Tuesday, January 18, 2011

End Caps


There are two articles on end cap repair. The first discusses both early and later model end caps. The second concerns later model Lazy Days.

The Problem

Most LD owners have seen at least some separation of the end caps, the vertical corner pieces. This obviously can be a major problem in that it allows water infiltration that can cause significant damage. Over the years, the Mothership has made some changes in how the corner pieces are installed. Former LD owner Don McGlothen has thoroughly researched this problem and recently posted an updated report:

The following reflects my opinion and experience and is not posted to be anything but just that.
I've seen many ABS End Cap Molding adhesion failures at gatherings of Lazy Dazes, mostly on coaches over two years old. I've seen pre-2004 Mothership end cap repairs that had not failed and many that had. I've been told of a recent Mothership repair of the rear End Cap configurations that has the `joggled' overlap joint between the rear upper and rear lower End Cap sections; that repair also did not last. The overlap joint had been filled with sealant, which I've found leads to quick failure of upper End Cap adhesion. The reason appears to be that as the upper and lower End Cap sections expand thermally, the upper cap section 'rides up' over the overlap joint and over the sealant in that joint. This essentially lifts the upper End Cap away from the aluminum body side panels and the sealant that holds the end cap tight against the siding there fails.

Those of you with End Cap problems know that the ABS End Caps have come loose in other locations, particularly the lower parts of the both front and rear vertical End Caps. If let go long enough without repair, ABS End Caps will break. They are not strong enough to handle constant flutter in the breeze at 60 mph, or a snag on your St. Bernard's collar. The longer you wait to repair them, the more expensive your repair may be. The end cap sealant fails because of differential thermal expansion of the end cap material and the body siding, and, body flexing. 

Not all Lazy Daze End Caps are merely cosmetic, in some years production, they may protect unsealed wood structure. For some Lazy Daze built before 1999, the sealant may not have been applied to completely cover all the wood structure under the End Caps. If you have partially disbonded End Caps trying to protect unsealed wood, you may discover a wet wood problem fairly late in its development.
(Of course, if you never go where it rains, never wash your coach and your large dog is well trained, no problem.) I understand that later Lazy Daze (around 1999 to 2000 and on) have all their wood structure under the End Caps covered with a sealant. That should preclude developing a wet wood problem because of end cap disbonding. If you are in doubt about your earlier production Lazy Daze, ask the Mothership.

On our 2001 26.5' Lazy Daze MB the rear end cap sealant was still in good condition after over two years of service with `Big Stretch" sealant applied where the factory installed adhesives had failed - EXCEPT – In my second and successful repair, I removed all the sealant I could from the overlap joint of the rear end caps. My experience is that correctly applied Big Stretch sealant to attach failed areas of VHB tape attachment will provide at least several years of service without failure. On the other hand, my experience with Parlastic and other PR255 recommended sealants failed after a short time. They just don't appear to stretch enough before they stop holding hands.

There is really good news for the future. The Mothership this year has replaced activated VHB tape bonding of End Caps in their production with a new adhesive. This new adhesive shows real promise for very long life without disbonding but it takes special equipment to install it and it is not something you can do.

I believe the Mothership could use this new production adhesive to repair in-service coaches that have end cap disbonding problems. By carefully applying heat and skillfully wielding a putty knife, any partially disbonded VHB tape adhesive and the rest of its End Cap should be removable. After cleaning off the old adhesive, ABS end caps in good enough condition - or new ones if necessary - could be re-installed on your Lazy Daze using that new production adhesive. Since 2006, the Mothership has done these repairs for a price - ask them. New end caps are often part of this repair. It looks to me that this would result in an End Cap installation equivalent to current new production.

Summary:

I achieved a long-lasting repair of our 2001 partially disbonded ABS End Caps using edge sealing with locally available materials. It really was quite easy to do and I still don't understand why others with the condition don't just fix theirs themselves. End Cap adhesion stopped being a problem for me and it can for you as well.

Not fixing or having someone fix partially disbonded End Cap(s) will result in further disbonding and perhaps more serious trouble.

Repair
I used DAP 3.0 crystal clear sealant to seal the seams and the end caps.
It works well in applications where a white sealant would cosmetically be inappropriate. My preferred sealant is 3M's 5200 marine polyurethane but it is not available clear. Since the seams and end caps are painted in both white and the color of the motorhome, a clear sealant is required to look correct.

To get good penetration in the seams, I applied masking tape to both sides of the seams, leaving a 1/4" gap to expose the seam. A bead of the Dap 3.0 was applied to each seam and then forced into the seam using a gloved finger. The masking tape contains the excess sealant, leaving a clean surface when the tape is removed.

The end caps required a thicker bead that was also forced deep into the gap. Some sections of the rear end caps needed two applications to totally fill the wide gaps.

