What do I need to start Part 2 Cabinets

Hi

The use of a cabinet when etching is a must, I know that the pro's have walk in rooms where the whole area is the cabinet and they are inside with full protective breathing equipment.

But for normal etching it is done inside of a smaller controlled space.

There are a huge range of cabinets available but they all should have the same basics and some are more advanced.

Sealed  The blasting media should remain within the confines of the cabinet and not leak out to be breathed in by yourself or anyone in the area.

Dust extraction  The process of blasting creates a lot of dust from the removal of the glass and the breakup of the blasting media and this needs to be removed as fast as it is created, you also need to see what you are working on as the dust quickly obscures your view of the job. The extraction is normally a hole in the side of the cabinet where you plug in your own suction device or on more expensive cabinets a built in extractor.

Bolt on extractor
On sale eBay £150

Bolt on fitted

Stand alone extractor

On sale eBay £285 plus £35 delivery

Dust extraction can also be made at home, I have made mine and shall look at that in a later post.

Vision  A Viewing window of a decent size and positioned for your preference, some are on the top to look down into, some are angled at the front to look straight ahead. Try before you buy.

Front view

Top view

Lighting  Generally a fluorescent strip light is fitted and the number of these is dependent on the size of the cabinet, these strip lights are quite often inadequate for the job.

So it is often the case that modifications are made.

I have used small outdoor security halogen lamps in my new cabinet, these give off a huge amount of light but also a huge amount of heat, great in winter.

Access    Getting into your cabinet to fill with media or position and remove a job is again dependent on which cabinet you buy, some have a side door or doors, some have a front door, some have the whole front lifting and some have the whole cabinet top lifting of the base it all depends on the design suitable for you.

Side opening single door
On sale eBay SBC 220L range around £190

Front opening
On sale eBay around £1100 plus £45 delivery

Top opening

Access For Working  Most cabinets are generic, the manufactures don't know what you are going to use it for, it could simply be for rust removal of car parts or just as easily for glass etching, so the generic route is to fit a pair of gloves. These protect the user from stray blasting material and also seals the cabinet from leakage. These gloves are made from heavy rubber and are virtually impossible to manipulate and work on a piece of glass. A simple answer would be to cut the fingers off , you still have the gloves but you then have a little more dexterity.
The more glass orientated cabinets have a different approach and fit either arm protectors which are a arm shaped bag with loose elasticated ends for you hands to go through or wide brush letterbox openings which are my preference and I have fitted this type to my cabinet as you can then put in and remove the smaller pieces of glass.

Standard heavy rubber gloves

More expensive cabinet with elasticated arm protectors

Hopper  The hopper is the lower section of the cabinet and holds the blasting media, very good idea as the media you blast then returns to the hopper for re-use, remember the larger the hopper the more media required to fill, mine holds around 50 kg and 25kg in the pressure pot at around £30 for a 25kg bag of Aluminium Oxide.

This top loader appears to be all hopper.

Size  Generally the size of the cabinet you buy is governed by what you want to pay but also by what you intend to use it for. We have looked at smaller cabinets for smaller work but from experience these are not very good at all, the main problems are,

They fill with dust very quickly so without a very good extraction system in place you can't see what you are doing.

The depth of the cabinet is generally to short for your arms, meaning:- that as your arms go in the cabinet you fill it and have no room to manoeuvre. 

The gun you are going to use when starting will more than likely be a syphon gun which has 2 unwieldy hoses attached that fill the cabinet, so unless you are going the air eraser route then be careful. 

The general advice would be to first have a look at cabinets and put your arms in, pick up the gun and move around while looking inside, see if you are comfortable with the work area. Check the height you may be a short or tall person, you can always stand on a box but crouching for long periods will soon put you off. Bench mounted or on stands will also affect how you use it, standing or sitting; lots of things to think off.

Looks very uncomfortable for this tall person

A lot more comfortable

Sitting comfortably and also using a Hydrovane compressor similar to mine.

Generally the cabinets are listed by Litres of space which is the area inside to work in.

