EVC pop top crack repair thread,....can't find it.

[Tom Clark]

OK, acrylonitrile styrene acrylate. I’ve never worked with it, but if you can get epoxy, or some other viscous adhesive, to stick to it, a good repair could be made with unidirectional carbon fiber, which is very strong. Of course this would need to be painted.

The problem with filling the cracks I see represented in this thread, is it is not going to be a satisfactory repair in tension, which is a problem; the top flexes and the tops are stretched. Decades old plastic becomes brittle and parts.

With fiberglass boat hulls, we have made repairs of cracked hulls with tapered layering of high tensile strength cloth, carefully fairing and feathering the repair in preparation for gel coat or paint.

In the year 2025, small pieces of unidirectional carbon fiber cloth are remarkably inexpensive.
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2003 MV Weekender

[TheOneTrueQuux]

[Tom Clark]

Exactly what is the top made of? Is it fiberglass? If so, what kind?
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2003 MV Weekender

[kourt]

I think the way I have my solar panels mounted is keeping the top and its inner shell together. My panels are mounted with aluminum Z-brackets that are completely through-bolted to the roof. That's 16 bolts clamping the roof together.

In hindsight it would have been better to bolt some 72" Rhino Rack tracks to the track channels, also through bolted. That would have put a more continuous clamping force on the whole roof.

kourt

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2001 Eurovan Winnebago Camper

[Abscate]

Just one addition I didn’t see mentioned. Kourt drilled “ crack stopper” holes at the end of each crack of about 6mm diameter. This is critical as it dissipates the strain on the plastic from the crack into a circular force which lowers the crack propagation.

The hard part is making sure you find the end of the crack before you drill, inspect both sides!
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[tdibiker]

I was thinking the same thing with the aluminum box tubing and was going to see if I could find a piece that would fit in the track channel that I took a picture of.

After reading Helge's post, it made me realize that without bolting through and pulling the inside layer up to the outside tubing, it wouldn't help. His post made me realize that it's sagging because of 30 year old glue failing.

Currently, I'm trying to keep my inflatable mattress up top to help support the inside of the roof, but it probably isn't doing much.

I'm up for more exploration of this subject and it's going to continue to be a problem for all EVC owners. Let's hope for some solutions other than welding back together. Thanks for the dialogue!
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95 EVC 217k
03 EVMV 367k
04 Vista 89k
00 Jetta TDI 384k
07 Touareg V10 TDI 83k
97 F250 WVO 411k
00 996 Conv 180k
....and others

[kourt]

Reinforcement:

My first thought was to buy 7' of aluminum bar stock and use 3M VHB tape to attach it to the insides of the sides. However, those insides are very irregular in shape and would not accept the bar stock. You could stick it on the outsides of the sides of the top, or even in the track channels on the roof, but they would be exposed to elements.

I think your link to Helge's posts about refurbing his roof is very instructive.

I imagine I will do this same process: remove the top, carefully dismantle it, repair and readhere the two halves, and then have my top painted.

I think painting may be a good way to add a layer of protection against sun damage--meaning direct UV exposure.

kourt
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2001 Eurovan Winnebago Camper

[tdibiker]

Thanks for the thorough write-ups on these repairs. We are all likely going to need to do this as this plastic hits 30 years old and aging. My first small crack appeared about 5 years ago and has reecently grown and this year another larger crack showed up on the other side.

Fixing these cracks is obviously necessary, but I'm curious if there is a way that we can prevent them? It seems that the sagging is the cause of the cracking. I've seen some of the roofs sagging like and old horse. How do we prevent that? Is there a way to add some reinforcement inside or outside? Do we have to take the shell apart like this fella did? https://www.thesamba.com/vw/forum/viewtopic.php?p=9521373

Here's pics of mine;

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95 EVC 217k
03 EVMV 367k
04 Vista 89k
00 Jetta TDI 384k
07 Touareg V10 TDI 83k
97 F250 WVO 411k
00 996 Conv 180k
....and others

[bcolins]

Sorry to hear about your long crack Kourt, as usual,...l an excellent writeup. Your finished repair is far cleaner/smoother than mine. I didn’t get enough of the MA 300 in my valley to completely fill it either.

