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Discussion Starter · #1 ·
so I revisited using a foam mold for my fiberglass project again this past week. the last time I attempted it, a few years ago, there weren't many detailed vids and the ones I watched didn't mention they were using a different type of resin that wouldn't eat thru foam, so of coarse the project soon turned into a disaster and I elected to start cutting out baking sheets instead. that only sorta worked because it wasn't sturdy enough to produce nice clean lines.

well this time, while I managed to keep my foam mold mostly intact, it's still not curing the way I want it too....




the carving was all done free hand, I was in a rush to get this particular piece together because im in a bind to get a 2nd vehicle for me and my ole lady so I'm well aware that it isn't symmetrical. im concerned about how uneven it layed down tho. its probably not very clear from the pic, but those splotches of gray and yellow are were the light is picking up air pockets detents and wrinkles on the under side. any idea what im doing wrong? none of that was there when I put it down, it was all nice and even like the front piece I molded to the upper
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some things it could be off the top of my head, I didn't sand the foam completely smooth before I taped it (was using a very rough construction foam), I taped it with ducktape brand ez pull packaging tape, and I'm not entirely sure how thick of a base layer i put down of resin before i added the first sheet of glass. would any or all of those be the cause?
 

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Ridin Dirty
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keep in mind that the stuff gets pretty hot while curing, it can melt plastic tape and the adhesive will release while hot. this has been covered before, but the mold is the hard part, you have to take your time and make it right. a release mold like that one should be sanded very well, then you paint it twice with latex house paint..let it fully dry..
(this will make the foam hold its shape better and resist resisns), then you coat that paint very well with a even layer of resin...let dry, depending on that turned out, you may need to sand that finishing with no less than 500 grit.
do yourself a favor, and buy mold release, I advise aginst the wax-based stuff, but the proper kind is sprayable and dries to a thin plastic film...and melts with water, so if your part for any reason doesn't want to come off, pour water behind the part and it WILL come off.
I get my mold release from U.S. Composites, good luck.
 

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Discussion Starter · #3 ·
thanks, I think that's the most detail anyone has ever given me on the subject aside from my cousin who lost me when he started talking about vacuum sealing (an engineer for you, some stuff he read apparently, as he's never wetted a piece himself). I never would've thought to use paint. masking tape was used in all the vids I watched. will the primer im going to use under the paint work, there're latex primers right? im a diesel mechanic by trade, so aside from the bedliner I used once on some old pieces, I've generally left the artsy stuff such as painting to some friends of mine that were pretty good at it. they're an hour away now however and not only that I'm wanting to learn to do the complete build anyway and not have to send off for anything. I've been using car wax for a releasing agent, something cheap that I discovered shaping from the old plastic.

For now, since I got all the mechanical problems worked out, I'm probably just going to grab a box top an just fashion a piece to cover the wires, quick and easy. That way I can sit back and take my time doing a legit mold. I asked this in the general form, but since you seem to know a pretty good deal on the subject, I'm still on the fence about the light. the one you see in the pic is brand new, never been on the road. I'm debating on selling it and making a light, but I'm selling the bike and I'm not sure which would be more valuable, a custom light or oem with custom glass around it. im trying to sell it and with 8500 miles on it the 4300 dollars it would get if restored is a hard pill to swallow. that price being the kbb excellent condition 23000 miles (06 gsxr 600). so I'm hoping since the mileage is so low, a good custom job would bring more and allow me to pick up another build or two. Ideally I'd like to sprout a business from this.

On a different note what part of la are u from? I grew up about 30 min north of Bogalusa in Mississippi.
 

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Ridin Dirty
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Yeah, I normally use vacuum to create composites, its really the best way to keep out air pockets out of complex shapes, and it also will "wring out" excess resin and compress the layers together. most high quality carbon-fiber parts will have so little resin left in them, they will sound like metal when you strike them. Vacuum bagging is a whole other black art, theres also heat-stamping, and auto-claves.
As far as the bike selling, man every thing I have owned I have customized, and when its time to sell something, it might make more people look at it, but when they go to fork over the money, theres no way to prove its any better than it was from the factory, and people just don't care how much you have in it. Now if your a reputable shop, you might get good money, but the time it takes to create customs is really never efficient enough for great profit. Keep your light for a future project, or sell it.
oh, the latex house paint will not eat the foam, it is water based, I don't know what paint you have, I know they sell only water based paints in Cali, but here nobody wants that stuff, and I know nothing about it. most of the paint I use is polyester based or urethane, and both will melt foam..I said latex because the stuff is laying around everywhere and it works..
I'm from Monroe BTW.
 
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Hi, i'm trying to work out what you are doing here, from the pics it looks like you are trying to make the parts directly on the bike, yet the title says molds ? ?
 

