Materials Tools & Equipment: Part 5 Photo Resist

Hi

As discussed the resist we use as a beginner is largely dependent on what we wish to create, for simple light etching we may use an airbrush mask or Fablon (light vinyl) then move on to sign vinyl for working a little deeper and then as we get more experienced move onto the more proper resist for carving or deep etching for infill. A lot depends on what you can afford to buy, or what you have available, of course, you may start and stick with the proper resist.

I started out with Fablon then acquired 4 full rolls of sign vinyl maybe 60m long each roll and I have only 2 rolls left; either lots of mistakes or very prolific, so maybe before you make each stencil try out your pattern with a paper print as you can't afford to make mistakes. I say this so that you may get used to checking before cutting as photoresist is very very expensive.

Once you get a bit more advanced into your etching hobby and designs get progressively more complex then you may wish to move onto Photoresist. These resists can recreate to perfection any design you can wish for whether it is intricate line work or photographic images, photoresist can reproduce it whether good or bad it is all down to the design; good in good out, bad in bad out. Not only will it take line designs and photographic images but there is no necessity for the images to be of a vector design as any black printed images whether .btm .jpg .png. or .tif basically anything you see in black and can be printed can be used but the better the quality of the artwork the better the output.

I have just received 5 A4 pieces of 2mil Rapidmask at a cost of £28 or $43 inc postage so not to be wasted on mistakes, also be aware of the shelf life of resist which is around 14 months, when I was sorting out what gear I had left to start etching again I found 4 sheets of Rapid and 2 of washouts which I had to throw away as they were well over 4 years old.

What is photoresist

Photoresist is a light sensitive material that when exposed to UV (Ultraviolet) light changes its form, it can change in 2 ways depending on type.

Washout

Washout resist is the more common of the resist family and is classed as a positive resist.

Wikipedia

• A positive resist is a type of photoresist in which the portion of the photoresist that is exposed to light becomes soluble to the photoresist developer. The portion of the photoresist that is unexposed remains insoluble to the photoresist developer.
• The developer in this case is water although some use a chemical.

Basically, the clear areas of the photoresist are activated by the UV light and harden into the resist while black printed areas of the design receive no light from the UV tubes and remain soluble and will disappear when washed under pressure, hence the name washout.

This is perfectly explained in this video by John Morris of Cornerstone Glassworks.

So, positive resist means that the design is etched as you would see it on your screen black lines etched while clear areas remain untouched.

Here is an example of what could be a downloaded flourish design in .jpg format.

In this video, we can see how converting a photographic image into a halftone using Photoshop and exposing onto our resist allows us to render the image onto the glass. It is also one of the best photoshop halftone conversion videos I have found.

Have a look at this work using washout resist Lapida online

This type of resist is produced by a company called Rayzist in California and produces 2 different types of resist the first being

SR2000 which comes in 5 different thicknesses from 3mil to 9mil. If using this resist then you also need to buy the adhesive to stick the resist onto the glass, this is probably not the best option for a beginner.

Etching paver using SR2000

SR3000 is Rayzists best resist for glass as it is self-adhesive and comes in 3 different thickness 3, 4 & 5mil, this is what is used in the above videos.

3mil being for detailed artwork and halftones
4mil being for moderate detailed artwork and moderate depth etch.
5mil being for bold artwork and moderate to deep stage carving

It can be used on all types of etching from wood, stone, granite, marble, soft metal and glass of course

The next type of resist is called RapidMask

Rapidmask

This type of resist is classed as a negative resist, meaning the black area's of the design are unaffected by the UV and the clear area's are exposed.
Unlike the washout resist Rapidmask is permanently in a resist state and when exposed to UV light for the prescribed amount of time will turn the exposed resist brittle which will be indicated by a colour change showing the outline of the design. When these brittle areas are hit by our sandblasting they break apart allowing the media to etch our design. There is no need to washout this resist you just expose with the UV, stick on the glass and blast.

 PDF INSTRUCTIONS

When after first buying your Rapidmask you need to check the exposure time required to turn it brittle, this may not be a fixed time as each different UV exposure unit may have a different wattage of tube, or tubes. I have not tested my new unit, but this has 6 8 watt black UV tubes so may have a shorter exposure time than a 1 or 2 tube unit.

This guide was snipped from the Ikonics site giving exposure times for different units.

