I **** with Fiberglass (Proof Inside)

[idiot 10+ year member]

So I slapped down two layers of fiberglass and popped the mold out of my car. Though I could pretty much determine this as I was making it, I was then able to behold incontrovertible proof that the enclosure was absolute shit. I don’t really have the time, patience, or resources to make another one (and I don’t really think that it would be much better than the first), so I’d appreciate some help in making this thing useable.

Also, I don’t know how you people manage to pull off all the painter’s tape… much of mine refuses to come up. Very Attractive.

Glamour shot:

As you may be able to see from the above picture, the side lying on the ground is rather bumpy. That is not good, I’m sure. True, some of the bumps were formed when I tried to squeeze the last bit of use from the resin as it was beginning to take on a gelatinous consistency; some of those chunks just fell and were glassed over. But many are air pockets of some sort. Very bad.

Close-up:

Also, there are several awkward angles in this mold. My favorite is about 70 degrees, so that when I tried to glass from the horizontal plane up the incline, the material would tend to fall down. Any additional resin seemed only to add more weight and make the problem worse. Extended tampering in the area only stuck the mat to the brush bristles, so that when I pulled the brush away, the entire piece of mat would come with it, and I’d have to reapply. Great fun, I assure you. Anyway, below is a picture of strands of mat that have refused to stick on both pieces of a given angle and subsequently fallen, curled over, and hardened.

On a side note, this is only two layers, and I’ve already gone through an entire gallon of resin.

So… is there any way to salvage this thing to be able to withstand some variety of 15” sub (D2, H2, Oz ME, whatever I eventually choose)?

Click to read more...

 

[Acidburn 5,000+ posts]

welcome to the world of fiberglass, you can probably still use it by just adding more layers until it is strong enough

 

[InhumanAcura 5,000+ posts]

Lay a piece of fleece over it..Start from the center soaking it with resin making sure its adhering to the mold. Work your way out from the middle making sure to keep the creases out of the fleece.

I had to do this after like 8 layers of mat wouldnt stop flexing. The fleece will soak up a good deal of resin and get super stiff.

 

[dbornotdb 10+ year member]

First off it is salvagable.

 

Next time for the tape problem, use Vaseline on it as a release agent. But the tape is OK there.

 

Sand down the area with all the bubbles and "chunks of hardened jelly". Don't try to get them all out, just get the waxxy surface off, then add some resin, when it is almost dry, get some fleece as mentioned before and soak it both sides and spread it out over the whole thing. To do this, it will have to be previously measured out and cut and ready to dip into the waiting container of mixed resin.

Then it should be stiff enough to use, or real close.

 

And if you used a gallon of resin for that peice, you definately used to much. Only mix a little at a time to get the best use out of it.

 

 

[slick rick 10+ year member]

how much would it cost rougly to make a fiberglass enclosure for 2 12's in a spare tire well?

 

[ramos 5,000+ posts]

Yep you used to much resin so far. But your not that bad off. Tape on the underside won't be seen once your done. Sand the beeyatch. And next time use a roller to work out the air bubbles to save yourself some sanding time . //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[saywhat? 5,000+ posts]

thats what i was thinking, since this is the underside, if u can get some fleeve to stengthen it up......looks really DONT Matter/

 

[idiot 10+ year member]

I was under the impression that fleece has less strength than mat. Also, I’ve read that fleece should only be used to make a shape, not add thickness or structural integrity, and that it is prone to shattering. What exactly would be the purpose of adding the fleece?

What kind of roller would you recommend using? I’ve read that the foam rollers disintegrate pretty quickly when contacted with resin. Do they make ones specifically geared towards fiberglassing?

I’ll certainly sand the bumps and the air bubbles that I’m able to. However, not all can be sanded. Below is a picture of some that are inside the mold, but not bumps; instead, they’re smooth and level with the outer layer. I’d assume that the only way to fill them in (since they’re not really sandable) would be to drill a small hole and use it to inject resin/hardener into the bubbles, or something similar… ?

Regarding the issue of rigidity, there’s still a lot of flex in the fiberglass. Granted, I’ve only laid 2 layers of mat down, but it still bothers me. To correct this, I’ve seen a few people put down a strip of MDF along the straight edges (like this) to increase the box’s strength. Would this be a beneficial thing for me to do?

Also, when I’m applying the mat, some more advanced fiberglassers have set down two layers of dry mat before adding any resin, thereby speeding up their application time. Would this be wise for me to try, at my stage, or are there certain difficulties this method entails?

 

[Jesse98 10+ year member]

I would just do the fleece then lots of layers of mat, almost like using your piece as a mold.

 

[ramos 5,000+ posts]

True, mat is stronger than fleece. I believe the reason they suggested fleece was for cosmetic purposes. I personally would sand out , and or fill the air bubbles. Then put a couple more layers of mat.

Yep they make plastic and metal rollers specificaly for glassin'. Worth thier weight in gold IMHO .

I prefer to glass in some strands of poly rope instead of the mdf strips. Stiffens really well, and it's alot easier to work around corners and curves.

I do several layers at a time, however I "wet" each layer individualy to keep from having soft spots where the resin didn't soak through. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[Jesse98 10+ year member]

by doing the fleece itll give you a new fresh "clean"working surface to mat over and work with

 

[ramos 5,000+ posts]

But you don't really need it if you sand all the first layer. Fleece is just going to cover the imperfections, not correct them. The bubbles will still be there, and will still be the weak points. Better to correct the problem than cover them. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[ShRapNeR 10+ year member]

just sand it down and make it smooth?

 

[ramos 5,000+ posts]

I would sand it smooth before I put something over top of the air pockets. Air pockets will cause problems later

 

[idiot 10+ year member]

I’ll be sanding rather than fleecing, then. It won’t solve everything, but hopefully it will be enough for now…

Could you give a bit more detail on the “poly rope” you mentioned? I’ve heard of people doing this; some say that the rope, if added between layers, will cause bubbling. Anyway, it’s generally referred to simply as “rope” … but what kind? Nylon rope? Hay rope? Would string/twine or yarn serve the same purpose?

I just got back from Home Depot, and I had looked for some sort of plastic or metal roller. All I could find was a cheap paint roller with a thin layer of foam and a thick plastic core underneath. I’ll rip off the foam and see how well it works…