Using a shotblasting cabinet

[culp]

Hello,
I've just invested in a shotblasting cabinet. I got a Clarke CSB20B it's not bad, inexpensive, a bit on the small side. Great fun to use, very satisfying "hosing" all that horrible rust and dirt off suspension components.

The aluminium oxide grit is full of dust and when I pull the gun trigger the whole cabinet fills full of a swirling cloud of dust and I cant see what I'm doing. Has anyone managed to recycle the grit and if so how? I can't see that sieving is going to work?

[moggyvirgin]

I'm using a shot blaster pot using aluminium oxide to remove underseal and paint from my moggy which is on a roll over jig in my workshop. I've enclosed the working area with a plastic sheet to catch the shot blast which as you say gets very cloudy. Then I collect the shot with a dust pan and brush, and pour it though a sieve into a bucket which I then pour back into the shot blaster.It is very time consuming but very satisfying.

[bmcecosse]

You should have dust extraction on a grit (I doubt it's 'shot' ) blast cabinet. The dust is very health damaging....the dust extraction must be to HEPA standard. Even with that - I urge you to wear a good professional standard dust mask. As for 'free air' - blasting......oh dear.....I can't believe it's allowed...

[ian.mcdougall]

The info on the web site says "Can be used with in conjunction with a vacuum extractor",I suggest you investigate using a vacuuum extractor to combat the swirling dust problem, the machine should already be recycling the grit in the cabinet,it will eventually lose its blasting properties and will need replacing

[culp]

thanks everyone for the help.

[philthehill]

I have the same Clarke grit blasting cabinet and experienced the same problem. This is caused by the O/E filter/vent blocking and therefore the excess air pressure cannot escape and where it does escape it is mostly around the lid seal which is not good and it stirs up the grit inside the cabinet.
To overcome the problem I purchased two Work-zone fire ash extractor/filter cans from Aldi when they were for sale at half price.
I ditched the O/E filter and fitted one of the ash extractor/filter bayonet fittings to where the original filter vent was fitted. You need the two ash extractors/filter cans so you have use of the two bayonet fastenings to connect the hose between cabinet and ash extractor/filter can (unfortunately only one bayonet fastening per ash can).
To make the ash extractor filter last longer fit a VAX filter bag over the filter cartridge and secure with a elastic band.
Connect your vacuum cleaner to the ash extractor/filter can and switch on the vacuum cleaner before grit blasting and you will not have any more problems.
In reality I find that very little grit gets into the ash can with this method of extraction.
Whilst the cabinet is small it is very useful and is well used by me and my friends

[don58van]

Hi
I have a similar cabinet which I have just started using. I am having the same problems with dust/visibility.

I have done a lot of research on the web on how others have tackled this problem.

The standard solution is to attach a vacuum cleaner. The problem is, the fine dust (material from the part you are cleaning and smashed abrasive particles) will very quickly clog the filter and probably ruin it.

The solution to this appears to be to use a cyclonic dust extractor between the cabinet and the vacuum. These work so well that it seems that almost nothing reaches the vacuum cleaner--the dust is mostly intercepted by the cyclonic extractor.

I have found three commercial manufacturers of the cyclonic extractor suitable for home setups, but there are plenty of designs for making your own on the web.

I have just bought a Dust Deputy (made in the US), but there are also French model and what appears to be a Chinese copy of the French unit which are cheaper. I haven't tried mine yet--I will have it set up in a few days time.

Have a look on youtube. Search for 'cyclonic dust extractor' or 'Dust Deputy'.

All the best for 2015
Don

[bmcecosse]

Make sure the vacuum cleaner is HEPA rated !! The cyclonic vac cleaners should do the job ok. Just bang the filter clean regularly.

[philthehill]

Don
My solution cost me £20 and an hours time.
The ash can filter does not clog because of the VAX disposable filter bag fitted over the outside of the ash can filter therefore the vacuum cleaner used does not get any grit into it because of those first and second line filters; and as importantly the top loading door seals are now effective in that no grit is getting past the door seals because there is now adequate vented air flow through the ash can filter/vacuum cleaner. Only clean air comes out of the vacuum cleaner which also has a integral dust filter - so cabinet air to atmosphere is filtered three times before exiting the vacuum cleaner
Phil

[don58van]

Hi Phil

I am interested in your ash can filter solution. It is certainly much cheaper.

