DIY FIBERGLASS Sub Box Making

[savvy]

So a month later I finally finished up making my sub box. For those of you who didn't catch my last thread I decided to embark on the world of fiberglassing. Keep in mind that until the day before i started my project I did not even know what resin was. So everything that I have done can easily be done by anyone with average craftsmanship skills.

Item List

Resin $35 a gallon at Home Depot
Fiberglass mat $6 each I used about 8 packs which is more than you really need.
Cheapest paintbrushes you can find $.79 i used a new one with each layer because these are cheap.
Disposable small bucket to hold resin $1.50 can be reused because the resin hardens and you just pour more on top of it.
Rubber Gloves $5 buy alot of them!
Respirator $25 You will NEED one of these. Not even debatable.
Blue Painting tape $6



I started off by taping off almost the entire trunk with blue painting tape. I strongly advise taping off an area MUCH larger than you actually intend to use. I also used a bag of packing popcorn to measure volume. I took a square box of know dimension and filled that with popcorn then poured that into a bag to get a rough idea of dimension.



I then used a spray adhesive and put tinfoil over the area i was going to be glassing to help make removal easier.



Now comes time to put down your first layer of fiberglass. The directions for mixing the resin and hardener comes on the bottle. You mix the stuff and brush a layer of resin over the tin foil then lay down your first layer of fiberglass and put more resin over that until it is nice and saturated. I did this when it was about 10 degrees out and this stuff took forever to dry. I used a space heater in the trunk and it still took about 5 hours to dry. Repeat this step until you have about 3 layers or enough to be able to take it out of the trunk and have it sit there on its own. I did 3 layers.



After about 3 layers i removed the back of the box from the trunk which is nice because your car will start to air out and not smell like resin anymore.



Once its out of the car you continue to lay down addition layers. Keep in mind the i'm using a W7 so that sucker is a HEAVY sub. You may not need as many layers as i used. I put about 6 layers on the back of the sub box and it was pretty damn thick. Some of the angles were weird and i used sticks from outside to hold up the sides because they kept falling down...i'm ghetto like that.



After you get all your layers on there and you feel that it is strong enough then you cut off all the excess fiberglass and use a hand saw to trim the edges to make them look a bit nicer. After that you make your wooden ring and i used a hot glue gun to secure braces to hold the ring in place. My ring came with my sub but most of you will have to make your own.



Once your ring is secured in place I then took a sheet i had laying around the house and cut it up to cover the front of the box. Yes those are penguins and I love them. I held the sheet there with duct tape. After you make the front of the box you then cover that with resin to harden it up nice and good.



Once that dries you can cover the front with more fiber glass. Again i used about 6 layers all the way around, and you will probably not need that many. After it all dried up I trimmed the edges smooth and applied some Bondo to fill in the divits and what not. PS bondo is F'ing amazing stuff



Bondo works wonders and gets nice and smooth after you sand it. You may need a few layers of it. I only did a rough job with the bondo because i was not planning on painting it but rather covering it in vinyl. I then cut the hole out for the sub and a small hole for the wire terminal.



Once it is fairly smooth and your holes are cut, you are ready to cover the thing in whatever you want. I choose vinyl but because of the odd shapes and turns it was VERY hard to work with. Getting the vinyl to look good was by far the most difficult part of this whole thing. Since only the top and the front of my box was going to be visible, I made sure those looked the best and just made due with what i could with the rest of the box. Overall this is a pretty large box 1.5 cubic feet to accomodate the 10w7 nicely. I think it looks pretty good considering I have never even touched fiberglass in my life.



