Blast it!

[ian65]

So i bought this from the restoration show a couple of weeks ago..... wanted one for years and finally got around to getting one.
I'm currently using crush glass blast media which is great on rusty parts but a bit severe for alloy..... it will probably calm down a bit once it's done a few cycles through the gun and broken down a bit but I want something a with a lighter touch to do my inlet manifolds....
Anyone else got a blast cabinet and what blast media do you use and for what? Any handy hints?

[slater]

Aluminium oxide is far more resistant to breaking down than the crushed glass but gives a simlar finish. A fine grade might work for you.

You could try soda if the parts are already quite clean. Its ni good at removing paint or rust but will clean ally quite well.

Could also try glass beads.

Good thing is with a small cab you can change quite easily and see what works best for you.

[Spudgun]

We use plastic media at work for aluminium aircraft parts.
Really does work well.

[scimjim]

I’ve just bought 25kg of fine grade aluminium oxide to try on alloys - I may be able to get to the workshop today to see how it goes

[slow2learn]

Glass beads instead of crushed glass.Make sure not to leave blind hole uncovered.

[93fxdl]

Media choice is only part of the process, grit size, media flow rate, air pressure and nozzle size, all affect the aggressiveness of your blasting and the surface finish obtained.
Media selection is mainly down to the type of blasting you are doing, heavy work on rusty plate will require an aggressive media in a coarse grit size.
Often walnut shell is a choice for engine/gearbox type work, it does not last too long but any media left behind will not cause damage.
The balance of media flow against air pressure changes how aggressive the blasting is, more media and less air gives a softer blast, and vice versa, less media and more air gives a harsher clean. The nozzle diameter also affects the blasting, smaller nozzle gives a harsher more concentrated clean.
Try not to use the same media for steel/iron as for alloys so you do not transfer iron oxides over and promote dissimilar metal corrosion.
Ttfn Glenn

[scimjim]

So I fired up my blast cabinet today and dropped 25kg of fine aluminium oxide in - then attacked some fairly corroded alloys I had lying around.









Pretty good results although it took quite a while - I have 6 or 7 sets of Wheels to do, so will definitely be sending them away rather than spending hours doing it myself














It struggled to remove the paint on these wheels - I even tried a different set in case it had been powder coated by a PO - but it seems that the factory paint is tough as old boots!







I was going to do a couple of manifolds too but got sidetracked. To answer the OPs question, I’d say that fine aluminium oxide would be ideal for alloy manifolds.

[droopsnoot]

Nov 19, 2017 18:14:32 GMT scimjim said:

It struggled to remove the paint on these wheels - I even tried a different set in case it had been powder coated by a PO - but it seems that the factory paint is tough as old boots!

I took a couple of the Avon wheels that were standard on my Vauxhall for a mate to blast, he couldn't touch the centre paintwork either. I've seen them done, but not sure what media or hassle they were.

[scimjim]

If I was only doing one set I’d probably start with a chemical strip?

[discostew38]

I've not got a cabinet but I have a shot blaster and I use either crushed glass or I get some "play pit" sand from B&Q

[paulthewall]

DON'T use sand.

Yes it might work but I'd read up on silicosis before you use it next time. link

was banned years ago as a commercial blast media becuse of the health risks.

[Deleted]

I take my steel wheel rime to a commercial blaster - last bill for 6 rims was £90 - sounds expensive but at £15 each I can find better uses of my time - my alloys go to an alloy wheel specialist where they tank dip them initially then blast them prior to repair again it's about better use of my time rather than waste a day trying to strip a set of wheels.

[stealthstylz]

The hot tank at work is great for loosening paint. Dishwasher might work the same.

[Deleted]

www.ebay.co.uk/itm/Air-Sandblaster-Sandblasting-Blast-Gun-Nozzles-Connector-Tube-Derusting-Tool-Kit/222717600825?epid=2119085764&hash=item33db00e439:g:6VsAAOSwjc5Z3xVo

best upgrade i made to my cabinet the small pipe on the pick up tube ensures a smooth flow of media to the gun, i can turn the pressure down for delicate work. I use glass bead for carbs, manifolds and small brackets i don't bother doing big stuff like wheels i have chem cleaning company at £15 per wheel, cheaper than the blast media and electricity you have to use.

[Mantasport]

Yeah adding an air bleed into the pickup line makes the gun shoot much smoother at lower pressures.

I've modified my cabinet a couple of times now to make the bottom a steeper slope down into a shoot with an external pickup for the media hose. That way there is always media over the pickup, so you don't have to stop and tap/brush it down the shallow sloped sides to the end of the pipe every 5 minutes or run a huge amount of media which gets blown around too much.