Diesel Place banner

1 - 18 of 18 Posts

·
Registered
Joined
·
2,484 Posts
Discussion Starter #1
Contents;

Preface
Safety Precautions
Tools and Supplies
A Note on Fiberglass
A Note on Resin & Hardener
The Subject at Hand
The Method Described
Cracks and Splits
Missing Parts and Pieces
The Mold
Trimming and Cutting
Finishing Up
 

·
Registered
Joined
·
2,484 Posts
Discussion Starter #2
Preface

To be very clear this is by no means a tutorial on how to repair this specific item. This is a beginners guide to aide you for basic to intermediate repair or fabrication. The methods described below are good for automotive application, fabrication and prototyping but are in no way suitable for marine application and boat repair.

There are a wide range of tools and methods used when fiberglassing, making molds, using gelcoats, epoxies and working with carbon fiber... but I'm gonna do this the very simple and basic way using methods that developed over time when I had just begun to work with fiberglass and various composites some 14 maybe 15 years ago. If I were to do this the "professional and proper" way, I would use several other available methods that require the use of special tools and supplies not readily available nearby.

That's the point. It's very basic, does not require 500-700, 1000$ worth of tooling and supplies yet being an effective fabrication and repair method.

So we won't be using any special tools or supplies. Mostly what you need you have already or can find at a store nearby with one exception; I will be using a graduated container to properly measure out .5 fl oz of resin, but there are many ways to accomplish that (e.g. walmart, kmart, target... something to measure out fl oz). A glass mix container is the best.

As for the fiberglass, resin, hardener. All Bondo Brand. Can be found at nearly all major auto parts stores, home depot, lowes... nuff said.

Also, in the true spirit of DIY, we will be using some old, nasty resin. Totally not advisable BUT also proving that it's still effective. I'll touch up on this a bit more down the line...
 

Attachments

·
Registered
Joined
·
2,484 Posts
Discussion Starter #3
Safety Precautions

Its some pretty nasty stuff. The resin and hardener are already bad by themselves. You'll need some nitrile gloves. Latex will start to melt and degrade pretty quickly, within a few minutes.

Respirator. Respirator. Respirator. I did not use a respirator during this small project however the amount of fiberglass used were mere scraps from previous jobs and the total amount of resin used during this process was precisely 1.5 fl oz. For particularly large jobs (e.g. a full body panel) that require a lot of fiber, the real problem is non-wetted dry fiber and the ones floating around that you can't see. The fumes get a bad rep but most people would use a fan for that which is fine but the loose fibers can get out of control pretty easily while becoming airborne, so keeping it controlled by just cleaning up as you go is highly advisable. I usually just have a "fiber cutting session" between cure cycles.

Other than those two common sense applies, if you're underneath it while wetting (applying resin mix) or cutting the stuff you'd wear at least some safety glasses or better; a full face mask... well I hope you would.

This one I'm not too sure of because it's never happened to me personally but I've "heard" of it happening; "If you mix too much hardener to the resin it will catch fire." It does create a bit of heat if left in a container, but I've always been cautious to get the mix right. I've had a few blocks of the stuff reach temps to be too hot to touch by hand, but never a fire. I do, did and always usually have had a fire extinguisher but I've never had to use one on this specific subject.

Use common sense, keep your gloves and respirators on and that extinguisher handy.
 

Attachments

·
Registered
Joined
·
2,484 Posts
Discussion Starter #4
Tools and Supplies

Your typical "tools" required;

Your hands
Some popsicle sticks
Razor
Sharp scissors
Hack saw blade

Some additional items I used;
A paint scraper and file.

Supplies;
Resin
Hardener (MEKP)
Matte
Mesh (commonly referred to as cloth)
Tape
Wax Paper
Cardboard
 

Attachments

·
Registered
Joined
·
2,484 Posts
Discussion Starter #5
A Note on Fiberglass

To keep things very plain and simple, there's typically two your going to find;

Matte and Mesh.

Matte is where the structure and strength comes from. Not very flexible dry. No more than 4 layers at a time between cures.

Mesh is merely used as a finish. Extremely flexible and considered difficult to cut dry. Typically only 1 layer for finishing.

You start with matte, always end in mesh. Trying to give matte a nice finish can result with some bloody aftermath. You can stab and cut yourself pretty easily trying to sand the stuff down. Then you say; well why not use a power tool? Simple answer; dust. It's much much easier to sand on mesh and provides an industry standard finish on its own.

For today's project I'm making single sided repairs and a single sided part. 2 layers. One matte, one mesh. As basic as it gets.

