Paint stripping

Ichy · World Chat Champion Joined: 15 Jul 2005 Karma :

Something I've never done before so I thought I would ask. I have some magnesium engine covers, I'm guessing they are magnesium aluminium alloy, that I want to strip and clean. Is there anything that I shouldn't do, any special prep for cleaning or painting?
____________________
https://www.metacafe.com/watch/1972097/how_to_behave_on_a_forum/

Walloper · Super Spammer Joined: 24 Feb 2005 Karma :

Ensure the material will not be damaged by the product you use to de-paint.

Someone was looking for a way to clean an engine and was recommended hydroblasting.
This looks like the3 most thorough safe way least amount of hassle factor too.,
____________________
W-ireless A-rtificial L-ifeform L-imited to O-bservation P-eacekeeping and E-fficient R-epair

Ichy · World Chat Champion Joined: 15 Jul 2005 Karma :

DrDonnyBrago · World Chat Champion Joined: 03 Jan 2010 Karma :

How intricate is the detail on the covers and how good does it need to look?

Depends on how good a finish you want but I have stripped the paint from lots of metal bike/car bits using nitromors and repainted, looked OEM. One part actually was a painted magnesium aluminium alloy toe slider from a pair of boots, did require a bit of fine sanding and general faffing about (more as a result of the poor casting than as a result of the stripping) afterwards but it ended up neat after a bit of fine sanding and autosol. If it is a prominent part of an expensive vehicle then blasting etc might be better but I have no experience of these methods.

If you want it done cheap then nitromors and a bit of time will do it at the expense of some neatness and simplicity.

stinkwheel · Bovine Proctologist Joined: 12 Jul 2004 Karma :

Nitromorse will have alloy covers totally stripped of paint in about half an hour.

Not sure how it would affect magnesium so probably better to spot-test it somewhere unobtrusive first.

Here is a set of CB500 engine covers i did with nitromorse. There is not a scrap of paint on them. The discolouration you can see is where corrosion had got in and lifted the paint.
https://cdn.bikechatforums.com/files/covers.png

EDIT: Top tip for painting prep. especially at this time of year is to warm the metal up first. Plastikote BBQ paint is the shizzle if you want them matt black, spray straight onto clean metal.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

Walloper · Super Spammer Joined: 24 Feb 2005 Karma :

Supermotard37... · Scooby Slapper Joined: 31 May 2011 Karma :

Hey,

Marki im wondering the same thing i have magnesium engine covers on my ktm wich have been powder coated a really horrid green colour so let me know how it goes if you do try it Wink

____________________
Fuck off..!! "You absolute contraception malfunction"

ZRX61 · Victor Meldrew Joined: 05 Nov 2003 Karma :

Mag usually has Dow 7 or Dow 9 coating on it to prevent corrosion...If ya take that off you're fucked.
____________________
They're not one night stands, they're auditions.

Ichy · World Chat Champion Joined: 15 Jul 2005 Karma :

I've done a fair bit of stripping and polishing aluminium covers so I'm aware of how to deal with those, just wondered if you need to treat mag alloy any differently.

Plan is to clean them down as well as possible and then just spray them to tidy them up.
____________________
https://www.metacafe.com/watch/1972097/how_to_behave_on_a_forum/

Walloper · Super Spammer Joined: 24 Feb 2005 Karma :

Walloper · Super Spammer Joined: 24 Feb 2005 Karma :

Vincent · Banned Joined: 16 Oct 2006 Karma :

Nitromors* is cheap and will make an ally cover go a dull grey finish......... but only if you leave it on too long. Paint it on and leave it for 30 seconds to a minute then wipe off the sludge with a wet cloth and rinse the case under cold water. You might find that you have to repeat this 3 or 4 times before all the paint is off but if you leave it on for longer it could damage the metal.

OP, are the cases a gold colour?

*For anyone not used to Nitromors, wear rubber gloves and don't pick your nose or similar Exclamation

____________________
Space Is Deep

Ichy · World Chat Champion Joined: 15 Jul 2005 Karma :

Nope, cases are a dirty grey colour.
____________________
https://www.metacafe.com/watch/1972097/how_to_behave_on_a_forum/

Vincent · Banned Joined: 16 Oct 2006 Karma :

That's Ok then, wasn't sure if you had the gold mag cases Honda use on some sports bikes.

If you want to pay for vapour blasting it's probably the best way but Nitromors should cut it, just be careful not to leave it on too long on exposed metal.

Oh, and you'll need some etch primer before painting.
____________________
Space Is Deep

DrDonnyBrago · World Chat Champion Joined: 03 Jan 2010 Karma :

Ichy · World Chat Champion Joined: 15 Jul 2005 Karma :

Thanks Donny, that would be really interesting. Thumbs Up

____________________
https://www.metacafe.com/watch/1972097/how_to_behave_on_a_forum/

DrDonnyBrago · World Chat Champion Joined: 03 Jan 2010 Karma :

Vincent · Banned Joined: 16 Oct 2006 Karma :

Walloper · Super Spammer Joined: 24 Feb 2005 Karma :

DrDonnyBrago · World Chat Champion Joined: 03 Jan 2010 Karma :

Looking around on the net it seems DCM was banned in Dec last year, I got mine in Dec last year (gf was buying Xmas decorations in Focus) for crazy cheap - big tin for £1.50.

Sounds plausible that mine is the last of the noxious stuff.

Ichy · World Chat Champion Joined: 15 Jul 2005 Karma :

Funny enough I brough 8 litre tins from Focus last year because it had been reduced to a pound a tin. I'll have a look later to see what I have.

I used to have a great collection of chemicals donated by my Dad, an ex tool maker. A lot of them got dumped after I forgot what was in various jars. The age old concept of licking and sniffing to test them didn't seem wise when at least one of the jars contained cyanide.
____________________
https://www.metacafe.com/watch/1972097/how_to_behave_on_a_forum/

stinkwheel · Bovine Proctologist Joined: 12 Jul 2004 Karma :

Carbon tetrachloride was always entertaining and an awesome solvent as well as being non-flammable.

A good trick was to put two carbouys of it in a carry rack and ask your mate to carry it through for you. Then watch them try to pick it up in one hand.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

Ichy · World Chat Champion Joined: 15 Jul 2005 Karma :

Yea!
My stock of nitromors contains dichloromethane and methane.
____________________
https://www.metacafe.com/watch/1972097/how_to_behave_on_a_forum/

Robby · Dirty Old Man Joined: 16 May 2002 Karma :

If you can't get or choose not to use paint stripper, then the most gentle blasting process I've come across is soda blasting.

I had it done professionally on a CB250RS engine, did an incredible job and didn't even damage the rubber seal I forgot to remove (hidden under layers of shit). Replace it during the rebuild of course, seeing as it had blasting media under it.

You can do it at home too. You'll need a big tub of soda bicarb (wing yip sells it), I have also heard of using powdered laundry detergent. Get a reasonable thickness of plastic pipe, put one end in the soda, then make a nick about 3 inches from the end and shove the nozzle of your air gun (from your compressor) into the nick, so its blowing air out of the end of the tube. Press the trigger, the air moving sucks up soda and sprays the workpiece.

You can do it outside, just wear a mask and goggle. The resultant white powder, which will be everywhere, can be hosed off.