In this post I will document the procedure involved in making a tray to suspend PCBs. The etchant (FeCl3 solution) is toxic and cannot be handled with bare hands. So I devised this easy and reusable method for suspending the PCBs with the toner into the solution.
If you are planning to make PCBs once in a while, then this method could prove to be really useful and time saving. But if you are a one timer then this a tiresome venture and I will recommend you not to do it.
Personally, I see no reason why you will want to do it only once. It’s like and addiction to me these days.
You will need
You will need this steel wire to make the tray. It’s really cheap and mostly sold in kilos. I bought 1/4 kilo and it cost me Rs.20
Make the Frame
The first thing you should do is to make the exterior frame of the tray. The size of this is determined by the size of the container you are planning to use for the etching process. I use an old fish tank for the process, so I made quite a big tray.
Once the frame size is ready, make thick by running another line over it. Remember this is what is going to give a mechanical structure for the tray so make it as strong and possible (consider running another line of wire parallel to it – just in case)
Breadth wise lines
After this cut out two sets of wires form the reel that are about 2 inches longer than the length and similarly the breadth. I will call them the breadth wise wires (Y-axis) and length wise wires (X-axis).
Start off with the breadth wise first. Place the wires at equal distance and tie them to either end of the external frame as shown in the image above.
Repeat the same with the remaining wires and make the look straight by adjusting the wire to the right or the left. Once everything is done, your tray should now have a frame and some lines in the Y-axis that are almost parallel to each other.
Length wise lines
Now let’s move on to the X axis wires (length wise). The same procedure applies for this also, only that you have to move the X-axis wires up and down the Y-axis wire so that they form a grid. See the above image for more clarification.
You have to start form one side and reach the other side of the rectangle. But you are not yet ready to tie up the ends yet. Just leave it open and move on to the next line.
While inserting the next line, which ever line went above the current line in the previous entry, will have to go below this time. This is done to ensure the mechanical stability if the tray.
Arrange the wires
Similarly, by following the same step you should have something like the below image. Now adjust the line so that they are equidistant and as usual almost parallel to the nearby line. This cannot be done very easily as you will notice that he tray in no longer fragile and it will give you a tough fight.
Once the arranging is done, you can precede to tie up the loose ends to the frame. Be very careful and have a first aid kit close by. I should have mentioned this earlier; I had a handful of bruises in my hands.
Beat it down!
This is the final step in the making of the base plate of the tray. Take a hammer and gently hit the knots so that they do not move around. But don’t overdo it as you might cut some wire (they are really easy to break).
The Base Plate
This how you final base plate of the suspension tray should look like. So far more than 75% of your work is done. Now you have to move on to make it spendable and give it a visual appeal.
Make it spendable
Add some extra fittings to the sides like the above. This is purely your imagination and you can have it any way you want. Do the same for both the sides and take care to make it look alike and of the same height.
Then I added a connecting line in between the two newly added side bars. Again this is not really necessary but all the time you spent in making the base plate will look good only if you spend some time over this.
Once this is done, you can see that I am able to make hold the tray in one hand. This is all I will actually need to suspend the tray into the etchant.
The Old Hanger Look
But again I felt like adding another feature that would allow me to hold the entire tray in one finger.
I got this idea form an old Aluminium hanger in my house. I just made a replica of it that would sit permanently over the tray for me to hold it with ease.
The Big Picture
Here is the big picture! You can see that I’m able to place multiple PCBs in the tray that means I can make a lot of boars in one GO!
I will soon make another post exclusively for making PCBs with Toner Transfer Method.