Teardrops n Tiny Travel Trailers

I recently discovered that my plastic hatch hinge has failed and am passing along my experience as an FYI.

The hinge was installed Aug. 2011 and the Dewey Diner rolled out of the shop in Sept. 2011. She has been garaged 70% of her life in Oklahoma and covered with a tarp during rain or snow. The hatch has not been raised when temps were below 30 deg. F., therefore...I don't think the failure is cold weather related. The base layer doubled red oak spars were layered with epoxy resin coated plywood, then a layer of butyl tape and then the hinge. Aluminum bolsters were installed on each side of the hinge for the entire length of the hinge. Screw interval is 2 or 3 inches, can't remember now for sure. Transverse cedar strips on the roof were covered in fiberglass tape and epoxy resin with a slight overlap onto the uppermost aluminum bolster. The gap between the bolsters was approx. 1/8", just enough so that they didn't rub on each other when the hatch was opened. A thin strip of ribbed EPDM weatherstripping was secured from below to the roof spar and is pinched by the hatch spar when the hatch closes... back-up.

The hatch is big and heavy. 78" W x 66" H and consists of doubled 3/4" ply ribs on the sides and 3 mid-ribs. It is covered in a layer of black gloss paint which was later scuffed for application of Titebond II and canvas. The usual hardware (taillights, license plate bracket and light, hatch handle). I apologize, I don't have an exact weight on it.

I think it is worth noting that the hinge split mid-span. In other words, the separation didn't begin on one end and then travel. There are no protruding screw threads, etc. that contacted the hinge. It's as if a razor knife were inserted into the tiny gap from above and then sliced open for about 20 inches. This is the most puzzling aspect, the mid=span separation/rip. I have no idea what might have caused extra stress in that particular area.

The plan is to remove bolsters, hinge and butyl and replace with a piano hinge bedded in butyl, fit into a small slot under upper glassed cedar and cover with a strip of commercial roofing membrane. Suggestions/advice are welcomed but my intent of this post is merely to convey my own personal experience with the plastic hinge. I can find no other reports of failures but may have missed something.

Lastly, it's important to know the exact product I used. However, I have a bit of hesitancy as I don't want this report to reflect negatively on the supplier. I ordered many items from him and was very pleased with the products, service and advice during phone conversations. Other suppliers may carry an identical product, I'm not sure. The hinge is black, some type of plastic, has a "flex" depression in the middle and can be ordered by the foot.

My conclusion is that my large/heavy hatch exceeded the limits of the hinge. In addition, I'm unable to keep the hatch perfectly in alignment when raising it, holding with one hand and positioning the props with the other hand. There is an albeit slight bit of flex/wiggle. I'm in the process of debulking the hatch to address that issue.... I"m not getting any younger.

I'd be happy to answer any questions, suggestions are always welcomed. Thank you.

I could see if it was not perfectly parallel
when closed, it could put stress in the center.
Imagine looking at it from the rear when it
is closed.
Now picture a slight bow, high in the middle
low on the ends.
It wouldn't take much. 0.020 inch would be quite a
bit. (about 1/64 of an inch)
As well fastened as it is to the mating surfaces,
there would be no wiggle room.
I can picture it trying to rub against itself, or
pinching the center.
Forcing the center of the hinge against itself.
If that makes any sense.

Where as a piano hinge has the little bit
of play in it, and the lugs the pins fit through
to support those same forces.
I could be all wet too.
I have looked at these hinges and considered
them for doors. I have a hard time convincing
myself to use them.
A door is another animal all together though.

You have a pretty major repair on your hands.
I hate to see it, but good luck.

Thanks for your reply and ideas. I think you may have hit on the problem. I was reviewing my build thread tonight and was reminded that I did have some spar flex that I attempted to address, maybe should have opted for steel! I wouldn't hesitate using a plastic hinge on doors or compartment hatches, it works well and is also the most reasonably priced. The 78" length I required for the hatch put me in the "custom length" category as far as hurricane or standard piano hinges go and I wasn't willing to sell a kidney for one. I used one of the salvaged piano hinges from a pop-up camper flip-out bed platform on my door, works great. Glad I saved the other one. The mounting flange is wide and the hinge is beefy, I'm thinking it'll do the trick. As of sunset the old hinge, bolsters and butyl are now gone, the area prepped and ready for the new hinge. Plan to do the bulk of the new install tomorrow. Thanks for your encouragement.