Overall i used about 3 gallons or resin, about 8 packs of fiberglass, a dozen or so brushes, about 5 disposible small buckets, a gallon of bondo, a yard anf a half of vinyl and more man hours than i care to share. Total cost was about $275 which is a bit more than i thought i would spend but it was a fun project and again I used more material than i probably needed to so you all can do it a bit cheaper. This can certainly be done by anyone with general building skills that can follow directions. It is just VERY time consuming and I have a new found respect for anyone who does good work with fiberglass

[Bwicked]

i willl give you credit for trying. I have done this in the past many times for many cars it is time consuming, as far as supplies go, yes u may have spent way to much on more then you needed. typical cost for something twice that is anywhere between $50-80 total. Aside from that you will need to purchase a breather, power sander, dremel, jigsaw ,, so first time trying cost should be anywhere 200-400 depending on quality of tools u buy to do this. also most subs wont come with the rings, and for a more flush look you should use two sets of rings one to sit on and one for outer, so buy some nice MDF wood 1/4 in to 1/2 depending on ur preference. good job though on the write up!

[usmanasif]

Very nice write up!

[gt3]

Thanks for the detailed write-up!

[zdero]

Great write up. I have done this in another car, but not the Z. I would add a few small details to your write up.

First be EXTREMELY careful not to get any resin on your car. I would recomend taping some plastic around the body where you are working as the resin finds a way to get on your shirt, and then possibly on your paint.

Second, the resin gets all over your gloves, so I would recomend putting on about 5 or 6 pairs of gloves, so you can rip one pair off as they get sticky. You don't want to spend much time changing gloves as the hardener in the resin can dry quickly.

[RareTrick]

I use to be an R&D tech for Composite & Ballistic Materials... we made crazy shat for the Millitary. For someone that knew nothing about the materials you did OK.

Resperator becomes useless as you get use to the smell... same goes for wearing long sleeves as your skin gets use to the Fiberglass... Carbon is worst but you get use to it... dont itch.. especially when its Carbon!!

Next Time try this...
1. - Make a Box from MDF... usually a speaker box with custom formed top doesn't have all the sides so start with your base first. You can use a little bit of bondo to fill the drill holes... sand flat. Take the MDF Base and Wax it... you can use Vaseline... apply just like waxing your car and rubbing into the wood... build up will cause voids so make sure the surface is smooth. *The box is now your mold!
2. - Working Table is good to have plenty of room to move about. You can pre-measure the resin & catalist (seperatly) into small plastic buckets or containers... have rollers, brush, plastic squige, gloves, mixing stick, fiberglass, and a watch so you can time the mixture... you will need to perform a test first! Mix up a set amount of resin and catalist... understand the % so you can add more catalist for faster gell or less for slowwer... if you add to much the resin will get very hot very fast... smoking, cracking, discolored, and bubbles will be the effect of to much... to little and it will take a long time to gell... you will be timing the process from Mixing point to Gell... Gell is refered to as the point were the Resin starts to solidify... you can see it start to happen by using the mixing stick... mix a little pull stick out and use the fall off the write on the surface of the resin... if it dispurses into the mix then its not gelled... when you can write on the surface and it takes about 5-10 seconds to dispurse...its starting to gell... that is your Final. At that point you should not use the resin, because it will no longer absorb into the fiberglass.
*Resin will NOT gell quickly in the cold... good working temp is about 75 deg. common mix is about a 30 min. gell time.
3. - Layering is good but you dont need alot of Fiberglass to make something strong. You are creating a Matrix... the resin consumes the area around the fiberglass, the fiberglass make the resin stronger. Most hand lay-ups consist of about 60% Fiberglass 40% Resin final product... that is alot in Millitary terms. You can do some tricks to make Less resin in the Glass if needed. You will be working out of a single mixture so make it enough to get you through... remember you have a time limit but dont rush... if it starts to gell...stop! Apply a layer of resin on the Mold (outside as this is the true form), then apply a layer of Fiberglass and work it to where the Glass becomes translucent (clear)... no bubbles... continuse abouit 3-5 layes and be consistent and do not overlap the edges of the fiberglass... cover edges with next layer. Work the bubles out untill you have no more time and Resin starts to gell.
4. - Curing resin is more than just sit and wait... honestly the best way is to add heat with out causing warping or damage to the mold. on a nice summer day you can take a black towl a make a tent over the mold... or if your inside with a small space heater place the mold and the heater under a table and drape or block of the sides so it makes an oven. Dont catch anything on fire. 200 degrees is plenty of heat... nothing crazy. After the resin has cured for about 1-2 of heat and about 12-24 after gell you can start the second part. Remove the part from the mold... air gun or rubber mallet will help release.... you will see the air seperate the FRP from the mold... usually air is white. Once off make sure you have no oddities like air bubbles or voids. Clean the part and trim the undeeded excess. If you have a Void you can make whats called Glass Bubbles - finely grind up the excess glass into a container like a powder (this may itch and its messy)... mix with resin and catalist (slightly hot mix) and make a paste... use this paste to fill the voilds or holes.
5. - Rag Top is an easy way to make a working part... mainly used in audio. Fabric expands when wet so realize this before you lay the fabric top. Make your speaker rings or amp mounts from MDF and wax them. Mount as desired and lay the fabric from the ring down... staple the fabric alot so it wont flex as much. Mix resin and litely brush the fabric... do not saturate... if you do it will simply leak to the inside of the box. Let it Cure... next day add a little more resin and build up with layers of Fiberglass. Let it Cure... use some heat... clean the excess. Use 80 grit sand paper to get the form and shape smooth... move to 120, to 220. then primer and sand... then paint to match whatever color you like.