Problem is, I don't know what they are .

I am from a penal colony called Australia and I don't know of such a thing.

Can you post any information that would help me understand what they are and how they are used?

Cheers
Don

[philthehill]

Don
I will post some pictures of my set up later on today.
In the mean time here is a link to a similar ash can/filter as used by my self.

https://www.machinemart.co.uk/shop/prod ... n%20filter

Ignore the comments about the internal filter blocking - the VAX disposable filter bag placed over the internal filter stops what little grit finds its way to the ash can getting anywhere near the internal filter so alleviating any possibility of blockage.

Phil

[don58van]

Hi Phil

Thanks for your reply.

I have never seen those. I will investigate whether anyone sells them here in the antipodes.

Regards
Don

[philthehill]

Photos of my dust/vent extraction system.
This photo is of the old internal O/E filter removed and the spare bayonet fixed on the outside of the cabinet. There is a seal between the bayonet fixing and the cabinet.[frame][/frame]

[philthehill]

Take the bayonet fixing off the spare hose and fix to the end of the hose so that you end up with a hose with bayonet fixings at both ends.
This is a picture of the cabinet end of the modified hose fitted into the cabinet bayonet fixing.[frame][/frame]

[philthehill]

Take a spare VAX disposable dust filter bag and fit over the ash can built in filter and secure with an elastic band as per VAX fixing.[frame][/frame]

[philthehill]

Connect all together and use.
The grey hose is the hose to the vacuum cleaner which just pushes into the top of the ash can.
With this arrangement very little grit finds its way into the ash can and no grit gets past the VAX disposable dust bag and the ash can internal filter to the vacuum cleaner so that your vacuum cleaner is safe and not subject to grit; also because of the three filters no dust or grit get to the atmosphere.
Replacing the VAX disposable bag at frequent intervals ensures that the ash can internal filter will last much longer.[frame][/frame]

[don58van]

Thanks for the pix Phil. All is perfectly clear now.

The ash cans seem to be a very rare item in Australia, but I have found one Ebay supplier in Oz that sells them.

To state the obvious, your system is essentially the same as the one I am putting together. A filtering and storing unit is interposed between the blast cabinet and the vacuum cleaner.

The difference is in how the filtering is done. As the unit I am building uses cyclonic filtering (if it works as expected) it will not need any maintenance (filter replacement).

I will report back in a week or so when I have had a chance to find it.

Don

[bmcecosse]

The important thing in all this is to use some sort of good extraction/filtration (with proper HEPA final filtration) - and to NOT use the blast cabinet without extraction! Edit - It seems Clarke DO provide clear instructions to use the cabinet WITH dust extraction. Well done Clarke !

[philthehill]

http://en.wikipedia.org/wiki/HEPA
bmc
I totally agree that there should be good extraction/filtration facilities for air exiting the blast cabinet; but unless one is prepared to modify the above cabinet and fit a more suitable extraction/filtration system the downside is a very small internal filter that gets blocked very easily and is not that easy to clean. As soon as the filter starts to get blocked the build up of air pressure inside the cabinet just breaks the seal around the door and grit/dust escapes past. The cabinet as sold does not appear to have provision to fit an additional extraction/filtration system.
Whilst my extraction/filtration system is not perfect (the ash can O/E filter is of a HEPA type) it is much better to that which was fitted and the vacuum cleaner used is fitted with a washable H12 HEPA type filter - but there again as described in the above link not all so called HEPA filters are HEPA compliant or certified.

[ian.mcdougall]

In the manual it clearly states.
"We strongly recommend that this unit be used with a vacuum extraction
device.
Air is extracted via a double filtration system at the right hand side of the
cabinet.
Please note that when vacuum extraction is used, air will be drawn into the
cabinet through the hole on the back panel of the unit. The hole is covered
on the outside with a filter plate, and housed within the plate is a foam filter,
which must always be in place. This is to prevent grit from being blown out, if/
when the vacuum extraction is NOT used."
link http://www.clarkeservice.co.uk/manuals2/csb20b.pdf