I have been to the Crystal Galleries works and had a tour and instruction from Kevin the General manager and from his instruction these times may well be over exposed, we tried 30 seconds and it worked fine.

Brittle test and using Rapid mask

Ikonics video showing how to use Rapidmask

Ikonics imaging. Showing negative images and using Rapidmask

Very good video on using Rapidmask

Rapidmask comes in two different thicknesses for different applications.
2mil for high detail and halftones.
4mil for halftones and deeper etching / sand carving.

Both types of resist can also be used for stage carving where each section of the pattern is removed in sequence for multi-stage carving.

In conclusion

It would be best to try both types of resist to see what is best for you as both appear to be very good although the water wash needs a bit more equipment in the washing equipment but may be a little less confusing with the positive imaging.

I have, since originally writing this had a lot more experience of Rapidmask with a lot of success but also a lot of failure and a lot of expensive lessons learnt. Firstly this material does not like convex curves, not really the materials fault more than the plastic cover sheet which is so thick and unweildy that it does not conform to the curve. Next is its hate of the minorist air bubble, when placing the resist a great deal of care and pressure combined to exclude all air bubbles from the underside, also cleanliness hold a big part in the application. All air bubbles must be removed either by roller or pricking and excluding the air, remember these holes must be covered before etching.

UV Exposure Units

I have now owned 3 exposure units although I can't remember using them very much as I tended towards machine cutting as most of the work I made seemed to be always on the large side.
The first machine I owned was a huge great box that weighed around 15kg, it consisted of a 4 tube UV light and had a vacuum pump integrated in the box. A vacuum exposure unit is arguably the best available as the vacuum pulls the resist and the acetate sheet tightly together for perfect exposure. Unfortunately it was designed to sit in a fixed position and never be moved, a luxury I never had, far to heavy and it ended up in the loft and then a skip.

My second was a Letralite exposure unit.

Letralite PDF Instructions

These units are produced by Ikonics and if you are lucky you may find one on eBay which, again foolishly, is where mine ended up. These units have a single large tube and are very widely used. Unfortunately they have a rather hefty price tag for what they are; $330 from Rayzist and by the time they reach these shores they have increased in price to around £338 plus vat = £406 plus £10 delivery. Have you worked it out yet in the States, that's $644 nearly double. Wow

I took a cheaper route, the resist doesn't mind how fancy the exposure unit is.

I must have hit it right as this unit I bought was on special at £150 and came with black UV tubes and one spare tube.

There are lots of different units out there and of course you could always make your own, just check out YouTube or Instructables as there's a huge amount to choose from.

Paul

Materials Tools & Equipment Part 4 Resist pattern cutting

Hi

As mentioned there are a number of methods of making resist patterns, from hand and machine cutting to the more modern photo resist masking, which requires ultra-violet light to activate the chemicals in the special mask, which we will look at in a separate post.

You may find as I did that hand cutting will become a distant memory and your machine will be used for everything you do, it will become indispensable as your designs become more and more complex until even your machine can't cope and you have to look at photo-resist masking which will take the finest of designs from artwork to photographs or off course you may stay with the knife.

Knife cutting

This requires the least equipment

but in the hands of a master can be fantastic. This lady is Donna Burrows, have a look and enjoy her work.

This style of work is for large scale pieces and maybe not what a beginner will be thinking off, well, maybe a little later.
Donna uses a projector to throw the image of her pattern onto the resist pinned to the wall and then following the pattern draws it on, this technique uses a projector and the design is printed onto an acetate sheet,
The resist is then stuck to the glass and the pattern is cut and removed in stages for etching and shading.

A more modest technique would be to either design your image on a computer and print it out or select from a book of designs and scan into your computer where you can then manipulate to the size you require. After printing, your design can then be transferred using carbon paper to trace your pattern onto the resist which can be either pre-stuck to the glass for stage etching or firstly weeded then applied to the glass.

Machine Cutting

I'm afraid I am a machine person I have now owned 3 machines in my time 2 used and the latest a new machine which I hope is my last, as these things are very expensive especially here in the UK.

The range of machines out there is huge and generally they are made with more advanced features than are necessary for simple stencil making where all that is generally needed is to cut a pattern and no more. 

My new machine is the GCC Expert 24, 24" being the width of material (60cm) that the machine can take, which I think is the perfect size. For another £200 I could have had the LX version which has the optical eye, totally unnecessary for what I require so if you are looking for a new machine look at the basic model as you may save a few hundred.