If you were to want to make a dual sided 5 layer part the layers would be as follows and in this order;

1 mesh
3 matte
1 mesh

If you were to make a dual sided 10 layer part it would need to be split up into two cure cycles and would go as follows;

1 mesh
4 matte
Break Time; Cure Cycle. Should take 30-45 minutes.
4 matte
1 mesh

Stray away from more than 5 total layers at a time. This can create a very considerable amount of heat.

Also, fiberglass does not do sharp, highly defined corners very well. To achieve that, build up the edge first. Then lay your main matte down. When working with defined edges use mesh for its flexibility. So you will have small pieces of mesh to "work a corner" or "build up a corner" then use your larger matte to give it strength.

When cutting (this particularly applies to the finer mesh) cut in short strokes towards the handles and slide the scissors backwards while cutting your stroke length. Cutting like it's paper... or just about anything else can yield unwanted results.

One more thing, when you cut mesh; don't worry about getting it perfect. Once it's cut, touch it as little as possible. The more you handle it the more it's going to unweave.

Picture annotations;

1.) Left: matte, right: mesh
2.) Bottom cut: using method described, top cut(if you can call it a cut): trying to cut normally like paper
3.) The effects of not building up your sharp edges and corners.
 

Attachments

·
Registered
Joined
·
2,484 Posts
Discussion Starter #6
A Note on Resin & Hardener

As stated earlier, I'm using some very old resin. You may encounter this from resin you just purchased. Return it if you can. You should not have to drill your way into the can. Lol. There are expiration dates on the bottom of the cans. Also, a good indicator that the can is old (most of these cans come with hardener), check the hardener that comes with it. When stored upright it will never leak out. When stored on its side, if it's old the hardener will have leaked out. This may cause you issues later on. Check the stuff before you leave a store with it. If it's old, ditch it.

Old resin can be signified by a greenish tint that you can see in the pictures. I had to make a test batch to see how much hardener to add because when it's old the directions do not apply.

The typical mix instructions (simpified) are 1 fl oz of resin to 10 drops of hardener. For this old can of mine, it turned out to be 1 fl oz to 14 drops. Note the color differences in the pictures.

The proper color indicated should be a light yellowish tan color after it's all cured up. At least 24 hours.

A dark brownish color post cure indicates a resin soaked workpiece and is just as bad as a workpiece that didn't harden at all. Resin soak causes brittle, weak parts and repair.

If your finding that your workpiece is not hardening (stays somewhat flexible and sticky, and is actually used as an advanced pre part method) don't worry. Just very lightly brush on some hardener. Does not take much, your just inducing a small chemical reaction causing the part to harden.

The weather and environment play a vital role in how much time you have to work the resin and how long it takes to cure.

Cold environments; longer cure.
Hot environments; shorter cure.
Humid; more time.
Arid and Dry; much less time.

The two extremes;

Cold humid environment (seattle, wa) youll have plenty of time. In fact you may want to increase hardener to resin ratio for proper results.

Hot arid environment (albuquerque, nm) youll have to work fast and may want to consider decreasing the hardener to resin ratio.

Always make a test batch and test a small piece of fiber. Adjust accordingly.

Picture annotations;
1.) Graduated measuring cup used.
2.) Note the nasty green tint. Created from bacteria buildup in my nasty old can of resin. Yum.
3.) Proper mix, proper color, but you can still note the green tint. Not the end of the world, still VERY effective.
 

Attachments

·
Registered
Joined
·
2,484 Posts
Discussion Starter #7
The Subject at Hand

So today I'm going to quickly repair my spare grill from an 84 for my 85 box body.

It actually took me all day to do this, because I've been constantly taking off gloves, taking a picture... etc. Writing...

But the total time this would normally have taken me is around 30 minutes for something like this. Including cure cycles maybe an hour and a half. Given proper planning. So think your project through thoroughly.

I also realize that I could have purchased this from rock auto for roughly 30.00 but it wouldn't have given me the chance to make this article, and that's 30 dollars I can spend on other things that are more important than a grill. If it ever breaks (unlikely) then I guess I'll make a DIY article on metal forming and shaping... which would require some special equipment therefore I don't think it would be in true DIY spirit. If I am to replace this grill with a new one it's gonna be steel.

Moving on...

So first you identify problems. They can usually be fit into two categories;

1.)Cracks, splits, crevasses, small chips... items of this nature...
2.)Missing pieces, panels... large chunks that are completely missing all together.

This was a good example for an article because it contains both criteria.

Before you begin to even identify all the issues your project has, particularly a repair... step one is to thoroughly clean said item. You may find things you missed or couldn't see due to dirt, grime, etc.
 

Attachments

·
Registered
Joined
·
2,484 Posts
Discussion Starter #8
The Method Described

Ok. Down to the nitty gritty of actually doing it. Unfortunately I can't take pictures of me glassing and doing it at the same time.

