So after reading a bunch of threads here on installing fans, I tried to synthesize some great recommendations and some things I kind of came up with on my own. You should know my skill level is pretty low, so this is a noob-friendly method of cutting a big effing hole in your van and dropping a fan through it.
Here's the process I followed:
1. Build a wooden frame out of 1x2 that fits the inside of the fan snugly. It doesn't have to be absolutely perfect but it should be within ~1cm. The fan will screw down into this frame through the sheet metal skin of the van. Screw and glue it all together.
2. Ideally you would treat this wood frame with polyurethane so that it doesn't absorb water in the case of a leak. I didn't do this mostly because I forgot.
3. When the frame is dried, seat the fan inside the frame and mark the holes. On the top side of the frame, mark which side is front and back so you don't wonder later.
4. Drill *partial* pilot holes through the frame. Like halfway is good.
5. Get some flat cardboard that is larger than the frame. Place the frame on the cardboard and trace the inside.
6. Cut out the cardboard right on the line. Try to make the cut really square - it will help later. This is now the exact size hole you need to cut. yay!
7. Get up on the roof. Put a piece of plywood down on top of a blanket or tarp to avoid scratches.
8. Place the cardboard on the roof where you're going to cut the hole.
9. Measure the tolerances on the side like 20 times. Get that cardboard exactly, exactly where you want it. Remember to take into account the total width and length of the fan and make sure it doesn't ride up on any roof ribs. You want to have the fan sit almost perfectly flush with the roof.
10. Take a sharpie and trace the cut line onto the roof.
10.25 Tape off a 5-6" area around your cut hole.
10.5 tape garbage bags or a drop cloth to the roof of the inside of the van. This will catch the metal shavings. Goes without saying, but don't stand inside the van while you're cutting and drilling.
11. With a small drill bit, drill pilot holes inside the square you traced
12. Using a 1" drill bit, drill larger holes at the 4 pilot holes. Go slowly and use some wd-40 to lubricate the metal.
13. Using a jigsaw with a sheet metal blade with as many teeth as you can find, cut on the cut line one side at a time. Err on the side of slightly outside the cut line rather than inside. A hole that is just slightly larger is ok, too small and you'll have to widen it. Using wd-40 helps keep the metal shavings under control.
14. Cut slowly!
15. Use small clamps to hold the square in place once you get 2 sides cut. Another approach is to take down the garbage bags / dropcloth and heavily tape the underside to hold it in place.
16. Cut the fourth side off and behold your perfect hole.
17. Use a file and file down the inside of the hole. Clean up the metal shavings.
18. Test fit the fan. Moment of truth. Ours fit perfectly the first go. If the hole was too small, you would either file down or re-cut a side to widen it slightly.
19. With the fan fit, use a sharpie to mark the screw holes.
20. Remove the fan, Drill out the screw holes. File the screw holes from the inside to remove any metal burrs
21. Clean everything with de-greaser to get the WD-40 off completely. Simple green works well.
22. Use rust-preventing primer to coat the inside of the holes and cut line. This prevents rust in case any water ever leaks. I just taped off the whole thing and sprayed all of it. It gets hidden anyway. Let the primer dry completely.
23. Place 1" wide butyl tape along the inside of the fan lip. The screws go through the butyl tape.
24. Just inside the butyl tape, put a bead of waterproof sealant. DO NOT use silicone.
25. One person standing inside holding the wooden frame (this is why you marked front and back) and one person on top, start screwing it all together.
26. You should screw it partially down but not so tight that there is no space left between the lip of the fan and the van
27. Using self-leveling sealant (search for lap sealant on amazon) squeeze a bead along the edge under the little gap you just left between roof and van.
28. Screw it all down tight. Be sure not to over-tighten and crack the plastic lip. Hand tight is fine. If you have a screw that doesn't fit for some reason, just quickly drill a new hole. Your drill bit will get nasty but you really don't want to pull up the fan at this point. Ours screwed together without issue.
29. Now, using the lap sealant, trace a think bead of sealant all the way around the edge of the fan.
30. Using the lap sealant, completely cover each of the screw heads.
31. Let it all dry and inspect for any gaps. Fill them with sealant again if necessary.
32. Optional: once it is completely dry, you can place a layer of eternabond (or is it endurabond? I forget) sealant tape over the whole thing. The reason for this is to try to prevent UV exposure to the plastic lip. Apparently over time it can crack. I plan on doing this also for aesthetics because my van is grey and the fan is white and looks kind of hackish. So the black tape goes over the white plastic lip and serves to really permanently seal it (the eternabond tape is bomber and often used to repair holes by itself) and also make it look a little better. I also considered plasti-dip and might still do that on top of everything for aesthetics. TBD.
Whew. Ok. That's a lot of detail but hopefully it helps. I'll upload a few pictures when I'm not working on airplane wifi.
