Spin Coat Machine

I thought I would upload this little spin coat machine I made. It is nothing fancy but it was cheap (free with parts laying around), easy, and very functional. It could be used for the purpose I made it which is spin coating TCO's on glass substrates, or other thin film applications (I will discuss this later in the instructable). It could also be used for fun like making those spin paintings you used to get at the school carnival (I don't know if the kids today have that but if your old like me you probably know what I mean). This isn't gonna be the best detail since I didn't really take pictures of it as I made it since it was really a quick build on a whim.

Materials:

1. A take out container bowl (or some large enough exterior enclosure with a lid)
2. Old cd, dvd etc
3. Old cpu fan (or some other fan with high revolution and enough torque to spin up with a bit of weight on it)
4. Power source (I salvaged a power supply from an old Tivo)
5. Variable speed controller (I grabbed mine from an old bay fan controller but could be from anything or make your own with a potentiometer)
6. Something as a spindle head a cylinder that can fit the cd center in it and can has enough height to lift it above the bowl. I used a scrap part from solar garden light but you can look around and find something else I'm sure.
7. Plastic tubing (the stuff for oxygen lines or aquariums) (this is not really necessary I just added it for drainage if I used it a lot)

Tools:

1. Glue gun
2. Dremel
3. X-Acto knife or box cutter

The way this is going together is

1. Fan
2. Spindle head attached to fan
3. Bowl glued to fan cage
4. CD glued to spindle head.

With that in mind measure out how high your spindle head needs to be. It needs to attach to the fan and rise enough above the bowl to hold the cd up for free spinning. For me it was about 3-4 inches. I apologize that I don't have a good photo of it post cut and the pics you see with it in there are a obscured by the fan or the cd. You can see the piece I chose pre cut though to get an idea of what I meant.

Cut your spindle head, cut a hole in the bottom of the bowl large enough to put the spindle head through and allow it to spin freely.

Glue your spindle head to the fan. Be very careful here as you need to get it centered well any amount off center and it's going to wobble and shake and not work right.

Set your bowl over the spindle and glue it to the fan cage. (If you didn't use a fan or motor with a cage you will need to do that yourself I'm sure you are clever enough to come up with something for this if you are reading this).

Glue your cd to your spindle head. Again be very careful here you want it level and centered so you don't have tilt and wobble.

Optionally you can cut a small hole in one side of the bowl and glue in a tube. This is not overly necessary I haven't used enough material to actually need it but it could be helpful as you don't want liquids building up and dropping into the hole on to the fan.

Finally cut a small round hole in your lid (not needed but a good idea to keep spray inside the container and the hole will let you stick your dropper in to apply the coating).

You can see the psu I pulled out of a Tivo. I used it because it has a molex connector and so I get a good 12 and 5 volt supply, it already fits the connection for my fan controller, and it was free and handy. Obviously if you do something like this or use an old pc psu be careful and don't electrocute yourself.

So for my project psu to fan controller to fan.

To attach the substrate to the platter I just use scotch tape. I know... but it works. You can see the pictures in previous steps on how I do that. Just center the substrate and apply the tape. Doesn't have to be tight on the edges it's just keeping it in place and using centrifugal force to keep it in there. Again be careful though. Glass spinning at high rpm's can be dangerous of course. Use the lid, wear safety glasses. Use common sense.

I use a dropper like the one pictured to apply the material to be spun. We had a bunch of these as will most parents of young children. Kids tylenol, motrin etc all have these things. So many uses for them. Depending on what you are doing drop the material and let it set for the desired amount of time then spin it up using the controller to get to speed. I know really complicated right? ;)

I should mention that my results have been pretty poor. The picture isn't actually the best one I have made. The reason is not the machine it actually works pretty well especially considering it's all scrap parts and what would otherwise be garbage. I haven't been able to produce a good sol-gel to use in making AZO. I don't really have what I need to do it currently. That includes lab glassware to make the Aluminum Chloride and a kiln to anneal the spun substrate. Basically what you are doing though is taking Aluminum Chloride (not hard to make or even buy but needs to be done safely and I don't have the gear or money) and Zinc Acetate (very easy to make and safe) either producing a sol-gel in alchol or creating the 2 solutions separately, spinning the Zinc Acetate then layering the Aluminum Chloride solution over it. Then firing it in the kiln. Anyway.... that's another story and I will probably have built a sputtering machine if I can find a few old microwaves first. Another potential option is Stanous Chloride (very easy to make or buy) but I haven't had luck with that probably because I didn't have a pure source of tin and the HCl I have is very weak solution (5-10%). I also used old solder from desoldering and it also could have been contaminated. For solar cells I am planning on trying lead perovskite as I have some old dead lead acid batteries that's for another time and instructable if I do.

You might ask what is the use of that anyway. Well TCO's are great for making LCD's, solar cells or cool projects where pcb is glass.

Other uses could include spin art. I have played with it for that with my daughter she thinks it's pretty cool. I love when she comes over and says "Daddy can we do spare-ments". Let's hope she enjoys that as she gets older too.

Improvements could include.

1. A better speed controller
2. A better way to attach the substrate to the platter
3. A rpm read out. LDR comes to mind as a way to make that.