So the best I can so is describe in detail what I'm doing. This is where your gloves and popsicle sticks come into play.

A note on the sticks vs a brush... this is a lesson learned the hard way. Don't get me wrong, I use brushes all the time. However they are more cumbersome and require some experience to use plus they soak up hella amounts of resin. They also stick to your fiber easier and the brush can pull your fiber right off your workpiece... and that will be bad and frustrating. The popsicle stick doesn't soak up anything unnecessary. They glide much easier across the fiber. They are used for wetting, rolling, scraping... pushing... like a paperclip it's just a wonder tool for this application. Most importantly... they are reusable whereas the brush gets disposed of. No amount of cleaner will prepare a brush properly for the next cure cycle. Once it's used, throw it away. No matter how much acetone, soaking... there's always gonna be that once piece of hardened resin left behind that will end up in the next cycle and that will create air bubbles and help delamanation occur. Moving on...

Keep your gloves resin free for a long as you can. Once the resin and hardener are mixed you have a limited amount of time to work with it. Maybe 5-7 minutes. So chaning out gloves every other minute is not going to work... so... popsicle sticks!

Take your stick and get some resin on it, spread it on work area like butter on toast.

Take your first piece, matte, and carefully lay it on, but don't worry about it soaking yet... just stick it on there so it will stay.

Take your stick, repeat. More resin on your first piece you just applied.

Take your next piece of matte, or mesh if this is a 2 layer application, and stick it over the first piece.

Get all of your pieces in place.

Now, wet the work area out. Soak it up. Use your hands, the popsicle stick, or dump it directly on. Be very generous. You don't want delamanation or bubble pockets. They will be signified by a "whiteish" area. You want it all dark and shiny. You will be using your hands in this step. The more resin on your fingers the better. This will prevent the fiber from sticking to your gloves and ruining your afternoon.

Now you don't want all that extra resin on your item, so take a popsicle stick and gently scrape off the excess. A resin soaked piece of finished fiberglass is brittle and weak. By the time it's dry you want to be able to feel the texture of the mesh with your fingers, you don't want it smooth to the touch. This means you have a resin soaked piece.

Once your satisfied. Walk away. Let it cure up for 30-45 minutes.

Picture annotations;
They are posted in order... I hope this gives you an idea.
You can thank my wife Megan for the pictures. Otherwise there wouldn't be any... lol
 

Attachments

·
Registered
Joined
·
2,484 Posts
Discussion Starter #9
The Method Described (pictures pt2)

More pictures.
 

Attachments

·
Registered
Joined
·
2,484 Posts
Discussion Starter #10
The Method Described (pictures pt3)

More pictures...
 

Attachments

·
Registered
Joined
·
2,484 Posts
Discussion Starter #11
Cracks and Splits

I won't be going into crack repair so much as it's pretty straightforward;

Identify the crack.

Sand surrounding area you will be attaching fiberglass too.

Glue crack together if you feel it's nessessary (I did not in this project, but if it's your first time I would advise it just for stability of the workpiece).

Clean with acetone just prior to application.(every time, all the time, just like paint)

Glass away.

I did this particular repair fast and easy, and did a one side repair, but if you wrap all the way around it will be much stronger. We will be doing that later on our missing piece.
 

Attachments

·
Registered
Joined
·
2,484 Posts
Discussion Starter #12
Missing Parts and Pieces

A very common error when attempting a repair with missing pieces is just jumping into it hoping it works. That never ever works. It's easier to make a sandcastle with soupy mud.

If you have missing pieces your gonna need to make those first, separately. Even if it's just a straight piece that's flat with no curvature, you'll need to make it before you attempt to repair your part. This is especially true if your part contains curvature. This could also be applied to the fabrication of a new part of your own design because that's what were basically doing.

This part could have been divided into an additional stage but I wanted to keep this super simple. The addition of a crossmembers beneath the mounting cup in hindsight would have been nice but oh well. This gets the point across.

Your going to need to start with a simple disposable mold.
 

Attachments

·
Registered
Joined
·
2,484 Posts
Discussion Starter #13 (Edited)
The Mold

This is where we're going to use cardboard, tape, wax paper and the razor.

Its pretty straightforward when it comes to making your shape but it's not so straightforward when it comes to the reality of applying the fiber.

Tape the mold to a suitable surface. Resin is very sticky and your mold WILL move on you if you do not find a way to keep it immobile. Sure you can use staples or nails but later on you'll want to remove said mold in its entirety to bake in the sun and trim the piece effectively so... tape.

Resin drains. If your mold has areas in which resin will collect, make drains. A resin soaked part is no good, and dealing with accociated issues is a pain in the arse later on.