  

My first machine was a Creation Pcut a Chinese copy of the GCC machine, GCC is a Taiwanese company, and they do make top cutting machines.

Quite frankly it wasn't a bad machine but I could rarely get it to work, nothing wrong with the machine as the lady who bought it from me already owned a couple for her business and told me she had it working in no time. Guess it was the software interface setup as getting it to link with the computer was beyond me and remember it was around 10 years ago. 

My next machine was my first GCC and was the first of the Jaguar range the JR 61 and what a great machine.

No problems with this machine even though it was quite old when I bought it, shame it died on me.

Sizes of machine can run from the small 300mm 12" or smaller, right up to the very large 1.8m 72".

So what is right for you.

Well as with everything it comes down to what your etching ambitions are, if you plan on doing solely small pieces then there are some very good machines out there, prices are quite expensive and there are I am sure cheaper Chinese machines but you gets whats you pays for.

Small cutters

Cricut Explore 300mm at around £250

Graphtec Silhouette Cameo 300mm at around £268

These may be small but fully functional and after watching the videos I am very impressed.


A few inches bigger can make all the difference (did I really say that) but its true, I have had to change a few designs in the past as my machines at 600mm were just too small, it is also a bit of a misnomer calling the machines 300mm, 600mm or whatever the size as these dimensions refer to the width of the material they will take, not the usable size of the cutting width.

All of these machines have width sensors on the cutting heads which track where the rollers are positioned on the white markers, once the material is in place and you switch on, the heads size the material by running back and forth then stamping down with the cutting blade where the rollers are and sends the usable width to the cutting program. I have measured mine and I get approx 550mm from the 600mm roll, I would imagine all machines have different parameters and a 300mm Cameo may only have a usable area of approx 260mm or so, so be aware when you purchase.

There are lots of good machines out there with names like Roland, Summa, GCC, Mimaki, Mutoh and Graphtec. These machines are the top brands and as such command a rather high price, but there are also a lot of used machines on eBay that will last you for a lot more years to come. A lot on eBay come with materials thrown in and once you weigh up the cost of vinyl for resist you may well feel this is the better option than new. There are also the Chinese machines, I would not decry these as I have read a lot of good things on blogs

Medium Cutters

I think I would categorise a medium as being around 400mm to 600mm and quality machine's run up to over a £1000 and more.

Graphtec CE 6000-40  at around £714

Now this is a quality machine that should give years of use, I was seriously considering this machine but as I have a couple of rolls of 60m long vinyl, resist and plotting paper all at 600mm I decided to go for my GCC also supplied through Graphtec.
It has a smaller width of 400mm around 15" but more than ample for most jobs.

GCC Expert 24  at around £700

Well I had to include this didn't I, not as expensive as the other machines of the same size but experience told me I don't need all of the fancy gizmo's to cut a pattern so I chose basic.

Roland Camm 1 GX24   at around £1300

Ok, now we are talking. If only, except do I need all of the extras.

These are just a few of the huge variety out there.

How to use.

Well like any tool you need to read, view and practice; read the blurb that comes with the machine, watch as many Youtube videos as you can and get a load of vinyl to practice on.

With all cutters come with software drivers these are necessary to communicate with the machine, though these drivers you can set the size of the material, the position you want the cut to start cutting, the speed of the cut and the force of the cut. Alternatively a lot of machines have these parameter controls built into the digital display of the machine so as you don't have to use the driver screen, mostly the choice is yours of how you set it up.

If you use the same material without ever changing it you will only have to set up once and the main parameter to set up will be the force,

Force of cut

The force is basically the depth of cut and each thickness of material you use will have to be setup, please don't do what I and I'm sure many other have done and go from thick resist to thin vinyl without altering the force, ha such fun! cost me a new cutting strip.
This is my driver screen and the force is g = grams of force /m. this is set for normal vinyl at 78g and it goes up to 250g so a lot of concentrated cutting force in one very small area.

All machines have a plastic strip that the cutting head runs along the idea is to not allow the blade to touch this strip as you can very easily cut into and damage it.

To prevent penetration of the material the cutting force is initially set low and a test cut made,

All machines have a built in test cut facility and the idea is to cut through the resist and just slightly penetrate the base board, so a couple of test cuts and you are done.