I got all these things on Amazon:
Fantastic Fan w/ wireless remote & rain sensor
Jigsaw blades
Butyl tape
Lap sealant
Eternabond tape
DAP Waterproof sealant
So, yeah. Hopefully I didn't mess anything up because it's done now. Huge thanks goes to Geek and this thread for informing this process:
https://sprinter-source.com/forums/showthread.php?t=17258&highlight=install+fantastic+fan&page=22
Here's the process I followed:
1. Build a wooden frame out of 1x2 that fits the inside of the fan snugly. It doesn't have to be absolutely perfect but it should be within ~1cm. The fan will screw down into this frame through the sheet metal skin of the van. Screw and glue it all together.
2. Ideally you would treat this wood frame with polyurethane so that it doesn't absorb water in the case of a leak. I didn't do this mostly because I forgot.
3. When the frame is dried, seat the fan inside the frame and mark the holes. On the top side of the frame, mark which side is front and back so you don't wonder later.
4. Drill *partial* pilot holes through the frame. Like halfway is good.
5. Get some flat cardboard that is larger than the frame. Place the frame on the cardboard and trace the inside.
6. Cut out the cardboard right on the line. Try to make the cut really square - it will help later. This is now the exact size hole you need to cut. yay!
7. Get up on the roof. Put a piece of plywood down on top of a blanket or tarp to avoid scratches.
8. Place the cardboard on the roof where you're going to cut the hole.
9. Measure the tolerances on the side like 20 times. Get that cardboard exactly, exactly where you want it. Remember to take into account the total width and length of the fan and make sure it doesn't ride up on any roof ribs. You want to have the fan sit almost perfectly flush with the roof.
10. Take a sharpie and trace the cut line onto the roof.
10.25 Tape off a 5-6" area around your cut hole.
10.5 tape garbage bags or a drop cloth to the roof of the inside of the van. This will catch the metal shavings. Goes without saying, but don't stand inside the van while you're cutting and drilling.
11. With a small drill bit, drill pilot holes inside the square you traced
12. Using a 1" drill bit, drill larger holes at the 4 pilot holes. Go slowly and use some wd-40 to lubricate the metal.
13. Using a jigsaw with a sheet metal blade with as many teeth as you can find, cut on the cut line one side at a time. Err on the side of slightly outside the cut line rather than inside. A hole that is just slightly larger is ok, too small and you'll have to widen it. Using wd-40 helps keep the metal shavings under control.
14. Cut slowly!
15. Use small clamps to hold the square in place once you get 2 sides cut. Another approach is to take down the garbage bags / dropcloth and heavily tape the underside to hold it in place.
16. Cut the fourth side off and behold your perfect hole.
17. Use a file and file down the inside of the hole. Clean up the metal shavings.
18. Test fit the fan. Moment of truth. Ours fit perfectly the first go. If the hole was too small, you would either file down or re-cut a side to widen it slightly.
19. With the fan fit, use a sharpie to mark the screw holes.
20. Remove the fan, Drill out the screw holes. File the screw holes from the inside to remove any metal burrs
21. Clean everything with de-greaser to get the WD-40 off completely. Simple green works well.
22. Use rust-preventing primer to coat the inside of the holes and cut line. This prevents rust in case any water ever leaks. I just taped off the whole thing and sprayed all of it. It gets hidden anyway. Let the primer dry completely.
23. Place 1" wide butyl tape along the inside of the fan lip. The screws go through the butyl tape.
24. Just inside the butyl tape, put a bead of waterproof sealant. DO NOT use silicone.
25. One person standing inside holding the wooden frame (this is why you marked front and back) and one person on top, start screwing it all together.
26. You should screw it partially down but not so tight that there is no space left between the lip of the fan and the van
27. Using self-leveling sealant (search for lap sealant on amazon) squeeze a bead along the edge under the little gap you just left between roof and van.
28. Screw it all down tight. Be sure not to over-tighten and crack the plastic lip. Hand tight is fine. If you have a screw that doesn't fit for some reason, just quickly drill a new hole. Your drill bit will get nasty but you really don't want to pull up the fan at this point. Ours screwed together without issue.
29. Now, using the lap sealant, trace a think bead of sealant all the way around the edge of the fan.
30. Using the lap sealant, completely cover each of the screw heads.
31. Let it all dry and inspect for any gaps. Fill them with sealant again if necessary.
32. Optional: once it is completely dry, you can place a layer of eternabond (or is it endurabond? I forget) sealant tape over the whole thing. The reason for this is to try to prevent UV exposure to the plastic lip. Apparently over time it can crack. I plan on doing this also for aesthetics because my van is grey and the fan is white and looks kind of hackish. So the black tape goes over the white plastic lip and serves to really permanently seal it (the eternabond tape is bomber and often used to repair holes by itself) and also make it look a little better. I also considered plasti-dip and might still do that on top of everything for aesthetics. TBD.
Whew. Ok. That's a lot of detail but hopefully it helps. I'll upload a few pictures when I'm not working on airplane wifi.
I got all these things on Amazon:
Fantastic Fan w/ wireless remote & rain sensor
Jigsaw blades
Butyl tape
Lap sealant
Eternabond tape
DAP Waterproof sealant
So, yeah. Hopefully I didn't mess anything up because it's done now. Huge thanks goes to Geek and this thread for informing this process:
https://sprinter-source.com/forums/showthread.php?t=17258&highlight=install+fantastic+fan&page=22
