Fiberglass: popping molds... HELP!

Poseur

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03.5 Lsr Blue P5
OKay, so I FINALYL finished up glassing the back side of my mold and now I'm stuck. or rather the mold is. I know it's not supposed to be easy and all, but this thing is rediculously wedged. I used blue painter's tape, and it's sti in there good. Possibly part of my problem may be that I've got MDF top and bottom giving it a solid backbon that doesn't want to slowly release. I'll likely eventually either get it to eventually pop or break it with the various methods of prying i've been going thrugh. Anyone got anytricks?
 
i dont have any info that can help, but it be nice if you could make a walkthrough on making a basic mold. i wanna learn but i have no idea where to start. in any case, good luck in getting info that you need.
 
I bet you didnt use any type of release agent did you?

That would be your problem.G/L getting it loose.
Matt
 
Prettymuch yea. I figured the painter's tape would be enough to do the trick... I've seen a couple write-ups where they did without and mentione dit being difficult, but in the end it still worked.... For future ref, though what sorts of release agents are good to use? I've heared WD40 or vaseline, etc. but I'd imagine there's somethign more specific, yes?

I also would imagine working with a release agent would make it trickier to get the first layer of glass down, yes? seems to be a delicate balance. ideally something with a stick-unstick switch would be nice *L*
 
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Dexter said:
if you didnt use any wax or PVA, its going to be .... pretty damn permanent...
Dex,I am curious ...what kind of wax are you referring to?
And what is PVA?
Matt
 
ah, I'll eventually get it, it's been sorta slowly pulling away. I just gave myself a timeout before I broke something. The tape is gradually pulling away. I'm just impatient.
 
Forcefed> is it a trick of the trade or something? do I have to know a secret handshake to get to know what to use?
 
Poseur said:
Forcefed> is it a trick of the trade or something? do I have to know a secret handshake to get to know what to use?
Nahhh..I know that WD will work but I know not how well.I am just getting into doing molds myself so I am still learning.This is why I hope Dex chimes in with a little more info.All of my glass is hand laid and without a mold.
Matt
 
AFaceInTheCrowd said:
use freakin cooking spray. that's what i use. works wonders. or petrolium jelly. that works well too.
Ahhhhh yes...the good 'ol butter flavor Pam!
I forgot you could use stuff like that!
Vaseline makes a mess.But nothing stick to it!
Matt
 
howthen would you go about geting the fiberglass to stick to it in the first place????
 
There are various mold release waxes out there to aid in the removal of cured fiberglass from mold surfaces.

http://www.tapplastics.com/shop/product.php?pid=68&

http://www.tapplastics.com/shop/product.php?pid=72&

http://www.fibreglast.com/showproducts-category-Mold+Releases-23.html

PVA is a liquid that is sprayed on molds to further aid in seperation. It must be sprayed, and not brushed. PVA isn't required to seperate molds from finished parts, but some people prefer to just skip the PVA, as it will leave an orange peel type surface on the finished part when pulled from the mold. This is unavoidable due to the nature of the PVA. That doesn't mean you can't just sand the finished part though.
 
Perhaps it depends on how gravity's related to the situation at hand, but for the right rear corner of a hatch, prettymuch everything wanted to fall off as-was.
 
Poseur said:
howthen would you go about geting the fiberglass to stick to it in the first place????
YOu dont want FG to stick to a mold...It is there for shape only.The resin will set-up in the glass and then you pull it away with the desired shape you wanted it to be in.
Matt
 
hmm.... ohwell. ANYWAY... guess I know how to do it better int he future.. for the time being. I sure hope I can get this b**** out... THink I might jsut wedge some wood scraps in between for now and let it sit and think about wether it wants me to get violent or not...
 
Ah Ha!!!

so y'see what a couple pool cues, some paint stirrer sticks, and a little bit of getting pissed off can do? (headbang) Wow, I finally feel like I've accomplished something... Thanks for the advice kids. it actually managed to come out without toomuch of a struggle once I left some wedges under it for a bit (that painter's tape really isn't allthat sticky... Who cares what the back of my mold looks like, it's gonmna be against my car anyway. Highly doubt I'll be pulling my sub to pull the bolt to show it off anytime soon.

Anyway, thanks for the advice (even if it is in the form of "hey you're dumb" we cna all use that on occasion and I'll know better next time)
 

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