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View Full Version : New to fiberglassing questions



lil azn 06
08-06-2008, 05:07 AM
This is my first project doing a fiberglass box install for a S2000 using Bondo resin and mat (Cheap, yes I've read up on it a long time ago but i can't convince my friend otherwise) and i have several questions. Here is a picture to begin with.

http://farm4.static.flickr.com/3235/2738191850_1520fbff83.jpg

My first question is the foil acts as a an easy mold removal correct? I shouldn't have to spray it down with Pam or Vaseline or should i still?

Next, I've seen many old posts where people just make a mold of the location using resin only, pop it out, then throw fiberglass over the mold. Recently though, I've seen people have been laying down the fiberglass down first, then resin it until it makes a mold and then pop it out. Wouldn't the first choice be easier to do? Well, which way is more effective?


Thanks

hoxie08
08-06-2008, 05:14 AM
i have always put down mat and then resined it and popped it out. havent tried it the first way though so i really couldnt tell you.

lil azn 06
08-06-2008, 05:30 AM
So how would i go about keeping the mat in its place when i am working above the floor? Hold a small piece of the mat and then throw resin and it will stick to the foil?

How many layers of resin/fiberglass did you apply before popping out the mold? Did you continue to add more layers once the mold was out?

Also, when fleecing, do i use a staple gun to hold its place onto to the fiberglass mold?

jdc753
08-06-2008, 12:18 PM
I haven't done too much with fiberglass but have some first hand experience. The foil will work as a release but you may get some foil stuck to your resin and just have to peel it off, some pieces become more pesky than others but in the absolute worst case you could easily sand the foil out of the fiberglass.

Its a pretty large area you are working with but if you cut the mat into smaller more manageable pieces it will be easier to work with and conform to the contours. Maybe some 12x12 squares and some 4x6 squares for the tighter spaces, just general shapes though nothing exact.

I would lay down the mat and then resin over that, it might come out cleaner if you put down the resin first and then push the mat into it and then add more resin on top but I think its pretty much 6 of one half a dozen of another.

For the sides and such where you are worried about the mat not staying in place, if you hold the mat there and then dab the resin into it the mat should stay in place and allow you to work with it.

It really isn't all that hard to work with, I did my first project with it a few months back and was actually surprised at how easy it was. Make sure you work all of the air bubbles out of it by pushing them to the edges of the mat and you should be good. Not sure if you have purchased all your supplies yet but a bunch of solo cups should work good for portioning out the resin and then add the hardener to them as you are ready to use them. Have plenty of latex gloves and cheap brushes to work with, the brushes won't be salvagable after the resin hardens. I would think adding 2 layers of mat and resin and allowing it to cure should be enough for you to pull it out of the mold and then start adding more to the insides and finishing it as you need to. If this is for a sub enclosure you will probably want around 7 layers or enough till you get pretty much zero flex.

For the fleecing a staple gun should work well, I am not sure if the staples will go into the fiberglass part though, so maybe use some hot glue and tack it around as you would have with the stapler.

Loud3
08-06-2008, 12:19 PM
I would still spray it with PAM.

jdc753
08-06-2008, 12:21 PM
I would still spray it with PAM.

Yea that too, I forgot about that when I typed out my response. Will certainly make it pop out easier.

bumpweLL.nYc
08-06-2008, 12:58 PM
You cant make a mold out of just resin and work off that. The resin will spill to the bottom of the well and leave nothing on the sides. Also resin works off a chemical heat reaction and if the mold is weak, the heat will warp it and it wont fit in the end.
The main objective is to layer it evenly and not have air trapped between layers (bubbles). First play with the mat only to see what size pieces you need and get 4layers torn up (by hand not scissor) and planned out. Big pieces for flat areas, small ones for curves. If you can spare the volume, cut a piece of 3/4 MDF to fit inside the well floor which would be a sufficient bottom and really cut work and material. If you choose to do just shoot some expanding foam on the well floor before the wood and let dry so it sits tight.
When you have a good handle of how its going to work out, mix up your resin in a $.99 plastic pitcher with a spout. Its the easiest way because you pour with one hand and work the brush with the other, spreading the resin and working out bubbles. Trust me its alot better than dipping the brush and dripping everywhere. Large mixes eliminate the need to count drops of hardener so you get a more even mix and critical time is not wasted. Also overstirring speeds up the reaction.
I would guess 1 liter per layer for that job. Mix it, lay it without taking sweet time with pour and spread/dab method, maybe have a buddy there to help place the mat. Wait 15-20 minutes for it to become a little tacky, mix another match, and get right back to work on the next layer using the same starting point. Its not good to let it completely harden between layers, so no goofing around! It shouldnt take more than 1 afternoon.
I would also get some 2x4's and go all the way with a false floor. How were you planning to top it off?

