Making the metal as flat as you can with a block of wood a hammer and a light touch would have helped a lot. Did you happen to scuff up the paint a little before applying the 4200? If not you might be able to get away around the perimeter of the adapter that is still in place and add a bead or 4200 around it. Maybe send us a picture of what it looks like now so we can give better advice.

 

I did scuff up the paint prior to the 4200. The fan is installed and has lap sealant covering the adapter, flang, and nails. It's raining today. I can take a photo tomorrow of how the adapter and metal look when I take the lap sealant off.

 

Part store for a hammer and dolly. Or body shop and ask for an old dolly. Light touch with the hammer after some youtube. You really need a shrinking dolly for that.

https://www.oreillyauto.com/detail/c/performance-tool/performance-tool-autobody-kit/pfm0/w1007db?q=dolly&pos=13

 

Part store for a hammer and dolly. Or body shop and ask for an old dolly. Light touch with the hammer after some youtube. You really need a shrinking dolly for that.

https://www.oreillyauto.com/detail/c/performance-tool/performance-tool-autobody-kit/pfm0/w1007db?q=dolly&pos=13

Thank you for the advice. Hammering the metal will stretch it, correct? The flang fits tightly in the metal hole with no wiggle room at this time, and if the metal stretches, I will be back at square 1 with a hole too small.

 

Yes it will. That's why I was thinking you need a shrinking dolly/hammer.

 

Trim off that warped edge and then let me know how large the hole is. Then we can make a custom adapter with larger outside dimensions to make sure the vent flange sits entirely on our adapter. Also looks like we will need to use our most forward adapter as a starting point because the flange will sit on the seam between the cargo and cab roof. We will provide the new custom adapter free of charge.

All the best,
Hein
DIYvan

 

Hein, I just sent you a PM. I insist on paying. Thank you so much for the advice and the offer.

 

Wow, very nice Hein! @blm0002 , you are one lucky guy!

 

Use a cutting wheel rather than a saw and take your time.

 

Do you recommend a cutting wheel instead of a jigsaw for the whole job? I haven't seen any examples of people doing so. From my research, I almost considered a sheet metal nibbler, but figured than maybe I didn't need to be a pioneer.

If a cutting wheel, could you point me to a device and wheel you'd recommend?

 

I would give a big c-clamp a try. The bigger ones have pretty large clamping pads will straighten an inch at a time.

 

Looks like Hein just wrote a new chapter in the book entitled Customer Service. 😀

 

Retired machinist here. I love abrasive cutoff wheels. With proper precautions they can be the most effective. Yes they throw hot chips. Protect your stuff. Low impact and the perfect starter for my jigsaw. I drilled 2 small holes just to find the centerline front to back.

 

 

My procedure was the same as Austincobrafreak's but I used 3M 08609 Window-Weld to adhere the adapter to the roof. Stuff is used to seal windshields to the vehicle and I have seen it fill in 1/2" gaps to watertight.
I think you should hammer as flat as possible like everyone else has said then place the adapter on dry, put blue tape around the adapter about 1/2" away from the adapter. Remove adapter, paint any exposed metal then run 3 decent beads of the window weld around the underside of the adapter. Flip and place on van. Clamp (as many as you can) around the adapter, utilizing your 2x2 frame you made. Then, run screws through the adapter (predrilled holes) through the sheet metal and into the 2x2 frame you have. Let dry then come back with the window weld and run a bead around the perimeter of the adapter for good measure. Remove tape carefully after about 15 minutes so you can take off any extra window weld that oozed out. This crap is nasty stuff that seems to get everywhere but it works wonders. Wear gloves!
Allow to dry for about 24hrs then continue the rest of the install with the Dicor BT-1834-1 1/8" x 3/4" Butyl Seal Tape and top off everything with the self leveling lap sealant.
Remember to park level before using the lap sealant because it will run. Also, get some 2" painters tape and go around the perimeter of the fan base and fold the tape up on the outer edge so that you make a little "dam". After the lap sealant has skinned over (15 min) remove the tape. This is to keep the sealant from running all over your roof.
Sorry for the book. Hope this helps!

 

My procedure was the same as Austincobrafreak's but I used 3M 08609 Window-Weld to adhere the adapter to the roof. Stuff is used to seal windshields to the vehicle and I have seen it fill in 1/2" gaps to watertight.

Let me try my question again. Why not just use butyl tape for both the fan to adapter interface AND the adapter to roof interface? There is no reason to use an adhesive for either interface because you are using 16 screws.
And if butyl tape is a good enough sealant for one of the interfaces, why isn't it good enough for both?

 

Here is what the metal looks like with the adapter after taking all the lap sealant and the flang off this morning. The 4200 did it’s best, and the adapter adhered to what it could of the metal.

 

I would also recommend "relief cuts". Short 1/2" cuts where every ripple is, so that you can hammer it flat and give the expanded metal somewhere to go. The metal "cuts" will end up overlapping and give the "stretch" somewhere to go.
Sorry for the crude sketch.
BTW, do NOT use your jigsaw for relief cuts.

