I suck at fiberglass
Thread Starter
Melting Slicks
Joined: Jan 2002
Posts: 2,682
Likes: 0
From: Atlanta GA
I suck at fiberglass
I thought I was doing great. The MDF tops for C6 comparment covers look stock, but my boxes sound like ***. I've done about 4 coats of resin and fiberglass mat over the original stretch of fiberglass cloth.
I think there is an air leak or something. The subs are giving a buzzing sound and sound terrible. The boxes are strong and there is no flex. I was able to stand on them w/out any problem.
I don't know if I should just start over, or give up.
Any ideas or anybody interested in making some production boxes for the C6?
I think there is an air leak or something. The subs are giving a buzzing sound and sound terrible. The boxes are strong and there is no flex. I was able to stand on them w/out any problem.
I don't know if I should just start over, or give up.
Any ideas or anybody interested in making some production boxes for the C6?
Race Director
Joined: May 2003
Posts: 14,137
Likes: 2,985
From: Iowa
St. Jude Donor '03 thru '26
maybe nothing is wrong with the box. things like speaker wire coming in contact with the cone can cause buzzing
never give up, best of luck to ya
"do, or do not, there is no try"
never give up, best of luck to ya
"do, or do not, there is no try"
Melting Slicks
Joined: Sep 2003
Posts: 3,306
Likes: 2
From: Wesley Chapel Fl
I would verify your adhesion of the glass to the MDF. Also check the for any air pockets in the glass. If your structure is solid then you should not have any problems related to the fiberglass. With a layer of fleeze and four layers of matt your structure should be fine. But that is assuming their are no airpockets. When laying the matt is important that the color stays consitent throughout the layup. White spots represent air trapped below the resin.
I often coat the inside of my enclosures with a spray on sound deadner. You might want to give that a try.
I often coat the inside of my enclosures with a spray on sound deadner. You might want to give that a try.
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Thread Starter
Melting Slicks
Joined: Jan 2002
Posts: 2,682
Likes: 0
From: Atlanta GA
Originally Posted by 65 Hardnoks
Could it be the box coming in contact with the well it's in? Fiberglass is gonna vibrate so you don't want it touching anything.
Randy, thanks for the tip. Sometimes I found it difficult to keep the layers in close contact as I was applying them. Particulary around the corners. I proably have more than 4 layers around the obvious leak spots near the MDF ring, and the corners.
What kind of spray on sound deadening stuff do you use? That may help. Another person suggested, glassing in layers of dynamat (or similar) to help the box become more acoustically dead.
Race Director
Joined: Feb 2005
Posts: 12,458
Likes: 27
Google up Noise Killer Blue for the spray.
I would personally use some 1/4" sheet cork to sandwich between the layers of FG then also spray the inside like Eatrice said. I built the sides of my kick panel pods using that technique and they have zero resonance.
I would personally use some 1/4" sheet cork to sandwich between the layers of FG then also spray the inside like Eatrice said. I built the sides of my kick panel pods using that technique and they have zero resonance.
Melting Slicks
Joined: Sep 2003
Posts: 3,306
Likes: 2
From: Wesley Chapel Fl
Lars...I use Stinger stuff for obvious reasons..lol. But there are a bunch of products out there. I forgot to mention something. Let the product dry longer then recommended. When I first started using the spray stuff the fumes ate the surrounds off of a few JL subs. Now this was many years ago and the products are not made the same way but I still let me enclosures dry over night and one day in the sun just to be certain.
If you are having problems with the material staying in place it is usually because it is not wet enough. Wet the area before applying mat and then throughly soak the mat. Sometimes I did cut pieces in resin and then apply them. For corners I usually use alot of small strips instead of large pieces. Overlap the strips.
I have done a few projects where I use a filler inbetween fiberglass layer but never in a car. The filler is only needed to get the fiberglass to a certain thickness without alot of weight. I have done that for some boat work and a few outdoor home pieces.
If you are having problems with the material staying in place it is usually because it is not wet enough. Wet the area before applying mat and then throughly soak the mat. Sometimes I did cut pieces in resin and then apply them. For corners I usually use alot of small strips instead of large pieces. Overlap the strips.
I have done a few projects where I use a filler inbetween fiberglass layer but never in a car. The filler is only needed to get the fiberglass to a certain thickness without alot of weight. I have done that for some boat work and a few outdoor home pieces.
Advanced
Joined: Jul 2004
Posts: 93
Likes: 0
From: Austin TX
it's possible air is leaking from around the sub to box seal. I had this problem and used black RTV to seal the subs to my boxes. yes I know it's a pain in the *** to remove the sub at a later date, but it sounds GREAT up until then. 
click the link in my sig to see pics of my c5 system
click the link in my sig to see pics of my c5 system
Melting Slicks
Joined: Sep 2003
Posts: 3,306
Likes: 2
From: Wesley Chapel Fl
operativex....if you are having a leak around your sub it is from either an uneven mounting surface or too large of a mounting hole. In your case from the pics I would have to say an uneven mounting surface. Not to be offensive but your glass technique is sloppy. Next time try covering your mounting baffle in masking tape before you lay you apply resin. Then you can just remove the tape instead of having to sand off the resin drips. From Lars' pics I would have to say his sub is mounted nice and tight.
Advanced
Joined: Jul 2004
Posts: 93
Likes: 0
From: Austin TX
Originally Posted by EatRice
operativex....if you are having a leak around your sub it is from either an uneven mounting surface or too large of a mounting hole. In your case from the pics I would have to say an uneven mounting surface. Not to be offensive but your glass technique is sloppy. Next time try covering your mounting baffle in masking tape before you lay you apply resin. Then you can just remove the tape instead of having to sand off the resin drips. From Lars' pics I would have to say his sub is mounted nice and tight.
no offense taken
and yes, the reason I needed to use RTV was party due to the imperfect mounting surface of the MDF but also of the subs themselves, which, having been screwed into another box previously, were less than perfect. I didn't see Lars' pics but perhaps if he is using used subs this could be part of the problem. best,
Drew
Melting Slicks
Joined: Sep 2003
Posts: 3,306
Likes: 2
From: Wesley Chapel Fl
If your subs basket is bent then you really should get a new sub. Somebody had to something really wrong to that sub to bend the basket. If it is bent then the cone will no longer move in a linear motion.
Advanced
Joined: Jul 2004
Posts: 93
Likes: 0
From: Austin TX
Originally Posted by EatRice
If your subs basket is bent then you really should get a new sub. Somebody had to something really wrong to that sub to bend the basket. If it is bent then the cone will no longer move in a linear motion.
