Media blasting

[Adrian Harris]

After Peter's warning about cleaning this burnt out Tiger, I wonder who here has experience with home media blasting ?

Cabinets seem to range from 90l for £70 to 200l for £200, plus a compressor, plus a media handling system.

But what do you use as the media, and how do you dispose of it afterwards ?

Some reviews seem to indicate that the dust tightness of the cheap cabinets leaves a lot to be desired, so there are also dust extraction systems to keep the cabinet free of dust and to provide negative pressure to stop it leaking around the doors.

Then I'd have to find somewhere to store and operate it...

Adrian.

[Adrian Harris]

Hmm, just had my own Eureka!! moment, albeit in the shower rather than the bath

This house has two lofts, and I already use the smaller one for rattle can spraying in inclement weather, so if I built a spray cabinet up there out of MDF, I can build it to my own specs, and have the vacuum cleaner and compressor in the box room and not worry about sharing the space with their noise and heat output...

Still interested to hear about other people's experiences though.

Adrian.

[Peter Silcock]

I've considered buying a cabinet over the years Adrian, but came to the conclusion that it was not worthwhile. Reasons being that large items (in my case car panels and other parts are too big to fit in) and I tend to prefer chemical dipping now. If you're looking only at tank parts then it depends how often you will need to blast clean parts rather than simply paint strip or rust removal. The only time I have needed blast cleaning on a tank was a Tiger which had been left outside for years and my local blaster charged £30 to do the whole job and turned it round the same day. Rust removal I use acetic acid granules which removes surface rust in 20 mins and costs £3 a kilo which lasts for ages. Can be done in a plastic tray as well and no nasty chemical effects( used in cooking etc). Media blasting usually involves aluminium oxide, walnut shell and similar and can be used many times so you will probably never have to dispose of it. Just my thoughts.

[Robert Reid]

Vast experience... with small cabinets and my current one, which is 8 feet long and will take an entire Silver Ghost axle! I started (and restored most of a Derby Bentley) in a tiny, crummy benchtop one. I don't recommend it. But it was what I had at at the time.

First, the 'really' cheap cabinets with the plexi windows are worthless. You will fill your shop with so much dust that it will be a disaster.

https://www.northerntool.com/shop/tools ... 9lEALw_wcB

In addition, they don't recirculate worth a darn and so you are staring through a fog of glass and oxide-dust.

The best ones to get are the small benchtop models or a small hobby-sized free-standing model. From a good maker.

https://www.tptools.com/HOBBY-PRO-HP-75 ... ?b=d*23498

The other key is a good vacuum and a good compressor. Whatever the maker says it needs for CFM... get more! That's a minimum. It sucks always waiting for the compressor to catch up. The vacuum should be purpose-built with a sealed or isolated motor. Don't use an old Electrolux as you can have a fire... and you need the vacuum to remove more air than you are introducing with the nozzle... to keep some negative pressure. Otherwise, dust will escape through every crack and orifice.

Media... I am not a fan of soda. Glass is fine and you can get lots of grades. Highly-aggressive Starblast down to... well... soda sized particles. Soda is all the rage due to the myth that you can use it for 'assembled mechanisms... Yeah, right. You bead blast components... never mechanisms. At least not mechanism's that won't come fully apart later.

Disposing of old media... unless you are removing toxic stuff (ie lead paint) the dust is nothing more than rust and glass... It can go in the bin or get spread on the lawn... it's just inorganic dust.

Last, there are some new 'wet' cabinets on the market which I think originated in the UK. They use media in water and are dust-free. I have been VERY impressed with what I have seen of those and though I have not tried one... would love a first-hand report. Dust-free, great abrasion... and there are hobby-sized units available. Anyone have one?

The net is that the cabinet/compressor vacuum/lines/dryers/regulators (don't forget those) won't be cheap. To do it right, even on a hobby scale, is going to end up costing you close to a thousand pounds... for good equipment. The payoff, however, is rapid and solid. You will instantly wonder 'how did I get along without this' as soon as you have a good cabinet working. And the side benefit goes beyond Armortek kits... a compressor has a million uses. Plumb your whole shop! The cabinet will become indispensable once you start using it. And it will cut your time cleaning/restoring things in an exponential manner. Your time will make the investment worth it many times over.

Ask any questions if you like. It's an investment worth making. But it's not a small one. Then again, compared to the cost of some of our kits... the price is small. And the ROI is immediate.

Cheers,

RPR

[Pete Nash]

I'm not recommending it as I haven't used it, but Machine Mart do a grit Blasting gun that can be powered from a 3 hp compressor that can use abrasive grit. Machine Mart also does grit in different grades.

Abrasive grit has the advantage of removing heavy deposits but is liable to leave a rough surface.
An alternative and more gentler is ground Corn Husk or Ground Walnut Shell.

