Grinding/Cleaning

[Cat_J]

I am sanding my chassis to bare metal for a repaint. I only have at my disposal a 2.5kW generator, a grinder and electric drill. I don't mind sanding by hand but can you get brushes or sanding discs for grinders, as that would make my life much easier.

Sorry for the silly question, but you know, we all have to learn...

Cheers.

[Ruuman]

what your after is something like this: http://www.toolventure.co.uk/Power_Tool_Accessories/Wire_Brushes/sc1331/p975.aspx?utm_source=google&utm_medium=googleshopping&utm_campaign=googlebase&utm_term={keyword}

Be sure you wear very good eye protection and some ear defenders. Also wear some heavy clothing, the amount of times I've thought I had a splinter in my leg and then removed a 3/4inch bit of wire.

This is about the most cost effective way i've found of cleaning a large area and they don't get clogged up with wax oil. I'd suggest chiselling off any loose wax oil or under seal. You will need a few for a chassis.

If you doing a whole chassis, might be worth seeing how much it would be to hire a sand blaster for a day.

[FridgeFreezer]

Yes you can get wire brushes for grinders, I got through quite a few removing the old paint & underseal from my chassis - and killed about 4 grinders in the process too.

You will definitely need some eye protection, both from flying dirt and from flying steel bristles which break off and embed themselves in your skin and overalls. The grinder will also grab things - any edges will make it kick, and you really don't want loose clothing near it.

You can find brushes cheap on eBay, they're V pricey from B&Q and the like, but that's true of all grinder consumables.

[Pinkrover]

watch out for the max speed of wire brushes for angle grinders, most are max 8000/8500 rpm, most angle grinders are 11000 rpm and these brushes are almost unusable due to vibration

Les

[ThreeSheds]

Angle grinder wire brushes are great - they come in two main varieties - cup and radial. Both are excellent at removing crud and loose rust, but when you get down to the hard stuff a flap-wheel is better, like this - but these can leave the surface so shiny it's difficult to paint so don't get carried away...

Since you are obviously new to the world of angle-grinders I thought I would say a few words about protection - hope it's not teaching my grandmother!

IMHO the full list of PPE (Personal Protective Equipment) needed for brushing and grinding with and angle-grinder is:

Eye, head and face protection: A welders cap and a clear full-face mask. These caps are not flame retardant but will stop nasty little sparks burning your scalp. The full face protection (rather than just eye protection) will stop bit's of shyte getting embedded in your face which is not only painful but gives awful zits afterwards.

Ear protection: I use top-grade ear-plugs, but grinders are horribly loud so make sure you fit them properly (most people seem to only put them half way in).

Thick overalls: Treated fire-retardant ones are preferable but still take care where your sparks are hitting when grinding - ten seconds of focussed sparks will put a hole in even the best overalls.

Gloves: Not welders gloves IMHO. Most cheap welders gloves are far too heavy for grinding and the thick leather (so good at keeping UV and weld spatter off) will wear right through in a split second on contact with a grinding or wire-brush disc! Kevlar lined welders gloves are good, but tend to be expensive and are still very cumbersome. Personally I go for a kevlar 'handling' glove with nitrile coating like these, you have to accept a reduced level of spark protection on the back with these though, so they are no good for welding since 'stuff' goes through the weave, but when you run a grinder into your finger you will be glad if you have kevlar in between...

Boots: Having dropped a running angle grinder and had it land disc-first on my toes I would strongly advise rigger-boots tucked inside the overalls to stop sparks going down them.

Hope this helps

Roger

[Turbocharger]

I'd add to ThreeSheds' list - go and get a welder's apron from Toolstation or similar. It's not finest Chamois leather but it'll go some way to stopping the grinder eating into your leg.

You'll find the right way to use the rotation of the brush to help you too - one side of the cup will settle into any nooks and crannies, but if you touch the other side it'll fling the grinder around your confined space. You won't get paint out of all the little nooks, but I worked around my chassis with a battery drill plus two sizes of wirebrush before I painted it - it's not "factory" condition, but definitely "better than before".

[FridgeFreezer]

I'd be wary of abrasive flap wheels, the rough ones will remove metal (not good in this situation!) and the smoother ones will polish it so nothing sticks.

[Cat_J]

Ive got a good makita grinder so that shouldn't burn out... I'm not new to grinding as such, cut a fair bit of metal before and hundreds of tiles so I know how they can kick, and fire in your eyes isnt fun. Haven't had to rub anything down with one before.

I've bought one of those brushes for it, got a good high speed one today. I've also bought an orbital sander. I'll do most of it with the orbital sander and use the brush and grinder to clean the wax oil off and the worst bits of rust.

As far as safety kit goes ive got most of it apart from the apron.

I've also got 2 of the abrasive flappy blade things but i'll only use them where i cant reach with other tools, and with care.

Thanks for all the useful replys, all cautions have been noted. I think i'll get some better gloves before i start.

[need4speed]

To be honest, if i were you id do most of it with the wire wheel. You might find if you touch the parts of the chassis that has most rust with the flapwheel it could turn into a hole rather quickly...

Just my tuppence worth...

Phil

[landroversforever]

I would vote for the Wire wheel in the grinder. Will shift through hundreds of layers of paint and rust on a 100yr old railway carriage .

Surely finding the holes is a good thing Phil? then you can fix them

[need4speed]

Surely finding the holes is a good thing Phil? then you can fix them

Very true Ross. I know what your saying but it depends how far he wants to go. I did the same with my old chassis and by the time id finished with the flapwheel i realised that i needed a new chassis Otherwise my chassis would have been a patchwork quilt of welds

[FridgeFreezer]

I found if you are firm enough with the wire wheel it'll find the rusty holes, the problem with abrasive flap wheels is they'll make a hole in good metal too

Here's the results from my rebuild, the whole chassis was painted, then military tar-based undersealed (at least once), then 20+ years of dirt and the odd extra few layers of green paint here and there. It took a long time and a lot of wire wheels to get it all back to bare metal.