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Media Blasting vs Angle Grinding

Posted: 17 Nov 2018, 19:44
by The Hairy Camper
I had a go with my media blaster today, cleaned up some areas on the van and had a short blast at the towbar.

The media blaster is quicker and can get to some of those harder to reach areas, but it doesn't seem to take it down to the bare metal as well as the angle grinder does? I may need to tweak the air and media mixture a bit more though?

What do you think?

Angle Grinder (Polycarbide Disc):
Image
Media Blasted:
Image
Almost looks like primer?

If anyone can recommend any other angle grinder discs that are good for stripping paint (and FILLER!), that would be appreciated.

Cheers!

Re: Media Blasting vs Angle Grinding

Posted: 17 Nov 2018, 20:00
by davidoft1
That’s what blasted metal looks like, it’s textured from the impact of the blasting media

Re: Media Blasting vs Angle Grinding

Posted: 17 Nov 2018, 20:04
by silverbullet
Blasted steel will also rust very quickly due to humidity and the metal being almost chemically clean.
Prime immediately and keep in a damp-free, dry environment. Not easy at this time of year in the UK!

Sent from my S60 using Tapatalk

Re: Media Blasting vs Angle Grinding

Posted: 17 Nov 2018, 20:14
by The Hairy Camper
davidoft1 wrote:That’s what blasted metal looks like, it’s textured from the impact of the blasting media
Cheers David, glad my blaster is working correctly then.

silverbullet wrote:Blasted steel will also rust very quickly due to humidity and the metal being almost chemically clean.
Prime immediately and keep in a damp-free, dry environment. Not easy at this time of year in the UK!

Thanks silver, i haven't got time to prime at the moment! Should i sand it down again before i prime?

Re: Media Blasting vs Angle Grinding

Posted: 17 Nov 2018, 20:46
by what2do
There are lots of different types of media. Some will leave the metal looking grey and dull, others will leave it shining like a new pin. Stuff used for heavy gauge such as your towbar generate a lot of heat and would distort body panels as was discovered by Boatbuilder at a huge cost to himself as the panels were trashed.

One type of media will not do all jobs, better to have a selection.

Re: Media Blasting vs Angle Grinding

Posted: 17 Nov 2018, 20:58
by The Hairy Camper
Thanks what2do, i will have speak to boat builder then. I don't want to distort any panels!

Re: Media Blasting vs Angle Grinding

Posted: 18 Nov 2018, 23:13
by Mr Bean
I don't do media blasting but am a great fan of Hammerite where I am not looking for a gloss and just need a hardy clean finish. Although for me it sucks when the surface is too smooth. I do find though that de-greasing is a necessity - I use IPA (not the drink) and have sometimes been temped to sneak the odd item into the dishwasher :shock: :oops: . Although Coke type drinks are claimed to be very corrosive. Sounds ridiculous but a few days outside will leave a thin film of rust on ferrous metal which when cleaned off will present a surface similar to a sand blasted finish which when hammerited will last for yonks.
Got to say though that I was very disappointed with smoothrite which I use to repaint the outboard motor bay in my boat and was horrified to find that it was not proof to petrol being completely different to hammerite.

Re: Media Blasting vs Angle Grinding

Posted: 19 Nov 2018, 11:35
by shaky
I find these pretty good:

Scotch-Brite Clean and Strip Discs, (or rather the much cheaper unbranded versions).

They wear away quickly if you are not careful but are bettter than wire brushes which just seem to "polish" the rust.

Re: Media Blasting vs Angle Grinding

Posted: 19 Nov 2018, 21:36
by The Hairy Camper
Mr Bean wrote:I don't do media blasting but am a great fan of Hammerite where I am not looking for a gloss and just need a hardy clean finish. Although for me it sucks when the surface is too smooth. I do find though that de-greasing is a necessity - I use IPA (not the drink) and have sometimes been temped to sneak the odd item into the dishwasher :shock: :oops: . Although Coke type drinks are claimed to be very corrosive. Sounds ridiculous but a few days outside will leave a thin film of rust on ferrous metal which when cleaned off will present a surface similar to a sand blasted finish which when hammerited will last for yonks.
Got to say though that I was very disappointed with smoothrite which I use to repaint the outboard motor bay in my boat and was horrified to find that it was not proof to petrol being completely different to hammerite.

Cheers Mr Bean, is IPA the best degreaser before painting? I might shop around for a cheaper alternative. I'm using Vactan primer, it's meant to be good on previously rusted metal.

shaky wrote:I find these pretty good:

Scotch-Brite Clean and Strip Discs, (or rather the much cheaper unbranded versions).

They wear away quickly if you are not careful but are bettter than wire brushes which just seem to "polish" the rust.

The scotch-brite discs are the one's i've been using :D They are great but they don't seem to last me very long :lol: I've just ordered another pack of three, hopefully they will be enough for now!

Re: Media Blasting vs Angle Grinding

Posted: 19 Nov 2018, 23:02
by Mr Bean
I forgot to add that:
Isopropyl Alcohol (IPA) is a powerful electronic cleaning solvent, which conforms to BS1595, ASTM D770 and DIN 53245 specifications. The solvent forms an azeotrope with water for effective removal of moisture from parts and components. The solvent evaporates after use, leaving no residues. Ideal for cleaning tape heads, disc drives, photocopier drums, PCBs, optical equipment, lenses, precision instruments and delicate components.
Or in simple English it mixes with most greases and oils but won't damage most paint and plastic finishes and will absorb any water/dampness which might be secreted among your crevices :oops: