Homemade Blast Cabinet

[David Sparkes]

Two compressors - make sure your electricity supply to the garage will stand 26 amps for the motors, plus the vacuum cleaner and lighting.

Perhaps I'm being sensitive here, as mine won't!!

Air capacity - this is tied in with the pressure you use. Less pressure equals increased flow, but although this results in more media striking the target, in practise it isn't travelling fast enough to be effective. (I'm using the caliper corrosion as the example here).

Frankly, if you want a better (and much faster) blasting performance you will be better served by adding a pressure pot to your cabinet installation.

Like you, I started with a suction gun, but eventually I saw I'd have to spend more money. It just took a long time to reach into my pocket!!

You don't say what pressure you are achieving when the suction gun is in use. I appreciate that twin compressors will help you achieve greater flow, at a higher pressure, but I doubt they will cut out while the gun is in use. They might cut off sooner after you release the trigger, but I suspect they will both be running continuously during actual blasting.

It's a bit like increasing the efficiency of a car engine, there is potential for greater fuel economy, but in practise people tend to use the extra performance, so the fuel spend remains the same.

As I've said, the supply from the compressor tank has always been unregulated (therefore unrestricted) for both the suction gun and the pressure pot installations.

I put a regulator (and gauge), plus a self draining water trap, where I could see them while actually blasting. I forget what pressure I set while using the suction gun, but I went for an almost maintainable pressure as this ensured the air bleed adjustment on the pick up was always satisfactory.

Now, with the pressure pot, I set it at 60 psi, which the compressor manages most of the time, but I always stop the flow while moving the target piece in the cabinet so the compressor has a chance to slightly recharge the receiver. If I'm doing something really big, that I have the pressure on for a long time, I do have to stop when the pressure reaches 40 psi. There is simply no point in continuing at that pressure.

I use Aluminium Oxide as the blasting media, it is reusable, and while some disappears as dust it's only a small percentage.

I'm told it's a special grade for this sort of blasting, which my latest supplier didn't recognise, but to his credit he researched the matter and found me some. Trade name 'Blastblend Dark', designation MXB40/60. IIRC is was the 'B' in MXB that caused the surprise (40/60 refers to the grain sizing).

I hadn't bothered to look up the detail before, But here is a link which shows the 'Dark' is a cheaper variation.

You aren't blasting every day, so your compressor may well last longer than you think. Mine is an ex-demonstration Fiamma, nothing special, and it's lasted several years. Like you, I'm a hobbyist, but on Series 2 Land Rovers, most items have rust to be cleaned off.

Correction, it's an Italian made fiac Miami V-twin.

One last point, I didn't recognise the word 'coelescer', but assumed you meant 'water trap'. After seeing the word repeated I looked in the Cambridge online dictionary in case I had misunderstood. It changed the spelling slightly, but came out with Coalesce - 'If two or more things coalesce, they come or grow together to form one thing or system.'

I read this as the opposite of what you are trying to achieve, the separation of water from the air stream.

Regards.

[mickeyw]

One last point, I didn't recognise the word 'coelescer', but assumed you meant 'water trap'. After seeing the word repeated I looked in the Cambridge online dictionary in case I had misunderstood. It changed the spelling slightly, but came out with Coalesce - 'If two or more things coalesce, they come or grow together to form one thing or system.'

I read this as the opposite of what you are trying to achieve, the separation of water from the air stream.

Regards.

David, I've always known of coalescing filters as for separating liquids from air.

Basics of Coalescing Filtration. Note the combining of liquid particles in the process to separate them fro mthe air.

Adrian, you've reawoken my thoughts of a self-build cabinet. I'd searched at length a while back, and found many methods similar to what you've done. Time however has not been on my side yet.

What you've built looks very tidy - I'm most envious! I like the use of the van window...I have a spare Defender rear window in the shed...hmmm....

For my air supply I have a Hydrovane HV01 that I am not expecting to provide sufficient air, but I also have another belt drive compressor that I plan to hook up the the HV01's big tank for when high demand is present.

One day I'll get there

[David Sparkes]

David, I've always known of coalescing filters as for separating liquids from air.

Basics of Coalescing Filtration. Note the combining of liquid particles in the process to separate them from the air.

Well, there you go!!

I hadn't given much thought to exactly how a water trap separated out the moisture from the air, so I was a long way from 'combine the small water drops into large water drops so they fall out under gravity'.

Every day is another learning opportunity, thankyou :-)

[B reg 90]

David,

Re power - I fitted a 60 amp supply to the garage to a seperate distribution board a year or two ago to run a inverter that can pull 40 amps on full load. As I don't use the inverter at the same time as the blaster I'm good?