With reference to Adrian only being able to use rattle cans and being restricted to the colours available in them, while searching for something else I noticed that a Company called 'Jacquard' in the USA do a refillable spray can that is pressurised from a bicycle pump.

Pete

[Robert Reid]

For painting... I would think that a small Paasche air gun and compressor would do anything rattlecans can do and more... No space, plugs in wall. Bigger 'bottles' let you shoot more color at a time.

The selection of media in blasting is almost unlimited. Corncob and walnut, however, work better in vibratory tumblers, but these are also very good options for some parts.

Our process in the shop with blasting is that after blasting, parts are wire-brushed to 'lay down' the roughness created by the blasting. That said, if a part is to be painted, the blasting creates some 'tooth' that helps etch primers stick. And does not cause problems with surface roughness.

Best solution is to match media to part.

BTW... any abrasive blasting of thin components (for example, a brass carb float bowl) will end in disaster. The blasting will work harden one side and almost instantly cause splits. There are techniques for blasting thin-walled-metal... but these are best handled with wire wool and other non-pressure procedures.

Cheers,

RPR

[Adrian Harris]

The only time I have needed blast cleaning on a tank was a Tiger which had been left outside for years and my local blaster charged £30 to do the whole job and turned it round the same day.

Peter, did you strip the Tiger down beforehand ? The quotes I've had range between £64 and £180, but I'm not sure if they read that it was lots of individual plates etc.

Robert, many thanks for your detailed breakdown of the pros and cons. I've decided to ignore some of it (Sorry ) and have bought a simple set up. Having looked round the various options, it came down to storage in the end, as I don't have room to have a dedicated blasting bench, so whatever I bought would need to take up as little space as possible. If it turns out to be cr*p, then it can go on ebay and prices on there look like I'd probably get most of my money back. One blasting cabinet I was following sold for more than the cost of a new one

Adrian.

[Robert Reid]

Hi Adrian:

Certainly understand and space can be an issue....

Also keep in mind that my cabinet runs 2 - 4 hours a day.... all day some days.

For hobby stuff, where you are squirting a part here and there... a benchtop cabinet will probably do fine! I know that some of the Armortek panels, by their nature, get some light surface rust on them. We aren't talking needing an industrial setup to 'puff away' the rust!

The burnt Tiger (tragic!) will be more work... but in reality, nothing close to doing a rusty car axle or major components...

I forget at times that the pace of hobby work is supposed to be slow, fun and relaxing... and you don't need production-level gear (or costs) to enjoy it!

Post some pictures of your setup when you get it running... and some before/after pictures of parts! Media blasting is fun... painting in reverse!

Cheers,

RPR

[Adrian Harris]

25kg of glass arrived today. The Parcelforce driver wasn't happy

Adrian.

[Robert Reid]

Our UPS guy is even less happy when a 750lb pallet comes in!

You get a discount at 15 bags...

Cheers,

Sirhr

[Peter Silcock]

The only time I have needed blast cleaning on a tank was a Tiger which had been left outside for years and my local blaster charged £30 to do the whole job and turned it round the same day.

Peter, did you strip the Tiger down beforehand ? The quotes I've had range between £64 and £180, but I'm not sure if they read that it was lots of individual plates etc.

Adrian.

Sorry Adrian missed this question. I did strip it down because the blaster said it would be cheaper and at the time I was giving him a lot of work. Your cheaper quote doesn't sound too far out of the way and I presume that's the one you went with. The higher quote is taking the michael somewhat! Incidentally now the work has been done be careful about cleaning any remnants of the blasting material out of recesses and holes. Doesn't half spoil the paint if you don't. (ask me how I know )

[Adrian Harris]

I ended up going with the higher end one, mainly because they were much more local.

They did go over the parts with an airline when I picked them up but the box with the wheels in still ended up with a decnet layer of media in the bottom

I'll go over every piece with panel wipe before I etch prime them, so hopefully that will remove any left over dust.

Mr Hall may be interested to know that the job which followed my parts through the booth was the complete chassis from a Land Rover, which was a lot more curvaceous than I expected, for such a box on wheels

Adrian.

[Chris Hall]

Mr Hall may be interested to know that the job which followed my parts through the booth was the complete chassis from a Land Rover, which was a lot more curvaceous than I expected, for such a box on wheels

Adrian.

A thing of beauty is a joy forever ..... and what are the majority of Armortek products, if not boxes on tracks ?

[Peter Silcock]

Mr Hall may be interested to know that the job which followed my parts through the booth was the complete chassis from a Land Rover, which was a lot more curvaceous than I expected, for such a box on wheels

Adrian.

Lets hope the owner ended up with more metal than holes - I've seen a couple of early LR chassis after media blasting and it wasn't pretty...

[Liam Mahoney]

Hi Adrian
The best thing for cleaning blast dust is warm soapy water, then blow dry?
You will find after the blasting the paint will adhere so much better.
Liam