lil azn 06
08-06-2008, 08:21 PM
I've started out the fiberglass box and ran into some problems. First off when i applied the first layer of fiberglass in pieces the floor came out fine (except for a few bubbles or bumps that need to be dremeled off) but it was hard to work in the curved areas even with small mat pieces and the result was the mat would partly hang off and dry. So then it would just bulge out. Do i just try to continue to make a mold and yank it out when ready and cut off the parts hanging off? I think one layer of fiberglass and resin should be enough to hold the form so i can take it out, dremel off the bulging parts and then put on a second and third layer.

fbi90909
08-06-2008, 08:32 PM
you need at least 4 layers of fiberglass before you pull it out of the mold area. if you leave only 1 layer and pull it out, then begin to add aditional layers the mold can warp on you. later on when you try to stick it back in it won't sit right.

can you pist pics of what you have accomplished so far?

i don't know what technique you are using to lay your fiberglass but i will explain this one to you. you may already do it or you may not, i'm not sure but w/e. anyways you want to use a "Stippling" technique. basically what you are doing is you are stabbing resin into the mat. don't paint on the resin. what you want to do is first lay a nice thin coat of resin to the area you will be working on, this will add some adhesive, then take a peice of mat and press it onto that thin layer of resin. with a SMALL amount of resin on the brush, stab in the resin into the mat.
note: you don't want to over saturate the mat in resin. only use enough resin so the mat looks wet. not soaked.

lil azn 06
08-06-2008, 09:35 PM
you need at least 4 layers of fiberglass before you pull it out of the mold area. if you leave only 1 layer and pull it out, then begin to add aditional layers the mold can warp on you. later on when you try to stick it back in it won't sit right.

can you pist pics of what you have accomplished so far?

i don't know what technique you are using to lay your fiberglass but i will explain this one to you. you may already do it or you may not, i'm not sure but w/e. anyways you want to use a "Stippling" technique. basically what you are doing is you are stabbing resin into the mat. don't paint on the resin. what you want to do is first lay a nice thin coat of resin to the area you will be working on, this will add some adhesive, then take a peice of mat and press it onto that thin layer of resin. with a SMALL amount of resin on the brush, stab in the resin into the mat.
note: you don't want to over saturate the mat in resin. only use enough resin so the mat looks wet. not soaked.

I'll post pictures later tonight, he has no compact flash reader and we are doing it at his house.

Blah, we just took out the mold, i told him to keep it in but i guess. It seems to hold its shape. Guess I'll just stick it into the trunk again. It seems to fit perfectly though.

Thanks, I'll try the stippling technique. :)

pawn man
08-06-2008, 10:40 PM
1st you put masking tape over the whole area you are glassing. 2nd put down foil.(it helps if you spray the masking tape w/ spray adhesive to make the foil stick) 3rd break up mat and put it every where you are glassing. 4th mix glass and glass the area. do atleast 4 layers.

lil azn 06
08-07-2008, 06:50 PM
I came back to the guys house and he decided to do another glass layer. Well, there are bubbles everywhere now.

What options do i have? Cut out all the bubbled area and reglass? Or am i stuck with rebuilding a new mold?

dannyz122001
08-07-2008, 07:17 PM
as much as it would ****, i would redo it.

if i were doing a well mold, i would do the following.

after degreasing the entire wheel well, i would lay multiple layers of good masking tape. make sure to overlap the pieces and then criss-cross the next layer of tape perpendicular to the first layer, to reduce the chance of resin seeping through.

volume depending, i would cut a piece of MDF to fit the bottom (as previously mentioned). this will help add strength and rigidity to the enclosure, as MDF is stronger over flat areas compared to FG on flat areas.

next, i would spray a light mist of spray adhesive one section of the well. allow it it tack and then proceed to lay out one layer of chop mat onto the glue. this will allow you to determine the positioning of the mat before its permenant. after you are satisfied with the locations of the mat, mix your resin and apply using the previously mention stippling (sp?) method, making sure to remove all air bubbles.

moving section to section, continue until all desired areas have one layer of FG. i would recommend doing no less than 4 layers of mat. depending on woofer location, you may even want to use some small dowels as extra support to reduce warping.

once all is cured and dried, keep the enclosure in the well for about a day, again to reduce the chance of warping. once cured and removed, you can dremel down any air bubbles, knocking down any high points and further securing the MDF to the bottom (more resin and FG between the joints)

again, all FG'ing is trial and error. This method has worked for me, but to each his own. GL with it all, its pretty fun once you get the hang of it, but make sure to get all of the air bubbles out! GL!!

slapmaster
08-07-2008, 07:27 PM
from the pic, i would lay a trash bag over and spray it down with something oil based. then lay presoaked matt down. the bag is easyer to release than foil. i personaly do not care if the tape, foil, or whatever i use sticks to my mold, as long as i do not make a mess or stick to trunk.

lil azn 06
08-07-2008, 09:14 PM
Thanks for the advice. These guys just want to stick with this box. I've been cutting out several bubbles and plan on re-fiberglassing the areas that need to be.

I say the box in non-salvagable but he is a cheap *** and wants to stick with this box. At the rate we are going i could probably have a new mold done by tonight.

