Fiberglass 101 - Tutorial

Fiberglass 101
Tutorial
By: TheSilentChamber

As fabricators and general car modification enthusiasts; we are often confronted with the dilemma of what materials are practical, reasonable, and best suited for the job. For many applications fiberglass falls in all of these categories. In this tutorial I am going to cover the basics, Fiberglass 101 per say, as I cover the building of a very basic but functional and attractive amp rack. This tutorial is part of a series; soon I will cover more advanced applications, different tricks and techniques, and composites other than fiberglass.

This tutorial will cover the building of a fiberglass amp rack that will fit inside a spare tire.

http://img.photobucket.com/albums/v608/thesilentchamber/fiberglass/01.jpg

Materials Need:

Fiberglass resin (polyester will be the most available)
MEKP (Hardener, most of the time it will come with the resin)
Fiberglass cloth
Paintbrush
Body Filler Spreader
150 grit sand paper
220 grit sand paper
Foam
Foil
Measuring cups
Acetone (Optional – needed if you want to clean and reuse measuring cups and brushes.)
Masking tape
Dremel (or other means of cutting the fiberglass)
Scissors

Step one:
We are going to start off with one of the most basic of forms, foam. This is insulating foam that can be found at any home improvement or building supply store. To get the basic shape I pressed it down on the lip of the spare, thus leaving the impression of the rim, simple but effective. Next I cut it out and sanded the edges with 180 grit and 220 grit sand paper to a smooth edge.

http://img.photobucket.com/albums/v608/thesilentchamber/fiberglass/02.jpg

Next we will be covering the foam in foil. If you do not cover it the resin will eat away the foam. Cover it and tape it on the back so it stays in place. If you put the shiny side up, the foil peals off of the cured fiberglass easily.

http://img.photobucket.com/albums/v608/thesilentchamber/fiberglass/03.jpg

After you have the foil on, the next step is to cut and lay out the fiberglass you will need. On this I will be using one layer of 18oz cloth and two layers of 4oz cloth. The weight of the fiberglass is how thick/strong the fiberglass will be. Also the heavier the fiberglass the more pattern of the weave will show up in the cured laminate and also how easily it will sand. The 18oz will provide most of the strength while the 4oz top layers will reduce bleed though of the heavier cloth on the bottom and provides a nice sanding surface. Most people will be using hardware store or auto parts store fiberglass, witch is usually around 6-8oz This builds up quick to provide strength and sands easily. If I were to build this amp rack with 8oz cloth I would want to use about 6 layers to provide the strength. I do a lot of fiberglass work so I stock various weights in bulk.

http://img.photobucket.com/albums/v608/thesilentchamber/fiberglass/04.jpg

http://img.photobucket.com/albums/v608/thesilentchamber/fiberglass/05.jpg

Once you have the cloth cut you will need to mix your resin. Most of your typical resin will be polyester base, it provides good strength, sands easy, and is the cheapest of different kinds of resin. You want to mix at 1-2% resin to MEKP (hardener). I use 1 cup resin to ½ tsp MEKP. You can pick up some stainless steel measuring cups at most all grocery stores and supermarkets. I do not recommend using plastic as they can melt.

Once the resin has been mixed you need to cover you foil in a good layer of resin. I use cheep natural hair brushes. They run around 75 cents each so they are disposable if you don’t want to clean them.

http://img.photobucket.com/albums/v608/thesilentchamber/fiberglass/06.jpg

Now lay on your first layer, on this layer I used the 18oz cloth, as it will be on the bottom. Spread more resin on top of this layer working it into it by using the tip of the brush in a dabbing motion. The cloth will start to become almost clear as it is saturated. I also use a putty spreader to work the resin into the cloth.

http://img.photobucket.com/albums/v608/thesilentchamber/fiberglass/07.jpg

Next we will repeat the last step with the next two layers. You should place the layers on a 90* bias to each other to provide maximum strength.
http://img.photobucket.com/albums/v608/thesilentchamber/fiberglass/08.jpg
After you have gone over the resin with the spreader to it should look something like this. The spreader will squeeze out the excess resin and help achieve a good wet out.

