DIY Window Flare

Midwestdrifter

Engineer In Residence
Greetings,

I am currently in the early stages of building out a 140” T1N. Since my design is dependent on the left-right oriented bed (I am 6’ 1”) I am starting with a custom made window flare.
Flare Space http://www.flarespace.com/ offers window flares, but for NCV3 body styles only. I have not seen anyone attempt to make of these from scratch… So here goes! :bounce:


The sprinter is approximately 73 inches window to window (at the lowest point). In order to have room for insulation and about 74inches of sleeping room, the flare will need to be at least 4 inches deep. The final dimensions I decided on are 48” wide by 22.75” high by 4.5” deep.
I thought through several fabrication methods and decided to attempt a one-off fiberglass part. This method seemed best given the curvature of the sprinters window openings.

I am essentially creating a plug on the side of the van, and then doing the layup in place.

My plan is as follows.
1. Build up plug out of polyurethane foam (pink stuff from Home Depot)
2. Remove foam to create desired shape.
3. Coat plug with drywall compound, sand smooth, paint for mold release.
4. Layup fiberglass on plug and van skin.
5. Remove part from plug/van trim edges and finish as necessary.

To date I have finished the foam base and started apply the drywall compound. I have ordered a selection of fiberglass materials; several kinds of fabric and chopped mat, as well as some polyester resin. I have limited experience with fiberglass, so any advice is welcome!
 

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chromisdesigns

New member
Plan on using a LOT of fairing compound, sandpaper, and time to get a smooth surface without
Taking a mold from your plug first and laying up into the mold. You also won't have a gel coat finish, so will need to paint after fairing. Lastly, get some PVA to spray over your last coat of resin on the outside so it will cure properly.

In case you were not aware, don't do the layup with finishing resin, which contains wax. That's only for top coating, but PVA works better in any case. For laminating you want the wax-free stuff.

If you are depending on the resin to glue the bump out moldings to the van sides you might want to consider epoxy over polyester, which does not adhere all that well to metal.

Added -- read the OP again, appears you will remove the molded part and fasten it mechanically -- best idea. In that case don't forget to use mold release on the van and plug! I'd wax the van first as well. Peel-ply or similar material on surface of plug a good idea as well. And be sure to taper the plug sides enough to get a good release.
 
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Midwestdrifter

Engineer In Residence
Plan on using a LOT of fairing compound, sandpaper, and time to get a smooth surface without
Taking a mold from your plug first and laying up into the mold. You also won't have a gel coat finish, so will need to paint after fairing. Lastly, get some PVA to spray over your last coat of resin on the outside so it will cure properly.

In case you were not aware, don't do the layup with finishing resin, which contains wax. That's only for top coating, but PVA works better in any case. For laminating you want the wax-free stuff.

If you are depending on the resin to glue the bump out moldings to the van sides you might want to consider epoxy over polyester, which does not adhere all that well to metal.

Added -- read the OP again, appears you will remove the molded part and fasten it mechanically -- best idea. In that case don't forget to use mold release on the van and plug! I'd wax the van first as well. Peel-ply or similar material on surface of plug a good idea as well. And be sure to taper the plug sides enough to get a good release.
Thanks for the feedback, it will probably save me plenty of time later on. :cheers:

I do plan on using peel-ply, and doing a full fair and finish on the outside. I also have wax free resin for the layup. Do I need to add a tack-free agent to my final layer? Since I will be finishing the surface, I thought I didn't?

Are you suggesting I use peel-ply on the plug before the layup? I was concerned that it might be hard to remove from the glass depending on how much resin bleeds through.

Thanks for the tip on the PVA, I didn't realize I needed to coat the exterior during curing. I will get some on order ASAP. :thumbup:
 

chromisdesigns

New member
Thanks for the feedback, it will probably save me plenty of time later on. :cheers:

I do plan on using peel-ply, and doing a full fair and finish on the outside. I also have wax free resin for the layup. Do I need to add a tack-free agent to my final layer? Since I will be finishing the surface, I thought I didn't?