Both of my tears have the plastic hinge, one is 5 years old now and sirs outside year round, it has been opened in the winter at below zero temps with no issues.
Of course both of my hatches are very lightweight and straight.

I wonder if the seals sprang the outside edges of the hatch up causing flex in the middle (as opposed to the opposite theory).

Is there any way to re-cut the edge & install a regular hurricane hinge? It needs about a 3/8" slot to drop into between the spars, but get a chunk & look at it first, depends on the type you find. It costs a bit more to use, but is a permanent solution to the problem.

We live in the desert & a plastic hinge would be done in no time here. The sun just eats this stuff. I just can't see a plastic hinge holding up a heavy hatch for any length of time & not having trouble sooner or later.

Gary,

I'm sorry to hear about your experience with the plastic hinge. I think your post is great information about a real world situation and you gave a fair assessment. It sounds like you've almost finished a repair. Congratulations!

Say hi to Dewey for me.

Take care,
Tom

KCStudly wrote:I wonder if the seals sprang the outside edges of the hatch up causing flex in the middle (as opposed to the opposite theory).

Don't see too many seals around here. Walrus either.

The second picture is a view of roughly 1/3 of the hatch span, curbside is to the right. I don't understand what would cause an offset flex that led to failure. Mid-span maybe, but offset that didn't originate at the end and travel??

Gremlins. Maybe it was stealth seals, or Seal seals.

noseoil wrote:Is there any way to re-cut the edge & install a regular hurricane hinge?

The piano hinge I plan on using is much stouter than any hurricane hinge I've seen. Not the flimsy ones carried in the big box stores. It's bomb-proof. It originally supported "old-style, REAL, heavy, 3/4" plywood" for a full-sized bed for a pop-up camper. Maybe there are variations but all hurricane's I've had on alum camper shells were much, much weaker in comparison and suffer from alum. on alum. abrasion... by design. Bottom line: By using the piano hinge I don't have to modify the existing spars, installation is much simpler and can be done today, I don't have to bend over on the cost of a custom length hinge with exhorbitant packing and shipping charges and wait for shipping.... but, most importantly I have full faith in the hinge.

I'm glad you're happy with yours, thanks for your comments.

aggie79 wrote:Gary,

I'm sorry to hear about your experience with the plastic hinge. I think your post is great information about a real world situation and you gave a fair assessment. It sounds like you've almost finished a repair. Congratulations!

Say hi to Dewey for me.

Take care,
Tom

Thanks, Tom.

Just another little bump, no biggie. Having problems with Red (93 F150) so Beavers Bend is a no go. The Dew and I were really looking forward to seeing you, Linda and the rest. Missing that trip hurts more, much more than the hatch problem.

noseoil wrote:We live in the desert & a plastic hinge would be done in no time here.

You lost me there. Please describe a door or galley hinge application that exposes the hinge to UV for any significant length of time.

Way too cheap for those specialty hinges I have always used good old Stanley door hinges of one type or the other

Then simply cover with epdm rubber


no leaks no errors no failures. They should outlive me !

We have to deal with heat & sun most of the year in Tucson. Temperatures can range from 25 in the winter to 110 in summer. That 110 is the air temperature. Add heating from the sun & cars get up to 140 on a hot day inside, with the windows closed. You have to be careful grabbing the steering wheel here on some days. Just saying that heat can be a big factor where we live when it comes to plastic anything. Dash boards crack pretty quickly, unless protected with a dash mat.

Camping in very cold weather could also be a problem over time. Opening a hinge when it's really cold could cause cracking to happen faster.

I just think a plastic hinge isn't a good idea (especially here in Tucson) if the trailer has to be stored outside all year, like ours is. Metal will never fail, unless something goes very wrong. I can see paying less for the plastic hinge because of a budget, but to me it's just something which will have to be replaced sooner or later anyway, so metal just makes more sense. Just my $.02 worth....

Bob, It is called frugal.
I use strap hinges with aluminum flashing bend down into the seam. Like a upside down W. The flashing is UV proof and the bend make for very little flexing.