http://img.photobucket.com/albums/v608/thesilentchamber/fiberglass/09.jpg

Let the resin cure. Depending on the temperature and the number of layers you put on it should take between 30 minutes and an hour. After it is cured you can remove the foam from the backside and peal off the foil. You could leave the foil on, but I always peal it off, as it will be on bottom and won’t be seen you can skip this if you want to.

http://img.photobucket.com/albums/v608/thesilentchamber/fiberglass/10.jpg

The surface will be relatively smooth already but you will want to sand it with 150 grit to knock down some of the high spots. I did this before I cut out the shape, it can be done before or after though.

http://img.photobucket.com/albums/v608/thesilentchamber/fiberglass/11.jpg

http://img.photobucket.com/albums/v608/thesilentchamber/fiberglass/12.jpg

Next I used a Dremel and cut-off wheel to cut the shape. The foam left a perfect outline on the backside that I followed.

http://img.photobucket.com/albums/v608/thesilentchamber/fiberglass/13.jpg
Check for proper fitment and sand the edges with 150 grit.

http://img.photobucket.com/albums/v608/thesilentchamber/fiberglass/14.jpg
You are now ready to paint. This could also be covered in various materials if you so wish. Primer it with a good quality high build primer

http://img.photobucket.com/albums/v608/thesilentchamber/fiberglass/15.jpg

Wet sand with 220 grit with a block to level out the surface. This was smooth enough that it required no body filler, depending on what you are making and things with more complex shapes may require the use of a body filler to smooth out the surface (more on this will be covered in the next tutorial).

http://img.photobucket.com/albums/v608/thesilentchamber/fiberglass/16.jpg

You are now ready to reprimer and finish out with the paint of your choice. I chose to paint it the same color as the amp, orange (yes I know the picture looks red).

http://img.photobucket.com/albums/v608/thesilentchamber/fiberglass/01.jpg

This is a very simple fiberglass laminate, but is something very easy for the beginner to start with. This tutorial will be followed by a couple more that will proceed to more complex builds and techniques. Feel free to ask any questions.

Awesome tutorial man 'preciate it. I think it may deserve a sticky!

Finally ;)

Now we need some more like free standing construction and Fleece streching/glassing. i am contemplating building a fiberglass structure for the computer componets that will be going in my truck for video/mp3 storage, i will probably use mat and fleece streching. If i do cary it out ill post up.

good work, something like that is what anyone should start with.

Yeah, more advanced stuff is comming real soon (seriously lol). And yes, it does deserve a sticky lol.

I might do some welding tutorials and metal working tutorials.

I had read a post similiar to this in a club I was with. That guy said i could cut the cloth in strips to get the mold I want, and use chicken wire(which im not after reading this). Im going to be doing a door of my car any tips on this?

Now that you have my attention, I'm also interested in the followups, as I'm planning a major customizing project, including Custom Ground Effects, and Rear Spoiler.

I'd like to see the process for LARGE parts (like a Fiberglass Hood, for example)!

Thanks for sharing your skills and techniques with those of us who haven't tried, yet! :icon16:

Awesome tutorial man 'preciate it. I think it may deserve a sticky!I agree. Nice

TS out

Chicken wire can be used in aiding free standing constuction... which is probably what he was talking about.

BTW. Fiberglass hood is a HUGE project...

Fiberglass hood can be a weekend project if you have all the materials ready to go friday afternoon. Follow ups with more complex will be posted in two weeks - give or take a couple days. Going to do a speakerbox that I may write a speakerbox tutorial on, but I dont consider that real indepth, so I might throw that up in a week or two, post it in the audio forum also. In the advanced write up I will be major interior work, all starting from scratch. Part three will cover all the differnt types of molds, freestanding buildup materials and such, tips and processes I have learned. Check back offen.

hmmm, i can post up basic surfboard repair... :) if anyone wants it... but it doesnt just apply to surfboards, body repair and other things use the same principals.

Cant wait for the interior/advanced stuff, the most advanced ive gotten was a ported fiberglass enclosure. nothing special. and i build a short board but that isnt all that advanced eitehr...especially the way it turned out.

I had some people ask, its held to the spair tire rim with velcro, there is also cable looped though it under the amp that is attached to the bottom of the car.

BTW. Fiberglass hood is a HUGE project...

I kind of figured as much.

I already have a one of a kind Fiberglass Hood that I'd like to repair, mainly, not necessarily build from scratch.

