Welcome to another Lightblade learning lab, I've got the sun shining on my face
through my workshop window it might make me look like a film star yeah I'm a bit
delusional I have to admit
anyway today we're going to carry on with something we started off last time
which is dots now today we're not going to really be talking too much about the
dots themselves we did an in-depth analysis of how dots can be formed why
they should be formed you know exactly all the things we're going to be looking
for in this session we had to do the preparatory work because there was a lot
to get through now this might look like white wine trust me it's not
it's just lime cordial
it's been a very hot day and I'm looking forward to the cool of
the evening and settling down showing you guys something interesting today
we're going to get into pictures and photographs and all our hard work from
the last time is going hopefully show some good results now there might be
some surprising results but I hope they're going to be interesting for you
now before we start we've got a couple of very important housekeeping tasks if
you really must perform at some stage before you start using this machine for
producing photographs or even for logos so we need quickly to just to jump into
RDWorks and I'll show you a little test program that you should design
yourself and you can use on this machine alright we're going to select a square
and then hold down the control key I'm going to just draw a square doesn't
matter what at the moment we're then going to put a handle around it and
we're going to come up here to the dimensions and we'll close the padlock
and we'll set one of these dimensions at the top here and there we go we've drawn
a 10 millimeter square and that's all our tests program is going to be we're
now going to come off across to the parameters I'm going to turn this into
an scan program we're going to scan it at various speeds so we'll just set this
to 400 millimeters a second which is one of the fastest speeds that we like to be
using on our tests power we'll leave it at 13% at the moment
no ticks X swing which is important the interval at the moment I'm going to make
it half a millimeter point five now that's a huge interval but you'll see
why in a minute okay now I've got a small piece of acrylic in there at the
moment I always like to use acrylic for test purposes and what I'm going to do
is just set the focus up to the correct focus for this particular lens at seven
and a half millimeters before I touch anything in the program we're going to
just run a test
the first line at the bottom there was done moving from left to right
and that is quite important to remember that if you remember these strange
pictures that I showed you before the actual beam itself carries on dying
white way much longer than the laser beam switching off now that's important
to note when we look at this pattern here because this pattern starts off
here and it runs to this side here and you can see there is the end of the line
where it turns off hangs over the beginning of the next line so what we're
going to have to do is we're going to have to put in what they call an offset
correction and RDWorks allows us to do that and let me show you where it
happens, now we need to come up here to config
and in conflig we've got system setting and if we drag up system setting just
here we need to tick beside this scanning reverse interval and now we can
come into this list here and I have not got anything set up for 400 millimeters
a second which is the speed we're running and it is important that you
always set up one of these parameters for the speed that you're going to run
at now in this particular instance we're going to run at 400 millimeters a second
now there's something here called reverse interval which is an offset that
we can apply at the moment we didn't have anything set up so the machine is
doing its own thing what I'm going to do is now that I've set 400 millimeters a
second up I'm going to leave it at zero and do another test and see what result
we get the other thing that's underneath here is called offset replay now you don't
need to touch that at all if you play with that all it would do is move the
position of this square pattern around so we don't want that to happen so we
leave it alone and there we are we can immediately see
the difference I've now set the offset to zero and the machine knows now that
there's an offset of zero I've got a point oh 3 shift in there which
is one thousandth of an inch I don't think it's made any difference it's not
made it better and it's not really made it worse, if we use X unilateral it will
take twice as long but we'll only get scan lines going in one direction so we
won't experience this problem now bear in mind we're looking for the perfect
dots to get the perfect dots we must have the focus set onto the surface as
perfectly as possible what we're going to do is we're going to check the focus
I think the focus on here should be about seven and a half so what I'm going
to do I'm going to set it to eight and a half
and then I'll set it to seven-and-a-half
and then I'll run down at six and a half now thing if you study those lines
carefully you can clearly see that the one in the middle is the thinnest line
which looks as though it's probably pretty close to the theoretical point
one because the gap between those lines the pitch between those lines is 0.5 so
