You Can Repair Fiberglass

[Kevin PDX]

I have a repair I could really use advice on. At some point in my trailer life, the rear either got whacked or jacked causing the frame rails to break through the fiberglass. My hope is that the repairs can be done from the inside.

I have lifted the body enough to put a 2" wide piece of metal between the rails so the body does not sink down again. I plan to take some wax paper and insert it between the frame rails and the metal with the hope that the fiberglass & resin will hold the metal in place without fusing to the rail.

Since the hole is on a curved surface, I want to take a piece of wax covered cardboard and tape in in place on the outside to act as a mold for the curve.

Does this sound possible so far? I'm really hoping I won't have to pull the body off to do the repairs from the outside.

All advice appreciated, Dave~!


Sent from my iPad using Fiberglass RV

[D White]

Originally Posted by Kevin PDX

I have a repair I could really use advice on. At some point in my trailer life, the rear either got whacked or jacked causing the frame rails to break through the fiberglass. My hope is that the repairs can be done from the inside.

I have lifted the body enough to put a 2" wide piece of metal between the rails so the body does not sink down again. I plan to take some wax paper and insert it between the frame rails and the metal with the hope that the fiberglass & resin will hold the metal in place without fusing to the rail.

Since the hole is on a curved surface, I want to take a piece of wax covered cardboard and tape in in place on the outside to act as a mold for the curve.

Does this sound possible so far? I'm really hoping I won't have to pull the body off to do the repairs from the outside.

All advice appreciated, Dave~!Attachment 84712Attachment 84713Attachment 84714Attachment 84715


Sent from my iPad using Fiberglass RV

You can do this. You need to get the weight off this area and then repair from the rear or inside. Your cardboard idea will work excellent as a mold, so do that on the front, or outside. Be sure to wear all safety gear and sand/grind the repair area and clean first. If there is room on the inside, I would like to see you do 2, 3 layer lifts. In other words, cut 3 pieces of mat at least 2 inches larger in every direction than the size of the repair, mix the resin according to the directions on the can, paint a coat of resin on the repair, apply and fully saturate a piece of mat, repeat until you have 3 saturated pieces. Let dry. Then I would like you to grind/sand/degloss what you already repaired, clean, and repeat for 6 total layers. I feel this repair needs the support of 2 lifts, or cured 6 layers. You must do it in 2 steps, do not just put 6 layers on at once! You can do this....get fiberglassing!!!!!

Fiberglass Dave

[Borrego Dave]

Dave, got a question for you about this repair. I understand the matting but wouldn't you want to use at least one layer of cloth also?

[Kevin PDX]

Originally Posted by D White

You can do this. You need to get the weight off this area and then repair from the rear or inside. Your cardboard idea will work excellent as a mold, so do that on the front, or outside. Be sure to wear all safety gear and sand/grind the repair area and clean first. If there is room on the inside, I would like to see you do 2, 3 layer lifts. In other words, cut 3 pieces of mat at least 2 inches larger in every direction than the size of the repair, mix the resin according to the directions on the can, paint a coat of resin on the repair, apply and fully saturate a piece of mat, repeat until you have 3 saturated pieces. Let dry. Then I would like you to grind/sand/degloss what you already repaired, clean, and repeat for 6 total layers. I feel this repair needs the support of 2 lifts, or cured 6 layers. You must do it in 2 steps, do not just put 6 layers on at once! You can do this....get fiberglassing!!!!!

Fiberglass Dave

Thanks, Dave! I was hoping I was on the right track just needed a little reassurance and confidence boost.


Sent from my iPad using Fiberglass RV

[pantherdustin]

Hello, I recently obtained a really neat old Nationwide cargo trailer. I guess you used to rent these (like U-haul) and use for moving or camping. I am thinking about fixing some of the fiberglass and specifically around the superimposed Nationwide Logo (United States). It is cracking (not all the way through) on the outside shell of the area. I dont see anything in this thread this light and any advice would be great! Also, let me know if you know anything about these molded fibgerglass trailers! Dustin



Nationwide Logo Photo by dus10panthers | Photobucket

[D White]

Originally Posted by pantherdustin

Hello, I recently obtained a really neat old Nationwide cargo trailer. I guess you used to rent these (like U-haul) and use for moving or camping. I am thinking about fixing some of the fiberglass and specifically around the superimposed Nationwide Logo (United States). It is cracking (not all the way through) on the outside shell of the area. I dont see anything in this thread this light and any advice would be great! Also, let me know if you know anything about these molded fibgerglass trailers! Dustin



Nationwide Logo Photo by dus10panthers | Photobucket

These cracks are superficial and need nothing unless it is for cosmetic reason, then clean out crack, fill with bondo type filler, prime and paint

[Johnny M]

Dave, any advice on filling small rivet holes? I applied resin/mat from the inside and then bondo filler from the outside but as I sand down it appears the bondo is not filling the wholes like it should and I am having to redo many of them. Using the bondo spreaders I am flexing the spreader as I spread over the hole completely covering it then let it dry then come back to sand. I thought maybe the holes were to small for the filler completely get in there so I thought about opening them up a little to the shape of a dome before filling...any ideas would be appreciated...also on the topic of bondo (this brand specifically) what color should the bondo be when I follow the directions with a golf ball size amount and about 1 1/4" line of the activator in the tube? I have tried a little more or less as it is setting or hardening extremely fast like in 2 to 3 minutes (Georgia heat in the 80 to 90's) and faster in direct sun...will it hurt if I use less of the activator in the tube than the directions say to? When sanding, some spots even after overnight to cure, I get gooey spots stuck to the sand paper, is this normal?