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Discussion Starter · #6 ·
the foams there, its just under all that mess. i shaped it on the bike freehand, then took it off and wet the glass. i had put it back on the bike to redo the tip, covered the tire and patched it right there. I've worked with this stuff enough on hard plastic to know that its not wetting the material i'm need help with, but rather the application to the mold. hence the title...

guy you sound like you work with this stuff on a daily basis. my cousin had mentioned some of that stuff but like i said he's and engineer. theres been more than one occasion watching him work on his truck that i've seen him take so long to walk off and dig for a specific wrench that i picked up the crescent and had it out for him before he had gotten back. in other words, i never know when he's going into overkill mode.

I've been wanting to break into the trade for some time now. i've been operating and working on heavy equipment (you already know its nothing but timber or oil down here) for so long that i've probably forgotten more shit than i know. I like mechanicing but i'm in the need for something more that just replacing broken shit with new shit. You said its hard to make money doing customs, how to the big custom shops get away with it? I've got an idea for a shop i've been mulling over with a tattoo artist friend of mine, who's also talking about buying my bike and getting into airbrushing. I've got this vision of a parlor style custom shop where the customer brings you their bike and you shape it right in front of them in the showroom. still do all the stripping down and heavy lifting in the back but they at least get a feel for having something to do with the creation. I have no idea if it would work tho, especially when down here were most of your bikes on the road are chromed out hogs.
 
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Hmm ok, just a heads up here fella in a previous life i had 14 years in the trade as a laminator & mold maker with some patternmaking thrown in for good measure so do have some idea of what to do if you want a professional finish

First up you have not made a mold you have made a plug or pattern on the bike & then skipped the mold making process & gone straight to trying to make the part which is partly why you are now in a mess, doing it this way can be ok for a local area mold but for what you are doing its not great if i'm honest

So having got that out of the way ..... the process should be make your plug on the bike if you want, i prefer to do as much off the bike as possible then fit to the bike for final finishing
Step two is to make a mold off that plug this can be one piece or split to avoid undercuts & to allow the finished part to release
Step 3 is to make the part, release it from the mold & trim it to suit before fitting & paint

Quick, easy, quite clean & you end up with a product as good as your original pattern, there are no shortcuts !
 

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Discussion Starter · #8 ·
mold/plug do we really have to argue semantics here? i need a piece of fiberglass to fit over the tailsection, what side of that piece i have to sand and finish i could give a fuck about. as you can see i barely have the patience to make a "plug" so do you really think im going to go through the trouble of making a "mold" from that? perhaps when its on the road and me and my girl have more than one vehicle to make our 30min commute everyday, but for now i need to know why the shit is pulling up the tape and not laying to the foam ok?

i didn't mean to sound like an asshole earlier, guy had mentioned something about the customization business and i was referring back to that, but if you've got to come in being a smartass about everything, just fuck off.
 
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Well someone got their panties in a twist

Its simple, what you have done is a fuckup & i was going to help you try & rescue it but now you can fuck off & cover your bike in as much shit as you want you arsey little tosser
 

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Discussion Starter · #10 ·
right, well correcting me on what to call a piece of foam is not helping one bit. i get that your trying to fill me in on the proper way, but i'm well aware of it, at least the method in theory. despite what the banner might suggest, i've been a member here off and on since 07 so i do have a minute amount of experience. the point of this was that i've only worked with foam twice and neither time i have been able to get the fiberglass to shape to it. I've done plenty of pieces like this working off of abs and while it works, i'm well aware the cons outweigh the pros of doing it this way vs the "proper" way. I need this fast however and working 50 hours a week, going to school, and having to get my ole lady to her job doesn't permit me to do anything but slap a piece together and spray it with bedliner to cover up the imperfections. still obviously doing something wrong i was trying to find out why it didn't turn out as expected, which was answered the day before you got on here talking about my misleading fucking title.
 
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Right .....
you seem to have, misunderstood my posts
My first was an attempt to understand what you are trying to acheive & how you have ended up in such a mess, it was done in a calm plain manner

My second was made in response to your what do you know attitude, laying out my experiance & trying to help by explaining the normal way this type of work is done, this was still calm & straightforward dispite your shitty attitude

My third was in response to your telling me to "fuck off" you obviously know more than me & i have no interest in trying to help someone who is not willing to try & learn

Now while i know the answer to you question theres no hope of me telling you now so i'll happily "fuck off" thanks for the laugh :yeah:
 

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Hey man,
It may not be the right answer, but it worked wonders when i made my tail--and it is a righteous pain in the ass, but if you bondo the foam (keep it thin!), and sand it down nicely, THEN tape the damn thing up it will work pretty nicely. The key is to take your time. Also, to get around the whole plug/mold thing just use the "lost foam" method--all you have to do is pour a little acetone onto the foam and it will melt away--this way you can actually have convex curves and don't have to worry about breaking your piece as you pull it out, if you are not using a plug/mold technique. just my .02
 

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AAAaaand, just btw, the guy before was trying to explain that you make a "plug" out of whatever, and it is essentially a replica of what you are trying to create. Then you glass that and make the mold, focusing on a good clean finish, throw some pva on and then lay your glass inside the mold, which makes for a super clean and professional finish

Good luck! and try not to get frustrated, building one-off pieces are an absolute nightmare if you set crazy time hacks for yourself, slow and steady does it!
 
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