just a quick estimate visually says yeah we're doing pretty damn good the problem
is we're not going to get dots that size we're going to get sausages that width
and that's going to be a bit of a problem when we run at 400
millimetres a second but that's all going to come later when we start doing
some some actual photographs and some dots I've got to go and set some scan
offsets for various other speeds you know how to do it now you don't need to
see me doing it now what I've got here is a piece of card which is one
millimetre thick and if we look at it you'll find that it's not entirely flat
it's got a little bit of a bow in the middle all I need is a couple of small
neodymium magnets in the middle here and that will hold that sheet completely
flat because we changed the thickness of the material set this back up to seven
and a half millimeters which is the ideal focus that we're after so I've got
the air assist turned off in the programme because otherwise any fumes
that come up will get blown down and paint the whole thing a brown hue
okay now despite the fact that I normally use Photoshop I'm going to be using
RDWorks in its entirety some of the tools are very clunky in here but I think it
will be better if people don't have to use Photoshop I've got a 300 PPI picture
here I'm going to use the bitmap handle you can see up here it
says 300 pixels per inch well one of the things that I can do is I can change the
resolution of the output here so we'll change that to 150 and we'll let RDWorks
do the change for us so I can apply that to the view
doesn't look as though it's changed much
now dithering is the thing that will turn it into black and white dots so
we're going to be using dot graphic
and we'll now apply that to view
now it makes a big difference
and that's what we need to start with apply to source and okay and now we should
find that we've got when we click on there
dottie graphics we're now go and set the parameters that green is just a border
an a4 border which is not going to print it's just so that I can locate in the
bottom corner let's just show you I've got my zero set down in this bottom
corner here that's where we're going to start and we're going to start across
the bottom of the picture because I want the scanning to move up the picture so
that any fumes get drawn across the paper and any picture that's produced
remains a nice clean smoke free picture behind it we're going to set the speed
to 50 and we're going to set the power down at 11 which is about the absolute
lowest that this machine will run at you take all the ticks away from here we're
going to set the resolution to a hundred and fifty {pitch} point one six nine three
make the line interval match the pixels okay let's see what we get now bear in
mind that that's a dotty picture at a hundred and fifty pixels per inch I have
to say that's come out substantially better than I expected
that's almost newspaper quality yeah but you see lots of dots in there but what
we really ought to do now is go and have a look at this under the microscope to
see just what sort of quality we've got on these dots I mean I can see all sorts
of little details in here despite the fact that they're dotty I can see in hairs. Quite remarkable actually
by looking at that streak of hair that runs across her forehead and well I
think generally when we look at this picture all we can see are fairly even
brown dots which is actually very good news because we haven't got gradations
of brown they're more or less all the same color
there are some black ones which are obviously where some of the pixels have
been doubled up but in general the single dots are all about the same color
now they're slightly sausage-shaped but not terribly so maybe one and a half or
two to one ratio we've got just a little bit of gap between those lines which I
suppose is good in a way because it does mean to say that well we put the pitch
at point one six nine and I suppose the lines the burns are about point one just
over point one maybe so it does make sense that we've going to get one or two
gaps between those lines while doubling the resolution has done absolutely
nothing for us at all except take all the color out of the dots as you can see
right this is 50 millimeters a second so we have still got dots but the dots have
lost all their color and that's because we have basically doubled the resolution
doubling the resolution for 150 to 300 has basically half the amount of burn
time for each dot I know it's a rather strange description but it looks as
though we're almost getting greyscale dots now these are our first two
pictures we've sat them side by side so that you can compare them closely now
there's always a temptation when you're doing this sort of work to rush off and
say ah yeah but we've got this we can we can we can make that picture a lot
better by increasing the resolution we can go faster we can get it done
quicker you know there are so many things that you could play with so many
factors but what I want to do is just stop you in your tracks for a minute and
say look let's have a think about this don't rush into it we know a lot of
information now let's put that information together and see if we can
start sorting out how we can get better or not pictures this picture here was
done at a hundred and fifty dpi in both x and y although the picture is 150 dpi
in both directions it doesn't mean to say that you have to
do it 150 dpi in both directions we can't change the number of pixels in
