Fixing cracked fiberglass

[Chris_Dresbach]

I'm open to anything on this. What's the best way to repair cracked fiberglass? For those who don't know, I'm in the process of restoring a 1964 John Deere 110 garden tractor. It's come a long way for literally being hauled out of a junkyard. It will be sandblasted in the next two weeks. Anyway, 110s came with fiberglass hoods. It seems like they all crack in the same place right up in the nose. Mine was no exception. The crack in mine is about 2 1/2" long but makes an "L" and goes right. (The front of the hood has a lip on it that goes down.) How do I fix this? I really don't want to pay $300 for a new hood either.

[sweetolbob]

I'm open to anything on this. What's the best way to repair cracked fiberglass? For those who don't know, I'm in the process of restoring a 1964 John Deere 110 garden tractor. It's come a long way for literally being hauled out of a junkyard. It will be sandblasted in the next two weeks. Anyway, 110s came with fiberglass hoods. It seems like they all crack in the same place right up in the nose. Mine was no exception. The crack in mine is about 2 1/2" long but makes an "L" and goes right. (The front of the hood has a lip on it that goes down.) How do I fix this? I really don't want to pay $300 for a new hood either.

Chris

Pretty much the same as this video. http://youtu.be/nBxnaY0mFMk Google remains our friend. You can open the crack up some to get filler in it to finish before you do the glassing to the back of the hood. You can buy a small repair kit with everything in it from you Flaps or big box store.

Just think, when you are done with the tractor, you can buy a Avanti and fix it.

Bob

[stall]

I own a 64 Vette and There are many posts about repairing Fibreglass fenders etc.. on the Corvette Forum. I'll post just one thread for you. If you want more reading and lots of pictures navigate to
http://forums.corvetteforum.com/zeroforum?id=4 and up in the right-hand corner (search) put in "Fibreglass Repairs". Everything is there and quite a few of the posters with photos
actually own and run restoration shops. Hope this helps, Murray
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C2 hood frame repair methods & materials recommendations

I 'm well onto the slippery slope of owning and maintaining a 40+ yr old corvette. I'm having a blast, but at times I feel like I'm a little in over my head... now is one of those times. I won't go into the story in detail, I'll save that for another post.

My general question is how to best repair the hood frame? See pics below. The entire perimeter of the hood skin is well attached to the frame. The points in the middle where the frame is bonded to the skin were once redone using fiberglass resin and have long since detached. The location of the largest crack is right at the hinge point on the left side of the hood. The one in the middle should be easier to fix and is less critical once I've reattached the frame to the skin. I am more concerned with the durability of the repair vs. cosmetic appearance, but if I can make it look good too then even better!

What materials to use to repair the cracks?
How do I prep the frame?
Is is possible make a repair that is strong enough to hold up to the flexing that happens when opening and closing the hood?
Any direction or suggestions would be greatly appreciated!!
Cheers,
David

http://i128.photobucket.com/albums/p...Hood-Frame.jpg

http://i128.photobucket.com/albums/p...inge-Point.jpg

http://i128.photobucket.com/albums/p...-at-Center.jpg

DansYellow66 01-13-2010 07:40 AM

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The only proper way to repair those areas is with fiberglass mat and resin. It's not an ideal situation since you can only get to one side of the frame unless you separate the frame from the hood skin. If you really want to do it correctly (and with the higest possible strength then you probably do need to separate the two so you can repair it from both sides. The repair is pretty straightforward - grind everything down and feather the edges - back up one side and start laying in layers of resin soaked mat, rolling each layer. Then flip over after it sets and clean up the back side - lay in layers of rolled mat and resin again. Then grind and sand the whole thing to contour and finish with a pinhole filler and sanding. You might make an acceptable repair w/o separating. In the mid-frame crack you would need to get something back behind it to form a mold and feather the repair out over a sizable area. My 2 cents anyway.

nomeansyes 01-13-2010 08:48 PM

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Quote:

