Thursday, 27 October 2016
As I determined I eventually needed a change to the Title so I set another in its place.BB
USING PAPER CARD AND PEN
P V A GLUE
The marking out having been made every line and brick was scribed out using a pen. Then every brick was raised by applying the glue carefully upon every brick several times. It took me four hours from picking up the pen to finish my brickwork pattern. I could not use styrenne because I need to bend this pattern over to make the inside of my tunnel. Styrenne would break. So it is back to good reliable paper card which will bend easily.
The Tunnel Entrance,i made way back in the Spring of this year. So i need to make a mould that will produce that inner wall and several more besides because i have a few larger tunnels like this one to complete later.
This one if all goes to plan will have a roadway re-emerging from it once it is fixed into place on the Canal Diorama currently under construction elsewhere near.
Above is the stone tunnel entrance which is high enough for a Double Decker Bus to come through without any bother of hitting the top.
This shows the box i designed to assemble and disassemble quickly for removal of the newly formed rubber pattern. There are three curved brackets and two end plates all constructed by gluing styrene sheets and paper card together. Which is fixed in place by using dress makers pins through the end plates. The lines on the rounded section are where the cuts were made to help form the shape. This will be more fully explained a little further on.
In the box lays the first brickwork pattern inscribed and this should produce the pattern needed to mould later in another simple to construct box. That pattern will be formed by pressing into place my own rubber mix,that will not be shown extensively here. Other topics of mine have already dealt with that in greater depth.
This is the preformed first impression pattern,and the rigid shape was made by using a blank strip of paper card. The card was scored many times across its width along its entire length with my craft knife. This allowed it to to form the curve required in the box. The plain side had glue brushed onto it and it was placed in the box with this glue showing on top. The inscribed strip was laid on top and tucked in by hand,and a heavy bag of metal shotgun pellets was placed on top and filled the entire thing up forcing both strips onto the curved brackets and into the shape required. So when the glue had set the middle section was strongly formed and could be removed as was the designed plan.
Lets see how it come apart shall we?
Out comes the curved section.
Off comes one end plate
With the removal of the other end plate it is completely dismantled. This means i have no need to destroy the box getting the rubber pattern out. Which is good because i might need to make another without needing to make up another box.
I will reinforce the sides later with another sheet of styrene.
I forgot to take a picture before so I`ve simply put everything back into place in order to show how the pressure from the heavy metal shotgun pellets forced the paper card down and into the required shape I need.
I have further reinforced the box by winding sellotape around it. After the pellets have been removed the box is fully ready for the rubber mix. Always pays to have that strong sticky stuff in ones stash!
Applying P V A glue to the inside walls
Waterproof P V A Glue
A couple of coats were applied to make the two sides waterproof.
This will be added insurance against the rubber sticking to these sides.
THE FUN BEGINS
A little Cooking Oil was brush onto the inner walls and the scribed brickwork as a releasing agent.
The box is prepared,and all I need is on show. No baby powder this time.
It is cooking oil in the bottle.
Off cuts oh paper card for doing the first lot of mixing.
I drank my tea and got started mixing the silicon and cornflour.
It all emptied out onto the flour
One has to cover it over with the white stuff from the edges.
And from the sides,and work it into the silicon using the card. Adding the oil and eventually one needs to get to grips with it by hand,adding oil and flour onto the hands helps. Do not wear rubber gloves because this rubber will stick fast to them making work impossible,because rubber sticks to rubber and darn fast too.Using hands the best tools one has work the stuff like one would pastry. Adding oil as needed. Sure some will eventually stick to fingers. But that is part of the fun.
I gradually added it into the box a third at a time pressing it into place against the Pattern and making sure the air escaped while doing so. Working the bottom first then each side in turn and then filling in the middle and finally smoothing off the top with my oiled up butter Knife.
It was very simple to do.
The little pieces left over made the Snowman.
Remember this is having fun?
THE BOX COMES APART
It soon sets hard. If the Snowman is hard so is the other Stuff.
Removing the sellotape then the pins mean it falls apart easily.
The Result was soaked in soapy hot water to get rid of the oil.
There is the Pattern. They are ink marks on the rubber and nothing to worry about . After all I used a pen to scribe every little brick.