this direction and we can't change the number of pixels in that direction but
we can in this direction if we want to change the interval and we could
effectively miss out every other pixel line so we've only got half the
information while I was doing this I imagined possibly that I could get
better results by increasing the resolution from 150 pixels per inch
to 300 pixels per inch so in other words if I increase the resolution
of the picture I'd better get a better quality picture well I think you can see
for yourself that isn't the case but why not because we've kept the speed the
same 50 millimeters a second the only difference is we have in fact changed
the Y pixels per inch so we've we've scanned half the information so let's
just stop for a second and have a quick think about what we've done well we know
that a hundred and fifty pixels per inch which is what this was done at it's
likely to look like this because at 50 millimeters a second we'll likely get a
dot which is around about point one and slightly sausage-shaped
now the ideal dot would be point one but at 150 pixels per inch
each pixel is point 169 and their dots are only likely to be
point one wide therefore we're going to get some white extra white between the
dots so in this picture as we saw we had we did have a small amount of separation
between the lines because we've looked at this piece here across this piece of
hair across here and we did see that we've got a small amount of white
between the pixels it probably wasn't as much as I've shown here but this is the
principle that we're basically operating on when we're working with this picture
now when I decided to do this picture at 300 pixels per inch but I made a silly
decision to only go down in Y at a hundred and fifty pixels per inch let's
analyze what I've done so in this particular case we've got a pixel size
of 0.0847 which is nearly 0.1 which is approximately the size that we thought
our dots were going to be so if we look at how they sit in this grid they sit in
there we've got the ability at fifty millimeters a second to burn probably
every single dot maybe not fully black because we've got half the amount of
time remember and half the amount of time means we're less likely to burn the
whole strength of the dot so that may will be black and that will make that
may well be only half black a gray or in this particular instance a half brown
and so consequently even though we're running at the same speed because we've
got half the amount of time for each one of these pixels we're going to
automatically get a lighter picture so there's a good logical reason why this
picture is much much lighter than that one even though technically it's at a
finer resolution although I've drawn these as dots as I've demonstrated on
here they could be single dots with a space between them or they could be
joined up dots I'll just leave that to your imagination. I know
they're not the same size but that's because I've drawn the same number of
pixels this is a 10 by 10 pixel block this is a 10 by 10 pixel block and this
is a 10 by 10 pixel block but it's at different resolutions and you can
automatically see how the size has changed quite dramatically but of course
the one thing that doesn't change dramatically is this thing here the dot
size is influenced by the power but we're keeping the power very low at the
moment so I'm keeping the dot sizes all the same so that you can see this
massive comparison as you supposedly think you're going to get a picture a
better picture by increasing the resolution now all you're going to do is
put the same dot if you choose you could in this particular instance look you
could at 300 pixels per inch as we tried to you could just use half as many
pixels or if you go to 600 pixels per inch and try and do every single line
you're going to get dots sitting on top of dots sitting on top of dots sitting
on top of dots and you're gonna get a very dark burn now I know this is a fact
because I have actually experimented with them but what I'm saying is you
don't need to experiment with them if you just stop and think about it look
we're going to compare these two pictures now this is 150 pixels per inch
and this is 150 dots per inch this one is 150 pixels per inch with 150 dots per
inch in both x and y now this picture doesn't have anything like that picture
why not well two reasons why not first of all I've increased the power from 11%
up to 15% so in terms of power this 11% is probably something like about 3 watts
and this 15% has jumped all the way up to probably something like about 14
watts so there's a huge difference in the
power for a very small percentage gain you need good control of low power you
do not get good control of low power if you've got an eighty or a hundred or a
hundred and fifty watt tube in. Your best choice for engraving is going to be
somewhere in the region of a 40 or 50 watt tube it's not your best choice for
cutting but it is your best choice for engraving now I've got a 60 watt tube in
this machine and I can just about get good results but I have to be very
careful at the bottom end here just pushing the power up from 3 watts to 14
watts has caused this pretty gross over burning but in addition to that to try
and compensate for the over burning look what I've done I've increased the speed
to 150 millimetres a second from 50 millimetres a second so there's two or
three variable changes and it makes a gross difference in the quality of the