Speed of cut

The speed you will soon learn, if you have a basic machine as I do that it may be set to the one speed but if you can alter yours then a square cut pattern can have a very fast cut but as your patterns get more complex with lots of curves then a slower speed may be necessary.

Width of material

As I mentioned the head automatically detects the width of your material but just because you have a 600mm machine does not mean you can only use 600mm material. All machines have guide rollers to keep the roll of resist pressed flat against the friction rollers the friction rollers grip the material and roll it back and forth while the cutting head runs back and forth and this is how it cuts.
These guide rollers can be moved to many different positions depending upon the cutting head width detection eye guides, these guides are white strips positioned on the cutting head rail and as long as the guides are positioned on one of these white lines all is well in the world. So to cut it short you position your guides for your 300mm piece of resist on the closest white line to the edges of the material.

or use the full width.

This is why I like the 600mm machine in that I can vary the resist to what I have.

Cutting Blades.

The bladed are housed in a special blade holder,

where it is kept perfectly perpendicular to the work and can rotate in a set of bearings so as the edge can always follow the line of cut, my blade disappears inside the holder until it is cutting not sure how this is achieved.

The blades are readily available online and one make of blade may fit many different machines, I know my GCC blades will also fit Roland cutters and maybe more.

The blades are set at different angles for different depths of cut and different material thicknesses, I have the 45 and 60 deg.

Cutting Blade Offset 

Ok getting a bit to in depth here but this is possibly more important for the glass etcher than the tee shirt designer as a poor cut on the corner can leave a lot of checking and trimming, work you don't need and if you miss the over cut nib then it will detract from your work.

So instead of me giving a crap explanation have a read from these links from people who know.

Roland 
Cutter problems
Accurate blade setup

Drawing

An excellent addition to owning one of these machines is the ability to draw out your pattern full size, this ability is priceless when it comes to either checking for mistakes, seeing if  the design fits in with what you are designing it for and for showing a client what it will look like full size.

Pens

and Paper

are available on eBay

I picked a complex Celtic design to show it's use, I had bought the felt tip pens as opposed to the ink type to give a more distinct picture and I have had these for many years and they are still working well.

You need to reduce the force a little when using as a plotter as you don't want to damage the felt tip.

Program software.

As discussed in the post about design software you will require a program to physically talk to the cutter and send your design to be cut, generally when you buy a machine the software will come with it and depending on the higher quality of the machine then you end up with the higher quality program.
I have had a search and found that there is a plug in extension for Inkscape called Inkcut, I have downloaded it but as yet have not had any success loading it and after a bit of a search I am not the only one so I will be happy with what I have.
If you buy a machine without design software then it may be an idea to look at the lite versions, most programs have this to get people started, after all if you design in Inkscape all you require the software for is the interface between your cutter and your design.

Paul

Materials Tools & Equipment: Part 3 Designs & Software

Hi

We are very lucky in this day and age that even the least artistic among us (me) can turn out the most amazing work and it can all be down to computers and the Internet. Of course, we have some very talented artists out there who don't rely on aids to assist in their endeavours and it's all the more pleasing to see their work; but I bet they sometimes cheat and have a little bit of computerised assist.

Finding quality imagery is not difficult as everybody out there wants us to view, download, copy or buy their work, publishing companies print a whole host of books with the most beautiful designs. EBay is full of offers for digital media selling you the logos of every company in the world and Cd's full of images and fonts are available in their thousands.

The problem is not finding images to work with, it's finding the right images to work with.

A lot of design images out there are someone's intellectual property and as such are subject to some form of copyright, to make you aware of this I have linked a page below to explain the rules of copyright.

Royalty free work is also widely available for all to use but also has it's limitation's on work for sale.

 Copyright and Royalty Free explained

You will generally have an idea in mind for your design and start collecting these types of images, but first a word of advice Keep them safe. I had years of designs on an external hard drive nice and safe or so I thought, I then plugged the external drive into my new iMac to use as the mac backup device thinking it would just use part of the drive. No! it wiped the drive to use it solely for itself, greedy apple. Anyway all gone, just a few I had on flash drives but years of converting to vectors lost. Be warned
I even lost the design of my favourite self portrait, one of my first deep work, bit ugly but had as screen saver for many a year

Images from colouring books are widely available and you can get great ideas from these, just this morning in the supermarket I came across a colouring book called Zen which had some marvellous designs, so don't be put off because these are designed for children. 