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Originally Posted by DansYellow66 (Post 1572738161)
The only proper way to repair those areas is with fiberglass mat and resin. It's not an ideal situation since you can only get to one side of the frame unless you separate the frame from the hood skin. If you really want to do it correctly (and with the higest possible strength then you probably do need to separate the two so you can repair it from both sides. The repair is pretty straightforward - grind everything down and feather the edges - back up one side and start laying in layers of resin soaked mat, rolling each layer. Then flip over after it sets and clean up the back side - lay in layers of rolled mat and resin again. Then grind and sand the whole thing to contour and finish with a pinhole filler and sanding. You might make an acceptable repair w/o separating. In the mid-frame crack you would need to get something back behind it to form a mold and feather the repair out over a sizable area. My 2 cents anyway.
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Dan, Thanks for the info. :thumbs: I suspected the best way to make this repair would be to separate the frame from the skin... I'm trying to avoid doing that :ack:, hoping someone here could offer up some ingenious solution.

The next question then is, how does one go about separating the skin from the frame?

Dave

firstgear 01-14-2010 05:05 AM

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Quote:

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Originally Posted by DansYellow66 (Post 1572738161)
In the mid-frame crack you would need to get something back behind it to form a mold and feather the repair out over a sizable area.
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drill a hole and shot a can of foam insulating material for the backer. then grind away and you have your backer.

DansYellow66 01-14-2010 06:41 AM

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Quote:

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Originally Posted by firstgear (Post 1572749157)
drill a hole and shot a can of foam insulating material for the backer. then grind away and you have your backer.
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That sounds like a good idea for creating a form. It might add a slight bit of structural strength also. I think you could probably make a satisfactory repair with this as long as you feather the repair out over a couple of inches and roll the layers of mat in carefully. My hood had a section of the rear part of the frame cut out to clear an old Accell distributor and I repaired it by putting something in there to back it up (can't remember what anymore) and it has held up fine. Separating the hood panels probably wouldn't help much in fixing the crack around the latch plate.

To separate the skin you need to clean all the paint off the edge of the hood and look for the parting between the panels which should show up due to the dark gray bonding agent. A good stiff metal paint scraper can be driven in to carefully break the bond and then work it around the perimeter of the hood to completely separate them.

Mike Geary 01-14-2010 08:18 AM

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No need to remove skin

Removing the skin should be a last resort. If you did, you would need to build a bonding jig to maintain the correct curvature when rebonding.
I've done it, and just takes a LOT of time to get it right.

Low expansion foam is a great idea for a backer.

Use polyurethane roof & flashing sealer to re-tack the frame to the skin, instead of anything rigid. I use a brand called PL from my big box store. It cures to a firm rubber consistency, and it's black.

67vetteal 01-14-2010 10:03 AM

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The less you disturb the situation the better off you'll be. It is very hard to formulate a successful repair without a hands on inspection. From a distance it looks to me like a good cleaning and a rejoining of damage with Epoxy is all that is needed. We use Epoxy for all sorts of repairs and mating of surfaces on Fibreglass in the Marine repair business. Al W.:flag:

Ron Miller 01-14-2010 11:01 AM

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Originally Posted by Mike Geary (Post 1572750554)
Removing the skin should be a last resort. If you did, you would need to build a bonding jig to maintain the correct curvature when rebonding.
I've done it, and just takes a LOT of time to get it right.

Low expansion foam is a great idea for a backer.

Use polyurethane roof & flashing sealer to re-tack the frame to the skin, instead of anything rigid. I use a brand called PL from my big box store. It cures to a firm rubber consistency, and it's black.
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:iagree: Don't remove the hood skin from the frame unless absolutely necessary, and it doesn't appear to be necessary in your case. If you've got a good bond between the skin and the frame at the perimeter, leave it alone is the best option.

Inside of the perimeter where your hood skin has come loose from the frame were never bonded at the factory with a rigid bonding material such as was used at the perimeter, go with something similar to that proposed above, it needs the ability to "move" slightly.

:thumbs:

nomeansyes 01-16-2010 01:13 AM

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Originally Posted by Ron Miller (Post 1572752253)
:iagree: Don't remove the hood skin from the frame unless absolutely necessary, and it doesn't appear to be necessary in your case. If you've got a good bond between the skin and the frame at the perimeter, leave it alone is the best option.