Are you suggesting I use peel-ply on the plug before the layup? I was concerned that it might be hard to remove from the glass depending on how much resin bleeds through.

Thanks for the tip on the PVA, I didn't realize I needed to coat the exterior during curing. I will get some on order ASAP. :thumbup:
The PVA will work same as tack-free additive.

Resin won't really adhere much to the peel-ply, especially if you spray it with mold release. In any case it will be easier than if you get adhesion to the plug itself.
 

Cole

OUTLAW SPRINTER!!!
I've thought about this quite a bit.

Would like to just toss out an idea or two on the topic in general if you don't mind?


I've considered just making essentially a bolt on spacers that bolts on just like the stock windows would. Then on the outside you could either bolt on a steel skin or a window.

You could shape the spacer to give a angled contour for looks/aerodynamics. etc.

You could easily put insulated curtains up or use the fancy double pane windows.(or both) for insulation on cold nights. But the rest of the time you could have windows if you like.
 

hein

Van Guru
Cool project. You are probably not done shaping your plug so have a suggestion. Taper the sides and especially the top. Looks like you have an area along the top edge that might pool water.
 

Midwestdrifter

Engineer In Residence
I've thought about this quite a bit.

Would like to just toss out an idea or two on the topic in general if you don't mind?


I've considered just making essentially a bolt on spacers that bolts on just like the stock windows would. Then on the outside you could either bolt on a steel skin or a window.

You could shape the spacer to give a angled contour for looks/aerodynamics. etc.

You could easily put insulated curtains up or use the fancy double pane windows.(or both) for insulation on cold nights. But the rest of the time you could have windows if you like.
I am having a bit of trouble visualizing these spacers. Do you mean something to change the curved opening to a flat/plane one?

I considered several other options for making the flare. My first choice was to have a local fab shop bend/weld up a box with mounting flanges. However, the curvature of the window cut outs (in the cross section) made that option unworkable. This curvature makes fabricating matching parts much more difficult. :thinking:

Cool project. You are probably not done shaping your plug so have a suggestion. Taper the sides and especially the top. Looks like you have an area along the top edge that might pool water.
Thanks Hein, your are right that area might collect some water. I do plan on having a flange where the fiberglass meets the van skin. I should fill that area in some more to prevent water retention.

I plan on using some fasteners to attach the flare, but I would also like to use a structural adhesive. Any suggestions on what to use?
 

Cole

OUTLAW SPRINTER!!!
I am having a bit of trouble visualizing these spacers. Do you mean something to change the curved opening to a flat/plane one?

Basically just a big flange that mounts to the body just like the stock windows do. Using the same mounting surface as a window would.

It would fit in the recessed window cutout surface, whatever that is 2" wide? Then just follow it around.

You could then essentially mount a factory style bolt in window to it with long bolts. (probably not the ideal solution but give an idea of what I'm talking about). Or, mount some other material to it. If it had a lip on the outside edge you could even mount the factory sheet metal you cut out of the van to make the opening.


Maybe just think of it as a 4" thick window gasket:lol: The neat thing is if you make them in 1-2" stackable versions you could customize the width.
 
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hein

Van Guru
I plan on using some fasteners to attach the flare, but I would also like to use a structural adhesive. Any suggestions on what to use?
Not sure I would use fasteners. Window weld or VHB tape would work and then seal the weather edge with Dicor or equivalent.
 

Badroadcamper

Precision engineer
Another possibility is to have a shop to weld a box in aluminium (or steele)-. Then cut the sides so it follows the curve over the window cutout. When it fits, you have a one inch flange welded on the edge.

Then cut a hole in the van and fit the box from inside with, for instance SikaTack car glass glue or if the box is made of Steele, spot weld it on.

At last give it a strip of Sikaflex.

