Here is a potentially novel way of making laser toner transfer paper at
home. It requires some ~140gsm card (at about 180um, thicker than
standard 80gsm laser / photocopy paper, but not as thick as the 200 to
220 gsm card which is more widely sold) "paper gum" (water-based, clear
glue from a craft shop), kerosene, acetone, and a hot air gun.
In the future, I will place an updated version of this
material at:
.
http://www.firstpr.com.au/pcb-diy/The purpose of a laser printer transfer paper is to accept the toner
from the printer and then allow it to be transferred to another surface.
A common use for this is to transfer the toner onto copper-clad PCB
laminate, where it will be used as a resist for etching. I am using it
for other purposes, which I will describe in the next few months.
Here are my thoughts on the desirable characteristics of laser toner
transfer paper.
The paper should run smoothly through a laser printer. I think this
means it should be 80gsm to 140gsm or so. Thicker card, such as 210
gsm, is stiffer and may not always feed so well. The Pulsar transfer paper:
.
http://www.pcbfx.com/main_site/pages/products/transfer_paper.htmlis about 228um including its gum layer. It weighs in at 172gsm with its
coating (10.37 grams per US Letter sheet with 16.577 sheets per square
metre).
The Pulsar paper feels a little stiffer than the card I am using. This
card weighs in at 145gsm (9.1 grams per A4 sheet, with 16.03 A4 sheets
per square metre). I guess it is 140gsm when dry.
The printable surface of the paper should not be paper itself, because
the toner will melt into the paper fibres, making full removal of the
paper impossible. The only way I know of achieving this is to coat the
paper with gum, such as dextrin (a starch).
The gum surface should be smooth, but not necessarily shiny. Perhaps it
helps if the surface has a matte finish, so the toner is less likely to
move around due to electrostatic self-repulsion, or vibration, between
being deposited from the drum and being melted by the fuser rollers.
Surface roughness may or may not matter in the final application, but
for one of the purposes I am pursuing, it is important that the surface
be smooth.
The Pulsar paper is quite smooth and the Olathe Post paper I wrote about
in a recent message (30334) has an irregular surface. Both the Pulsar
paper and the DIY paper I am about to describe were good for my
application which required a smooth gum surface. The Olathe Post paper
was not suitable for this application.
The paper would ideally be insensitive to moisture levels at the time of
printing. With both the Pulsar and Olath Post paper, I found it best to
humidify the sheet just before printing, such as by placing it face down
on a wire rack one or two cm about some vaguely warm water for a few
minutes, with a tea-towel on top of the paper, which had previously been
resting on the rack. This level of moisture is not enough to make the
gum sticky, but (for me at least, using Brother HL-5250DN and HL-4040CN
printers) solve the problems which occur when these papers were too dry,
including the toner being fused together but not actually bonding to the
gum, presumably because the gum was too dry and hard.
The paper which results from the process I am about to describe has a
thinner gum layer than the Pulsar or Olathe Post papers. My initial
tests indicate that it is not so fussy about moisture levels, since I
can print on it when it has just been hot-air dried, and the toner bonds
perfectly. I think this is in part due to the gum being thinner and not
so hard a surface, since its hardness depends more on the underlying
paper fibres. However, the nature of the starch/gum itself could be
quite different to that of the other two papers, with its thickness not
being such an issue.
The DIY paper I am about to describe seems good in terms of surface
flatness (depending on how evenly the liquid gum-water mixture can be
distributed), but there are some difficulties making the whole sheet
nice and flat before printing. Ideally, the sheet should be absolutely
flat, rather than having a curl in any direction, because such curls
will make its travel through the printer more error-prone.
Finally, the transfer paper should be easy to remove from the new
surface with water. The Pulsar and Olathe Post papers peel off nicely
after a few minutes in cold or warm water. Any residual gum/starch is
easily removed. This DIY transfer paper is easy to remove too. In my
initial trials like this, the whole sheet peels cleanly away, taking
most or all of the gum with it, after two or three minutes soaking in
warm water with a little detergent.
The major difficulties making transfer paper seem to be obtaining the
gum/starch and spreading it thinly on one surface without causing the
paper to become soft or deformed. Here is how I solve these problems.
Step 1
(I assume people are wise to the dangers of chemicals, fires, etc.)
Make a mixture of 1/3 kerosene 2/3 acetone. I do it by weight, but by
volume would be fine.
Place the 140gsm card on a flat surface such as a Formica table-top or a
sheet of glass. Spray or otherwise spread the mixture so it soaks the
entire sheet. (I put my mixture in a Windex sprayer.) Then, using a
light, fine, squeegee, or perhaps a roller of some kind (or perhaps
tissues) remove all the excess kero/acetone from the sheet and put it
out to dry for five or ten minutes.
The acetone will evaporate within a few minutes and before long the
somewhat kerosene-damp sheet will smell only of kerosene.