[kourt]

I was on a long drive from Bend, OR to Austin, TX and we camped one night in Utah at a very cold place. In the morning, with 20F air temps, the poptop on my EVC cracked when I closed it. It was a long crack--half the width of the top.

Time to do a big repair!

What you need:

Plexus MA300 adhesive with dispensing kit
Dremel tool
Dremel 125 High Speed Cutter
1/8" drill bit
rubbing alcohol
shop towels
blue masking tape
plastic scraper tool
Sharpie marker

Process:

Clear obstacles off the top and pull away the poptop seal in the affected area. Use alcohol and towels to clean the crack areas. Using the Sharpie, mark the ends of the cracks with a dot:

I used the Dremel with its router attachment to plunge a 1/8" drill bit into the top to terminate the cracks. You need only penetrate about 1/4" to 1/2". Be careful and feel for resistance to fall away as you get through the Luran plastic:

Mask off the crack areas and switch the Dremel bit to the 125 cutter:

Your goal here is to cut a V-channel in the Luran plastic along the length of the crack. The channel should be small--about 3MM. The Plexus Technical Data Sheet says that their adhesive does not want to see a gap much larger than 3mm.

The flat parts are easy to do safely with the router attachment. Set the bit depth for those parts to just 3MM or so below the router base.

For the insides of curves, extend the bit farther and keep one side of the router base in contact with the poptop, while freehanding the other side in the air carefully. Using this method, you can still have a lot of control with the Dremel and get a consistent depth cut:

The cuts should be narrow and shallow. Jagged is fine. Use a fingernail or a knife to clear loose plastic from the grooves:

The actual application of adhesive went far too rapidly to take photos, and you need to be prepared for this. Have all your tools ready.

You want to do all of your application, which is like using a caulk gun, at the same time. Do not fill one crack and then set down the applicator and scrape it down--that will result in a clogged applicator. The nozzle on the applicator is a single use affair--once you let it sit for 3-5 minutes, it's permanently blocked and you have to get a new one. Therefore, do all applications in one continuous effort.

Once the applications are done, carefully set the applicator down and away from your work surface and scrape the adhesive down neatly with your plastic scraper. Work quickly, as the Plexus adhesive will start to melt your plastic scraper. Just get it as flat as you can.

Set the scraper aside and remove your blue masking tape immediately, otherwise it will be permanently embedded. Again, you are working quickly here.

A trick I used years ago when repairing fiberglass boats was to immediately apply smooth, clear packing tape over wet epoxy. That usually imparted a more smooth, level finish and it let me use my hands to press the wet epoxy around. This reduces sanding time and effort. I tried that here, but by the time I had the tape on, the Plexus was set:

About an hour later, this is the finished product:

Lessons learned: stay on top of the little cracks on the edges of your poptop and you will be less likely to have the big surprises like I had.

I will now carry about 6' of RV roof tape to temporarily seal cracks in the future.

kourt
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2001 Eurovan Winnebago Camper

[bcolins]

[mikemtnbike]

The paint match is super close. I paid the piper and used paintscratch.com, a coat of their adhesion promoter, a coat of primer, couple coats of touch up paint, no clearcoat.

https://www.paintscratch.com/cgi-bin/order-form.cgi

EDIT: Looked at the picture again- you can see the break between the old paint and new paint, it's the straight (tape) line above the repair. I will be leaving directly to camping after work, won't be posting anything else until after the weekend. The touch-up actually matches the body better than the top, it's perfect to the body.
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1991 Vanagon GL 2.1 AT Westfauxlia. "Frankie" Totaled https://www.thesamba.com/vw/forum/viewtopic.php?t=764510&highlight=carnage
1995 Eurovan Camper "Marzivan"
2020 GTI SE manual

[bcolins]

Actually looks pretty good. I can't tell from your picture if all the white we are seeing in the pic is new paint,...or if it is both the original top and perfectly matching paint. Thinking it would be impossible to match the top perfectly or near perfectly...... any chance of another picture from further back so we can see how well the paint matched (or not). Also, what paint did you use?

