Repairing cracked fiberglass top

[fun in dirt]

The weather has gotten cool & rainy enough where I need to start thinking about repairing my junky hard top laying in the back yard. I just finished reading "Basics of Basics" Fiberglass repair by Brian Martin from an old post to get an idea of what all is involved. But I have 2 questions:
1.) How long do you let each layer of resin & mat set up before applying the next?
2.) How do you get a good starting foundation when you can't get to the backside to make a "mold"? I have a single wall top, but some of the cracks are in the corner where it is kind of double walled Does this make any since?
Okay, maybe 3 questions...Is there a post that shows picture steps of a repair? I've searched but don't see anything.

[red71cheyenne]

Wish I had an answer for you, but I'll be watching to see if maybe someone else has one. I've got to do the same thing to mine, only its a double wall. Maybe someone will chime in with some insight here.

[71jimmy]

You can sand and apply additional layers as soon as the first layer is hardened and not sticky any longer.

The only way to layer, when you can't get to it from underneath, is to flair the edge about an inch out all around the repair area, so that it is really thin at the repair site, and then build it back up one layer at a time, each layer being a bit smaller than the prior layer.

Hope this helps.

[red71cheyenne]

What if, like mine, the repairs need to be done on the edges where it bolts to the bed? I have an idea to lay a 2x4 inside with pre-drilled holes for the bolts to run up into. It will fasten to the inside with screws. Then start laying layers of fiberglass on that(leaving the bolts holes open) until it is back to the nearly original thickness. I'm not worried about the stock weather stripping under it, I was going to use some aftermarket stripping like for garage doors instead. Does this sound insane? I can't think of any other way to replace the metal bolt strip than this. Mine is rusted beyond repair.

[fun in dirt]

Originally Posted by red71cheyenne

What if, like mine, the repairs need to be done on the edges where it bolts to the bed? I have an idea to lay a 2x4 inside with pre-drilled holes for the bolts to run up into. It will fasten to the inside with screws. Then start laying layers of fiberglass on that(leaving the bolts holes open) until it is back to the nearly original thickness. I'm not worried about the stock weather stripping under it, I was going to use some aftermarket stripping like for garage doors instead. Does this sound insane? I can't think of any other way to replace the metal bolt strip than this. Mine is rusted beyond repair.

My flanges that bolt down onto the beside are totally busted up too. What worries me is that's what seems to be where most of the weight of the top would be directed. I'm not sure how to do all this stuff, so think I 'll just go buy some mat & resin & get started doing something. I can't mess it up any more than it is now...I hope!!!

Maybe I 'll take alot of pics during this attempt. And if it turns out descent, post them for other to be totally confused by

[red71cheyenne]

The little bit of fiberglass I have done, I noticed he's right. You can lay one layer right over the other as soon as its dry. It just took a long time for mine to dry. Not so sure how well I did measuring the hardener though. I'd pay attention to that if nothing else. And I agree, you can't mess up something thats already broke!! Good luck!!

[red71cheyenne]

Any progress?

[fun in dirt]

Originally Posted by red71cheyenne

Any progress?

YES - I started the other weekend grinding off all the globbed-up kitty hair the PO had smeared on it and most of repair mat I could pull off with my fingers. They didn't even bother sanding before trying to repair. Then I picked it up to set on the workbench & it literallly fell in half. I have repaired with fiberglass resin & mat all the interior side of the hatch & edges. Hope to finish the outside by this weekend & start on the top. The top only has one stress crack that I can see right now.
Here are a few before pics of the hatch, I will take some during & after this weekend.

[red71cheyenne]

Wow, that is even worse off than mine. I'm trying to split mine in half so I can remove all the metal parts and blast and paint them. Haven't quite gotten it done yet. Now it'll be a while since I'm overseas. Thanks for the update! Jeff.

[BigRed Beast]

Geez, you go away for a few weeks and the things you miss!

I used to have a fiberglass surfboard repair company--back in the day--and am applying some of the old techniques to my double wall top (the one that flew off the sawhorses a few months ago).

For big holes, use a rigid foam for a backer--Hobby Lobby and the like sells a variety of different products, and you can also use building foam. I haven't tried the spray in type used for window indulation, but I'm going to! BTW, higher density is better. Cut and stuff the foam in the hole and laminate over it.

For cracks, take a grinder or equivalent and carve the crack so that the surfaces are even with one another--also widen the crack a bit so the resin has something to adhere to.

For some of the structural stuff, that'll depend on where and what you're trying to do. Remember that the glass is only partially structural--it becomes stronger the more layers that are applied. Really heavy mat--the type used on a variety of RV and boat parts--is a heavy series of mats. This stuff is probably not applicable for repairs to a top. More on the mat below. So, build a piece to fit in the area you're trying to repair out of wood or foam, stuff it in there and start laminating.

