Reinforcing Seam Where Mold Meets Fleece

Hi,
I'm working on my first fiberglass subwoofer enclosure for my Celica. Here's what it looks like so far.



I was doing some reading about someone's fiberglass sub enclosure exploding, and it kind of got me worried. When I stretched the fleece over my mold with the MDF ring and soaked the fleece in resin, I only applied two layers of fiberglass around all of the edges where the hard fleeced material met the existing mold, and now I'm worried that this area may not be strong enough.

I've heard about people mixing up some sort of a mixture of Bondo-glass and resin and MEKP so that it's pretty fluid, and then letting it fill in the seams so that they're stronger. Should I do this in my situation? Or is there something else you guys would suggest?

that looks pretty good so far.  im in the process of building my first fg boxes as well.  mines not that smooth yet tho, as i havent bondo'd it yet.  but i was thinking the same thing about reinforcing it.  it seems to me that the seam is kinda weak in comparison with the rest, so i think im just going to put some bondo in the crease when i do the rest of the box.  but i was also thinking about using expanding foam for that instead. 

well, I always used at least 3 layers of glass

my rule of thumb is, if you can stand on it, its solid

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Hot-Modder

well i can definately stand on mine.  in fact i had my 200lb buddy jump on it, just to see and it didnt even flex, so i think im good strength-wise.  but i think i still want to reinforce the seam just in case.  after all it can hurt so i might as well.

well i can definately stand on mine.  in fact i had my 200lb buddy jump on it, just to see and it didnt even flex, so i think im good strength-wise.  but i think i still want to reinforce the seam just in case.  after all it can hurt so i might as well, but im still deciding whether foam or bondo would work better.  i think im starting to lean towards expanding foam a little more.  any other suggestions?

the foam will take uyp more of the internal volume and not be as strong. the bondo-glass and resin will work for what you guys need. there are also other additives that you can add to resin to make it thicker and stronger, yet still fill the gaps on the inside.



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audiomechanic wrote:

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the foam will take uyp more of the internal volume and not be as strong. the bondo-glass and resin will work for what you guys need. there are also other additives that you can add to resin to make it thicker and stronger, yet still fill the gaps on the inside.

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Other additives like what?

Also, when mixing the Bondo-Glass and Resin, would I use just MEKP to make the mixture harden?

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I thought i had the same problem with my box for an eclipse 15. All i did is take my extra resin and mix it up (no bondo) and roll it around on the edges, making sure to get them real well. Add some mat on the inside and it will be fine. I havent had one problem with mine.

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dream it, build it, fiberglass it

thanks guys

I've taken to reinforcing my seams by adding strips of modeling clay around the seams (on the inside) and then adding an additional 2-3 layers of glass mat over that.  It creates a double-walled crease in the form which helps reinforce it structurally and make the form more rigid to control flexing.