SETTING UP THE PATTERN
The two rounded end plates were cut out the same using the first as a template,and the outside edge on each was ticked. Turned over and place flat down on the table I lined it up with the Pattern and made two ink marks. Then the other end plate was butted up against the first one,so both tick`s were to the table top,and marked out the same. Theses marks are simple guides that line up perfectly with the rubber Pattern.
So each having this mark was lined up and pinned into place by angling the pins and pushing them into the rubber through each end plate.
My craft blade was a bit blunt. Silly me I`d run out of them at this time,but the edges will server their designed purpose OK! One uses what one has at the time.
The Plaster of Paris was made up creamy-like and brushed onto the Pattern all over it with a cheap brush this made sure no air bubbles would be trapped. Two styrene off cuts were pinned in place upright to the sides,then the plaster from the same mix was poured into the cavity formed and using a smaller brush stuck into it the plaster was worked and well settled into place,by an up and down action of agitation. With both sides done quickly then the top was creamed over with the same mix using the large brush and the smoothed over with the butter knife. An Ace Cool Tool!
The job completely done in 5 or 6 minutes before the creamy Plaster of Parish went hard. It takes practice working with this stuff,but one learns the roadway to success by doing it. Do not use the builders plaster they put on walls. Use Plaster of Paris,used by Master Masons even today. Long ago I worked with one Old Boy who taught me well before he retired in 1964. Fresh from school I was 15 years old at that time and very wet with ignorance behind each ear.
Old Jack Sewell,taught me well and gave me a darn good grounding which eventually took me into the world of Engineering skills,developing steel Patterns in a very big way. That perhaps is another story for another time.
Working on my own I was unable to photo shoot these action photo`s because I needed two hands to remove the Pattern. On the second casting from the same Pattern Mrs B,was kind enough to snap these pictures that clearly show easy it was to remove both parts from each other.This was very kind of her and as always I was extreamly greatful . So sit back and scroll down. BB
RELEASING THE PATTERN
This was explained after the removal.
I left the plaster to harden for 4 or so hours. Then released the Pattern from the casting not the casting from the Pattern. Pulling it off would or could break the casting.
So before the Pattern could be released I cut a wedge out so the rubber will flex in towards the middle. As the rubber was pushed away from the edges of the casting by my thumbs, the seal was broken the air enters,and working slowly un-rushed both sides of the Pattern. Once both sides were worked in this way, i started again pushing a little more away from the casting again. One must remember these are deeply inscribed layers of bricks and so are not smooth sided or topped.
Having two thumbs certainly helps . Ones hands are very specialised tools most take for granted that is for sure.
Eventually the Pattern falls away with a little Jiffle of encouragement using ones hands.
One might well ask ,"Why not cut the wedge out while the rubber is soft?" That is a good question to ask. Well this stuff is rather on the sticky side of softness and trying to cut the wedge shape out could pull the rubber away from the impression one is trying to copy. This could spoil the work. So it was my choice to cut it out. If i had a wooden wedge I could have pushed it into the rubber creating the shape required but working with limitations i had no such thing to hand.
The very first casting is a very exciting thing to be made because the results are not yet known.
The outcome here is a very clean result considering this is a scratch build using tools most have in their homes.
A little trimming or none at all makes for easiness that is for sure.
I will leave this casting to dry out over a couple of weeks and it will go white,and will become much lighter but it will remain very strong indeed as a tunnel design is one of proven strength time and time again throughout history. Eventually it will be dipped in a homemade colour wash to bring out the detail even more.
I am often asked if I sell,and my, reply is always no,but I show how to do it, so others can do simalar things unique to themselves. My Masters are always destroyed along with the Rubber Moulds.So I am the only one in the entire world that have the results of them. This is not a point of vanity on my part it is to stop Pirates and other Recaster ripping my stuff off. This is my way for I have no great need for money at this time in my life,and at 67 i am content with what I have,and in doing my hobby and tutorials.
THE HONEY WELL CANAL
This tunnel will be placed where the bus is,and a roadway will be eventually put into place on the Canal Diorama, which is ongoing at this time with landscaping to do.I intend to squeeze in somewhere Beano Boys Cafe,made many years ago. A place for plastic tourists to tumble from the bus and visit because everything started with that first tiny scratch build.
This Topic is now Ended
Thank you for taking time out to look and perhaps learn a little from eccentric me,
a simple Scratch-Builder. Stay Safe BB