picture that you get just to sort of reinforce this situation that I'm
talking about here at 600 dots per inch here is a 600 dots per inch image and to
try and stop it over burning which as you can see it's got lots of gingereness and
burning and smoke stuff and I can I can feel her eyes are very nearly burnt out
when I touch her hair it's got a 3d feel to it because of the way in which it's
burned into the picture here and in fact let me just stop a second yeah that's
exactly as I remember her... to try and compensate for the extra power that I
put into it because at 600 dots per inch I thought well I need to go a little bit
more powerful I also went very very fast of 400 millimetres a second yeah it
still works but the problem is when we start looking at the dots in here and we
will go back and have a look at some of the dots in these in these images you
will see that we do not have dots they've disappeared what we've got are these
what I call greyscale splurges different levels of colour caused by the fact that
we have got insufficient time at 400 millimeters a second and insufficient
space because we've got 600 pixels per inch those two factors are working
together to make the time scale infinitesimally small for any single
pixel so to try and get the pixels to burn you put more power in but that
means that when you do get blocks of pixels that are joined together this
power takes over and you get terrible burning so trying to find a compromise
you say right okay 600 pixels per inch we run 600 pixels per inch resolution
down the page as well and we'll run slower to try and get a bit more color
into it but we'll put less power into it at 12% it still doesn't work at the end
of the day the most balanced picture that we can come up with is one made up
of dots these are not dots as you will see when we look at them under the
microscope the crispest picture is that which is done slowest 50 millimeters a
second and a very coarse resolution but the point that I'm trying to make here
is with photographs running fast running powerful and running with high
resolutions is not going to get you a good quality picture you're going to get
your best results probably down at low resolutions and low speeds it's probably
better to experiment with maybe 60 or 70 millimeters a second trying to keep the
dot as round as possible but increase the resolution maybe a
little bit up to 200 now the one thing that you must not forget is that your
lens has got a theoretical spot size let's just look the best spot size that
we can think of which is a one and a half inch lens with
a spot size of point zero seven five millimeters well put it another way
point zero zero three inches now that means that basically the best that we're
going to get if we put these dots together like this is three hundred and
thirty three pixels per inch anything above 300 pixels per inch resolution
picture and really I think you're wasting your time now do not lose sight
of this fact because this is fundamental and the other thing that you must
remember is this is a theoretical spot size and when you come to put it on your
material whatever that material is if you do a test burn you may well find
that your spot size is not as you think that size but it's actually that size
and you could be down quite easily at a hundred and fifty P P I for your picture
putting more than 150 PPI into the picture it's not going to get you
anywhere now if you're after an art poster this one looks quite a nice soft
dreamy effect hazy soft focus but if you want a good creation then you're looking
at something like this where the dots are actually crisp and clear and it's
your eye that gets fooled this is that curl across her forehead that I look at
as a reference every time and we can see clearly some lovely brown lines that run
across there and we've got separation between the lines so that means we've
got our scan lines which are actually quite well defined but the gaps between
them are because this is only done at a hundred and fifty dots per inch in the Y
direction and so these are exactly the same line separations that we saw in our
very first crisp clear
dot image the difference is that this is not a clean crisp dot image this is a pseudo
grayscale as I keep calling it because look with all these shades of brown in
the background where different amounts of time different amounts of power are
causing different colored dots so yeah this is not a grayscale picture because
we are using the same power Max and min and grayscale pictures come from using
different power Max and min so this has been created by a completely different
mechanism but even though it's not part of this session I have a little bit of
curiosity that needs to be satisfied so I've imported this 600 PPI picture again
and we will just set up a different set of parameters speed same as it was
before 400 millimeters a second power well this time the minimum power that we
ever found that we could use was 11% and the maximum power that we used was 40%
now we need to come down to here and this time we're going to output direct
and basically what that's going to do it's going to give us grayscale
engraving now I'm going to set the interval exactly the same as it was for
the last picture which is 150 dots per inch in the Y direction which is point
one six nine three well we can clearly see the beam is on virtually
continuously and stable the whole time except when it turns off right at the