Of course, please remember the above advice on copyright, no more said.

Understanding Images

Images can be downloaded free to use from many sites out there, just type in free designs and you will get hundreds but you really need to know what type of design you can work with before you download.

Downloaded designs are rarely the size you want, you will mostly have to enlarge them as opposed to shrinking to fit and this is where your problems will start. 

The ordinary images you search for to download are in a format called a Raster or Bitmap, these can have a number of extensions such as .bmp .jpg .png .gif or .tif with .jpg and .png being the most common and as such are ideal for viewing and printing but pretty useless for working with. The problem is that these images are made up of dots on a grid pattern and as you try to enlarge the design the grid and the dots enlarge giving you an out of focus image.

For a better understanding of extensions have a read from Scantips extension basics

So instead of a clear image you end up with fuzziness which if you are just printing off to trace around then no problems but if you want a distinct design either for complex tracing or as a lot of people do; send to a cutting machine, then a different format of design is required.

The preferred format is categorised as a Vector image, images in a vector format are made up of paths in the form of lines, curves and angles, they have start and stop points and are fully scalable to any size you require without loss of definition.
Vector file extension's are .svg and .eps so if you see these extensions on the end of a download file then you have a vector drawing.

SVG; stands for Scalable Vector Graphics and are my preferred format to look for, the other extension is.
EPS; which stands for Encapsulated Postscript and is the second preferred choice for me, although I have found it to be the most common.

I have found the best source of designs out there comes from a publisher called Dover, they have some excellent designers and produce books with the designs printed in both black outline and colour with a cd of the designs in a number of formats, .eps and .svg being the ones we want.

They can be found on eBay so keep an eye out as you may grab a bargain but first look at my blog page titled Dover to find what's good and bad.

You can find the whole library at Dover Books

These are great to start a collection of designs in a royalty free vector format, my favourite  books are the Celtic and Art Nouveau from a designer called Allen Weller.

Designs can also be downloaded free and the link for Craftsmans Space should give you some great designs.

The web is full of paid for designs which I have looked at and even bought but a word of warning they are expensive and as happened to me you sometimes don't get what you paid for. With these sites you are required to buy credits to pay for your design, click what you want and down it comes, except my £12 for 2 vector designs came out as .jpg which were totally useless and too complex to convert. So beware.

Not all download sites are like this one and a good one I used to use is Digital - Clipart lots of designs to choose from.

Having these designs is one thing viewing and using them is another, this is where the software comes in. Dover books come with a viewer on the cd so as to look at what you want but to use them a program is necessary and there are a lot of free viewers and design programs out there.
The problem with vector files is viewing them as previews so software like Irfan or Mystic Thumbs may be for you as they will group your whole collection to pick from.
Another good viewer for single images is EPS  Viewer

A lot of people have their preferred program to use and the best are Coral draw and Adobe Illustrator these are both paid for programs and can cost a great deal of money, but both of these have the ability to send the finished work to a cutting machine. For us beginner's a more modest, free program is readily available and this is Inkscape.

I have never used this before having a program supplied with my old GCC cutter called Signpal which is a version of Flexisign, and because my cutter was (back then) top of the range the program was the high-end edition with everything I needed. A top version of Flexisign now costs over £3000.

I now have Signgo pro for my new machine and am still learning its capabilities, the machine is normally supplied with Signgo lite 

but the company selling advertised it with the pro version, by mistake as it turned out. The Lite program is not expensive to buy at £82 but the machine was only £25 dearer than what I had negotiated with another company with the lite included which made me think it was a bargain for the pro version;

Don't think they were too happy when I called and asked why I had lite and not pro, anyway the pro arrived next day by recorded delivery and no profit on that sale as it cost way more than the lite.

Why do you need a program like Inkscape.

Firstly any image you have in either, .svg or .eps format will be the size it is, not the size you want it to be, you may wish to have multiple copies of this design in your artwork or you may wish to have different elements to make up your design or you may want to design your own artwork, I can go on; no, well basically it's indispensable.

I often find that the vectorization supplied in these discs or downloads are at times a little basic, curves out of shape or lines to close together, with Inkscape you can alter all of these defects by adjusting the nodes on the paths.

