------------------- UPDATE: 15-07-19------------------------
Found out that my sedan has pre-cut holes for the original blower, so I will be measuring and editting the drawings to be fitted for the original holes.
Might need to re-print the whole thing, but it won't need new holes ;)
The measuring has to wait for a little while though because sadly I won't be near the car for the upcoming two weeks.
Added a narrower for the blower part(Blower_narrower.stl) which should increase the airflow. Not sure if needed though, just a part in advance.
In my opinion the slit of 10mm was far to wide, this has been decreased to 1.5mm with the added part.
For a while now I've owned a Oldtimer Opel Kadett B.
When driving in rainy weather or in freezing conditions the rear windshield likes to fog up and thus limiting my line of sight.
Normally you'd be able to use the rear window heating element but unfortunally mine has broken traces, so it won't be working.
In search to fix this I've encountered a solution on the dutch Kadett B forum, which looked very promising: http://www.kadett-b20.nl/smf/index.php/topic,12255.0.html
After asking the howabouts of the projects there were no more updates, so after a little while I've decided to draw one myself. After designing the parts i have printed and assembled them. I haven't mounted them into the car yet, but when testing I can notice a warm breeze coming out of the blowers
The demister makes use of the following components:
- two 80mm Fans
- a ceramic heating element. I salvaged mine from a Dunlop car heater like the one shown here: https://www.action.com/nl-nl/p/dunlop-keramische-kachel-/ (I've got mine in the dutch store called Action) (for some reason the link doesn't get completely recognized so you might have to copy + paste it)
- 2x M4x15 screws(for mounting the top)
- 2x M4 threaded inserts(for mounting the top)
- 8x M4x40 screws(For mounting the fan)
- 8x M4 nuts(For mounting the fan)
- 2x M3x15 screws(For mounting the ceramic heater)
- 2x M3 nuts(For mounting the ceramic heater)
- two pieces 50mm Hose with a length of +/- 500mm(depending on the car and mounting options) for this I went to a local petshop, who had 50mm spiral hose(meant for ponds) which does the job perfectly
This project will be updated as soon when it's mounted and I have test results, but at the moment that might take a little while. For dutch readers, the project is also updated at the following forum post: http://www.kadett-b20.nl/smf/index.php/topic,13285.0.html
Important note before printing:
Because of the design using a heating element I've chosen to use PETG, but ABS should also be suitable. When being used without the heater PLA might do the trick, but keep in mind that a car can heat up to pretty high temperatures in the summer, so that might not be the best choice here.
Step 1: Prepping the parts
An obvious step, remove the supports from the prints. on parts like the blowers you might have to sand the last bits down a bit for fitting a hose over it. but sanding down the support bits on the inside of the parts isn't a bad thing to do.
Same goes for screw/nut holes where some supports might have been used. Make sure your screws can go in. The nuts can have a tighter fit for locking purpose, but you have to be able to get them in.
Step 2: First mount the heater (Optional, but it's the easier to do it now)
For mounting the heater you need:
- the Achterruit Ontwasem_Hoofd_Aanzuiging part
- the base_heater part
- the ceramic heating element
- 2x M3x15 screws
- 2x M3 nuts
Start by inserting the nuts into the top of the base heater.
When the nuts are in place you can mount the heater on the bottom, and screw it in place. Make sure there are no large gaps between the bottom of the base_heater and the ceramic heating element. this ensures maximum airflow through the element.
When the heating element is mounted it can be inserted into the Achterruit Ontwasem_Hoofd_Aanzuiging. before that it might have to be sanded a bit due to there being no tolerances in the drawings for the heating element.
This was to make sure that the airflow is guided through the element and not around. Just sand it down enough so it won't go in easy, but just enough that it'll go in. In most cases the pressure fit will do the trick here because in my case the tabs broke off.
you can carefully use clamps to evenly press in the base_heater into the Achterruit Ontwasem_Hoofd_Aanzuiging.
Make a hole in the bottom of the Achterruit Ontwasem_Hoofd_Aanzuiging and guide through some cable. Crimp/solder connectors to it for easy replacement.
You'll probably have to bend the connection part of the ceramic heater to prevent them blocking the fan from rotating.
The base with the ceramic heater installed
Step 3: Mounting the fans
When mounting the fans you'll need:
- the previous assembly off course
- 2x 80mm Fans
- 8x M4 nuts
- 8x M4x40 screws
- 2x Achterruit Ontwasem_Aanzuiging
Start by inserting the Nuts into the Achterruit Ontwasem_Hoofd_Aanzuiging. When done you can sandwich the fan between this and one of the Achterruit Ontwasem_Aanzuiging, and fasten them with the M4x40 screws. Do the same for the other side.
Here you can execute the first of your tests(preferably without mounting the top part first).
- Run the fans seperately from the heater(to check initial airflow)
- Run the fans with the heater(check if the main part distributes warm air, and does not melt down your print)
When running it with the heater be sure to check the printed part around the heater. With the right material there shouldn't be any melting. After verifing the heater works, you can turn off the heater, but I'd recommend to leave the fans running a little longer.
Step 4: Mounting the Top part
The Blower/Heater combo is mounted in the parcel shelf via the top part. The Blower/Heater goes into the trunk through a hole and secured via two M4x15 screws. The hole for the heater should be a 70mm hole. But for now let's test fit the top as a prep for mounting.
- The blower/heater assembly
- 2x M4 Threaded inserts
- 2x M4x15 screws
- Achterruit Ontwasem_Afdek Kap Hoofd Aanzuiging(Top Part)
Insert the threaded inserts into the blower/heater assembly. This should be able to do as is, but using a bit of heating makes it a lot easier. When the inserts are mounted screw in the screws to check if they go in straight. If not, now is the moment the straigthen them out.
This can be done by heating the screw carefully and ever so slightly bend the screw until it's straigthend out. Leave this to cool down for a bit before taking out the screws.
After the screws cooled down, take them out, add the top to the blower/heater assembly and put back the screws. You should be able tho hold the assembly by the top part now.
The heater/blower assembly with the top part mounted
Step 5: Mounting the blowers
For mounting the blowers you need to cut a slit, and two holes into the parcel shelf. As mentioned i haven't had time to mount mine so most of this is my testing with the blower:
- The complete Heater/blower assembly
- 2x Achterruit Ontwasem_Blower (Windshield Blower)
- 4x M4x?? screws
- 4x M4 Nuts
- 2x 50mm spiral hose of about 50cm in length(This might depend on your space in your trunk)
Mount the hoses to the heater/blower assembly, and into the windshield blowers. Next measure out where you want to mount the windshield blower in your trunk. cut out the slit and holes for the blower. Next you can screw them down. The hose should fit tight enough, but you can use a hoseclamp of zip tie.
Step 6: Electrical wiring
To hook up your demist device I'd recommend the following setup if possible.
When your car has a seperate switch for the rear window heater and the demist, then cable them both. The ceramic heater should be wired up to the rear window heater, so it can only be used when the engine is running. Wire the fans to your demist switch so you can operate the heater and the fans seperately.
The rear window demist will also work with hot air within the cabin of your car. But for that little extra boost you can also use your ceramic heating element. This way you can also cool down the ceramic heater quicker by leaving the fans running and turning the heater off.