Blast cabinet

[jordhandson]

you don’t want any flex pipe either as that massively reduces duct velocity. should be proper ducting.

if you have to make a transition it should be gentle sweeping bends

sharp changes in direction and flex ducting will cause dust to settle out and build up, reducing extraction performance.

plus flex ducting won’t last long at all due to the coarse abrasive nature of the dust

the Regs require these sorts of e traction system to be tested and inspected 6 monthly as it’s well know the dust eats away the extraction ducting

Ah this is the stuff I use. 150mm

 

[Parm]

Ah this is the stuff I use. 150mm

View attachment 271961

that’s the proper stuff, but if you do have to use it it must be minimum 3 duct diameters from a flange, ideally it should be double that

 

[jordhandson]

that’s the proper stuff, but if you do have to use it it must be minimum 3 duct diameters from a flange, ideally it should be double that

 

[Parm]

iveyou want I’ll share some info you may find useful from my industrial extraction ventilation bible?

 

[jordhandson]

iveyou want I’ll share some info you may find useful from my industrial extraction ventilation bible?

cant hurt learning pm me anything you think may help Thanks Parm

 

[Parm]

cant hurt learning pm me anything you think may help Thanks Parm

will do at some point Tommorow

 

[jordhandson]

will do at some point Tommorow

Cheers

 

[Barking Mat]

Id be interested too @Parm, i got some plans...

 

[Parm]

Id be interested too @Parm, i got some plans...

I was planning g to upload a few pics from my book straight in here

 

[Barking Mat]

I was planning g to upload a few pics from my book straight in here

Good man.

 

[Agroshield]

Mr Parm can advise better than me, but for real good performance, consider making or buying a rectangle-to-round transition piece to go straight on top of the rectangular cut out on the cabinet top. This will funnel the airflow more nicely than a flat surface with a hole in it.

The secret of any successful fluid flow, be it extraction, internal combustion engine intake, two stroke exhausts, SR71 turbines, is gradual changes of diameter and direction. Fluid is sneaky and recalcitrant. It does not like being told what to do. So you have to massage it into place so it does not realise it has reduced from 6" dia. to 4", and by the time it does realise, it is too late to resist or turn back.

 

[Parm]

Mr Parm can advise better than me, but for real good performance, consider making or buying a rectangle-to-round transition piece to go straight on top of the rectangular cut out on the cabinet top. This will funnel the airflow more nicely than a flat surface with a hole in it.

The secret of any successful fluid flow, be it extraction, internal combustion engine intake, two stroke exhausts, SR71 turbines, is gradual changes of diameter and direction. Fluid is sneaky and recalcitrant. It does not like being told what to do. So you have to massage it into place so it does not realise it has reduced from 6" dia. to 4", and by the time it does realise, it is too late to resist or turn back.

Argoshield had put this very eloquently

 

[Parm]

Here’s the page from my book, not as helpful as I thought it may be !

The headline to take away is the number of air change rates that should be maintained and the minimum duct velocity

figures are in “American” but I’m sure you clever folk can do the conversions

 

[brightspark]

mine uses a woodchip extracta with 4 inch flexi hose .even putting 28cfm in from the gun the cabinets negative pressure and can still draw in more air

 

[Parm]

mine uses a woodchip extracta with 4 inch flexi hose .even putting 28cfm in from the gun the cabinets negative pressure and can still draw in more air

So she sucks like a good un ?

 

[brightspark]

So she sucks like a good un ?

yup it needs to because i use quality kiln dried sand and i value my health

 

[jordhandson]

Love it thanks Parm “not as helpful as you thought” that tells me im are on the right track, no joking aside it is helpful, I will try and figure a way of measuring the air flow from the cabinet, I have plenty of suction from the extractor, enough to pull the skin off a rice pudding at 1 metre away



Today I added a baffle inside the cabinet 40mm under the outlet to stop the extractor sucking out the grit I will get a pic of it tomorrow as it explains better. I was going to add air inlets but decided against it at the present as I have 4 arm holes not gloves and can only use 2 at a time if it needs an inlet I can add later. I get what they mean about channelling the air via a smooth reduced will look to it.

The extraction on this build is going to be a lot better than on my other Guyson cabinet that comes with its own guyson extractor I may even try and use this extractor on it to improve it.

Cheers

Jord

 

[brightspark]

i use a gas bottle base and a fine mesh filter of a frying pan on the side of mine then ducted through the extracta works perfectly . removes the dust without loosing media

 

[jordhandson]

This little bad boy arrived today only bought it on the auction site a day or two ago delivery was very quick with the pallet network.



I am hoping to strip it all apart and get it up and running, its a pressurised pot with the pop up valve in the top,



I couldn't resist it at a 100 quid the grit valve would cost you more.


I did some research on it and its 5A pressure blasting pot from Power Blast International LTD and they are still trading with spares available.



Once I have it fitted with a foot controlled dead man I think it could be a perfect fit addition to this cabinet. May even make another cyclone to go over the top.

 

[brightspark]

hope you have a decent size comp . how many cfm ???