There are :-
Width x Depth x Working Height most tapper up towards the back so I am listing the back size

SBC90L which has a working area off 560mm x 460mm x 280mm or 22"x18"x11"

SBC150L which has a working area off 620mm x 540mm x 470mm or 24" x 21" x 18.5"

SBC220L which has a working area off 840mm x 540mm x 370mm or 33"x21"x14.5"

SBC350L which has a working area off 875mm x 680mm x 450mm or 34"x 26.5"x 18"

SBC420L which has a working area off 1120mm x 680mm x 570mm or 44"x26.5"x20"

SBC990L which has a working area off 1175mm x 885mm x 850mm or 46"x35"x34.5"

Work Area   The hopper top is covered with a mesh to allow the used media to fall back through, the mesh should also be strong enough to take the weight of the piece of glass or an easel to position your work on. It should also be fine enough so that any resist pulled while inside of the cabinet does not fall through and block the outlet hole.

These cabinets have large diamond mesh approx. 25mm x 15mm 1" x 1/2" which will allow debris to mix with the media

Drain  At some point you may need to remove the media and provision should be made for this, this is most important if you plan on setting up a pressure pot system as what ever you blow into the cabinet must be removed to re-fill the pot.

Inlet / Outlet  Most cabinets come with the basics, these are generally an air inlet pressure reducer and gauge with a air hose running into the cabinet through a sealed gland, a syphon gun and pick up tube. This basic set up will allow you to start etching once filled with media. The pickup is placed into the media, plug in the gun to the air hose and of you go. 

Pressure regulator

Not all cabinets have a media outlet but some do, the outlet is a hose running from the bottom of the hopper into the cabinet and plugs into the suction part of the syphon gun. This allows for the removal of the pick up that comes with the gun.

You can see in this shot the bottom pick up and the hose coming through the cabinet to the gun.
If buying a cabinet like this you need to ensure that a hopper drain is available in case of having a pressure pot.

This cabinet comes with everything, foot switch, bottom suction outlet, extractor, and blasting gun.
On sale eBay SBC 450 £700 plus £45 delivery

Foot Pedal  As a lot of the more expensive cabinets have the suction hose fitted directly into the bottom of the cabinet (see picture above) to suck the media through the gun, these guns do not have triggers like a normal syphon gun and an on off control switch is fitted, this is a air control switch fitted in a foot pedal, press the pedal and air on for blasting, release and air off.

On sale eBay £35

Gun that requires a foot pedal either air or electric operated.

Solenoid and Pressure Control  Some cabinets have a switch panel situated on the top or side of the cabinet that allow you to open the air via a solenoid valve and you can control the pressure from right in front of you.
A solenoid valve is a magnetically operated valve, a current is applied to a coil creating a magnetic field which lifts the valve stem, release the magnetic field and the valve closes. You can also regulate the air easily for different type of etching.

This cabinet is a SBC350 cabinet which was my first choice to buy before I decided on building my own. It has a electric foot pedal that opens a solenoid valve allowing the air to flow, an extractor and regulator on the top panel

On sale eBay for around £600 with £45 deliver.

Pinch Valve Control  A pinch valve controls the flow of the media as opposed to the control of the air, these valves are used in conjunction with a pressure pot outlet so that the pressure in the pot is maintained while the flow of media is stopped. The alternative to the pinch valve is to have a valve on the end of the hose to stop the flow. I used this method for a number of years and it does have it's disadvantages the main one being that you need two hands to open / close the valve (one for the valve the other for the hose) and you are mostly holding the glass with one of these hands.

The valve has a Buna rubber membrane which is resistant to the abrasiveness of the media, when activated by air pressure from an air foot actuator, the membrane closes stopping the flow.

These are available on eBay for a hefty price of £135 for a 1/4" and £170 for a 3/8" wow, and you still have to buy the foot switch.

Only the very expensive cabinets use these as they are part of the integrated pressure pot system and these cabinets new run into the £1000's but are obviously the best systems. They are designed for continuous use as the pressure vessel automatically refills after use so you always have media as opposed to the external pressure pots where you are required to remove media from your hopper to refill the pot.

This fantastic cabinet is a Rayzist design and they start at around $3500 around £2300 up to the top grit pit at around $8700 around £5700

Of course there are cheaper but less designed options.
This is a Blue Point and for those who don't know Blue point is also the name for Snap On tools

and you could also convert your existing cabinet with this handy conversion kit.

This comes with everything you need, they make the flange arrangement to fit your cabinet, of course you have to own a larger professional cabinet with a recognised base flange to bolt onto.

I will look at pressure pots and syphon guns in my next post but have you considered building your own cabinet I shall also look at mine in a separate post.

But in the meantime have a look at these home made cabinets, virtually anything box shape can be used and probably has been.

Can you guess what it is yet.

Washing machine.

Chest freezer.

Large fridge

Lots of oil drum conversions.

