Grit Blasting

[Parm]

had my first go at grit blasting today. I've got a cheapo gun from Halfords and a very big bag of crushed glass I got from a client.

It was slow but worked an absolute treat on my cast iron sewing machine legs, poor old compressed was constantly running but kept up.

Couple of questions now. In a rush I slapped on some spray primer from a can, can I paint over this with hammerite as that's the final finish I want.

Secondly would it help if I had an additional reservoir for the compressor ??

 

[rtbcomp]

That crushed glass is brilliant stuff.

An additional reservoir wouldn't really help, you could fill it before you start and you'd get more done until the compressor cut in, but from that point it would still keep running.

With a trigger operated gun you can save a bit of air by releasing the trigger as you move from one part of the work to the next, also with glass grit you could try turning the pressure at the regulator down a bit, that would save some air.

Really you need more CFM, and that means adding a 2nd compressor or getting a bigger one.

 

[julianf]

I think hammerite (etc) is supposed to go direct to oxidised metal

 

[Cobbler]

I've used the 'old type' Hammerite over primer, not used the reformulated stuff though. I've sprayed the original & it gives a good finish using a cheap spray gun, but you had to use their thinners. I understand the new stuff you can use ordinary thinners or white spirit with.

 

[brightspark]

I think hammerite (etc) is supposed to go direct to oxidised metal

it is but if I paint owt half decent I use etch primer 1st

 

[Cobbler]

it is but if I paint owt half decent I use etch primer 1st

I sprayed an alumium diving cylinder years ago, I spoke to Hamerite about primer & the girl on the switchboard said you don't need any primer for our product. Needless to say it all flaked off, when I rang up to complain I spoke to someone who worked on the development dept, I was them told if you wanted a hardwearing finish on ally to use a self etch primer, for a purely decorative finish it was ok without. I wish I'd been told this in the first place. Someone let me have some self etch which was 2 pack clear liquid & went on like water to give a thin clear film, but the only thing was it made you high as a kite. I sprayed the cylinder with my feet 2 feet of the ground.