Apply the resin with a throwaway brush--you can make one last a long time by cleaning with acetone and propping it standing up so any residual resin flows down toward the handle leaving the bristles workable for another round. Use the plastic sqweegee to the pull the resin over the mat, smooth out bubbles, etc. Remember, the resin is going to follow gravity and will pull the mat with it, so for applications which have a top and a bottom, do it in multiple steps--wet out and cure layers on one side, then flip the piece and do the same for the other side. You can use a small piece to wrap an edge after you have the desirable effect on the balance of the repair.

For pieces that can't be made to fit flat, cut the mat larger than you need, use a tape along an upper edge to hold it in place and wet it out with a fairly hot batch of resin. Be careful not to wet out the taped portion of the mat--it's the difference between cutting the dry mat with scissors and grinding and sanding. After it fires, pull the tape and cut any dry mat away.

After you have the requisite number of layers, apply a final coat of a resin/catalyst/sanding agent to the entire repair (gravity's not a big issue in this one) and let it fire off. Dry to the touch means it's sanding time. You sand just like wood, heavy grit to fine. Machines can do a bunch of removal in a hurry, so I tend to use them sparingly and usually only in the initial stages--doesn't take much to sand through a repair, so don't be too aggressive with the heavier grits, either.

The mat itself is usually sold in auto parts stores, but see if you can find a fiberglass supply in your area. They not only carry the basic mat (usually 8 ounce) but also carry a variety of other mat weights. The weight of the mat can be identified by the actual size of the mesh itself. 8 ounce has a bigger mesh opening that 6 ounce. For most of my repairs, I would prefer to use multiple layers of 6 ounce rather than one layer of 8 ounce--again, strength.

The fibergalss supply with also sell a variety of resin and catalizers, cheap applicator brushes, sqweegees, acetone and...sanding agent. The usual missing element in the sanding process is the sanding agent. It is a wax-like additive dumped in a regular resin-catalyst mix. You don't need much, and all it does is seal the resin so you can sand it without getting a semi-gooey surface. Sand with a variety papers depending on how smooth you want it--you can approach it like body work and get up to a wet 1500 grit polish if you want.

I don't sand between coats--if I have hairs sticking out, a real rough rasp will knock 'em down. I cut out air bubbles if I have any prominent ones.
The resin will eventually harden no matter how much catalyst you use--the more you use, the hotter it'll fire and the quicker it'll go off. A hot batch will turn a little brown due to the heat, so gauge your needs accordingly. You can usually get two-three layers a day with a moderate use of catalyst. Weather will affect it as well--a hot day vs. a cold day. Be smart about doing this around a garage heater or any type of flame

I'm sure I'm missing some stuff, but ask and I'll try to answer. It's pretty easy stuff to work with, so don't be afraid that you'll get in over your heads. Like Bondo, if you don't like it, grind it off and start over. Enjoy!

[fun in dirt]

Great tips.. THANKS!

[red71cheyenne]

Thanks for the tips! Hopefully, I'll get to use some of them in about 2 years!

[Critter]

I'm about to try some of this stuff myself. I have read through most of the FAQ posts on here concerning fiberglass and I am fairly confident in myself...confident that I can undo anything that I screw up at least!

[old man jimmy]

Thought this would be a good place to re-post about the tops. Might save some of you from having to repaire them. About double wall tops.. When you got one new the dealers gave instructions on how to remove the tops. They said it was imparitive to unbolt it, slide it back on the bed rails far enough to get at the last bolt on each side. Them make a brace to go across the two holes, and drill it out and put the last two bolts back in, to keep it from folding in the middle when you picked it up from the sides. I made mine from old bed frame angle iron. I think very few of us left out their who ordered theirs new. So think these instructions have mostly been forgotten.

[Shock_Me]

old man jimmy, that's a good tip. I assume it applies to single wall tops as well?

Pete

[BigRed Beast]

Based on the truck pics that post for each of your signatures, I can't imagine having too much trouble with glassing--I mean, you obviously know how to wrench a bit and you wouldn't own one of these trucks unless you had a pretty large set! Be nice if all you had was minor league repairs to practice on, but Fun in the Dirt's going right to the big leagues based on his pics.

The biggest thing to keep in mind is that it is a process, and the materials really won't let you skip steps or go too fast. You'll see bubbles or sags as soon as it catalyzes. You can pay dearly for trying to shortcut a step in the sense that you'll get to start all over, but that's about it.