I figure we have a well-dispersed, but not saturating, body of kerosene
in the whole volume of the card now. This is our temporary
waterproofing system. (Other attempts at DIY transfer paper involve
spraying expensive pressure-pack leather/cloth waterproofing liquids
onto the paper or card, making it permanently waterproof, which
significantly delays the final step of washing the paper or card away.)
I have prepared some 80% gum, 20% water (by weight) and stirred it well.
I add a few drops of red food dye so I can see where this gum is as I
spread it.
The gum I used is sold as "Paper Gum":
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http://www.miyartcrafts.com.au/Craft-Smart-Paper-Gum.htmlIt is a clear, uncoloured, liquid, not milky and not a paste.
The package states:
> ... adheres to most surfaces, including metal, plastic, glass and
> ceramics. For scrapbooking and memory craft it has distinct
> advantages. It is pH neutral. It dries clear and will not
> yellow with age. Equipment cleans up in water.
I assume this is a dextrin gum of some kind. This is not "glue", "PVA
glue" or any such thing. It is ∗gum∗. It is a clear, viscous but
smoothly flowing uncoloured liquid which can be thinned with water. The
dry gum will dissolve in water, though it takes a bit of rubbing if
there is a substantial blob of it.
It is possible that the term "gum" is more widely in Australia and New
Zealand for this particular type of adhesive. Googling for:
"clear gum" ml
turns up similar products in .au and .nz. One product which seems to
be the same or similar, and which is available in all countries can be
found with Googling:
Pentel "roll'n glue"
.
http://www.pentel.co.uk/products.asp?group=5&type=23&pid=198There's a 300ml refill bottle for these. I am reasonably sure that this
substance would work exactly the same as the "gum" I used.
This Australian page:
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http://sewingcraft.com/wordpress/?page_id=2072lists 16 types of liquid adhesive found in craft shops. The one of
interest is: Helmar Professional Acid-Free Glue:
> ACID-FREE, (NEUTRAL pH),SETS CLEAR, NON-TOXIC, FLEXIBLE BOND, WILL
> NOT YELLOW. Helmar Acid Free glue has been specifically designed for
> memory albums, book binding, mounting photographs, preserving old or
> precious books, documents, scrap books, most craft projects, etc.
> Featuring excellent adhesion to dense papers, high flexibility, long
> term life of the bond. Sets clear, dries quickly and will not yellow
> with age. Non-wrinkling ! ACID-FREE ! Neutral pH level.
This product is surely suitable for the process I am describing. It is
from the USA - $7.45 for 8.45 fl.oz. :
http://www.helmarusa.com/index.php?page=shop.product_details&flypage=vmj_naru.tpl&product_id=8&category_id=1&option=com_virtuemart&Itemid=7I have just discovered that "envelope gum" can be purchased in small
containers, such as:
.
http://www.crafterscompanion.com/Envelope-Gum_p_32.html.
http://www.crazicards.co.uk/crafters-companion-envelope-gum/prod_698.htmlThis is probably different from the glue I used. It is meant to be
applied to paper and then left to dry, to produce a traditional gum
layer which can be moistened and used to seal the envelope. Perhaps
this material would be suitable for making transfer paper without any
mucking around waterproofing the paper beforehand.
Step 2
I lay the sheet on some scrap paper, such as a few layers of newspaper.
I pour some of the gum-water mixture on the card and using a kitchen
sponge spread it quickly and reasonably evenly over the card. The
kerosene greatly reduces the rate at which the gum-water mix soaks into
the card. However, it does soak in to some extent and this stage needs
to be done as quickly as possible. I found the sponge worked reasonably
well in producing an even coating. I also found a light squeegee (for
cleaning windows) helped spread the mixture evenly. It is possible that
a roller would work well.
Perhaps if the mixture could be sprayed from a compressed air spray gun
- this might work really well if the drops were very fine and evenly
distributed. I have a spray gun. Later I will try using it for both
the kero-acetone stage and for distributing the layer of gum.
As soon as there is a reasonably even coating, dry the sheet with a
hot-air gun. To do this, I place the sheet on a dry sheet of newspaper
(since the first sheet now has gum where the edges of the A4 sheet were)
This will cause it to curl to some extent, but it is not as bad as if I
had not used the kero-acetone mixture.
The drying will get rid of most of the kerosene. If the gum-water mix
is too viscous and/or is in too thick a layer and/or if the drying heat
is too intense then bubbles may develop in the gum coating. This is
unacceptable, so I suggest less aggressive drying.
While the sheet curls somewhat, it does not become soggy or wrinkly.
The curl can be reduced by running the sheet, on its own, through a
laminator. This will dry off more of the kerosene.
Now, the sheet is ready for printing.
I haven't investigated storage, but I think that if I make a bunch of
sheets and press them together in a flat stack, they should be fine to
use at any time in the future, and will probably not be as curled as
they are initially.
After transfer (I am using a laminator, but some people use an iron to
melt the toner onto the copper-clad PCB board) the paper can be removed
with water, or warm water with a little detergent.
- Robin