It seems to be too thin in some areas, and the edges are very fragile, to where they are cracked and broken.

It's a Cowl hood with Ram Air scoops! I'd like to fix it up for a Display, as it's just a pin on hood, and not very functional, anyway.

Mostly, I'd like to see how to "reinforce" the Fiberglass that I already have, if there's a way that I can.

That is very possible.
i would post up thoes repair pictures for you to draw some ideas BUT i cant find them on my computer...so untill next time...

....so TSC, where's the rest of the fiberglassing tutorials?? it's been awhile and i've been damn patient enough. haha. but seriously, are you currently working on any more about glassing or what's the deal?

:grinyes: I am a fellow "fiberglass technician". Any questions I will attempt to answer. Be specific!

:grinyes: I am a fellow "fiberglass technician". Any questions I will attempt to answer. Be specific!

I got a question for you. I'm new to this whole fiberglass thing so please be patient with me... anyway i'm currently trying to make a custom light housing and face for some BMW euro-projection headlights. now my question is when i make the mold for the housing do i have to concider how thick the fiberglass is going to be? thanks.

I got a question for you. I'm new to this whole fiberglass thing so please be patient with me... anyway i'm currently trying to make a custom light housing and face for some BMW euro-projection headlights. now my question is when i make the mold for the housing do i have to concider how thick the fiberglass is going to be? thanks.

Wow, that is a good question. TSC? CF? You guys have this one.

I got a question for you. I'm new to this whole fiberglass thing so please be patient with me... anyway i'm currently trying to make a custom light housing and face for some BMW euro-projection headlights. now my question is when i make the mold for the housing do i have to concider how thick the fiberglass is going to be? thanks.

You allways have to take into consideration the thickness of any materials you work with. When you refer to mold, what exactly do you mean? Mold is a common term that alot of people use in referencing composites, but its rarely used in the right way.

what i mean is the foam mock up of the housing, i'm going to use the covers that cover openings to access the bulbs from the original BMW headlights, so i need to make the mock up have basically the samething incorerated in it. I just need to know if i have to make the mock up just a little smaller than the finial product, or if i make it the real size will it work anyway...
I know.... a bit of a stupid question, but like i said i'm new to this whole fiberglass thing....

In general if your using foam as a base you will want to make it smaller than the final product.

sweet... thanks for the info. one last thing what is the average thickness of fiberglass. i know it depends on the amount of layers used, i was thinking 12oz layered twice, does that sound right for a light housing?? do i need more or a different weight of cloth??

Thats not going to be strong enough for anything more than pure cosmetic piece. I'm still not real sure on exactly what your trying to make here, so its hard to say how strong it needs to be.

REPLY

Someone asked me about fabrication of a headlight bucket? I can't find your post, but i'll try to help. I made one to replace a crappy rectangle headlight on a Tomos scooter once, and here's how.
I wanted a round one, so I actually used a ballon for the shape. Since the polyester resin would eat through the ballon and pop it before the gelcoat hardened, I spraved PVA (Poly Vynl Acetate) on the ballon as a relese agent. This worked better than wax because it assured me a good thick coat and was quick. I then applied my gelcoat and a layer of fiberglass mat. after lightly scuffing up the glass, I then built it up with heavier glass. If u don't do this u will get print-through of the pattern of the glass due to heat from the curing process.
I deflated the ballon and took it out, and cut the mold down it,s center. Keep in mind the front of the bucket was unnecessary, so i didn't make an entire sphere. O.K., I cut it so I could remove the part from inside of it w/out damaging it later. Be carefull cutting to not chip off gelcoat from it's edge.
The 2 halves i placed on a waxed peice of plate glass, and laid down gelcoat and sucessive layers of glass to form a lip that would mate to the other side. Pull both pieces off the table and put yhen together lip-to-lip and align them. clamp the flanges together when they're flush inside, and drill some holes through the flanges to put bolts through. with bolts in place and both halves waxed, here's your mold
To mahe headlight mounts, make them in the finished part as tabs glassed in from the inside. a nice peice of shiny cardboard waxed up cut into a ring for acess put against the lamp opening will work great. Hot glue will temporarily keep ot there for you and peel off of your gel w/out damagong it.

