First time working with fiberglass and need help!

Fuelie74

Fuelie74

Well-known member
Joined
May 7, 2008
Messages
767
Location
Monroe, WI
I have never really worked with fiberglass and need to do some glass work on my 74's floorboards. I want to cut out a small section and move it back to make more room for my transmission yoke after doing a trans swap. I also have a few cracks that need to be repaired. So is matting and resin all I will need and what is the best type of resin to use? Any other advice would also be great!

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probably smc, so you have to use smc resin and mat. Cut out section and make it so the hole gets thinner towards the middle. I used 80grit to prep my 90's floors. Then make something to form a new contour for the floor, I found metal patch tape works good for forming contours because it holds the shape. After done do the bottom side as well.

cracks grind into them and fill them with mat & resin

after done sand smooth so you will have a finished look, then uncoat bottom repairs and paint inside floorboards.

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I'm not afraid of fiberglass work. Do it a lot now. But for that, I would just drill a new hole in the cross member and move the trans mount over 1/2" to get the yoke away from the floor.
 
enkeivette said:
I'm not afraid of fiberglass work. Do it a lot now. But for that, I would just drill a new hole in the cross member and move the trans mount over 1/2" to get the yoke away from the floor.
Click to expand...

That will change the driveshaft angle and most likely it is going to vibrate.

I'd check the angles first - maybe the transmission tail needs to go over a tad anyways, maybe you're lucky.

My TKO yoke is very close to the floor too, maybe have 1/8" clearance... not a lot... and that's after I beat a small dent in the floor (steel floor on the '79)....

If you end up cutting the floor, that SMC resin is good for both, fiberglass and SMC.
 
I think I am going to end up cutting it. Like I said I have some cracks in the floor that need to be fixed and they are right behind where I will be cutting. So I figure this will kind of be a two for one fix.

Right now I have my driveline angles just right so I don't want to mess with that.

Hopefully I will have the mat and resin by the weekend so I can get started on this.
 
No expert but from what I've read and what I've learned hands on, the fiberglass cloth is a stronger product but harder to get a finished surface. So for the area you're talking about, I would use the cloth. For a painted surface use the fiberglass mat.
Just know going in that the resin will stick to almost anything. So if you want to make a mold for the shape, you will need to coat the crap out of it with wax or release agent unless you want your mold to be a structural part of the repair. Just sayin'.
 
MYBAD79 said:
enkeivette said:
I'm not afraid of fiberglass work. Do it a lot now. But for that, I would just drill a new hole in the cross member and move the trans mount over 1/2" to get the yoke away from the floor.
Click to expand...

That will change the driveshaft angle and most likely it is going to vibrate.

I'd check the angles first - maybe the transmission tail needs to go over a tad anyways, maybe you're lucky.

My TKO yoke is very close to the floor too, maybe have 1/8" clearance... not a lot... and that's after I beat a small dent in the floor (steel floor on the '79)....

If you end up cutting the floor, that SMC resin is good for both, fiberglass and SMC.
Click to expand...

I was waiting for someone to say that. My T56 is angled a bit to clear the floor, no vibrations. :thumbs: I suppose he might not be as lucky though, only one way to find out.
 
Twin_Turbo said:
Then you either lucked out and got the angle right or are not noticing it because the angle was off in the other plane too

The engine/trans should point straight back..... read this:
http://www.vettemod.com/forum/showthread.php?t=338
Click to expand...

There are three hole slots on my cross member for the trans mount stud. I just use one of the holes on the sides, not the center hole. It's only off by a 1/4." Isn't the entire engine 1" off to the passenger side anyways?
 
enkeivette said:
Karsten is that true? SMC resin will stick to steel?
Click to expand...

It might, I haven't tried this one yet but the SMC adhesive that I used (Evercoat) seems to stick to pretty much anything including skin, concrete, wood..(don't ask).... :clobbered:

Anyways, I believe you would need to use primer on bare steel as I don't think the resin will provide much corrosion protection.... not sure, might be wrong....
 