Fun in the Dirt: fiberglass adheres to about anything, so clean up the nasty gram that the PO left you, stuff something solid in there and maybe put a few screws into the repair from the inside and outside of the top to hold everything in place. For that matter, you could fit a piece of wood to fit inside the bottom lid of the hatch, stick some epoxy/ JB Weld on the inside of the repair and stuff the wood in the hole. Regardless of how you hold it place, it then just becomes cosmetic repair. Multiple layers and larger and larger mats.

As far as strength, this'll either reassure you or just make you roll you eyes: one of my shop specialties was was putting old surfboards back together...as in, they were busted completely in half. This was for older boards, ones with sentimental value where additional weight wasn't any big deal. We would put make 5-6 holes on each half of the foam part of the board by pushing a pencil in the foam. We'd mix up a batch of resin with a fiberglass base to form a paste, stuff it in the holes and along the entire surface of the exposed foam. We'd push the two halves together and clamp it as best we could and let it go off. We'd cut a mat for the top of the board to cover the repair and then some, glass it, flip the board, glass the bottom of the repair, mat and glass the sides of the repair. The key was overlapping the various mats and extending them well beyond the actual repair. We'd sand the edges of the repair, gloss coat it and sand and polish that.

There are guys still using boards we repaired years ago. I can't see a top repair having more strain than a surfboard--unless you're upside down, a whole different issue!

I'll probably tackle my top this weekend--I have to glass a bunch of baseball bats for the local sporting goods store, so I might as well make up a big batch and get after everything at once.

I think I'll glass the cat as well

[fun in dirt]

I got tired of working on the hatch, so started on the top. I think I'm through with the major cracked/missing areas so it's time to start sanding now. The fiberglassing was actually kind of fun...at least the learning something new part. I've gone through lots of disposable gloves the last few weeks!
I had some tread plate left over from making my sidepanels, so cut two strips off. I will use these over the lip of the top (to sandwich the fiberglass between the truck & plate. Figured this would spread out the stress instead of it being so much pressure around each hole and as a plus it'll match the panels!
Gonna try to get through this weekend so it can be at the body shop to get covered with bedliner early next week. Maybe the next pics will be completed & installed.

[old man jimmy]

to Shock Me... I don't know about single wall. I got mine early in the 72 run, so they were still using up the double walls. The doubles are seamed down the middle, so probably more important with them. Singles came out in 72 but they used up all their left over doubles before going to them. I personally like the doubles better, I think they look a little cleaner. But then again I don't take mine off.

[red71cheyenne]

Jimmy, was the support for the seam running down the middle in the double wall? My top seems to be plenty strong, but I don't move it around much either. Its either on or off. And its been off for about 2 years now, sitting on 4X4's.

[old man jimmy]

Originally Posted by red71cheyenne

Jimmy, was the support for the seam running down the middle in the double wall? My top seems to be plenty strong, but I don't move it around much either. Its either on or off. And its been off for about 2 years now, sitting on 4X4's.

Not sure what you mean. Doubles don't seem to have any support down the middle. It's like they made them in left & right halfs and glued them together. Is yours a single? Haven't seen inside a single for many years. But from what I remember they have like a bunch of squares inside. Which may be a stronger set up for picking them up.

[red71cheyenne]

Right, mine's a double wall. There is a seam on the inside, in the middle. I meant was putting the bolts thru the ends with a wood or metal support supposed to keep it from breaking? Sorry, wasn't very clear. I just meant that my double wall seemed plenty strong even without putting the supports under it while installing or removing it.

[old man jimmy]

right Red. I read your post wrong, sorry. Yes it is to stop from cracking at the seam running down the middle. I know they seem pretty strong, or so I always thought. But after looking at some of the tops the guys are working on in here, It makes me wonder. The angle iron is just so when you pick it up the sides don't spread out, which would fold the middle seam inward. Keeps it solid, and in original shape.
Tom

[fun in dirt]

Finally got the hatch & top almost finished and put back on for the winter. Still have to add the handle in center of hatch & a few pieces of weatherstrip.
Ended up bedlining the outside of top with same stuff that used inside on the floors. I'm really tickled with the way it turned out. Also put lexan in place of the glass hatch window. This made it sooo much lighter & easier to work with than getting a piece of glass cut & that rubber moulding is a headache. I love the look of rollbars through fresh lexan (that's the drag racer in me). This time last month, I was ready to throw the thing in the creek and find another one. Now I'm confident in repairing anything fiberglass..it just takes time & patience...but what doesn't

[Yukon Jack]

Looks good! The cage does look cool.

[red71cheyenne]

That does look good! How about some close up shots of the repairs?