To claim your a "fiberglass technician" your a fucking dumbass. You dont use gelcoat to lay your glass in, "print though" as you call it, is not caused by heat, and the last part about shiny cardboard I'm not even going to coment about.

really? What do you use, Dupont basecoat-clearcoat? you are the fucking moron

Gelcoat cures anerobically. I'm sure you dom't know what that means, so I'll explain. When you put gelcoat in a mold to make a part, it never fully cures untill you lay up your fiberglass on top of it. The gelcoat hardens when it is no longer exposed to air. THAT IS WHY YOU BED FIBERGLASS IN IT. IT IS CHEMICALLY DESIGNED FOR THIS PURPOSE.

Gelcoat cures anerobically. I'm sure you dom't know what that means, so I'll explain. When you put gelcoat in a mold to make a part, it never fully cures untill you lay up your fiberglass on top of it. The gelcoat hardens when it is no longer exposed to air. THAT IS WHY YOU BED FIBERGLASS IN IT. IT IS CHEMICALLY DESIGNED FOR THIS PURPOSE. And if you have ever tried to pit fiberglass in a mold w/out gelcoat, you will realise it is very difficult to remove all the air from your laminate schedule.

Print-through is caused by building up too much material derectly on your gelcoat. The reason is that fiberglass produces heat when it cures, and that heat causes the gelcoat to shrink-i.e. print through. And as a moldmaker and custom fabricator, you use anything you can that suits the purpose. and in the case of the "shiny cardboard", anything more would be unnecessary. This thread is for people that wish to gain knowledge, so please know what the hell you are talking about before you try to discredit my help. If you attempt a battle of wits or knowledge with me you WILL lose.
thank you

REPLY THE RUSSIAN

I found your original question. If you are going to make a production mold, it should be strong. you will want to use tooling gelcoat (it is harder than regular, and comes in black or oarnge). But first you need to make the shape that you want your part to be, and use this to create a mold from. This is called a plug. Styrene foam is good to use, because it's cheap and easily sanded or cut. Use this to approximate the desired shape, keeping in mind that you need to build it up with something to make the finished surface smooth and non pourus. Bondo works great for this (cheap and easy to work with. some epoxy fillers work better (they're less pourus) but requre specific mix ratios, are harder to sand, and are bad to get the dust on your skin or in your lungs. Bondo works good, you just need to wax it really well before you make your mold from it. Finish the bondo with about 220 grit, and apply a few coats of wax. I like using Johnson's paste wax on bondo because it fills in the pores. Apply it, then buff it off using a clean soft rag. I would do 4 coats. PVA works great, too. This plug should exactly resemle the desired shape of the part.
You need to build up the thickness of your mold, so after you have applied a good thik layer of tooling gel to the waxed plug, and the gelcoat has cured, put 1 or 2 layers of light mat on it. Use enough resin to leave the surface smooth enough to lay up your next layer. If it looks like the silent chamber's picture, you have used way too much resin, and didn't get the glass to lay down well enough (lol). After the layer of glass is cured, scuff it up a little with 80 grit to allow the next layer a mechanical bond.
Woven roving is usually the best to go with on sucessive layers, cause it forms well and it's cheap. you don't want to use it on production parts, though: it ends up being heavy and brittle. Use a bi-directional cloth.
repeat the scuffing and laying of roving untill you get a good thickness (usually 3/8" for a good mold of this type). There you have your mold.
Flanges made in the mold to create a multi- piece mold (to be able to remove the part) are usually put in when fabricating the mold.The heavy type of craft paper that has a shiny surface works good, because it is easy to cut, and can be curved slightly to make the mold pieces fit together more accurately. Position it so that the seam created will allow the part to be pulled out of the mold. Cut it so that it's edge is flush with the plug's surface, and"spot- weld" it in place with hot glue on one side only(the side opposite if the first half you make). Wax the crap out of it, and lay up one half of your mold. Remove the divider, wax the flange of the existing mold half (and the plug again, you've probably wiped some wax off in the process), and build the other mold half, using the existing flange to make the other half. Keep in mind that you need to use putty when laying up fiberglass in a hard corner, or it will create voids. The best way is to make a pie bag that you put catalised putty in, squirt it into the radiuses, and laminate on top of it before it cures, trying not to force the putty out of the corner.
Oh and one last thing. Keep in mind that your mold must have a draft angle to allow the part to come out.
This type of mold should work very well for you, and the opening for the headlamp should allow you acess to make the part inside of it.
You should make your part with 1 layer gelcoat, 1 layer fiberglass mat, and probably 2 layers of an 8-10 oz. cloth. you will be able to tell once you make a part how stiff it should be. You can also reinforce stress or mounting locations with more material in these locations. Have fun and good luck.