end of the stroke and then back on today yeah we've only got about a 10 percent
variation in power across there because in the end I had to set it to between 11
and 20 percent because otherwise I was just burning through the picture so I
obviously haven't got the correct parameters here but these are parameters
similar to the last picture that we created with dotting and this is really
all the comparison is about it's quite entrancing isn't to watch I've been
dancing around
ok now the one thing I keep meaning to say when we're looking at this
picture that mauve is not the laser beam that mauve is just ionised nitrogen
it's the powerhouse that drives the carbon dioxide to go into lasing mode so
just because you see that beam there does not mean to say you're necessarily
going to get power out of your laser because if there's no carbon dioxide
left in your tube you'll get no power out but you will be able to see that
lovely mauve beam in fact that beam might go slightly paler and whiter as it gets
towards the end of its life because there's more nitrous oxide from the from
the free oxygen that's been released from the carbon dioxide when it's broken
down into carbon monoxide and oxygen so just bear that in mind the mauve is a very
good sign that your power supply is working but it's not an absolute certain
sign that you're getting power out at the end of the tube. What you've just been
watching is me trying to produce something called a grayscale photograph
when this picture started off life originally it was full of color the
first thing that RDWorks did to it was remove the colour and when the colour
is removed it left a black-and-white picture which is basically a mixture of
shades of grey and that was what we have tried to simulate here with this dot
picture we've created the same sort of thing we've fooled the eye into thinking they are
Shades of colour on that picture but there
are not we've only got black dots and nothing it's just the different
densities of those dots are fooling your eye into thinking this is a photograph
now as we've already explained the way in which the laser produces this picture
is very simple it takes the power parameter 11% and it sets it at a fixed
value of 11% the dot every time we need a dot the power switches on and we
produce a dot and then it switches off then it travels along to the next dot or
in this instance group of dots and then it switches off dot dot group of dots
there is a very powerful function built into RDWorks it has the ability to
look at a grayscale picture and sort out every single pixel into a gray value now
the value of gray runs from white at 255 down to black at zero every one of those
shades of gray is given a power value and then this is where the clever bit
takes place when you run your program the first thing that happens is the beam
switches on and it stays on for the whole of your program but every scan
line that goes across looks like this it starts off zero and then it looks at the
very first pixel and says oh yes that's a mid gray that's halfway up the scale
and so it produces a pixel value like that and then it looks at the next pixel
and says oh that's nearly white white is not much power at all so we'll turn the
power off then the next pixel is a slightly heavier shade of gray and then
a lesser shade of gray and as we go across every pixel
has a varying power obviously if you start running the machine too fast
ie 600 pixels per inch or at very high speed the machine is just not capable of
keeping up with your requirements even though the requirements are there the
power supply and the laser just cannot do it this is how we basically would
attempt to produce my grayscale photograph now obviously I can only hope
to perform something like this on a piece of organic material because with a
piece of organic material I can get different shades of brown when it comes
to a non organic material such as acrylic in this instance or glass or
stone or slate or granite or something like that then the only choice that
you've got is a colored dot of one shade or nothing
so there is no gradation that you can use with solid materials now how
successful were well there we are the answer is not very it's a horrible fuzzy
picture yes it's grayscale but no there is no definition in it at all so we were
using the same resolution base picture 600 dots per inch we were using the same
scanning rate of a hundred and fifty dots per inch down the page we were
taking about a quarter of the information but that isn't the reason
why it's fuzzy because when we did it using the dot method exactly the same
picture looks like this so there is a huge difference between using dots and
using gray scale basically grayscale is not for producing grayscale pictures
it's another completely different function that you can use grayscale for
it's for 3d carving and we will get on to that subject which is a fascinating
subject in a future session the only way that you're going to get a picture of
any sort onto a material is with the dot process now you don't always
see the dots this is a smeared dot picture it isn't a proper dot picture
this is a proper dot picture and you can see that there's an element of crispness
about this that there is not there as soon as you start running at different
speeds and different different resolutions you could smear the dots
overlap the dots overlap the powers and you get all sorts of interesting
pictures some of them very soft focus something like this