The wax paper and tape. Not only does the mold need to be firmly secure, so does the wax paper. Without the wax paper the part won't separate from the mold and you'll have a mold stuck to your part. That's no fun. Stray away from methods such as panty hose, chicken and fence wire... though very popular for some reason it's more trouble than it's worth. The wax paper must be secure for the same reason the mold base (cardboard) is secure. Resin is sticky and will everything will become displaced when glassing.

When using the tape to stick the wax paper down in compound curved areas, be sure to double wrap the tape. Wrap it once for a poster, sure... but it has a hole in the center that lifts up. You'll need to wrap it on the other plane to prevent this.

The whole goal of the mold is to keep it as STABLE as possible. You don't want anything moving around while glassing. If it can move... IT WILL. That will ruin your day. Take your time with your mold design.

So use the cardboard to create layers and shapes. Tape them up thoroughly to secure. Tape said shapes to the mold base to secure. Be sure to tape on as many planes as you can. X axis, y axis, z axis. Planes.

Once your mold is complete, cut out your glass accordingly and get it done using the method described above. Plan your pieces accordingly. Pre lay the cut pieces on the mold to check it's sizing and modify if nessessary.

When all is said and done you'll end up with one solid piece.

There are several methods for making a mold. This was just a fast and effective way to make a disposable mold. Most common type I use for repairs.

Other ways to create a mold;

Sand and glue or epoxy mix
Foam blocks
Bondo
Wood
A product called PorFoam is great but $$$. I stray away from this typically unless it's required.

Or a combination of any of those. $#*+, use whatever works. Just keep in mind how you intend on releasing the part from the mold.

A good product for this is PVA Mold Release, but again... $$$. You can also use cooking oil, bar soap, candle wax... anything that reminds you of wax paper or any of those materials will likely work. Today, it's wax paper.

Picture annotations;
2.) Note the possible gap in the tape. Plane 1. Axis plane 2 needs to be secured. So fold it over. Everything must be secure.
5.) Note the grill structure reference marks. Also note in pic #1 The reference for front. We will use the reference marks later. Definition of front and rear can be vital. This workpiece is definitely directional.
 

Attachments

·
Registered
Joined
·
2,484 Posts
Discussion Starter #15 (Edited)
Trimming and Curing

Two different things to be noted at the same time. Do not wait for glass to cure to trim it. That's a pain and difficult. Sometimes resulting in a fair amount of blood. Trim when it's halfway hard, halfway flexible, but not sticky to the touch (yea those gloves are getting used up a lot don't touch with your bare hands).

You can use several methods of trimming. For long straight pieces you can use a sharpened paint scraper. For other more intricate areas; scissors and a razor work just fine.

Once the workpiece gets to a "certian" point all your left with is a hacksaw honestly. You can use a dremel or other cutting methods. I don't ever bother. A hacksaw byfar is the most effective manner in which I have found to cut this stuff when it is cured.

Picture annotations;
1.) Note those reference marks from earlier.
2.) Precutting when you can with a straight edge. In this case a sharpened paint scraper.
3.) Cutting with razor.
 

Attachments

·
Registered
Joined
·
2,484 Posts
Discussion Starter #16
Trimming and CuringTri (pictures pt2)

More pictures...
 

Attachments

·
Registered
Joined
·
2,484 Posts
Discussion Starter #17
Trimming and Curing (pictures pt3)

More pictures...
 

Attachments

·
Registered
Joined
·
2,484 Posts
Discussion Starter #18
Finishing Up

When your part(s) are cured up you may proceed to what you originally started doing. Attach the part in the same manor you would with the cracks, except you wrap the glass around said part if possible. Much stronger bond. In this case the grill would crack and bust up before that part would let loose.

In essence, take your time. Plan your next move thoroughly. Do not make haste. Use your imagination to overcome. Think outside of the box.

And above all, don't be afraid of the stuff. If you feel like what you did is subpar, pull it off before it cures. It'll slide or peel right off. Youll have about 10 minutes after your done to decide. 20 minutes from the second you mix the resin batch. Some light sanding and start again. Not really a big deal at all.

I hope you found this article useful.

Hope to see some stuff you guys make. It'll be cool. Broaden the horizons so to speak.

PM me or just shoot me an email if you have a question, I'll get to it as soon as I can.

-Michael.

Picture annotations;
1.)post trimming. I didn't bother with making this looking super nice and oem but it could be achieved with some resin, a syringe, some sanding, add some more layers on the crossmember and a support underneath and you would never know it was repaired...
2.)note I drilled the mounting hole post release from the mold but before I glasses it on
3.)grill without flash
4.)grill with flash
 

Attachments

1 - 18 of 18 Posts
Top