Brian

[mikemtnbike]

I found a picture of the 4 inch crack pre paint, not totally sanded.

So, here's that.

As you can see, it's proud a little bit, but not much, and you can see what I mean by feathering out.

ANOTHER TIP: I used the plastic spatula that comes with a Bondo kit to push the Plexus into the crack after I made the v-shaped groove with the small dremel. This worked well. At the very edge, under the trim piece- it's only the ASA layer, no ABS interior. I also pushed the ASA in from the back at that edge.

And here's another pic of a painted and more sanded repair. I opted to leave more Plexus in place than worry about sanding as much as possible, one could probably get it to look better, I decided it was good enough.

I can grab a hold of the top next to the repairs and twist as hard as I can with two hands , no movement.
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1991 Vanagon GL 2.1 AT Westfauxlia. "Frankie" Totaled https://www.thesamba.com/vw/forum/viewtopic.php?t=764510&highlight=carnage
1995 Eurovan Camper "Marzivan"
2020 GTI SE manual

[bcolins]

Thanks Mike!

[mikemtnbike]

My recommendations are pretty simple for using this:

- I pulled the top tight using NRS straps around the exterior. Did it help? Don't know. But, I did it.

- The ASA is thin at the edges. Careful with the dremeling. I used a really small, really cheap, battery powered mini-tool off Amazon and the bulb-shaped small bit that came with it with good results.

- Used the same tool to drill small holes at the end of each crack. Using this small tool helped with control so I didn't punch through the ABS interior shell.

- Following the directions timing wise- as usual- is very important.

- You'll see posts that talk about it shrinking as it cures. That's true. I actually went with 3-4 coats, sanded lightly between, and feathered out. It stands a bit proud, but I painted with color match paint and it looks pretty good- way better than a crack.

I'll try to take a picture tomorrow, I don't like taking pictures while I work unfortunately.
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1991 Vanagon GL 2.1 AT Westfauxlia. "Frankie" Totaled https://www.thesamba.com/vw/forum/viewtopic.php?t=764510&highlight=carnage
1995 Eurovan Camper "Marzivan"
2020 GTI SE manual

[bcolins]

Hey Kourt,.. could we meet on a cool morning at your place for a top repair session? Happy to share the cost of the material.

[kourt]

Brian,

I've got a crack in my top as well. I've ordered a tube of the Plexus MA300. I won't need much of it, so perhaps you can buy my leftovers, if you're interested.

Kourt
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2001 Eurovan Winnebago Camper

[mikemtnbike]

Brian, you might be talking about me.

I repaired several cracks in the lower edge of my top using the methods outlined here:

https://forums.sailboatowners.com/threads/plastic-hunter-crack-repair.192123/page-2

The Hunter sailboats were made from the same ASA plastic used in the Winnebago tops and this was the dealer recommended repair.

This was well over a year ago and the repairs have been rock solid. The longest crack was about 4 inches, the others were all under 2 inches, some less than 1/2". The Plexus adhesive has a ridiculous shear strength rating of 3-4000 PSI. The product was hard to find, here's where I bought mine.

https://www.usplastic.com/search/?q=plexus

I think this is obvious, but I recommend this method. Sailboat dorks out-dork van dorks by many orders of dorkitude.
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1991 Vanagon GL 2.1 AT Westfauxlia. "Frankie" Totaled https://www.thesamba.com/vw/forum/viewtopic.php?t=764510&highlight=carnage
1995 Eurovan Camper "Marzivan"
2020 GTI SE manual

[OB Bus]

I could not find that magic "plastic".
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Larry in OB
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69 Westfalia and 2002 Eurovan Camper.
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