need advise to make a mold/cast for fiberglass.

ok so I’ve been looking into making some parts out of fiberglass and need some type of cast or mold so I can just lay the resin and cure.
I’ve made a v stack for my buddies eg hatch, B20v 250+ HP and nitrus motor out of a head light.
so it basically bolts in as OEM and it has a 4" outlet in the back. id post pics but this site won’t let me upload pics from my phone.
so now I want to make a 4" cold air intake integrated into the stock air box but need to make a mold or cast first.

any help.

Your Google search found this… 94

You can also make a mold out of the part itself in most cases with some basic glassing know-how. Just make sure to grease that lil piggy up first or you’ll want to fiberglass a foot in your arse xD

well I’ve seen people on TV use a fabric of some type to make a subwoofer box and just lay the glass and resin on that. I’m trying to make a clean circular funnel vstack type shape on back of the headlight lens.
I already made a aluminum frame for the lens area now I need to figure out how to make the v stack funnel in the back.
I was thinking I could use fabric to shape it then lay the resin and glass over it.
any input

fleece, just go buy some fleece fabric at wal mart or a fabric shop, shapes pretty easy

sweet that’s what I thought it was. thanks Bryan.

i’ve used to typically to build speaker boxed in the past and door panels, but think i wanna make a rear window wing for a db1 and will be using fleece if i do lol

U make a wing or visor I want one

you know I was thinking of making a mock up down draft spoiler out of aluminum, and maybe make a mold of it just like the monte carlo.

Whoa whoa whoa…that “Fabric” you saw them use to make the speaker box IS FIBERGLASS…that fabric is the fiber glass itself and the resin is just that, it’s a 2-part resin you mix together (gotta add hardener to it) then you lay down a layer of the resin, a layer of the mat(fiberglass comes in 2 types, mat(which you wanna use…and weave which looks like CF if you paint it black) you can use fleece or something but that’s just half-assing it… no offense to anyone since I know what it’s like being broke. but for body parts bro…learn to fiberglass on Youtube or something…like really learn. Than practice with fleece and crap. Once you feel confident go and get both mat and weave fiberglass(“fabric”) since you’ll need both kinds for body panel strength( so a kicked up rock don’t punch a hole in it ) and criss cross the layers for best strength. I used to work on boats and glass crap all day everyday…oh yea wear gloves and long sleeves!) but just my $0.02

When it comes to fiberglass sub enclosures, they DO use fleece. That’s not half assing it, that’s how they do it… it starts with a wood ring and some framework essentially, they stretch fleets over that to get the shape. Not sure I would use fleece for any other glass project tho.

ok so im just trying to make a velocity stack in place of a headlight.
im not gutting out a headlight im actually making the funnel in the shape of a eg light then have it come out back to a 4" outlet
what else can I use to mold or shape it and still keep it as simple and smooth.

You can do it many ways , but as for fiberglass your best bet is to tape off existing headlight really good and glass the the whole thing and when done you will now have a mold of the light. usually also you would put a couple of tabs in it so you can screw the mold back together. (ill post a drawing.) once you have the mold you want to put wax inside the mold REALLY good and then lay a couple of layers inside the mold of fiberglass and put 2 halves of mold together and let dry, then break apart and it should release from mold easily due to the wax you put down.

its just an example, but you kinda have to get creative when designing the mold.

Others ways is using molding clay and carve out a design and then make a mold from that.