REPLY THE RUSSIAN

Oh and one last thing. Keep in mind that your mold must have a draft angle to allow the part to come out.
This type of mold should work very well for you, and the opening for the headlamp should allow you acess to make the part inside of it.
You should make your part with 1 layer gelcoat, 1 layer fiberglass mat, and probably 2 layers of an 8-10 oz. cloth. you will be able to tell once you make a part how stiff it should be. You can also reinforce stress or mounting locations with more material in these locations. Have fun and good luck.

i don't know what you mean by draft angle... could you explain that to me... and i stoped by NAPA today and picked up some fiberglass cloth 12oz, resin, hardener, sand paper, etc. i didn't see any fiberglass mat... where is a good place to pick that up..
thanks alot guys, its been alot of help.

I will loose huh? Gel coat cures due to a chemical reaction, has nothing to do with air. Gel coat has no physical properties that makes it appropriate to use insted of resin, which is what you are suggesting you do. Gel coat is usefull when mold making, not completeless nessassary, and not used in the manner you are suggesting. It should be used as a base, and as a base once it sets you lay your struction up on it, not into it. You may not need anything more than a piece of cardboard, but nobody can tell what the fuck your talking about, its not even in broken english, its in some form of jigberish.

They have an edit button for a reason.

Struction? Jigberish? Try spellcheck asshole before you go and knock someone else. Duh. I should show that one to my english professor. Sorry if I misspelled something, I was too busy replying to you instead of people who needed my help. Try reading a book - gelcoat fully cures anerobically. You obviously have nothing better to do than knock me all day instead of offer advice... you claim to know so much more than me why are you wasting your time writing to me at ALL? Hmmm. L O S E R

i don't know what you mean by draft angle... could you explain that to me... and i stoped by NAPA today and picked up some fiberglass cloth 12oz, resin, hardener, sand paper, etc. i didn't see any fiberglass mat... where is a good place to pick that up..
thanks alot guys, its been alot of help.

A draft angle is like when 2 plactic cups fit together... or are stacked together. Does tha make more sense? One has to pull out of the other. If you are using the bottom cup as the mold, the top cup (your part) has to come out of the 1st cup.
If you want quick access to fiberglass materials try Home Depot. They have bath tub repair kits that should contain mat... they also sell resin and cheap brushes. If you happen to live near any bodies of water... lol... a store called West Marine (or any marine store) will give you a better selection.

thanks it does help... a bit... i finally found some fiberglass mat... autozone... go figure.... and i got all my other supplies other than the gel.
i'm going to start on the box later this week.... we'll see how that one goes. thanks alot guys, if i need some more help it will be on a its own thread showing you guys my issues.
thanks again

Struction? Jigberish? Try spellcheck asshole before you go and knock someone else. Duh. I should show that one to my english professor. Sorry if I misspelled something, I was too busy replying to you instead of people who needed my help. Try reading a book - gelcoat fully cures anerobically. You obviously have nothing better to do than knock me all day instead of offer advice... you claim to know so much more than me why are you wasting your time writing to me at ALL? Hmmm. L O S E R

I'm waisting my time because I'm tired of all the people who have played with fiberglass once thinking they are experts and posting false information. I'm not saying everything you say is wrong, just some of it is not entirely correct, like the gelcoat you keep bringing up, it cures by chemical reaction, it does however remain tacky if exposed to air. You have posted some helpful information, and I give you credit for that.

Try this. Mix some gelcoat and put enough to make a good size chip on a mold surface. After it cures, take it off, take a rag with acetone on it, and try wiping both sires. The exposed side will leave gelcoat on your rag, the mold side won't. That is because gelcoat is designed to make a chenical bond with the fiberglass; it isn't fully cured. Oh, and i've been a custom boat builder for the past 8 years, professionally. How about you?

Like I said, the exposed side will remain tacky, but not nesassarly uncured.