I hope this make sense. I´s a bit difficult for me to explain in English
 

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K-9 SPRINTER

Well-known member
you should check up on the law


with that much of an overhang , you may be required to have Dually lights added (the amber and red lights, required on the wheel wells of vehicle's that have the dual wheel sticking out past the body. you see them mainly on pickups with dual wheels)
 
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Midwestdrifter

Engineer In Residence
Another possibility is to have a shop to weld a box in aluminium (or steele)-. Then cut the sides so it follows the curve over the window cutout. When it fits, you have a one inch flange welded on the edge.

Then cut a hole in the van and fit the box from inside with, for instance SikaTack car glass glue or if the box is made of Steele, spot weld it on.

At last give it a strip of Sikaflex.

I hope this make sense. I´s a bit difficult for me to explain in English
I understand, your description is good. :thumbup:

Thanks for the information, I may end up going the sheet metal route depending on my fiberglass work goes. I made a few mistakes during my layup, and I may need to start over. I am much more comfortable fabricating metal, but I enjoy trying new things.

My plan was to do 2-3 layers of FG and then remove from the plug for the remainder of the work (it is getting cold here). During my second layer I must have mis-measured the catalyst, because the resin started gelling after about 10 minutes. Thus the second layer has a number of voids. No big deal I thought, I have plenty more FG and resin, I will just start over...

The primer I used on my plug was water based, I was stupid and didn't test the PVA release agent. Apparently PVA adheres to water based paint? The result is that the layup seems to be stuck to the plug. :frown: There probably wont be enough warm days left in the year for me to start over with a new plug, I will post if I have any luck removing the part.

Lessons Learned
1. I should have used an Epoxy Resin with a longer work time. I also should have tested my plug surface for release prior to the layup.

2. I should have done a better job waxing as well.

3. Wetting out FG on a vertical surface is difficult.

4. Nitrile gloves dissolve when exposed to polyester resin.

5. Work in smaller areas. I would have been better off using smaller FG cloth sections, and slowly covering the plug, working with 35x60" sheets can be hard in the wind...

I will post up some pictures of my failure when I get home.
 

220629

Well-known member
It's a DOT Federal standard which kicks in at 80" wide or over. Under that you're fine.

Technically, if you exceed that, at minimum you need the 3 red lights rear bar. You'll likely need side clearance lights at the widest points also.

As a practical matter if you don't exceed the width of your mirrors then nobody will notice.

vic
 
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Badroadcamper

Precision engineer
Sorry, I cant advise you in fiberglass work. My experience with that, is limited to glassing a new bulkhead in a sea kayak. I have never worked with fiberglass on plugs.

But yes, you need thick rubber gloves for working with polyester and especially with epoxy...dangerous stuff. It goes right thru regular thin rubber gloves in minutes.
 

chromisdesigns

New member
I understand, your description is good. :thumbup:

Thanks for the information, I may end up going the sheet metal route depending on my fiberglass work goes. I made a few mistakes during my layup, and I may need to start over. I am much more comfortable fabricating metal, but I enjoy trying new things.

My plan was to do 2-3 layers of FG and then remove from the plug for the remainder of the work (it is getting cold here). During my second layer I must have mis-measured the catalyst, because the resin started gelling after about 10 minutes. Thus the second layer has a number of voids. No big deal I thought, I have plenty more FG and resin, I will just start over...

The primer I used on my plug was water based, I was stupid and didn't test the PVA release agent. Apparently PVA adheres to water based paint? The result is that the layup seems to be stuck to the plug. :frown: There probably wont be enough warm days left in the year for me to start over with a new plug, I will post if I have any luck removing the part.

Lessons Learned
1. I should have used an Epoxy Resin with a longer work time. I also should have tested my plug surface for release prior to the layup.

2. I should have done a better job waxing as well.

3. Wetting out FG on a vertical surface is difficult.

4. Nitrile gloves dissolve when exposed to polyester resin.

5. Work in smaller areas. I would have been better off using smaller FG cloth sections, and slowly covering the plug, working with 35x60" sheets can be hard in the wind...

