Fiberglass and door hinges on '75 Trillium 1300

[Kelly H]

The door more or less fell off. My husband tried to put larger screws in as a stop gap, but I think the fiberglass is too badly damaged. Would a body shop be able to fix this? Could we bondo it over and then drill new holes? We are absolutely clueless when it comes to fiberglass repairs.

[brendadave]

I used JB Weld putty stick, it was either the steelstik or plasticweld, I would have to check and see if I have any left. Worked well, set fast. Cleaned out holes best I could, the filled with putty, used a knife shortly after to remove excess and make it smooth, pre-drilled the holes, then while still a little soft put the screws in gently so that it would have nice threads when it hardened. Let it sit a couple of hours and put the door back on. Did that last year (or year before) to our '76 Trillium, still holding strong.

[Raz]

I have a newer Trillium but it was made using the original molds. I had to reset my hinges. Most original Trilliums have a piece of wood inside to hold the screws. After time it rots. You might find my solution useful. Raz

http://www.fiberglassrv.com/forums/f...air-47624.html

[ckayaker]

I did the exact same repair and so far, so good. One thing I wasn't sufficiently careful about was making the sure the door was properly aligned before I drilled the holes for the hinges. The door sags slightly (it did before the repair), so when I get the chance I will redo the fix, this time taping the door in place perfectly and then drilling the holes!

[David Tilston]

Here is what I did:

Typically the hinge pulls out of the trailer side, and stays on the door side OK. I would pull the screws on the door side. leave the hinges on the trailer side.

Clean out the area around the screw holes, then stuff as much fibreglass and resin into that area as possible. Fill up the post beside the door. Sand smooth, then paint.

Tape the door back in place, you should have an even gap all the way around. Use the hinges, which are still attached to the door, as a drilling guide for the new holes. The size of holes will be determined by the screws you purchase. Fibreglass will crack if you use screws that are too big for the holes. When you put the screws in mix up some more resin and stuff some glass, soaked in resin, in the screw holes. Then screw in your NEW screws. Once that sets, repeat on the screws in the door. You should not need to repair the door. Just stuff in some glass and resin, then put the screws in. Again, use new screws. I bought stainless screws.

The screws in the door are quite short. To get the correct screws, Pull one screw from both the door side, and the trailer side and take them to a specialty fastener shop. I went to Calgary Fasteners. A box of screws cost as much as 4 or five from Home Depot.

For the next door I do, I am contemplating making a metal bracket with threaded inserts pressed in. This would be inserted on the inside of the fibreglass using a biscuit tool to cut a gap at the hinges, or maybe a larger gap at one hinge, and work the bracket up to the other hinge. Then using machine screws pull the bracket tight in and then once again fill the area with fibreglass and resin. Once it sets, I will pull the machine screws out and put the door back on with the same machine screws. I expect that the fibreglass and resin that I stuff in the support post will hold the bracket in place.

BTW, P. Raz's link is awesome!

[getaway1]

Hello I just fixed my Trillium door by drilling out the holes to 3/16" and inserting a wooden dowel coated with 5 minute epoxy. cut the dowel flush once the epoxy is set. drill a small pilot hole for the "new " screws. You can do both the door and trailer body this way. Use stainless screws if you can find them. This will keep the rust stains away. Good luck and take your time aligning the door. do it once, do it right !

[Kelly H]

Hubby went today and bought JB Weld, but we have our first hiccup. I'm guessing the hinge disassembles in some way? How do you get the pin out (and subsequently back in)? We can't remove the top screw on the trailer side off because the pin is in the way.

[brendadave]

Just use a hammer and a nail or something like that and tap up from bottom, only needs to move about 4mm before pin is loose.

Sent from my Nexus 4 using Fiberglass RV mobile app

[Raz]

I suspect if the wood is rotten JB Weld will only provide a temporary fix.

Be aware that it is not possible to align the raised band on the door with the raised band on the trailer. The misalignment is in the molds and wasn't corrected until 2011.

To disassemble the hinge tap from the bottom with a punch as suggested. Here's a picture. Note the washers. Raz

[ckayaker]

I did this repair about three years ago, but this thread got me thinking. I had a look at the hinges yesterday to see how they were doing and discovered several of the stainless screws had loosened with time, vibration etc! I tightened them in again, but will think of doing something more when I get home...

