Fabricating Fiberglass Pieces

[desert_starion]

I was lookin at Pimp My Ride on MTV, and i really get fascinated by those fiberglass fabricated sub boxes and enclosures and interior covers.

 

I recentley gutted the back my car and took all the carpeting out, remounted my battery! I decided not to put the trim pieces back in, some of them have broken clips and plastic parts and personally I just never liked it anymore, since they hold on to dirt and dust. Plus I want to build a better middle console that can accomodate an LCD plus a few gauges and a cd/dvd player.

 

I always wanted to learn how to do what those guys do and kind of build my own trims out of fiberglass material so i can cover everything back up again, and maybe throw some electronics back there and hide them up real nice.

 

Is there anyone that can give me info on what materials i need and some info as far as fabrication? I know having someone build it may cost an arm and a leg and probably better due to better experience and knowing that fiberglass dust is some horrible stuff to breath in!! but I am always up to new challenges and learning new stuff..

[D_Venable]

they usually use fleece, and fiberglass resin. you can find fleece at wal-mart (fabric section), and the resin at any autoparts store.

 

and buy lots of sandpaper, fiberglass is a complain to sand.

[OBSESSIVE_ENT.]

I HAVE BEEN DOING A CUSTOM PROJECT FOR A FEW YEARS NOW (KEEP STARTING OVER) YEH FLEECE AND RESIN. BUT I GET MY PRODUCTS FROM SELECT PRODUCTS YOU WILL NEED SPEAKER RINGS IF YOUR NOT THROWING IN A BOX. IT TAKES AT LEAST 4 LAYERS OF FIBERGLASS FOR A RIDGID PART AND AN EXTRA 2 FOR SANDING PURPOSES. THEN A LAYER OR TWO OF BONDO. GOOD LUCK SANDING WITH HAND IS A KILLER. BUT AFTER A WHILE YOU WILL GET IT. YOU CAN SEE SOME OF IT ON MY SITE OBSESSIVEENTERTAINMENT.COM IN THE OBSESSIVE RACING SECTION. IF YOU HAVE ANY QUESTIONS JUST GIVE A HOLLER

[shift1313]

if you can it really pays to make a mold. When they do it on pimp my ride they form it right on the panels usually but molds make your sanding time very minimal. Wood can be a really good mold material and its very easy to sand, but you have to seal the wood!!! Same thing with bondo. Its easy to work with and sand, but its porus so you need to seal it, paint usually does the job but several coats, then clear, then 4 layers of wax. And make sure you have the righ wax, car wax will work but what for silica content, it will bond with the resin if you buy the bondo stuff. I found this post online.

http://www.the12volt.com/installbay/forum_...=74519&PN=1

 

i think most guys do it this way with an mdf frame. I know a guy that makes a full box and then lays the glass. I dont do speaker stuff, i mostly work in motorcycle parts but to me this seems really heavy.

 

My advice to you would be to play around. Dont try to build a final piece on your first go around because chances are you wont get it right, or you will have to spend alot of time sanding. Keep lots of gloves on hand. Precut your fiberglass, you probably want to get the random strand stuff for somethign like this, it will form into tight corners better, keep chip brushes around($.50 from walmart) and i keep rubber spreaders around to consolodate, alot of people use special purpose rollers which are probably better but the spreaders or spatulas seem to get the job done for me.

 

good luck

[Burton]

What they said...

 

 

Only, I never hand sand FG. You're gonna have to finish it out with some bondo anyway, so you might as well make it easy on yourself and work the FG in with a right angle grinder- much easier. AND WEAR A MASK OF SOME SORT!!!! I spent a day in the hospital and two weeks out of work and school after sanding FG without a mask one day on an old Vette we restored.

 

 

I've played around alot with FG. While I'm no expert on the subject, I dare say I know a little more than the average bear so I'll try to run you guys thru the steps...

 

 

Anytime you can use wood as a frame, the better. For instance, if I were to build a sub box I would make a 4 or 5 sided 3/4" MDF box, but leave the 1 or two surfaces that eventually will be FG open. Use MDF to make rings for the subs to mount in, then a frame work to hold them in place. After that is done you can start thinking about laying the fleece and resin. First tho, you will want to either grind or sand with a corse grit on all the wood surfaces that will come in contact with the FG- this will give the resin something to "bite" into which will keep the FG from separating from the wood once you start building up SPLs in the box.

 

At this point I'll start laying fleece. I start by just brushing on a little resin on the wood in all the areas that the fleece will meet it. I then take my piece of fleece and stretch it over the contours and staple gun it in place on the sides. I always leave about 6" extra fleece all the way around on my first layer. Once the resin you brushed on is dry and the fleece is stuck to the wood good, its time to coat the whole first layer of fleece in resin. This first layer is tricky- you want to get planty of resin to soak into the fleece, but you don't want too much. Too much may weight the fleece down and cause it to stretch before the resin dries. I only resin the areas of the fleece that I want to leave on the box- my 6" of extra fleece I try to keep the resin off of as I plan to cut the extra off. Once the first layer is cured, I cut the extra fleece off just past the edges where it meets the wood frame. At this point I take my grinder and rough up the whole surface slightly, giving special attention to get the edges of the fleece where they mold into the wood part and the surrounding wood area cleaned up and scuffed well- once again, for "bite". Now you can start puting down more layers- there's a couple ways to do it 1) cut the fleece to size, soak it in resin, and lay it over the first layer making sure to overlap your first layer and go about an inch further onto the wood frame than the last layer. Or 2) brush a nice layer of resin over the whole first layer and an inch past the edges, stretch and stick the next layer of dry fleece over it and make sure you like how it lays, then resin the whole area of dry fleece before your glue layer of resin dries. I usually opt for #2.

