You Can Repair Fiberglass

[Harvey9]

Excellent thread.

[PhillyPhixy]

Nicely done Dave

I have a couple of questions. I have worked with FRP quite a bit myself for prototyping mostly. Good point about mixing containers. I once mixed material in what I think was some sort of waxed container and it stayed sticky forever. Lesson learned. I like to use tin foil trays. I find pouring the resin out in a thin layer also helps it from going into exo therm prematurely.

I am not sure the best way to deal with the numerous cracks I have above my front window , rear window and around the rear sides. The door has a few too. These are a bit more than star cracks. They seem to have a little "lift" to them. I could probably stand them flat and fill but I fear the problem will reoccur shortly. I think I may need to rough sand and cover with cloth or veil (I notice you don`t advice) and fill. I would prefer to reinforce from behind but that is pretty hard with a 73 trillium.

I am also working on a sportmobile roof with a gazzion pinholes on the edges of the roof rails. I ran a wooden ruler over the edges and broke them open, then filled with gelcoat. Painful.Not sure what you might have done ...other than not break them open.

Thanks

[D White]

Originally Posted by PhillyPhixy

Nicely done Dave

I have a couple of questions. I have worked with FRP quite a bit myself for prototyping mostly. Good point about mixing containers. I once mixed material in what I think was some sort of waxed container and it stayed sticky forever. Lesson learned. I like to use tin foil trays. I find pouring the resin out in a thin layer also helps it from going into exo therm prematurely.

I am not sure the best way to deal with the numerous cracks I have above my front window , rear window and around the rear sides. The door has a few too. These are a bit more than star cracks. They seem to have a little "lift" to them. I could probably stand them flat and fill but I fear the problem will reoccur shortly. I think I may need to rough sand and cover with cloth or veil (I notice you don`t advice) and fill. I would prefer to reinforce from behind but that is pretty hard with a 73 trillium.

I am also working on a sportmobile roof with a gazzion pinholes on the edges of the roof rails. I ran a wooden ruler over the edges and broke them open, then filled with gelcoat. Painful.Not sure what you might have done ...other than not break them open.

Thanks

It's hard to give a direct answer about cracks, other than you need to determine why the gelcoat cracked in the first place. On the uhaul here, the cracks were caused from the po jamming the ill fitting and too large furnace into place. That stress won't be repeated, so deep sanding and filling with filler is acceptable (however in this case it was reinforced from the rear also)...If you're unsure why the cracks have happened, then you should grind them out deeply and fill with mat (not veil, no strength there)and resin. Most cracks have happened either from snow load, or more commonly, something pushed in the fiberglass at that point once, and it won't continually happen again. All bets are off when the cracks are around hinges or some other load bearing things. Structural corrective action is required before repairing the cracks, as the cracks will soon reappear. Excellent question.

[PhillyPhixy]

Thanks for the response Dave

Good point about why the cracks were created. I often seen (and have) star cracks in my truck topper from hitting it from the inside. Snow load is a good reason but it seems that the cracks are too close to the windows and on the curve to be the culprit. When I first got it, I noticed that the wooden frames were rotten and I since replaced them. Hopefully that was it. (they don`t seem to be getting worse).
My resistance to want to use matte in that area is that I think I can get a more consistant surface with cloth (or 3-4 veil) and less filling/sanding in the end. I also think that cloth has better flexibility and strength for large "straight" areas like that. Let me know if I am off the rails here.

BTW I was just doing some glassing and another tip I think worth noting:

I use talcum powder to dip my sticky gloves in when I am glassing. Helps to keep you sane. Also put some on the sweaty hands to make it easier to get the gloves on and off.
I throw the unused catalyzed mix into a 5 gal metal bucket filled with water to prevent forest fires.

[shelley w]

What if you have a 6x6" sized hole to fill, but don't have 'waste' pieces of fiberglass with which to fill the hole? We were considering filling the furnace vent hole if we decide against putting a new furnace in, but I don't have any pieces of waste fb to use. I gather I would need to layer the fb matting until the desired thickness is reached, but how do I 'back it' so that it doesn't fall through? Or what about for smaller holes, like a 1" round puncture? What do I 'back it' with so the resin etc., doesn't drip through the other side?

I have 2 'dents' on either side of my roof. They are visibly indented and cracked, but not gaping holes. The ensolite is still glued and intact on the inside. I'm not sure how I could go about fixing these as they are on a curved portion of the roof. Do I sand them down? Cut them out? What do I use to support behind that will provide the proper curve when repairing?

You also said not to use 'just bondo' to fill screw holes. What should be used? I have quite a few extra holes in my shell that need to be filled.

Sorry for all the questions ... but I'm terrified of doing this part of my repairs and just want to do it correctly! Thank you for taking the time to post this excellent thread!

[dylanear]

I'm putting in a new top vent/fan. I took out the old, but the new one's hole don't line up at all.