enjoy...

Peace
Drew

[Int3rlagosZ]

Where exactly do i get the fiberglass mats? And will the resin drip if like i applied it for a peice under my rear bar?

[SuperBlack350z]

Originally Posted by Int3rlagosZ

Where exactly do i get the fiberglass mats? And will the resin drip if like i applied it for a peice under my rear bar?

boating stores, most hardware stores. yeah, it will drip a bit even if you mixxed in more hardener.

[SMART Auto Perf]

I'd like to do this in my Tundra (rear storage bins, fill with three 8").

[mw9]

Very nice DIY. This site has alot of good DIY's.

[slick_9191]

Originally Posted by savvy

Dude, did u buy those sheets from one of my moms garage sales?!?! Those exact penguin sheets were mine when i was a kid!

[350 Rookie]

Heres my first project. This picture is not done yet. But i have finished the project and ill post pics of the final product.

[adamtaylorpcb]

nice write up

[j rad]

so since its 100 out here in texas, drying time shoud be alot faster right?

[savvy]

Originally Posted by j rad

so since its 100 out here in texas, drying time shoud be alot faster right?

haha yeah drying time reduces with heat. I know shops with heat lamps are able to put down several layers a day and dry them all versus my one a day in the freezing cold.

[35OcraZy]

Originally Posted by savvy

I then used a spray adhesive and put tinfoil over the area i was going to be glassing to help make removal easier.

So what kind of spray adhesive did you used? And did you spray the adhesive directly on the Painter's Tape, then put tinfoil over it?

And whats the purpose of that exactly? Just so u can remove it from your trunk, correct?

[HyperSprite]

I did a similar writeup here http://www.hypersprite.com/auto/tech-z-006/default.asp
On the page I also linked my sources since it was my first FG box.

The biggest difference from the OP is half of my box lives half under/half over the stock trunk floor. This allowed it to be held in by the spare tire and take less space. I also used far less tape and resin.

[35OcraZy]

Also, anybody know the difference between fiberglass mat, and fiberglass cloth besides it's appearance? Or what each is best used for

[savvy]

Originally Posted by 35OcraZy

Also, anybody know the difference between fiberglass mat, and fiberglass cloth besides it's appearance? Or what each is best used for

I am by no means an expert but what I gathered from this whole thing was that the cloth is much thinner and much easier to manipulate around corners and curves than the mat is. However being much thinner than the mat, you need many more layers. It's almost like comparing a thin cloth sheet to a thick flannel one. I had used both kinds, the cloth for the first couple layers to get the best shape possible, then i switched over to the mat for thickness.

[sintaxeror]

Originally Posted by 35OcraZy

Also, anybody know the difference between fiberglass mat, and fiberglass cloth besides it's appearance? Or what each is best used for

the cloth is not meant to be structural, although you could still use it for a sub box -- it would just take a zillion layers.

Use the mat, and just get some lower weights for the corners.