I will post up some pictures of my failure when I get home.
Oops...PVA is not a release agent, it's for sealing the last layer to allow it to cure, in place of using tack-free resin. You coat the plug or mold with release agent, lay up the laminate, then spray PVA on the outer surface.
 

Midwestdrifter

Engineer In Residence
Oops...PVA is not a release agent, it's for sealing the last layer to allow it to cure, in place of using tack-free resin. You coat the plug or mold with release agent, lay up the laminate, then spray PVA on the outer surface.
In the past (8 or 9 years ago) I used PVA on hard painted surfaces with decent success. On this project the PVA worked great on the van itself (peeled right off the OEM paint), but it seems to have fused with the paint/hard wax I used on the plug. It made sense once I read the PVA bottle, lots of alcohol as a solvent, which is what the paint suggests for cleanup...

I now realize I should have used a soft wax prior to applying the FG. :professor:

If I decide I can fix the voids in this layup, I may just pour some acetone behind the plug to dissolve the foam. I am going to need a gallon of fairing compound I suspect. :shifty:
 

d_bertko

Active member
I think that permanent flares are justifiably unpopular. They are obnoxious in parking lots and add road wind resistance when you're unlikely to be using them as a bed extension.

I would instead put a movable extension on one side only and deploy it only when sleeping in camp. The simplest implementation would be a large hinged window that would open to allow an insulated hardshell to extend out in camp. A standard Sprinter cargo area window adapted to a hinge would satisfy the opening dimensions nicely.

Just my 2 cents.

Sorry to offer criticism so far into your project. Not all of us need year-round bed structures and I was just thinking out-of-the-box. Feel free to disregard if it doesn't fit your needs.

Dan
 

Midwestdrifter

Engineer In Residence
Here are some photos. The first is of the bare plug with PVA (green stuff).

The second and third are with 2 layers of FG. I started with 3/4oz mat. The second layer is a middle weight woven roving. You can see that the WR sagged on the bottom edge.

I will need a couple hours on the weekend to see if I can salvage this part. I was considering grinding down the high spots, and vacuum bagging a layer of 1.5oz mat (once I get this mess off the plug).
 

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Cole

OUTLAW SPRINTER!!!
Curious why you didn't expand this to fill in the window cut out? Seems like a space that could have been gained and a ridge in the body line that could have been filled.
 

Midwestdrifter

Engineer In Residence
I think that permanent flares are justifiably unpopular. They are obnoxious in parking lots and add road wind resistance when you're unlikely to be using them as a bed extension.

I would instead put a movable extension on one side only and deploy it only when sleeping in camp. The simplest implementation would be a large hinged window that would open to allow an insulated hardshell to extend out in camp. A standard Sprinter cargo area window adapted to a hinge would satisfy the opening dimensions nicely.

Just my 2 cents.

Sorry to offer criticism so far into your project. Not all of us need year-round bed structures and I was just thinking out-of-the-box. Feel free to disregard if it doesn't fit your needs.

Dan
I welcome any reasonable discussion. :thumbup:

A deployable extension is not a bad idea. But making something custom that will seal well (dust and water) adds a bit of complexity. We often camp in rainy and adverse conditions which would require a hard shell type unit. The other issue is storage for the shell inside the van (definitely a space eater).

When we travel, we are usually on the move every other day, (the van is our primary transportation when we are on the road). Our philosophy is that setting up camp should take less than 10 minutes, and should be doable in adverse conditions. Our last road-trip took us from Alaska to Panama. So we saw a lot of different weather and camping locations. Everything for freezing mountain tops, to street-side camping in busy cities.

As for the added wind resistance; the cross sectional area of the flare is less than 1 square foot. I suspect my fuel economy would change less than 2%. I can post some numbers once I get something installed.

As for parking; I did some driving with the plug installed. Due to its height it easily clears most cars and small SUVs. It sticks out less than the mirrors do. It doesn't even obscure my side-view mirror! :rad: Honestly this is a very small protrusion (48”x22.75”x4.5”) and because I am following the vans profile, it sticks out about 3" total at the top edge.
 
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