my entire carrier this way.

 

paper suit and a good respirator are a must.

 

you get a nice finish on the steel where upon you can spray your etch primer base.

 

Getting OT again !

 

Something like a carrier / armoured is a different kettle of fish (that I would use a different approach - probably needle scale the lot off then DA sand ) to prep thin Birmabrite (supposed) alloy panels on a Lightweight with loads of fiddly sticking out bits that you need to avoid , and the good going is relatively small area - Only the bonnet and a few other area can you crack on with a DA

 

My aim is to get rid of the thick IRR clag , get a nice smooth & even base , fine papered to give good adhesion to a base-coat & then go from there ,,

[ruxy]

My chemical approach , sometimes works .

 

Rough up the IRR with a 40 grit open coat using a small palm sander (aids spirit penetration) , the Italian make / model - I gave the link to RUPES they are good (I did work for B&D for over 5 years) , then on a overcast day to stop fast vapping off - I soak cheap standard thinners / industrial gun-wash into old towels and drape them over panels , one or two at a time - sometimes this will penetrate the paint and bleb it. Odd couple of times I have had excellent results on a couple of coats of IRR and it easily scraped off.

 

I did once get lucky with a 88" CL that I dragged back from Ruddington , I noticed that large chunks of IRR were flaking off , so I blasted it with a steam cleaner , the whole lot fell off leaving sparkling DBG As suspected the factory delivery wax coating had not been cleaned off prior to painting LoL

[Sean N]

 

I have noticed on my LR Mk8 FFR that over time the two colours on top of the DBG are coming off in large layer chunks, which have been assisted by the pressure washer.

 

I wondered if the use of OX8 was a way of removing the layers on top of the DBG factory finish.

 

Will it hard the DBG finish?

Will it remove the paint from Galv parts effectively and not affect the properties of the Galv?

 

The paint's probably coming off the DBG because the DBG wasn't prepared properly originally. This is quite common with military painting! The smooth shiny surface of the DBG doesn't allow the following coats to grip properly - it needs to be roughened to provide a key, which didn't tend to get done!

 

If the paint isn't keyed the chances are brake fluid will lift it more easily, and it may penetrate the DBG less, but ultimately brake fluid will attack pretty much any automotive paint scheme.

 

It shouldn't hurt the galv, that's a different thing entirely.

 

Note that a mix of semi-melted IRR paint and brake fluid isn't exactly the most environmentally friendly stuff in the world and probably shouldn't be flushed down the nearest drain!

[paulbrook]

Ahhh heat or chemical - not both.

 

And clearing up properly is really important.

[Sean N]

If your going to remove paint with grinder you are better off fitting a wire wheel rather than paddle disc.

 

I did my entire carrier this way.

 

paper suit and a good respirator are a must...

 

It's horses for courses, whatever you're doing. What works for an A vehicle may be no good for a softskin, what works on steel panels may be no good for aluminium. Larry hasn't mentioned what vehicle he's doing, in this thread at least.

 

I think tool and abrasive choice has a lot to do with individual preference, skill and technique as well; one man can achieve a good result with, say, abrasive flapwheels while someone else might struggle or gouge. Something that works on IRR might be no good for bare rusty metal or pre-war celly. You listen and learn, and find the techniques that work for you.

 

All interesting discussion but a long way from Larry's original question about whether to leave the guard on!

[ruxy]

Larry AFAIK - only has a Lightweight , but he may have purchased a Sherman on the QT.

 

I do use flapwheels & flapdiscs , but things have moved on from the original Garryson type. I have yet to come across a type special for stripping paint. So much available , so much to test - I need another life.

 

I have tended to use SAIT stuff esp. their thin (1mm) slitting discs , a factor I use was pushing Dronco over SAIT (probably he gets a better discount) , suggested their discs as a lot cheaper - I did but IMHO not quite as good but difficult to call on VFM.

 

There again - I buy a bit of Pick-N-Mix off this factor & then bulk buy on the internet when I shelf stock.

 

I suppose I will have to try these LoL

 

http://www.dronco.com/xist4c/web/JET-Flap-Discs_id_41443_.htm

 

http://www.sait-abrasives.co.uk/Products/NewProducts.aspx

 

http://www.sait-abrasives.co.uk/Portals/0/Documents/Brochures/SL-Wind_UK.pdf

 

I see where Larry is coming from , guard off to keep flap-disc flat as possible to surface , however - I don't think that is the intended usage - could be all this new stuff , there may be a thingie waiting to be found..

[Delboy]

Personally, wouldn't use a flap disc on alloy, all to easy to gouge the surface.

 

They're great to dress welds and rough edges etc. Too hardcore for birmabright.

 

I would use nitromors to shift the ir paint as it doesn't tend to touch the original deep bronze green.

 

As for removing the guard, use welding gauntlets to maintain your digit count.

[redneck]

I've just finished a project at work that involved removing paint (many layers) the paint removal was for NDT inspection which have very specific surface finish conditions, adding to the problem was the minimal parent metal removal allowed.

This is the second time I have run this project (10 men for a month), and having tried many different types of paint removal, by far the best and easiest way to achieve the finish required was Scotchbrite clean and strip discs XCRS.

 

As for a grinder without a gaurd, been there done that, got the scars.

Just don't, it's really difficult to use tools with fingers missing/broken.