Plastic box.

And not forgetting the very useful cardboard box.

But my all time favourite.

The back end of a VW camper, these thing are worth a fortune in the UK, bet he wishes it was still a van.

As I said about compressors your first port of call for a used cabinet should be eBay as there are always lots for sale either new or used but if after used then please remember that these will be predominately buyer collects so think of the weight and size for transport before you put a bid in.

Paul

What do I need to start. Part 1 Compressors

Hi

Deciding what to buy depends on what you want to do.

There is a huge array of compressors for sale from the very small suitable for an Air Eraser to the big 3 hp that can be run from a household 13 amp supply, the choice of what you buy largely depends on what you can afford, the space you have to work in, what you want to work in and whether you want to future proof what you buy.

Mini Compressor.

These are mainly used for air brush work and come in a variety of sizes, the larger sizes are suitable for use with an air eraser.

This is mine, its a Kestral CP203 model 1/6th HP motor with an air displacement of 1.5 cfm (46 Lt/Min) with a max pressure of 60 psi and a small 3 litre receiver but with a cost of 145 pounds.

Kestrel CP203

This size would be ideal for an Air Eraser although they do come a lot cheaper.

What is a Air Eraser

Basically like a air brush but instead of paint in the hopper you load fine abrasive, not that you can use any air brush you have lying around as these are designed specifically for abrasives. 

Used by air brush artists to remove paint or jewelers to abrasively clean metals but can also be used for glass etching.

I found a forum called Make the Cut where these photo's of air eraser work where posted, looks great.

Prices of Erasers vary greatly I have found them from 20 to 90 pounds but as with everything 'you gets what you pays for'. 

Remember when etching using air abrasives that care must be taken with your health, you must never use normal sand either from the beach or fine silver sand used for block paving as when the media hits the glass a part of each grain will break off into very fine dust particles which, without protection you may breath in. Sand is the worst of all abrasives because of it's silicone content and you may contract silicosis of the lungs so only use the correct abrasives and protection which we shall look at in another post. Erasers use around 150 to 220 grit abrasive and can be collected for re-use.

Small cabinets that are suitable for small work are readily available and a vacuum cleaner can be used for extraction.

A small cabinet like this sells for around 60 pounds on eBay, but of course you could easily make your own.
If you want a hobby etching glasses for presents or jewelry then maybe this is the way to go.

Large Compressors

Again decisions to be made on what hp, cfm, fad, decibels, drive, usage and affordability before you buy, there is no reason not to buy a used machine. Try Gumtree, eBay or as I have done twice, have a look at compressor sales and service companies in your area as they generally re-furbish traded in machines and you could grab a reliable bargain.

I wrote in my last post about the first compressor I bought which was a 3hp direct drive Sealey machine and boy did it hurt the ears. So if all direct drives are as loud then beware and price in for a good pair of ear defenders and a very annoyed wife, husband, children, neighbors, passer's-by. 

Belt driven are the most common compressors available and sizes from 1, 1.5, 2, 2.5, 3 and 4 hp are readily available with the prices rising accordingly, expect to pay around 450 pounds or more for a 3hp machine with a 150 lt tank, a lot quieter than the direct drive.

Lower horse power machines will also work and a basic rule of thumb is that each hp equates to around 3 cfm so when buying you can have a bit of an idea what you are getting, but personally I would not go lower than 2.5 hp and even then you may require the use of a pressure pot as opposed to a syphon gun as the syphon gun uses a considerable amount of air and have large nozzles. I shall look at pressure pots, syphon guns and different nozzles in a separate post.

Also ensure that if buying a 3hp machine that it is happy to run off a 13amp plug, otherwise you will have to run a new supply from your fuse box and fit a larger fuse. A qualified electrician will easily sort you out.

I am no expert on air volume versus nozzle sizes as in my experience big is best as you can cover most bases when you have plenty of air at your disposal.

So I have linked a number of informative sites below from people who know what they are talking about.

AZ Glass Classes, CFM v/s PSI
Glass Etching Secrets, Which compressor

Etchmaster Which compressor

CFM explained

Nozzle sizes explained
Ehow, Sizing air compressor
Gray Dog, Compressor selection
Free air delivery explained
Glossary of air compressor terms
Wikipedia CFM explained

My personal preference after trying different compressors is the Hydrovane so if you have the money then give one ago you won't be disappointed. Before you buy any compressor check out the data sheet for your model, this is mine.
Hydrovane HV02

Paul