no dithering at all all it is it's basically a black-and-white picture now
here we have a completely different material this is anodized aluminium and
you see that we've managed to get a photograph down onto the surface it's
only again a binary surface white and the background colour in this instance
we've got a silver background so you would expect that probably a silver
background wouldn't show through at all but as you can see we get a sufficiently
good contrast to see quite a reasonable photograph I will point out to you two
things first of all 80 millimetres a second very slow speed and 11% power
very low power now look what happens when I changed just 10% look at the
quality difference in the in the image again I'm reinforcing that control of
low power is an essential thing when you come to engraving well we've banged on
enough about dots and photographs and I think you've now got enough information
in your toolbox to go away and play for yourself so for the final part of this
session what I'm going to do is show you a real project that I had to carry out
for a friend of mine so it involves Photoshop I'm afraid or some sort of
photographic processing software because quite often you cannot get the correct
image that you're looking for down onto the medium that you want to apply it to
now this particular project is basically going out of my comfort zone I'm gonna
have to go into Photoshop which okay I know my way around Photoshop but but I
am NOT a graphic artist in fact I'm not any sort of artist
except the up against the wall type so you'll have to forgive me for some of
the liberties that I might take I'm an engineer not an artist and I make no
excuses for that at all so I hope that what we're now going to see is a
practical demonstration of all the elements coming together that we've been
learning about I've got a real job to do for someone a friend of mine who has
asked me to immortalize her dog on some coasters as you can see this is not
exactly the best picture in the world to work with it's not a studio quality
picture so somehow I've got to get the essential qualities of this dog's face
onto a piece of wood now I'm not going to take you through every single step in
detail but I am going to show the outline of what I'm going to do to
manipulate this picture so the first thing I've got to do is to physically
crop the head fairly tightly so that I don't get too much of that bright red
coat in the background now let's bring the picture up to a decent size so we
can see what we're working with o M G is your immediate reaction look at the
state of his tongue saliva mud so we'll choose that area there and there we'll
start working away to try and put some pink once this goes into grayscale
it'll be a shade of gray well that's not a perfect tongue but at least it's
better than it was so we then used the clone stamp to copy
the colors off of his muzzle here and try and get rid of those mud spots we
can do this with a lasso tool we can work our way around his head
approximately
so now we've got another layer which is
that layer there and you can see we've probably removed a large part of the
background we also removed some of his tongue but this is not what I finished
up with now the biggest problem that we've got here is if we take a look at
image adjustments we can check brightness and contrast and we what
we're trying to do is to bring his eye up this eye here is not very prominent
even when I push the contrast up which is what I should need to do
that eye is not very distinct I'm going to capture this eye here
rather carefully
edit copy edit
paste and you say well you haven't done anything
well yes I have because if I select this layer and I now use the pointer look I
can pick up his eye
and I can now put that over there
so now I've got two fairly bright eyes to work with the other thing that I've
got to do is because I know that when these eyes are on wood they will not
show up against this black dark background and so consequently what I'm
going to do I'm going to choose some rather hideous color like that and I'm
going to turn him into a werewolf now you definitely wouldn't want to meet
that dog on a dark on a dark night would you and so you can see how I had to
basically manipulate that oh one other thing I didn't mention which I had to do
I had to take a clone stamp and I had to clone these little frilly bits of the
tops of his ears here and I had to put them on the crown of his head because
there was no definition between this white section here and the background so
although this hair isn't real it just gives the impression it delineates the
outside of his head so you can see if you look at that in detail it's not
necessarily a very good quality picture okay now when we import that picture
into RDWorks it looks pretty scary doesn't it so the first thing we're
going to do with that picture is make it ninety five millimeters and then I'm
going to create a square 100 and then we're gonna put that square around the
outside of the image and we'll make that into blue
so the bitmap is black and we're going to have a go at cutting that in a minute
at about a hundred and I think we'll probably set the power to just a little
bit over the minimum I think that 12% is pretty good blowing no we'll check the
cut speed the cut speed is about five millimeters a second because this is
going to be done out of probably five millimeter marine ply probably 67
