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