I'll never work with other people again.

lil azn 06
08-07-2008, 09:37 PM
Say i was to rebuild it,

Would birch be fine to use as the floor mold and as the baffle ring?

How would i eliminate the bubbles? Just press them out before it dries?

Ripping the fiberglass mat always made loose ends of fiberglass stick up. Instead, if i was to cut the mat wouldn't it be more effective?

Is there a special brush to use when working on resin? I am using just a regular painting brush (non foam) and it seems to stick onto the fiberglass.

SRim23
08-07-2008, 10:48 PM
heres a nice s2000 install i came across a couple days ago. maybe itll help

http://www.s2ki.com/forums/index.php?showtopic=560816

fbi90909
08-07-2008, 11:45 PM
****, next time i get a hold of some fiberglass mat i'm going to take a video of how to lay glass.

lil azn 06
08-08-2008, 11:44 AM
I think it is coming along nicely now. The stippling technique worked great. Thanks


Old Box

http://farm4.static.flickr.com/3066/2744389704_39445d6e1b.jpg


New Box

http://farm4.static.flickr.com/3014/2743555547_b9477df9ba.jpg

audiobahnuser18
08-08-2008, 11:47 AM
Not bad , try to get your hands on some actual like glass mat that they use on boats not chop mat it's alot stronger and works alot easier;).

lil azn 06
08-08-2008, 12:55 PM
Blah, if it was up to me, i wouldn't be using this crappy bondo resin/mats. For my own fiberglassing projects I'll have to up the ante and get the good stuff :)

So 4 layers need to be laid down before it is pulled out. How many layers would a typical fiberglass box incorporate before it can be "finished?"

fbi90909
08-09-2008, 07:11 PM
depends on the subwoofer and the pressure it can create really. you could do 7 layers. and be good with it. at 7 layers it should be quite solid and not flex much of any. also at 10 you could probably stand on it.
when i did an enclosure for my 15"XXX i went with around 15-16 layers, even with sooo many layers, it still flexed.

your second attempt is looking really good. remember, patience is key!

lil azn 06
08-12-2008, 07:29 PM
Do i need to do 7 layers where i am fleecing as well? Will a staple gun used to hold down the fleece really go through 7 layers of fiberglass?

fbi90909
08-12-2008, 07:37 PM
you don't need to use staples when attaching the fleese to the back side of the enclosure.
get a hot glue gun and lots of hot glue.
what you want to do is wrap the fleece and hot glue it it down.
let me try to explain this.
prep work you will need a bowl of ice and some ice water.

give me a minute while i type this up and kind of draw a picture or 2.
EDIT:
ok, here is a little picture of what you should do.
http://i110.photobucket.com/albums/n104/fbi90909/325c76dd.jpg
basically you want to wrap te fleece around it. instead of using staples, use hot glue. imo start at the top.
leave at least an inch from the tip of the enclosure to the point of where you are adding glue. you want to add resin to that area later on when you are wetting the fleece, well what you need the ice for it to help speed the cool down process of the hot glue, basically at the top lay a strip of glue maybe 1" long, press the fleece in, then rub it down with the ice to cool down the hot glue from being all jelly and ****.
then stretch from that area to the bottom of the enclosure and then lay a strip of glue again, press in the fleece, then cool it down with the ice. now, just work your way around the rest of the enclosure, remember to leave at least an inch of space between the glue and the tip of the enclosure. when you resin that area up the fleece will bond with the outserskin of the enclosure.
before you put on the fleece have you set your speaker ring and dowels in??

lil azn 06
08-12-2008, 08:12 PM
I am about to go there and make the baffle and dowels now. I assume you can just hot glue the dowels into position? The box will be curved awkwardly in the right corner. I didn't think hot glue could hold the strength of the fleece especially after stretching it? I guess i will find out.

Thanks

lvjeffro
08-14-2008, 02:38 AM
http://www.gadrivers.net/~dwicker/fiberglass.html

I thought this tutorial was very good on the subject...HTH

lil azn 06
08-16-2008, 07:10 AM
Here is the box fleeced with resin.

http://farm4.static.flickr.com/3293/2767757936_c114a51c3b.jpg
http://farm4.static.flickr.com/3242/2767759700_293326eff8.jpg
http://farm4.static.flickr.com/3209/2766914835_398fb4d5d3.jpg

After throwing the fleece on with resin the box would barely fit into the trunk mold anymore. I guess i will have to cut it (Picture below). How many layers of fiberglass must be laid onto the fleece? I plan on doing a layer in the inner areas of the box as well.

http://farm4.static.flickr.com/3074/2766906857_00921ccf41.jpg

lil azn 06
08-16-2008, 07:32 AM
Wait am i supposed to fleece/resin/fiberglass overlaying the mold or do i just basically stop where the mold ends?

lil azn 06
08-16-2008, 11:31 PM
Here is a picture for the question above

http://farm4.static.flickr.com/3072/2769846656_30a668ab10_o.jpg