Anyone have tips for repairing 20 or so rivet holes?? Resin won't stay in the hole long enough to harden. Some sort of epoxy putty? Perhaps with some small fibers in it for strength? Stuff a tiny ball of glass mat each hole and put a few drops of resin on there?

Worse case I guess I just caulk them.

[DannyH]

dylanear, I filled some holes like you describe with resin. I duct taped the back side of the hole so the resin would stay in place and harden. If you scroll down on this thread, it shows how I filled in my skylight. http://www.fiberglassrv.com/forums/f...ion-40411.html .

[dylanear]

Cool, I was thinking about tape, but feared the resin would melt through it. But if duct tape worked for you....

Very nice restoration sir!

P.S. I dig your photography BTW.

[PhillyPhixy]

Shelly,
You may be able to lay up a pc of glass on another material like waxed counter top material. I like to use a thick pc of HDPE like what they make chopping blocks out of because I don`t have to wax it. You can even put a simple, slight curve in it if need be.

[D White]

Originally Posted by PhillyPhixy

Thanks for the response Dave

Good point about why the cracks were created. I often seen (and have) star cracks in my truck topper from hitting it from the inside. Snow load is a good reason but it seems that the cracks are too close to the windows and on the curve to be the culprit. When I first got it, I noticed that the wooden frames were rotten and I since replaced them. Hopefully that was it. (they don`t seem to be getting worse).
My resistance to want to use matte in that area is that I think I can get a more consistant surface with cloth (or 3-4 veil) and less filling/sanding in the end. I also think that cloth has better flexibility and strength for large "straight" areas like that. Let me know if I am off the rails here.

BTW I was just doing some glassing and another tip I think worth noting:

I use talcum powder to dip my sticky gloves in when I am glassing. Helps to keep you sane. Also put some on the sweaty hands to make it easier to get the gloves on and off.
I throw the unused catalyzed mix into a 5 gal metal bucket filled with water to prevent forest fires.

For many reasons, I stand by my use of mat only on our fiberglass trailers. never use veil for any structural use...it has NO strength

[D White]

Originally Posted by shelley w

What if you have a 6x6" sized hole to fill, but don't have 'waste' pieces of fiberglass with which to fill the hole? We were considering filling the furnace vent hole if we decide against putting a new furnace in, but I don't have any pieces of waste fb to use. I gather I would need to layer the fb matting until the desired thickness is reached, but how do I 'back it' so that it doesn't fall through? Or what about for smaller holes, like a 1" round puncture? What do I 'back it' with so the resin etc., doesn't drip through the other side?

I have 2 'dents' on either side of my roof. They are visibly indented and cracked, but not gaping holes. The ensolite is still glued and intact on the inside. I'm not sure how I could go about fixing these as they are on a curved portion of the roof. Do I sand them down? Cut them out? What do I use to support behind that will provide the proper curve when repairing?

You also said not to use 'just bondo' to fill screw holes. What should be used? I have quite a few extra holes in my shell that need to be filled.

Sorry for all the questions ... but I'm terrified of doing this part of my repairs and just want to do it correctly! Thank you for taking the time to post this excellent thread!

Lots of good questions tonight. If you go back through the thread, you will notice that I used a waxed paper covered piece of plywood as a backer...you could then just use 3 pieces of mat/resin over that, instead of a waste piece. Another thing that would really work better in your small hole would be a galvanized "tin" shingle. They come in various sizes at the box stores, and the really cool thing is, just put a couple screws to hold the ther piece under the outside the repair area, and glass away (after grinding, etc)...the fiberglass wont stick to galvanized, and leaves a smooth backside! Screw holes or any holes need at least a small ditch ground and a small piece of resin/mat before bondo...remember, nothing over ANY unscratched surface...IT WON'T STICK

Your dents can be ground down and filled almost to the surface with mat/resin, then ground and filled with filler. it will work, and you Can do it...give it a try...worse thing that can happen, is too much hump to sand down!!!

Small holes with no back acess will stay in place, they will just probably be deep because they want to sink...regrind and fill after it hardens, or put tape behind it as suggested...I like metal furnace tape

[D White]

Originally Posted by dylanear

I'm putting in a new top vent/fan. I took out the old, but the new one's hole don't line up at all.

Anyone have tips for repairing 20 or so rivet holes?? Resin won't stay in the hole long enough to harden. Some sort of epoxy putty? Perhaps with some small fibers in it for strength? Stuff a tiny ball of glass mat each hole and put a few drops of resin on there?

Worse case I guess I just caulk them.

If you use a small grinding tool, (dremel) or by hand sanding a ditch you can put a small piece of resin/mat, then fill with bondo...if you don't use mat, there is no strength and the hole will fail at sometime because the thickness of the shell is too thin and won't support a filler.

[Kenny Strong]

Originally Posted by shelley w

What if you have a 6x6" sized hole to fill, but don't have 'waste' pieces of fiberglass with which to fill the hole? We were considering filling the furnace vent hole if we decide against putting a new furnace in, but I don't have any pieces of waste fb to use. I gather I would need to layer the fb matting until the desired thickness is reached, but how do I 'back it' so that it doesn't fall through? Or what about for smaller holes, like a 1" round puncture? What do I 'back it' with so the resin etc., doesn't drip through the other side?