[lamimartin]

Originally Posted by ckayaker

I did this repair about three years ago, but this thread got me thinking. I had a look at the hinges yesterday to see how they were doing and discovered several of the stainless screws had loosened with time, vibration etc! I tightened them in again, but will think of doing something more when I get home...

This problem can be patched up or cured. In my humble opinion, the best permanent repair would be a metal plate behind the fiberglass which is the typical way to assemble critical parts on a sailboat. You may think using stainless steel all the way will be a permanent cure... not necessarly. On this link, you will see that in a wet environment, without air, stainless steel rots too!
brokenchainplate.jpg Photo by lamimartin | Photobucket

There are a few mistakes to avoid:

1-Galvanic corrosion: https://en.wikipedia.org/wiki/Galvanic_corrosion
Two different metals or alloys in contact will provoke an accelerated chemical reaction in a wet environment. In order to reduce the chances of premature corrosion, it is wise to check for compatible metals (Galvanic and Corrosion Compatibility Dissimilar Metal Corrosion - Engineers Edge) and to eliminate the direct contact between the fastener and the holding plate by using plastic washers or spacers.
2-Stainless steel anaerobic corrosion: in presence of salt and water, without air, stainless steel will rot over time. Stainless, like aluminium, is protected from corrosion by a coat of oxide on metal surface. Without air, in presence of water, the protective effect of this oxide coat is compromised. On a Trillium, salt and water is easy to prevent by using high quality butyl tape behind hinges to seal the stainless steel fasteners without clogging the threads. Using silicone may clog the threads and cause the SS bolt to snap as it jams into the locking nut behind the plate.
3-Vibration, as you point out will likely compromise any screws holding only in thin plastic, unless you use very high quality epoxy and large diameter and coarse thread ... and even so. Without a holding plate behind this is a risky solution. The hinges holes are very small, the weight, heat and vibrations is substantial. The fiberglass shell is thin and remains flexible. In order to make a permanent solution, I think the illustrated srtategy (opening a cut and inserting a holding plate is the way to go. Remember that epoxy is six times stronger than polyester resin for repairs, because it has a much stronger chemical bound, but without fibers, epoxy is not very strong unless it is confined into a cavity.

I've been inspired by my sailboat repairs, and I'm about to make the same repair on my trillium, thanks for inspiration !

[Anne MP]

Hello everyone. My 74 Trillium has a door that is beginning to sag. This is an awesome thread, though daunting.
Thanks

[lamimartin]

In case you are interested to see more technical pictures, here are a few web sites that show how to properly seal hardware on fiberglass using stainless steel fasteners and BUTYL, (not silicone): It is no surprise to most of us who had to reseal RV windows. Butyl tape is the best permanent sealant for bedding RV window frames and most hardware. Such logic even finds it way into the ultra conservative sailing community.

The Most Controversial Article You'll Ever Read About Bedding Deck Hardware - Messing About In Sailboats
Windtraveler: Bedding with Butyl Tape
VIDEO:
Bedding Deck Hardware Using Through Bolts & Butyl Video

Of course, as you can see behind Kelly's hinges pictures (or mine), some structural and cosmetic repair is needed in order to make sure fiberglass will hold and look perfect. If any structural repairs are needed, I strongly suggest to use marine epoxy with fiber such as Interlux watertite or West System Epiglass with woven fiber. Don't forget prior cleaning with Interlux Solvent Wash 202 that will remove any wax residue and increase the chemical bound on old fiberglass. On old fiberglass, structural repairs should NOT be done with polyester resin, which will likely delaminate under stress. Epoxy 5 minutes does not contain fibers, so it will split under stress too.

Body shops crews are great for cosmetic repairs on cars, but for structural repairs that are looking perfect too, guys trained for marine repairs are far better. On a sailboat, there is a basic rule: anything structural or under the waterline repair is to be done with epoxy. Polyester resin is used to build brand new hulls, but then only for cosmetic repairs on old fiberglass. On small pieces Polyester resin patch may still do fine when it is overbuilt (and heavier), but it will never match light and rugged epoxy/fiber repair.