[D White]

Originally Posted by Johnny M

Dave, any advice on filling small rivet holes? I applied resin/mat from the inside and then bondo filler from the outside but as I sand down it appears the bondo is not filling the wholes like it should and I am having to redo many of them. Using the bondo spreaders I am flexing the spreader as I spread over the hole completely covering it then let it dry then come back to sand. I thought maybe the holes were to small for the filler completely get in there so I thought about opening them up a little to the shape of a dome before filling...any ideas would be appreciated...also on the topic of bondo (this brand specifically) what color should the bondo be when I follow the directions with a golf ball size amount and about 1 1/4" line of the activator in the tube? I have tried a little more or less as it is setting or hardening extremely fast like in 2 to 3 minutes (Georgia heat in the 80 to 90's) and faster in direct sun...will it hurt if I use less of the activator in the tube than the directions say to? When sanding, some spots even after overnight to cure, I get gooey spots stuck to the sand paper, is this normal?

Good questions
By flexing the applicator you are digging out the hole...overfill and sand smooth...or scrape flush with a razor blade
If the bondo is hardening too quickly, cut back on the hardener. However, you must mix thoroughly or you will have the gooey parts uncured...not good...
By the way, we don't use bondo brand filler in the shop. I use that term and recommend Bondo only because it works, it's cheap and almost the only thing people can get at the box stores.

[Johnny M]

Originally Posted by D White

Good questions
By flexing the applicator you are digging out the hole...overfill and sand smooth...or scrape flush with a razor blade
If the bondo is hardening too quickly, cut back on the hardener. However, you must mix thoroughly or you will have the gooey parts uncured...not good...
By the way, we don't use bondo brand filler in the shop. I use that term and recommend Bondo only because it works, it's cheap and almost the only thing people can get at the box stores.

Thanks Dave, I will try this today and we hopefully will be finishing up the body work sometime later today. As regards to cutting back on the hardner, is it possible to use to little hardner? Should it be more towards the gray side or more pinkish when mixed correctly?

[Ben J.]

I have an RV that has what I would call a "weird" failure of the fiberglass surface. It looks like the aftermath when someone pops a zit, and shouldn't have.
I posted pictures on IRV2, and hope it is ok to link to it:
Delamination / water damage? - iRV2 Forums

Someone suggested that it looks like excessively long screws were used inside to attach things. I cannot prove that theory. Kind of wondering how to attach this. Shown is the worst area. The wood under the outside seems swolen, but there is not sign of any water entry anywhere. My initial thought was to cut away the damaged skin, remove some of the swolen wood, and fill with resin/cloth. I know this is not going to look correct without paint, and we may do that after we prove that the repairs are permanent.

I could really use advice since nobody I ask seems to know what caused it nor how to fix it.

[Bob Miller]

Hi Ben and welcome to the group.
Unfortunately this is a site for MOLDED fiberglass RV's and it appears that you have sheet/composite fiberglass construction which is an entirely different bird.


You might want to cast about on some of the sites for that type of construction.
Good Luck

[Johnny M]

Are you sure that it is fiberglass and not aluminum? Aluminum can corrode from reactions with other contacted metals...

[Andrew Gibbens]

Yep, certainly doesn't look like fiberglass - it looks like aluminium that has been dented from the inside by sharp objects. The dents even appear to have stretched the skin out over large areas, which can't be done with fiberglass.

[Johnny M]

Originally Posted by Andrew Gibbens

Yep, certainly doesn't look like fiberglass - it looks like aluminium that has been dented from the inside by sharp objects. The dents even appear to have stretched the skin out over large areas, which can't be done with fiberglass.

I may be wrong on this but I am pretty sure from the pictures, that what appears to be dents is actually corrosion that has caused the aluminum to bubble up from underneath the surface due to contact with either a different aluminum alloy or some other type of metal all together...this will be a difficult fix as you will have to not only make the repair but also prevent it from re-occurring by putting something between the different metals to prevent them from reacting with each other, like maybe a rubber gasket where they meet?

