Strategy for this fiberglass repair

[Elkhorn]

This trailer was damaged because of an apparent snow load as stated by a previous owner. It has a couple other splits that are much more straight forward and I have repaired them using polyester resin and fiberglass mat.

What are people’s thoughts on how to tackle this particular repair? It is difficult to line up all the different planes as is. I thought of drilling a hole and pulling back a spot that is spring out pretty good with some twine.

I put a poke inside the trailer to get rid of a bit of sag and lineup the top of the window. The ensolite insulation is intact and in good shape so I would like to leave inside as is if possible

This is my first ever fiberglass job I have read a lot of stuff on here including a thread from Dave b which I found helpful for the more simple repairs this is just a bit more technical.

[John in Michigan]

D, as a DIY project I would suggest checking boatworkstoday website and youtube videos. He has recorded various types of fiberglass repairs, and does a good job of explaining techniques, tools, products used, etc.

For your type of repair, because you want to leave the ensolite intact, you need to construct a good brace inside your camper that conforms to the curves. For the fiberglass repair patch, following boatworkstoday techniques would require at least 3 layers of chopped strand mat, coarse sanding, then brushing on gel coat, then more sanding. For the final finish, you either try matching the gel coat or painting the camper.

[Thom Rowland]

I know you don't want to disturb the ensolite but to give your repair some strength you will need to put multiple layers of fiberglass on the inside of the damaged area. If you don't the filler that is put in the damaged area will only crack again in the future.
The first layer should be a little larger than the damaged area, then each layer after that should be larger than the previous layer. That way you put strength back into the damaged area.

[Jaketheplumber]

This was the best suggestion someone gave me a few weeks ago when I was facing many large holes and a few similar but larger cracks in my 83’ Casita.

This guy is amazing. Here is a video series he did on hole repair. I’ve watched this series no less than three times.
I was able to follow his repair suggestions easily and the trailer is stronger than before.

https://m.youtube.com/watch?v=i9hfpOCnzEs

[Jim Bennett]

My thinking is that you could make adequate repair from the exterior, though a layer of cloth on the inside would certainly ensure it would work better.

If you only go from the outside, I would taper the existing shell from thin (basically nothing) at the center of the crack, out 3" from the center. I would then put a layer of glass cloth (easier to use than matt over a wide crack and will provide backing for the next matt layers) as the first layer the full width of the repair. Allow this to set, and lightly sand out any rough stuff leaving a smooth indented layer with no holes. I would then lay subsequent layers of glass matt a bit smaller with each layer. Use a grooved roller to keep the layers pressed tightly together squishing out excess resin. I would use about 4 layers of cloth up to near what is close to level. Then sand off the area to remove anything raised above the surface. You could then use a fibre reinforced filler to level things out to a nice smooth finish.

My making the repair essentially 6+" wide, it should have at least as much strength as the original shell, or more.

If you do remove or peel back the liner in this area, I would sand and clean the inside of the shell and apply the layer of fibreglass cloth on the inside, with subsequent layers of matt on the exterior. I have done this many times with great results.

[Tony O]

Originally Posted by Jim Bennett

My thinking is that you could make adequate repair from the exterior, though a layer of cloth on the inside would certainly ensure it would work better.

If you only go from the outside, I would taper the existing shell from thin (basically nothing) at the center of the crack, out 3" from the center. I would then put a layer of glass cloth (easier to use than matt over a wide crack and will provide backing for the next matt layers) as the first layer the full width of the repair. Allow this to set, and lightly sand out any rough stuff leaving a smooth indented layer with no holes. I would then lay subsequent layers of glass matt a bit smaller with each layer. Use a grooved roller to keep the layers pressed tightly together squishing out excess resin. I would use about 4 layers of cloth up to near what is close to level. Then sand off the area to remove anything raised above the surface. You could then use a fibre reinforced filler to level things out to a nice smooth finish.

My making the repair essentially 6+" wide, it should have at least as much strength as the original shell, or more.

If you do remove or peel back the liner in this area, I would sand and clean the inside of the shell and apply the layer of fibreglass cloth on the inside, with subsequent layers of matt on the exterior. I have done this many times with great results.

Good advice. I've also had experience with this method. Taking the time to fix both the inside and outsides of severe damage like this one will actually make the entire job easier as well as result in a much more reliable, long-lasting repair.

BTW: The damage to the shell of the OP's trailer was not caused by snow load. This was impact caused. The worst a snow load might cause are stress cracks in the outer shell. Just my opinion having seen several FG trailers that were involved in accidents.

[redbarron55]

If you cut and carefully peel back the Ensolite you can reglue and hide the cut with some caulking stippled with a wet sponge to match the rest of the interior.
Paint will cover that and you can hardly notice the repair.
Best is the taper the repair from the inside and use cloth in steps to fill and then go out and do the same from the outside where you actually grind into the original repair to "overlap" .
If it were me I would use epoxy resin, but others may disagree.

[Jim Bennett]

Originally Posted by redbarron55

If it were me I would use epoxy resin, but others may disagree.

Epoxy would work, but would be overkill. Properly done even with polyester the repair will be stronger than the surrounding area. The nice thing about polyester resin is how fast it sets up, allowing you to move to the next step faster. Depending on the ration of catalyst to resin, it is usually less than an hour. With the epoxies I have used, mostly cedar strip boat building, you have to wait at least a day before the next step.

I too am a convert as I always used epoxy before doing work on fibreglass trailers and used to it. Once I started using polyester I immediately realized the advantages in this type work.

You can do

[FRED SMAILES]

I'm sure you could scrape the ensolite away from the glass as I have done several times to make the repair. Then you could screw the pieces to a backer board and glass one side at a time. Happy to see your staying with polyester resin. Starting at post 187 in the link might give you some ideas.
Fred
http://www.fiberglassrv.com/forums/f...r-55601-8.html

[k corbin]

Originally Posted by Jim Bennett

Epoxy would work, but would be overkill. Properly done even with polyester the repair will be stronger than the surrounding area. The nice thing about polyester resin is how fast it sets up, allowing you to move to the next step faster. Depending on the ration of catalyst to resin, it is usually less than an hour. With the epoxies I have used, mostly cedar strip boat building, you have to wait at least a day before the next step.

I too am a convert as I always used epoxy before doing work on fibreglass trailers and used to it. Once I started using polyester I immediately realized the advantages in this type work.

You can do

Epoxy is not all the same. There are slow, medium and fast setting catalyst. No doubt you have heard of 5 minute epoxy, that uses a fast setting catalyst.

People working on cedar strip boats generally want a medium to slow setting epoxy so they have plenty of work time before the adhesive starts to thicken.

The ambient and surface temperature has a lot to do with how fast epoxy kicks off. If I want it to kick off rapidly I warm the containers of epoxy in a hot water bath. But I have to be sure to work quickly because once mixed it will thicken very quickly. In the colder months I always use a hot water bath since the ambient temperature is not in the recommended range for the product.

I typically work with a medium setting catalyst when making a large repair. Sometimes in July or August in Seattle I cool the catalyst down in the fridge so it does not kick off too quickly.


But if you have you don't have any experience of using epoxy for repairs on a regular basis you would not know that there are different formulas and that there are tricks to control how fast or how slow it kicks off.