I have been in every aspect of composites- from materials buying, design, fabrication, finishing, testing, to quality control for about eight years also. You clearly know more about the subject than I initially believed when I first tore into you, and for this I am sorry. We get alot (and I mean alot) of people around here that know absolutly nothing that try to pass themselves off as experts. I am in no way an expert, but I have real life world experience in full time composites, in everything from non structural accent pieces to pieces that have to endure constant beatings and stresses. I'm sure you share alot of the same knowledge and experices that I do, and I'm sure between us there wont be any questions that will go unanswerd in the new fiberglass forum.

Thanks for the respect. It will be returned.

Anyone got any tips on how to hop up a 10 horse Craftsman riding mower engine? I garbage picked one and I'm making the framerails and body out of lewan and door skin, laminated with a high grade polyester and covered in light cloth. I'll post my pics so you can all laugh at me or be inspired, your choice.

I was just in other threads in the fiberglass thread and wanted to ask where you guys got the idea of covering your shit in tape to make a mold from it? You prep a part to mold it with a release agent - wax or spray on PVA. This retains all the detail of the original part. 3-4 good coats of a wax designed for this purpose does the job, and the mold actually comes off the part. You apply the wax, and either while it is drying or after it does you buff it off with a rag.

Don't know where I got the idea from, but it's cheap and fast. No waiting around for wax to dry etc. I don't do it often tho...

My understanding of gelcoat is that it's a hard protective layer for the composite materials. Otherwise the mat or cloth would become exposed and the part would fail.

That being said, I've never used it, mainly cuz I can't get it at Home Depot:grinyes: . I've done the below hood and airdam with HD stuff, mat was from Aircraft Spruce. I wonder, is there any reason I should start to use gelcoats?
http://img.photobucket.com/albums/v609/v8z/zcar/myv8z-05-04-23msa-60.jpg
I still need to color sand the air dam...I made a female mold for the airdam using the same materials (no masking tape tho!).

That's one of my favorite cars, but you need to fix that gap between the front air dam and the fender. How did The Silent Chamber get banned?

here's my question.
i'm planning on custom-making a gauge cluster for my truck.
i wish to remove the old one, and modify it.
i don't think i need to custom fabricate a whole new one, as i can cut the old one up and use the basic shape and frame to create a new one.
here's a pic
http://www.gmcpaulstruckparts.com/Pix/85%20Chevy%20interior.jpg
not my truck, but same dash panel.
i want to move the speedo over to the section with the 4 smaller gauges, and eliminate the right-hand large hole.
then move the 4 smaller gauges to the center, and block out the shift indicator (moved my shifter to the floor)
i know this is possible, and i'm hoping that fiberglass is my solution.
i'll gladly post a how-to once i'm done, i just need a professional opinion of some kind before i tear my truck all up.
can this be done?
how long will it take?
what materials should i use? (thickness, etc.)
just any help is appreciated.
i'm buying my new gauges and senders etc. in about a month or two so i'll keep checking back.

i use wax paper instead of foil,,doesnt rip on me as easy lol,, and for the chicken wire,,anything that will hold the wieght of the glass is fine to use,,as long as its easy to rip out after,,or never going to be seen, i've used everything from wire,,wood,to some cardboard,,and the cardboard work won a number of prizes in car shows,,lol

P.S. one of the most important thing bout fiberglassing is to make sure you roll,,squeeze,push,shove out all air pockets,,is the #1 mistake that you even find the gaint automakers make every day

I want to fiberglass this bottom valence to my rear bumper. Here is a bad picture of what I want:

http://i3.photobucket.com/albums/y97/DeusExMaxima/Maximacenterexhaust2-1.jpg

Any ideas and suggestions as to how to make this part?

i'm new to fiberglassing and want to know some things. today i bought a Bondo repair kit just to try it because i didnt want to spend a lot of $ and be terrible at it. my question- im trying to mount a PSP in my car with a simple case. i want to use something similar to the back of this case as my mold. (i dont need a front as i want it to be removable) would this even work? would i start by waxing the case and then applying the Resin/Hardener and cloth? would mat work better? and is this all i would need to complete this. like i said, i am new to fiberglassing so please be patient with me. thanks
http://www.daydeal.com/files/images8/psp2000_protector_clr_4.JPG