percent 67 percent which is about as high as my tube will go okay so now
let's go back to the picture itself
bitmap handle and you can see we've got a resolution here of over a thousand
think we'll set that to 200 we'll push the boundaries of what we've just
discovered and then we will do dither and we'll set it as dot graphics we
could play with the contrast and the but at the moment I think it probably looks
reasonable so we say apply to view and immediately we lose all the detail
so now we can play with these colors here contrast and brightness apply to
view
and there we go we can get some of the detail back here's you see now that
looks like a reasonably balanced view so we can say apply to source now and then
when we look at this there we go
and this time you can see the smoke being pulled away nicely towards the
back of the machine where it's extracted down the slots
well I've now put the cover down so that we get a good jet of air flushing across
the surface there and as you can see you can probably see hardly any smoke at all
it's all being dragged backwards really really quickly
now what you're seeing at the moment is a cut taking place where the air assists
has actually turned on automatically on its own
now if we take a look at the quality of that cut you can see that there is
absolutely no smoke burning on there at all except
the only hint of browning we've got is at the very very start point there and
the very very finish point but everywhere else is absolutely clean
and the reason why we've got a lovely smoke-free finish here is because the
smoke is passing all the way through this job
there's nothing hitting the top surface it's all going down underneath then is
either being drawn away by the airflow underneath or has been condensed on this
surface here as you can see leaving a Hobby horrible sticky goo behind
now that's another reason why I'm using a solid steel plate because when this
job is over all I'm going to do is to wipe that plate clean if I had been
using a honeycomb table I can't clean the honeycomb table as you can see all
this muck on here look it's all horrible Browns sticky muck that's the stuff that
would have gone on to the top of your cut and onto the top of your job had you
have had the air assist on while you were engraving and that's the stuff that
actually paints the surface of your wood Brown you don't want it you want to get
rid of it before you blow it back down onto the job so basically for air assist you
only need it for cutting and you want to blow all your muck out of the bottom of
the job but for good engraving you want to let it drift up into the air and get
it sucked away and not blown back onto the surface of the job
See all this brown muck here? Well sometimes you can get away with something as simple and benign as a
white vinegar so let's give that a try it really depends on the debris itself
now because that's a natural wood and that's probably just a normal resin it
came off fairly easily with white vinegar but here we've got
some acetone now obviously it's not the sort of thing that you would let
kids play with and you would normally have rubber gloves on or plastic gloves
so that you don't take the oil out of your skin
but I'm afraid at my age I've got a very tough skin I've been involved in
engineering for many years
for just a few seconds work it's not a major problem but if I was handling this
stuff all day my skin would literally dry and crack so it's not the sort of
thing you normally use without gloves now here are our coasters and you may
possibly spot that there are two at the back look slightly softer they're not
quite as crisp as these when you look at them with the light across them and
that's because these are coasters and they are going to be subjected to
spillage whether it be beer wine whiskey something is going to be spilt on these
you can be assured of it if it's me well it's got to be black cock here I've got
some just natural beeswax this is called bright way it's mainly beeswax with a
sort a little bit of sort of something like white spirits in it to make it
slightly soft it's not hard beeswax as you can see in here it's a sort of a a
slightly soft creamy mixture but it is a natural material and it sinks in to the
wood and so what I do with these I protect the wood
when you first put it on you think oh my goodness what's happening here we're
gonna fill in all the engraving
but because it is a wax and oils what tends to happen is over a few minutes
maybe 20 minutes half an hour you'll find the the wax actually sinks into the
wood and here we are look
when you first do it it looks pretty horrendous but just be patient and all
will come good in the end paint the edges which sells any coloration that
may be wanting to come off it seals it in and then we do the backs as well, so just paint
it on with a brush don't put it on with cloth because cloth will leave lint and
various other pieces of white in your engraving yeah it feels so real now I do
hope that that lasts practical demonstration has brought the whole
thing together now it was no cheating with that at all
there was no practice I went straight in with a resolution I went straight in
with a speed I went straight in with a power and we got excellent results and
that's what I hope this session has given you confidence to dive straight in
with a set of good maybe not perfect but good parameters so until the next time
Cheerio
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