Inside of the perimeter where your hood skin has come loose from the frame were never bonded at the factory with a rigid bonding material such as was used at the perimeter, go with something similar to that proposed above, it needs the ability to "move" slightly.

:thumbs:
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Believe me, I have NO desire to remove the hood skin, so I will consider other options, like using epoxy or other adhesive. I am aware that the center bonding areas on the frame should be somewhat pliable. I read in another post awhile back to use a 3M marine adhesive... picked up a tube a few months back. I appreciate the input! Thanks!

nomeansyes 01-16-2010 01:33 AM

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Quote:

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Originally Posted by 67vetteal (Post 1572751638)
The less you disturb the situation the better off you'll be. It is very hard to formulate a successful repair without a hands on inspection. From a distance it looks to me like a good cleaning and a rejoining of damage with Epoxy is all that is needed. We use Epoxy for all sorts of repairs and mating of surfaces on Fibreglass in the Marine repair business. Al W.:flag:
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Al, There was once an attempted repair but using what appears to be fiberglass resin but the surface was not cleaned well and it came unbonded from the surface. I suspect the crack has gotten worse as it flexes when the hood is opened and closed.

I've thought about using epoxy or possible some glass impregnated resin to add some strength. However, I was worrkied that just joining the ragged edges of the crack, there would not be much strength.

But this would certainly be the easiest to do. After thoroughly cleaning the area, I can fill the crack and rejoin the damaged edges.

Also, I do like the idea of using the foam to create a backing (thanks Mike!) and enlarging the repair to an area larger than the crack.

This thread is a great example of why this forum is so awesome! I truly appreciate the feedback. I'm not quite ready to do this repair so keep the comments and input coming!! Dave

[52 Ragtop]

Chris,
Fiberglass is VERY easy to work with, and NOT rocket science! I have been doing collision repairs for the last 35+ years, and I did work in a "glass shop" for awhile out in the LA area. I was actually hired to finish all the plug work (the part that the molds are made from) on the 1936 Auburn Speedsters, But while in the glass shop I learned a lot.
Grind the glass back from the crack at least 3-4 inches, while grinding, taper it back away from the crack, don't be afraid to grind too much, as it's easy to repair. IF you have missing pieces, use a piece of cardboard COVERED with masking tape. (prevents the resin from soaking into the cardboard)
Cut at least 3 strips of fiberglass, each one wider than the first, mix up the resin PER THE INSTRUCTIONS!! and mix only what you will use in 15 minutes, soak the glass with a disposable brush about 1-2" wide, brush on some resin on the hood, then lay the 3 strips of glass as you go. DO NOT worry how it looks, you can grind it down after it cures. Once the first batch cures, then grind the back side and put on large piece of glass over the whole patch on the back side, You can use regular glass, or if you have some fiberglass cloth as it is more "inter twined"
Once you grind it to shape, if too thin, add another layer if needed.

Use some latex or nitrate gloves on your hands, and you MUST wear a good mask while grinding, oh and fresh fiber glass will make you itch a LOT! <G> When you are done, take a COLD shower (closes the skin pores) wash off the dust, then shower as usual.

Jim

[benaslopoke]

Not trying to steal the thread, but is carbon fiber made (not repair) much the same way?? No need for great detail, just curious..

Ben

[52 Ragtop]

Ben,

NOPE, completely different

Jim

[KGlowacky]

fiberglass

I also have worked in a Corvette shop and I want to add PLEASE DO NOT USE the fiberglass screen that they use on Boats. You need to use the mat . The boat material looks like a screen, it will bleed through in a cople monthes and you will see the screen. Use the mat that looks like chopped up strans of thread. Make sure you completely saturate the mat when you put it on. I use to place it on a piece of cardboard apply the resin (with a cheap throw away paint brush) then wet the fiberglass surface you are going to repair with resin then put the mat on it and then wet the entire patch for final application. Good luck.

[Milaca]

The easiest way to repair a broken John Deere lawn tractor hood is to replace it with a steel IH Cub Cadet hood.