I have linked a group of training clips from You tube so you can get an idea of how to go about using Inkscape, after only a couple of days practising with Inkscape I have found it amazing and for a free program it is loaded with ability.

There is one major problem I have noticed with Inkscape and that is it does not import .eps format images, there is a way around this and I have linked it under Inkscape tuition, but I have found an easy way that is by converting the image to .svg and importing this saved image.

So that problem solved.

The really indispensable part of these type of programs is the trace function and Inkscape has a top trace feature.
Tracing is basically the ability to take a bitmap image and convert it to a vector, you can then make up your design and use this image in a cutting machine or print for tracing and hand cutting.
I have spent some time looking through the videos and found it very easy to use, I am quite used to vector conversion with having to do lots over the years, this program was a little different to what I am used to but no problem.

I started by pulling an image from a search onto the desktop, then picking it up and placing into Inkscape.

Next go to Path and click Trace Bitmap, use Brightness cuttoff and change the threshhold to over .5, this picks out more of the design.

Click Ok to start the vectorization.

Go back to your image and pick up the top layer, this is the vector.

You can now delete the bitmap image, and to keep the ratio before any sizing click the padlock button.

You now have a vector, to check the paths (lines) are nice and smooth you can remove the fill and have a nice line image.
Highlight the image by clicking on it, then go to Object and click Fill & Stroke, firstly click on to the Stroke paint box and click the darkest box next to the X then go to the Fill box and click the X button. Your image should now look like this.

This is a wireframe of your design and any manipulation can be done in this form but first you need to activate the nodes by clicking on the 2nd button down on the side bar and you will get.

You can zoom into any area and check and manipulate the paths to any shape you want.

Have a look at the tuition videos and you will soon get the hang of it.

These images can be saved as .svg and opened in your cutting machine program, most of these programs have a vector facility so you can work on them there to make up whatever design you wish.

Paul

Etching Cream Testing

Hi

We have talked about easy access into etching at home by using readily available etching cream, I say readily available which is not quite true for some as in a lot of the States in the USA it has become a little difficult to get hold off. 

Etching cream has a few dangers associated with it and because of this has been, if not totally banned, then has had it's over the counter easy accessibility removed. The dangers come from its chemical makeup and before using the cream a little time spent reading the MSDS (material safety data sheet) will make you aware of its dangers.

USA dept of health

Armour etch MSDS

Etchall

A little history of etched glass

A long long time ago, around 1850 actually, in a not quite quaint little island called Great Britain a giant monster called the Industrial Revolution was ravaging cities all across the land. People were coming from far and wide, leaving their wonderful country life of shooting the pheasants and beating the peasants to feed this ravaging monster, and the monster was getting bigger and bigger. 

The people were being massed together in tighter and tighter communities, made to work 25hr day's, living in slums with whole families in one small closet. Sanitation was basic if at all and slowly but surely the monster's ally disease took hold of the population. 

Many died and no one knew the cause until one day a brilliant young doctor realised that the drinking water was full of poop, of course this did not go down well with the population; being dead is not what they had come here for.

How can we survive with the water full of poop cried the populace, when a handsome young engineer came to the fore; build a sewer network to take away the stinky's said he; and the population of Great Britain rose up on mass and shouted NO! Let's drink more beer and thus the people had spoken. (and haven't stopped drinking beer since)
Beer bars sprang up on every corner of this idyllic isle (until the smoking ban and £3.50p a pint then they all closed)

Pretty much true really, for many the only access to clean water was beer which had been boiled during the brewing process, so was safe to drink, as more bars sprang up then the glass on the windows and the seating partitions began to be decorated by the artisans of the time and more and more elaborate work was done. Glass work in Britain had come of age.

Of course, Armour etch wasn't in the shop then so a more corrosive and much more dangerous acid was used.

Hydrofluoric acid was and still is used to chemically etch glass in a safe industrial environment however it is extremely harmful to humans and animals alike and should certainly not be considered for use at home, although it is still considered by some people wanting to etch glass.

This exert was taken from Everything Stained Glass and shows that ignorance of this highly dangerous acid is definitely still out there.

HSE

SO DON'T EVEN CONSIDER IT.

I have spent a little time researching etching cream and there are a lot of conflicting theory's out there on how to get the best results, in fact, a lot of people can't even decide on the spelling, Creme or Cream. Guess that depends where in the world you live.

