Fiberglass mat not sticking

Hey, I'm working on a FG box/amp rack for my std. cab dakota. Things have gone well so far, but I'm having trouble getting the fiberglass mat to stick to my first couple layers of resin. I tried dipping the mat in the resin and sticking it on, or brushing on some resin to the box and then sticking it on, but it just doesn't wanna stay put! Any suggestions???

Also, I was wondering if there is anything wrong with doing all of the strengthening (i.e. bondo glass, FG mat, extra layers of resin) on the inside of the box instead of the outside? Just figured it'd make for less sanding later on. The couple layers of resin I have now are pretty smooth except for the normal pits and bumps. I'm guessing I can just put on some body filler, sand it, prime it, and paint it?

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MG

I don' t understand why it's not sticking either? Maybe try painting a resin layer, then sticking dry mat to it, then tapping resin into the dry mat till it's saturated.  Are you trying to resin a vertical surface?  You could also be using a waxed resin and the wax layer is stopping the bond, if that's the case, just sand it a little before laying the next layer.  I usually use a wire brush between dry layers when using waxed resin.

As for the structural stuff...... the more the better.   One clue i should leak is that resin isn't strong, resin+mat is strong.  The trick to strength is to use only as much resin as needed. e.g: you want just enough resin to saturate the mat. As long as you dont leave any bubbles, use as little resin as possible.  Don't go overboard on the resin for strength, it's all about the mat and reinforment on flat surfaces.

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Im not sure if even dipping the mat into the resin is a great idea, I mean too much gooey resin wont be too sticky especially if the mat is over saturated.  What I do is pat a little resin to the surface, then stick the mat against the moist surface and then dab more resin with a paint brush.  I ususally cut my paint brushes so that there's only about 1 inch of bristles left, this makes the bristles stiffer and you can jab the mat with the resin better - its good for matting corners especially....

Try using spray glue (Super 77) to stick the mat in place.

Yes, you can strengthen from the inside. I do that on the pieces I can reach the inside of. Sometimes you just can't pull it off though.

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CarAudioHelp wrote:

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Yes, you can strengthen from the inside. I do that on the pieces I can reach the inside of. Sometimes you just can't pull it off though.

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Check this method out...

https://www.the12volt.com/installbay/forum_posts.asp?tid=37575&PN=1

Okay, so I'm working on my box with a buddy and so far we have NOT used ANY fiberglass mat. I know, i know, sounds awful, but hear me out. We've used Bondo-Hair (the stuff with the fiberglass strands mixed in) and so far its pretty strong. The only problem is that for some really small areas that are behind the bracing for the sub, we couldn't get any of the goop back there, so its a little flimsy. I mean, its hard, but there is some give when you push on it. We've done all of the strengthening from the inside so far, and the outside is pretty darn smooth because its just resin. What do you think we can do to strengthen these little spots behind the braces? They're really close to the ring too, will that be really bad? I guess we could start throwing some fiberglass mat on the outside of the box, but I don't want to ruin the smoothness! Help!

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MG

Alright, I gave in and started using regular fiberglass mat on the outside of the box, and its really hardened up a lot. Looks like I'm going to have to use a lot more body filler and sand a lot more, but oh well, at least the box won't blow apart when I crank my system! I'll post some pics when she's all done.

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MG

pasting the resin on first is a good idae, i find it to work well. how every if u r doing it in a damp place it wont work. Try sanding between coats to give it some thing to key to. if that dont work e mail me.

try and sand it . it probably has wax in the resin.


is it finishing resin???

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