MYBAD79 said:
enkeivette said:
Karsten is that true? SMC resin will stick to steel?
Click to expand...

It might, I haven't tried this one yet but the SMC adhesive that I used (Evercoat) seems to stick to pretty much anything including skin, concrete, wood..(don't ask).... :clobbered:

Anyways, I believe you would need to use primer on bare steel as I don't think the resin will provide much corrosion protection.... not sure, might be wrong....
Click to expand...

I hope it does. I didn't primer my header before I glued it on. I just cleaned off the rust with a dremel.
 
The better SMC resins are just epoxy (different variants, over 2000 available commercially) and stick best to clean bare steel. It should be as rough as possible as in grinding with a 20 grit disc. Steel etched with an acid is also good but any residue must be removed and neutralized.
It also works well on roughened paint, but you rely on the paint's adhesion to the steel.

Epoxy can be mixed with an infinate amount of "fillers" for a specific purpose. One of the hardest combinations is silicone carbide, which is used to repair steel shafts etc. Other fillers include glass flakes, glass fibers, bronze powder, copper powder, ceramic powder, steel, alloys, and simple plain sand for concrete repair. The list is almost endless.
 
010752 said:
The better SMC resins are just epoxy (different variants, over 2000 available commercially) and stick best to clean bare steel. It should be as rough as possible as in grinding with a 20 grit disc. Steel etched with an acid is also good but any residue must be removed and neutralized.
It also works well on roughened paint, but you rely on the paint's adhesion to the steel.

Epoxy can be mixed with an infinate amount of "fillers" for a specific purpose. One of the hardest combinations is silicone carbide, which is used to repair steel shafts etc. Other fillers include glass flakes, glass fibers, bronze powder, copper powder, ceramic powder, steel, alloys, and simple plain sand for concrete repair. The list is almost endless.
Click to expand...

That's really good to know, so for doing metal to glass body seams, or a glass cowl in a metal hood, epoxy and resin then filler is the way to do it right?

I read a study done once that 80-100 grit is the magic number for body filler adhesion. Even better than 60 or 40 grit. I was surprised, I wonder if glue is the same.
 
enkeivette said:
010752 said:
The better SMC resins are just epoxy (different variants, over 2000 available commercially) and stick best to clean bare steel. It should be as rough as possible as in grinding with a 20 grit disc. Steel etched with an acid is also good but any residue must be removed and neutralized.
It also works well on roughened paint, but you rely on the paint's adhesion to the steel.

Epoxy can be mixed with an infinate amount of "fillers" for a specific purpose. One of the hardest combinations is silicone carbide, which is used to repair steel shafts etc. Other fillers include glass flakes, glass fibers, bronze powder, copper powder, ceramic powder, steel, alloys, and simple plain sand for concrete repair. The list is almost endless.
Click to expand...

That's really good to know, so for doing metal to glass body seams, or a glass cowl in a metal hood, epoxy and resin then filler is the way to do it right?

I read a study done once that 80-100 grit is the magic number for body filler adhesion. Even better than 60 or 40 grit. I was surprised, I wonder if glue is the same.
Click to expand...

Not sure if I'm reading this right, but mix the "filler" you want to use into the resin part (maybe called Part A) until you have the right consistancy, then add the activator (Part B) mix, then use. As a filler, I mix my own as well from epoxy, adding either microballoons or cabosil. The only reason I do it that way is because I have the stuff on hand and it ends up being a lot cheaper and convenient. Strength is not an issue because it all ends up being over the top anyway. I always go for "rougher the better" but sometimes less will do, especially when not structural.
Nothing wrong with the premade stuff like Fusor or 3M, good stuff, but I've always just mades my own for years.
 
Well I got my floor all fixed up. I just have alittle bit more sanding left to make it all nice and smooth. Thanks for all of the help!

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Yes I did. Scraped and wiped it down to the bare glass then sanded it down. I was still alittle unsure the other day so I jumped on youtube and watched some videos on fiberglass work.
 
Maybe I should of cleaned a bigger area, but I figured as long as it was clean where the bonding was happening I would be good.
 
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