I hope my little marine repair experience will inspire you all if you dare to repair your own Trilium sagging doors and loose hinges. It is not difficult to do with a multitool for quick and chirurgical precision cuts. Even if you only fix the structural problem and get a body shop assistance for the paint/gelcoat restoration, this will save you a lot of money.

Good luck !

Martin

[David Tilston]

It should be noted that while epoxy itself may be stronger, then polyester resin, most of the strength is in the glass. Many people from a boating background recommend epoxy. But there are problems with epoxy. Mainly the cost, and that only epoxy sticks to it. Our trailers were built with polyester resin, and that is what I use when doing fibreglass work. Epoxy is just not necessary.

[lamimartin]

Originally Posted by David Tilston

It should be noted that while epoxy itself may be stronger, then polyester resin, most of the strength is in the glass. Many people from a boating background recommend epoxy. But there are problems with epoxy. Mainly the cost, and that only epoxy sticks to it. Our trailers were built with polyester resin, and that is what I use when doing fibreglass work. Epoxy is just not necessary.

I must say that the main problem is that polyester resin has a very poor adhesive power over cured fiberglass It is strictly a mechanical, not a chemical bounding. It must also be understood that waxless gelcoat would not cure in presence of air, so waxless gelcoat is initially sprayed inside the mold on new shells then fiberglass layers are applied on gelcoat that is not completely cured, to create a chemical bound. Once the fiberglass is cured, gelcoat will not create a chemical bound anymore, but it only relies on mechanical bound. Note that on polyester or epoxy, the result is the same.


The other consideration is that Inside the original mold, wax has been applied. On cured fiberglass repairs (polyester or epoxy) only waxed gelcoat can be used so any repair over gelcoat will likely delaminate under stress because of the absence of a chemical bound and the wax contamination from waxed gelcoat. Sanding gelcoat will not eliminate wax, but it will contaminate the micro pits and compromise the mechanical binding we try to create with sanding.

In short, no matter what repair you want to do, a structural repair that will withstand vibration requires to remove the wax residue with a product such as Interlux solvent wash 202 (much better than acetone which evaporates too quicly), sand to create a good mechanical binding and preferably use epoxy for critical and structural repairs because it will chemically bind to cured fiberglass.

As for the myth that gelcoat cannot be applied over epoxy, please check the following link: WEST SYSTEM | Projects | Fiberglass Boat Repair and Restoration - Polyester over epoxy

Our test clearly demonstrates that polyester gelcoat will bond to a properly prepared WEST SYSTEM epoxy as well as to a cured polyester laminate. This test confirms that polyester gelcoats can be applied over cured WEST SYSTEM ™ epoxy on repairs below the waterline.

Of course, I must say that it is true that delamination has more chances to occur under the waterline than on an RV door hinge mount. Delamination on boats is caused with the fact gelcoat is not 100% waterproof and that water may cause delamination over time. On an RV, let's say our only concern is a strong repair that will last. Experience proved that the original hinge mount design does fail over time, so why use the same material over again ? Why hesitate for epoxy considering the advantages: (see http://www.amtcomposites.co.za/sites...0Polyester.pdf)

■ Better adhesive properties (the ability to bond to the reinforcement or core)
■ Superior mechanical properties (particularly strength and stiffness)
■ Improved resistance to fatigue and micro cracking

I think the above advantages of epoxy are still worth the extra cost for someone who will perform the repair on his own and wants to make sure the repair will last with minimal technical experience. For instance, Interlux watertite is a 50/50 mix (easy calculation), as opposed to polyester resin hardener dosage.

Considering the small amount of epoxy that needs to be purchased for resetting hinges mount, it is worth every extra dollar in my humble opinion, but I understand that an experience pro will probably do a good enough job with polyester resin repair by avoiding most mistakes a handy man may overlook.

By the way, I'm not a professional, but I have the bad habit to read instruction manuals and technical specs prior to use anything.

[David Tilston]

Many people from a boating background are sold on the West system. I am from a boating background, but wood boats. We have used West system epoxy though.
As for the hinges failing again, that is likely true, but mine were still operational after thirty or more years, so I have a hard time calling that a problem. I do however plan to try metal plates on the inside of the fibreglass, the next Trillium trailer I do the door on. I still have five to go.