[squatch-lover]

QUESTION: I removed an awning rail and awning on my Bigfoot. We are in the process of patching the holes leftover from the screws and brackets. We have what appears to be extensive cracking in the gel coat in both pictures along with holes through the fiberglass (the horizontal 'lines' under the holes is leftover silicone caulk). Should we use bondo for the smaller screw holes in pic #1, and mat and glass in #2? Or bondo all the way around? Also, any info on preparation of the holes would be greatly appreciated. Thanks!

Sent from my ASUS_Z00AD using Fiberglass RV mobile app

[TheWanderers]

Originally Posted by D White

I had wanted to do a bondo, prime, paint thread but I ran into a problem with this thread that really isn't a problem, but is just really the nature of forums. Although I am not an expert at anything, I have owned a fiberglass shop for 39 years. It seems that when a question is asked of the author of a thread, it is answered by many people who may or usually do not know the answer to the question. These experts that chime in for the author of the thread really should start their own thread. Instead they spread misinformation that waters down the original thread and has, in many cases with this one, stopped people from trying. However, I know more people have been helped than not. I am always available by PM and help many people on a personal level this way. I have not figured out a way to solve this problem, so until I do, I won't be doing anymore self help threads, just helping by private message. Thanks...Fiberglass Dave

Dave, please don't be too disappointed by the confusion that pops up here regarding those chiming in with their own answers. Others like me recognize that you started this thread and will read through understanding that while others may offer additional advice or their own answers, we're all looking for your posts as the author. Thanks for taking the time to start this thread so very long ago and having the patience and courage to stick with us as you light the way for many to instill the faith in our own ability to simply try. Great advice based on years of experience will always be appreciated. Your words are priceless.

[D White]

Originally Posted by squatch-lover

QUESTION: I removed an awning rail and awning on my Bigfoot. We are in the process of patching the holes leftover from the screws and brackets. We have what appears to be extensive cracking in the gel coat in both pictures along with holes through the fiberglass (the horizontal 'lines' under the holes is leftover silicone caulk). Should we use bondo for the smaller screw holes in pic #1, and mat and glass in #2? Or bondo all the way around? Also, any info on preparation of the holes would be greatly appreciated. Thanks!

Sent from my ASUS_Z00AD using Fiberglass RV mobile app

Here you could get some JB weld at the auto parts store (or similar) fill the holes and scrape flush with a razor blade....let cure....paint the spots with something similar...there are also 2 component fillers that are white in color and would match close enough without painting in the spots. don't worry about the cracks and see if it leaks after the repair. Fiberglass Dave

[D White]

Originally Posted by TheWanderers

Dave, please don't be too disappointed by the confusion that pops up here regarding those chiming in with their own answers. Others like me recognize that you started this thread and will read through understanding that while others may offer additional advice or their own answers, we're all looking for your posts as the author. Thanks for taking the time to start this thread so very long ago and having the patience and courage to stick with us as you light the way for many to instill the faith in our own ability to simply try. Great advice based on years of experience will always be appreciated. Your words are priceless.

Thanks for the kind words...my above words sound quite pissy...there are many ways to achieve a goal and mine are just one way. I encourage others with other methods to start their own thread so we all (including me) can learn. It is mostly boat people (of which I am also) that bring confusion to THIS thread thinking fiberglass is fiberglass is fiberglass. We molded trailer people have very easily repairs that I believe can be done by anyone with no need to pay someone like myself $125 a shop hour to fix. Boats can also be done by most anyone, but they are quite different and a little more complex. Boat repairs done to our trailers are not better or necessary is the only song I sing, here on the molded trailer site. I really like helping others to see the coolness of fiberglass. It truly is a unique medium. Fiberglass Dave

[dbu1057]

Fiberglass Dave...help! I just put a hole in my 2 month old Toyhauler. I measured wrong and the screw I was using to mount my new tv in the garage area was to long. You guess it, right out the side it came. The end of the screw left a small hole. An earlier post by squatch-lover showed you a picture of a couple of small holes. You suggested to use JP weld. Only question I have is, I'm just wanting to patch it, sand it flat, being careful not to make it any bigger and just cover with a decal. After the JB Weld should I put anything on it first....primer..touch up paint.

[D White]

Originally Posted by dbu1057

Fiberglass Dave...help! I just put a hole in my 2 month old Toyhauler. I measured wrong and the screw I was using to mount my new tv in the garage area was to long. You guess it, right out the side it came. The end of the screw left a small hole. An earlier post by squatch-lover showed you a picture of a couple of small holes. You suggested to use JP weld. Only question I have is, I'm just wanting to patch it, sand it flat, being careful not to make it any bigger and just cover with a decal. After the JB Weld should I put anything on it first....primer..touch up paint.

Look at this as a good thing. You have your first of many blemishes that you will get using something. The JB Weld idea is a permanent, cheap anyone can do idea that will not be covered. For you, just put some latex caulk or any exterior repair type putty and scrape flush with a razor blade so you don't disturb any more finished area than necessary. Let dry and cover with your sticker....then...forgetabboutit...camp the hell out of the unit and have fun...may the forest be with you...Fiberglass Dave