 

I think doing it that way may cause cracks in the future. If metal is cracking, they say to drill a hole at the end of the crack to spread the stress out and stop the crack. Cuts into the roof could give it a weak spot and start a crack.

You could add some aluminum flat stock to the bottom (inside) and use stainless bolts and nuts to pinch the warped roof between the adapter on the top. I'd countersink the extra bolts into the adapter (in places where the fan doesn't mount).

Not to be rude but if the OP is having to ask, it may be time for him/her to take the van over to the body shop. They have tools and techniques that the common van owner doesn't.

 

Went with Hein and others recommendation. Used two angle irons to sandwich and hold the metal with a couple screws and guide the jig while cutting. Hung a trash bag for the metal shavings, tape all around, and cardboard around on the roof as well. I’m paranoid about rust. Slow and steady, and it went well. Again, thanks Hein for your help. Will post more photos when get the custom adapter just to finish this thread for anyone who finds themselves in a similar bind. Now, for some elbow grease to get the 4200 off.

 

I wonder why RV and trailer places use metal cutting shears to make their holes?

 

For what it's worth... Hammering the metal right against a dolly (on dolly) will stretch the metal by making it thinner. Hammering on a high spot with the dolly on the low spot (off dolly) with shrink the metal by making it thicker. If it were me, and this is the technique being used, I would place a dolly on a low spot (or on 2 low spots, bridging a high spot) and SLOWLY hammer the high spot down until it is flatish. This will be a slow process, but will eventually get it as flat as you want it. Remember if you hit the metal with a hammer when it is right against the dolly the metal will stretch (bad in this case).

As mentioned earlier, you could also use large C clamps and do the same thing. But I don't think (could be wrong) that you won't be able to get the last bits flat using C clamps.

There are lots of YouTube video on flattening metal with hammer and dollies if that is what you end up doing.

Good luck with the project and keep us informed with your progess.

 

First time poster. Long time reader. I'm converting a 2020 transit 148 WB HR EB. And right off the bat, I had an heart dropping mess up so now I'm dropping my pride and reaching out for help.

I cut the metal hole for the Maxxair fan 1/16 of an inch too small. At the time I only had a jig. So I tried to shave off the metal with the jig...and the photo below is what happened. Yes, I had a metal blade with 32 teeth. It looks like a kindergartener had some fun with power tools. What the photo doesn't do justice is how WARPED and bent the metal is along that line now. I stopped and hoped everything would be fine with enough butyl tape and lap sealant because I was only making it worse with the jig.

Because of the warped metal, Hein's adapter wasn't flush, and because of this, the 4200 marine adhesive didn't bond the adapter to the roof. I still went on ahead. Butyl'ed the flange to the adapter and screwed everything to a wood frame on the inside I made out of 2x2s. (I was vigilant about metal shavings, cleaning with alcohol, pilot holes, etc). Then A LOT of lap sealant.

Now I have a leak - dripping in one spot towards the warped metal. My fear is that because of how warped and messed up that metal is, I will ALWAYS deal with leaking. I think I should take it all apart and start all over again by smoothing out the metal with a grinder I now own, but I fear I will make it worse or start making the hole too big. And I would possibly have to drill more pilot holes adding to more spots for risk of leaking?

What should I do? Any helpful tips would be appreciated. (side note - the dome fan and all my windows went in well with no leaks and no kindergarten metal cuts so I learned?)

Thank you in advance for the help, Transit community.

View attachment 151924

Being a Sheetmetal guy by trade, I would suggest using malco hand seamers also sometimes referred to as tongs. I think you can get them in Home Depot now a days or Amazon. You can get a good squeeze on the metal with out beating the **** out of it.

 

It's perhaps too late for the OP, but for others, here's a pretty simple method from a pro:

Hat tip to @xeapoli from this post: Another Maxxair Fan Install Instructions

 

We are close to installing our Maxxair fan and thought of my experience of cutting through the sheet metal on my project car to access the fuel pump access plate on the fuel tank. After drilling a couple of corner holes, I used tin snips and it was remarkably easy and clean to cut a straight line through the sheet metal. Though at this point, I don't know how the transit roof sheet metal thickness compares to my car's sheetmetal. Will research it.

 

The square I just cut measures .035".

 

Finished the fan last week, and everything is great. No leaks after plenty of tests.

As posted before, sandwiched the bad metal cut with angle irons to stabilize it and guide the jig. Went well - photos are earlier in the thread. Primed and painted.

Received the custom exterior adapter from Hein, and it worked perfectly for the location and how forward the hole was. Pre-drilled the new drill holes for the new location. Adhered adapter to the roof with 4200 marine adhesive, also put a bead along the edge, and let it cure over night - sorry, no photos of just the adapter.

Next day, applied butyl to the recently cleaned flange. Applied to the top of the adapter and clamped. I attempted to line up Hein's interior adapter to the pre-drilled holes, and I couldn't. I ended up screwing in to the wood frame I kept from the first install, and I placed the fore to aft interior adapters along it and adhered them together (see photos).

Lap sealant, and done! Perfect and leak free. Installed a roof rack while at it that day....I do not recommend putting a roof rack on a high roof by yourself.

 

Nice recovery!!