 

Repeat the process of grinding resining and laying 4 to 5 times for a subbox or other sturdy part or 2 to 3 times for speaker pods or lightweight trim pieces that don't need as much rigidity. Once you get the thicknes and basic shape desired I take my grinder and use it to sculpt the FG to the exact shape I want. I will then use smaller pieces of fleece and resin or sometimes FG filler or "kitty hair" to fix smaller areas and contour that need build up. Then I grind those areas out to blend and be smooth.

 

Now you can start laying plastic filler or "bondo" down on it and start using sanders/sandpaper to get it finished out perfect and smooth. From there its pretty much just like doing bodywork on a car. Fill and sand til your satisfied, spray with numerous coats of filler primer and wetsand that out to perfection. Paint it, clear it, install your subs and BUMP!

 

Speaker pods are done similarly, but are way easier. Sub boxes need to be sturdy and flex free to build up good SPLs. for mid range speakers the sturdiness and thickness is not as important. For pods that will mount to a flat surface I will start with a 1/4" thick board for a backing- pegboard works great for this. Then I build up my frame where I can with wood and wrap it the same as the sub box, but not as many layers.

 

For pods that will be mounted in contoured areas- like say some kick panel pods in an area that carpeted and contoured- I will first start out covering the whole area and surrounding area in masking tape. I then take spray glue and spray the tape. From there I lay and stick a dry piece of fleece over the tape in the area where I want the "back" to be. I then resin that piece and right before it dries completely I lay some chicken wire down and leave extra on so I can use that to help form the frame work of the sides and face so the fleece has "skeleton" to stick to. It works weel because you can shape it and use wire to hold it together and also hook your speaker mounting ring in. Once it cures you can peel the tape from the carpet or whatever and the whole piece will pop out. From there you just cover the entire skeleton/pod with a couple more layers of fleece and resin grinding between layers, finish grind the part to get the desiered shape, then start using fillers to finish it perfectly.

 

 

Making custom trim parts out of FG will work the same way. build a base or framework and build from there.

 

 

Just remember that you must always where a mask when grinding or sanding and also be sure to cover areas of the car in the vicinity you are laying resin and such to keep it off parts you don't want it on. The 3M blue masking tape, aluminum foil and saran wrap will be your best friend.

 

 

Of course, this is just how you go about making custom, one-off pieces. For making a nuber of the same type of parts you'd probably want to build a mold.

[jonesh242]

Here's a link to a great place to buy all your materials...specifically for the do-it-yourselfer who wants to do a professional job. I buy all my raw materials and CF cloth from here....

 

www.fiberglast.com

 

PS...they also have great How-to books for mold making and modeling parts.

 

John

[shift1313]

we invested in a vacuum bag setup at work and its nice. I made a custom dash pod for an acura and it came out great. I spent alot of time on the mold to get the shape and front lip right.

 

i got the vacuum bag stuff from www.aircraftspruce.com their vacuum bag kit is $100 and their vacuum pump kit was like $250 i think. its pretty much everything you will need except maybe some gel coat and pigment to change the color from white if you want. also you want pva release film and release wax if your doing work with a mold. I think all said and done i spent $600 on all the supplies with a lot of extra cloth.

 

http://filebox.vt.edu/users/maperez/DashFinalSmall.JPG

 

i cant tell you what its in the new piece cause its proprietary but i thought id show you the pic. There was no finishing work needed making a mold and using the vac bag setup. I threw a coat of black paint on it and covered it with speaker cloth. there is a front tinted lexan lens on the piece as well.

 

 

alot of the stuff you read online for speaker boxes is great but if you want to make trim pieces you dont want them super heavy and you dont want them to have bondo on them if you can help it. Trim pieces that snap into the factory locations are a tough thing to do but it can be done. if you want some more info about the vac bag stuff let me know

[IntercooledFlatty]

yeah i know this is old, but it sure looks kinda easy to make a stock hood in glass..... Burton ?

[Burton]

It's not what I'd call easy, and in this community, it's deffinately not profitable. I had to send my molds overseas to get the price down, but now it looks like all the molds are either gone or destroyed. Last month was a bad time to have my FG supplier be in the Philippines

.

[383chevelle]

While it may sound easy in theory there are countless hours put into prep of the plug, then the mold, just to make sure that the part looks right when it comes out. Just to give some reference, for the last several years I have made the plugs, molds, and body work for our fsae team. The whole process takes about a month if your shaping the plugs by hand from a block of foam. We switched to 5 axis cut plugs and it shaved about 2 weeks off the process but it is still ALOT of labor. It is fun though if its a hobby thing.

[IntercooledFlatty]

Burton, could you take one of our cowl hoods and duplicate it like this ?

[Burton]

Yeah, that's what I'm going to have to do... make all new molds. Or at least some of them. Still trying to figure out what's fine, what got destroyed, and what got swept out to sea LOL I probably won't be selling the SQ stuff anymore tho... At the price they sell for, I only make about $5/hr for my time. Can't do that anymore when I'm already turning away work that would pay $30/hr.