I have considered everything I have read and here is my take on it, for what it's worth.

I have concluded that it ain't half bad.

It is very easy to use and gives an excellent finish. The finish is much more subtle than blasted glass, a lot less grainy textured, clearer and virtually disappears when washed. I would consider it ideal as a hobby for home with the added benefit of no major noisy equipment to be bought.

I've read a lot about splotchy finished, about shaking, about lumps and large grains, about temperature, about agitation of the cream, just about everything and watched a whole load of You Tube videos.

Well I have put it all together in a scientific experiment Ha!

I have bought 2 different types of cream for the test, the first being Armour etch which is widely available in most countries around the world and the second a virtually unknown from a large stained glass supplier called TGK in Germany which I bought from a UK outlet. The cream came in a plain squeezy bottle with no instructions or safety data as possibly decanted from a larger bottle. I have written to TGK asking for an MSDS but have been expertly ignored so after a search I believe I have found what they use which is called Glasotan etching cream

My experiment consisted of 3 main elements.

Time: The main concern's from what I've read are concerning the time the cream should be left on the glass, times range from 5 minutes to overnight, I am more inclined to believe it a matter of minutes rather than overnight so I gave a time of 15mins 30mins and 1 hour for both types of cream.

Agitation: The same problem of a splotchy finish keeps cropping up and after watching a video about the agitation of the cream to prevent splotchyness I incorporated movement into the experiment.

Manufacturers: Is one make better than the other.

I started by cutting the glass in 150mm squares and deciding on a pattern, my new cutting machine had arrived so after getting it set up I tested it on cutting the stencils.

I have rubbed the cuts of the stencil with white art pastel, I use these in preference to chalk as there are very soft and don't lift the resist, the cuts are now highlighted for easier weeding.

I weeded all of the patterns.

I next set out all of the required items, apart from the roller which has gone walkabout.

After washing the glass in a vinegar solution, I dried and cleaned with the alcohol wipes and stuck on the stencils.

A bit of interesting reading that came to light was that the best temperature to activate the chemicals was 60 degree C, so after a vigorous shaking of the bottles I let them sit in hot water for 10 mins to soak up the heat, I kept renewing the water to maintain the temp.

I was then ready, so another vigorous shaking of the bottle and I started with the Armour etch on a 15 minute test piece.

I had to decide the best way to achieve the agitation part of my experiment and decided on a battery toothbrush (sorry Lynne but a sacrifice required) I used this to apply the etch and kept it running to get it into all of the pattern. The thickness as you can see is nicely covered but not overly thick and I gave it another rubbing with the toothbrush vibrating every 5 mins for the 15 min test and every 15 mins for the others.

I set up a timer and got to work on the next test.

The etch cream is re-usable which is a good thing as it is not cheap, the Armour cost around £15 for the 10-ounce bottle from Amazon and the TGK was £8.50 for 60ml (approx 2 ounces) on eBay. The Armour is definitely the best value.

I used the plastic end of my smoothing tool to remove the cream when the time was up and replaced in the bottle, this was the 30 min test.

I then washed the glass getting all of the cream out of the pattern.

I repeated the test until all of the pieces were finished.

After the removal of the resist, I gave them a good clean again in a vinegar solution then alcohol wipes before comparing, first the difference in cream manufacturers.

The first is the 15 min test and they both look good, missed a little resist on the TG which didn't get etched but apart from that Ok.

The 30 min test came out just as good no splotchyness at all.

The 1 hr test is fine as well.

Conclusions

Time
Another thing I read from someone is that once the etching process has been complete it basically stops, it does not get anymore etched / whiter so to speak and examining the 15 min to the 1 hour I think I agree. I should have done a 5-minute test to see the difference between the 5 and 15 but leaving it on for an hour or even half an hour does not seem to matter.

Spotchyness
This problem has not occurred, the look of the etch is equal over the complete work, this may be down to my agitation of the cream or the 60-degree temp I don't know.

Depth of etch
Having said that the time does not matter on the whitening of the etch it does on a fingernail scratch test over the work, it feels slightly deeper, maybe only microns but if using a colouring such as Rub & Buff then the small increase in depth may be the difference you require.

Well not really scientific as I could have added a few other parameters but what the hell I'd ran out of glass.
I can see no difference between the two makes so go with what you have available to you and it should come out as good as any other make.

Paul