I have 2 'dents' on either side of my roof. They are visibly indented and cracked, but not gaping holes. The ensolite is still glued and intact on the inside. I'm not sure how I could go about fixing these as they are on a curved portion of the roof. Do I sand them down? Cut them out? What do I use to support behind that will provide the proper curve when repairing?

You also said not to use 'just bondo' to fill screw holes. What should be used? I have quite a few extra holes in my shell that need to be filled.

Sorry for all the questions ... but I'm terrified of doing this part of my repairs and just want to do it correctly! Thank you for taking the time to post this excellent thread!

make your own! measure the opening or make a pattern of the opening by tracing over the hole. cut a piece of matting the size needed. mix up the resin and soak the piece, lay it out onto a piece of wax paper on a flat surface. when set up put it in place as shown in previous illustrations. make it bigger than the opening by several inches or 10 to 15 centimeters

[DannyH]

About the holes to fill in the shell. I forgot that I did take a rounded dremel tool and hit both sides of the shell. This formed a sort of dumb bell shape and I figured it would be secure and couldn't work its way out. I've had it out on some pretty rough roads and all the plugs have held well.

[dylanear]

Originally Posted by DannyH

About the holes to fill in the shell. I forgot that I did take a rounded dremel tool and hit both sides of the shell. This formed a sort of dumb bell shape and I figured it would be secure and couldn't work its way out. I've had it out on some pretty rough roads and all the plugs have held well.

Thanks for the suggestions folks. I did buy some resin and cloth on a whim at the True Value yesterday. I'm contemplating putting a one layer strip of cloth about 1 1/2 inches wide around the hole.

The vent was cocked far from straight/aligned with the trailer. Best I can tell that was at the factory and makes me doubt Scamps quality. In addition there is a sag in my roof that was slight, but got worse with no vent to add stiffness to roof. Anyway, so in my attempt to align the new vent/fan it's created some areas I need to cut and will leave some areas where my vent will not have fiberglass under it. So filling in those areas and reinforcing the whole thing seems in order.

[dylanear]

OK, impulse buy. Is this Bondo brand resin going to bond OK to the Scamps fiberglass? Is this stuff decent to use?

Bondo Fiberglass Resin, 1-Pt.

And I got this cloth.

Bondo Fiberglass Cloth, 8-Sq. Ft.

[shelley w]

Originally Posted by PhillyPhixy

Shelly,
You may be able to lay up a pc of glass on another material like waxed counter top material. I like to use a thick pc of HDPE like what they make chopping blocks out of because I don`t have to wax it. You can even put a simple, slight curve in it if need be.

What is HDPE?

[shelley w]

Originally Posted by D White

Lots of good questions tonight. If you go back through the thread, you will notice that I used a waxed paper covered piece of plywood as a backer...you could then just use 3 pieces of mat/resin over that, instead of a waste piece. Another thing that would really work better in your small hole would be a galvanized "tin" shingle. They come in various sizes at the box stores, and the really cool thing is, just put a couple screws to hold the ther piece under the outside the repair area, and glass away (after grinding, etc)...the fiberglass wont stick to galvanized, and leaves a smooth backside! Screw holes or any holes need at least a small ditch ground and a small piece of resin/mat before bondo...remember, nothing over ANY unscratched surface...IT WON'T STICK

Your dents can be ground down and filled almost to the surface with mat/resin, then ground and filled with filler. it will work, and you Can do it...give it a try...worse thing that can happen, is too much hump to sand down!!!

Small holes with no back acess will stay in place, they will just probably be deep because they want to sink...regrind and fill after it hardens, or put tape behind it as suggested...I like metal furnace tape

Thanks for clarifying! I don't know how I missed the part about wax paper covered ply! I am attaching pics of my dents for you just so you can see. The ensolite is intact on the inside and I would prefer not to remove it if possible.

The front:
Shelley Work's Photos | Facebook

Shelley Work's Photos | Facebook

The back:
Shelley Work's Photos | Facebook

A few other spots:
Shelley Work's Photos | Facebook

Shelley Work's Photos | Facebook

Shelley Work's Photos | Facebook

This one around the vent had already been repaired by someone - they used the existing piece that broke off, but did a really terrible job of it. Ideas?
http://www.facebook.com/photo.php?fb...type=3&theater

[D White]

Shelly...those are easily doable by you...just grind the area down so there is room for at least 2 layers of mat (not cloth...ever) then safely glass away, and put filler over the sanded repair!!!

[Roy in TO]

Great thread Dave.

I wonder if one could use the silicone cookie sheet liners as a backer for the larger holes. Or to cover gel coat while setting if PVA is not available. I know that when I tried wax paper or plastic wrap it was prone to wrinkling.

Shelley, HDPE is High Density Poly Ethlyene, commonly used in the white plastic cutting boards.