Proper preparation is needed to ensure that the sealant does its job.
The entire rig was wash and dried. Compressed air was used to blow out the seams and then left to completely dry. The end cap gaps were cleaned and scraped to removed any loose paint and old sealant and to provide a place for the sealant to be placed.

You could re-glue the cap and use screws to pull the cap back into place until the adhesive cures and then remove the screws. That might be a better solution since the caps often crack around the screws.
There is a lot of stress applied to the caps, both from the twisting and flexing that the body goes through while on the road, not to mention the thermal expansion and contraction forces. LD builds a strong body that stays that way unless the wood frame gets and stays wet, allowing rot to weaken the structure. Our responsibility is to make sure water does not get in.


Contributors: Don McGlothle, Larry Wade, WxToad

Revised: 12 Oct 13

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A Rehash of Sealing End Caps


Supplies:

Enough gloves

Blue tape

Acetone/MEK/lacquer thinner 

3M 5200FC

DAP 3.0 crystal clear sealant 

Razor knife

Toothbrush

Paper towels/Soft cloths (like tshirts) to remove 5200FC and DAP


Most of this content is by Larry Wade taken from several of his posts and emails. I have merged his words and mixed in my experience. While I wound up going in different directions from Larry, I would have never gotten anywhere without his guidance.


I am going to use the word solvent to mean acetone, lacquer thinner or MEK. I have a preference for MEK as it is designed to dissolve epoxy and does not affect the paint if wiped off. Acetone is reported to be able to remove the black paint from the window frames. MEK has much less smell than other solvents.


Prep

If you need to get above your head, put sawhorses or platforms in place before starting.


When using 3M 5200FC, wear old clothes and disposable gloves. The stuff sticks to everything and is very difficult to remove when dry, one of the reasons it works so well.


5200FC must be used in 24 hours of opening it.


Start the job wearing three pairs of disposable gloves. That way when a glove becomes contaminated, you can just peel it off and keep working.


Clean the gap to be filled. Cut away with a razor knife as much old sealant as possible. I found after scraping and cleaning with MEK that the solvent would dissolve some of the old sealant and allow more to be removed. I used a toothbrush soaked with a drop of MEK.

When done scraping, use solvent to clean the gap. Spray brake cleaner, a fast evaporating solvent, to blow out debris.


Now use blue masking tape on any place where you do not want the 5200FC.


Application


Larry Wade suggests applying an oversize bead of sealant along the gap to be filled the entire way and then use a gloved, wet finger to push the sealant firmly into the gap and then remove the excess and smooth the sealant. I found the 5200 to be too tacky for this to work for me. I did find that smoothing with a cut-up piece of t-shirt soaked with MEK smooths and cleans perfectly. I did the smoothing about 3 minutes after application. The difference is probably in technique, I have not seen how Larry does it.


As soon as you are done smoothing, remove the tape before it has a chance to start skimming over. When removing the blue tape, pull it gently toward the sealed seam, which minimizes the chances of "stringing" sealant onto the unsealed surface. [Thanks Joan] If there are spots where the sealant has spread, let it cure for about 45 minutes and then use a solvent to gently remove it. I found that MEK can be used right away to clean up


Joan uses craft sticks (popsicle sticks) rather than fingers for "pointing" the 5200 into the seam so she only needs a dozen or so glove changes rather than two dozen! I could not make this work for me. I cut the smallest opening in the 5200 applicator to make a thin bead this worked best for me. I just moved the applicator back and forth until the seam was filled.


I had been quite apprehensive about applying the 5200. It turned out to be easy to work with. I even filled some hairline cracks freehand - no tape. After a minute or so, I was able to wipe with MEK and the crack has disappeared. 



DAP 3.0 crystal clear sealant can be used for sections of the caps that are not white. [5200 only comes in white and black]

3M VViVid tape can be used to cover over the DAP. Unlike the 5200, I had problems with the DAP. It did not flow into narrow cracks, but rather stayed on top.


Have a cold one. Let it cure overnight.


OTHER LEAKS


The three-piece rear windows can leak if the rubber around the glass shrinks. The fix is the application of a thin clear silicone around the perimeter of each piece of glass. Larry Wade suggests Permatex 81730 Flowable Silicone Windshield And Glass Sealer, 1.5 Oz  This is good stuff and easy to work with. My gasket was compressed and I was able to fill the four-inch depression without removing the window.





You can see a slight compression of the gasket. Enough to allow a few drops to enter every time there was significant rain.



The external seal around the perimeter of the window frames shrinks with age and can cause the seal to pull back and leak. Resealing the perimeter of the frame with Black 5200 FC is Larry’s fix.



I had a leak from the ceiling over the entry door. Larry recalled that I had replaced the AC two years ago. He noted that a major cause of roof leaks is the A/ C as the gaskets can compress and need retightening. I pulled the interior cover and tightened the bolts four turns. I put a hose on the AC and after 30 minutes no water was noted. Well done Mr. Wade.


Contributors: Larry Wade, Don Malpas

Revised: 19 Oct 20


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