Hey ppl, nice forum…
I’ve been working with fibergalss and c.f for about a yr now… but not steadly, just now and then. I’ve done several flat c.f peices that seamed to work out good, but i didnt know till i found this places that i needed more layers of epoxy and then clear coat… (that explains why mine didnt look like i thought)
Just recently i got some toling gel and i want to start using that to make molds so i can move on to more complex peices. mainly making replacement peices for various interior parts on my car…
Now if i’m just overlaying the c.f on an existing part i only need a femail mold right? but if i want a replacement part i will need both right?
probably most will be overlays though… But for making both this is how o plan to go about it…
1st using the oem part and applying tooling gel and fiberglass to make the female mold. after its finished, i’ll wax the female mold and apply tooling gel and fiberglass to its finished side, and when it cured i should have a male copy of the top of the part… (this is mainly for semi flat parts ie. the rear deck lid) parts that dont have flanges and stuff…
I have a bagging setup already that i used before and got mixed results, but i used it without a mold and that i think is why…
So what do’s, dont’s and advice can you give me?
Hi Robby,
You certainly do not need to make both female and male molds. Just a female mold will do in most cases. If you’re running a bag setup, you’ll need to create parting flanges. If you’re not sure what that is I can take some pictures of my plugs for you to see.
Good luck,
Evan
yea pics would be good… i think i know what your talking about but not sure. the part wheer i can seperate it from the mold?
Evan,
That would be awesome if you could post some pics.
I’m going to starting learning how to make molds and any visual examples would really help.
Thanks! 
Here’s a plug with 6" parting flange all the way around. I’ll add more pics and explainations over the weekend. I am having a wicked flu.
Evan
shinny, is the plug clear coated? or just waxed all to hell
That plug is clear coated although that is not the way to go. Heat caused by the tooling gel coat will do weird things to the clear coat. The best way to go is wet sand and buff it as best as you can.
Evan
Well i finially got some time this past weekend to try out mold making… and it wasnt too bad… Made a mold of an ‘a’ pillar with 3 pods for gauges… although getting the mold off the plug was difficult since we forgot the wax… but it came of in one peice finially. Now this next weekend i’m going to try and lay up some c/f in it and see how that goes…
I plan to wet out the mold and let it tack up before fitting in the c/f by hand… since i dont think the vaccume bagging will be able to get inside the pods enought to hold it… or will it? and advice for the next step…
I also wondered would having flanges on the plug help later on… cause right now there is only about a 1/2" overhang all around… (what hung over when glassing over the tooling gel… )
btw here are some pics of the mold… not too pertty on the outside but looks nice on the finish side… Another q i have is… after i make the part in c/f do i need to brush on more layers of resin over the top? then sand then clear coat?. and if that is what i need to do would that mean i dont need to sand the mold to a smooth surface, since i will be adding and sanding more resing over the top? Or should i just smooth out the mold and not put extra layers of resing over the part after its made…
Hey Robby,
Congrats on making a mold. That looks neat. From reading your post I’m assuming that your mold surface isn’t smooth. That means that you’ll need to do some refinishing on all the parts that you pull out from that mold. If you think about it, it’s much better to sand the surface of the mold down smooth. Now if you think about it even more, it’s much better to sand the surface of your plug smooth before making your mold. But since you’ve gotten this far, it’s not possible without going back and redoing the whole thing.
If you create enough pleats in your bag, it’s certainly doable. If you don’t want to then just do what you have mentioned. You don’t need a flange on smaller parts. You can just place the whole layup inside a sealed bag. Flange makes sense on larger parts because you can cut down on the bagging material needed.
Evan
Yea i wet sanded the mold yesterday with 400 and got out most of the ruffness, although i wasnt too concerened since this whole mold and layout is just a test… so i can better understand it before i try and make parts for my car. some things i have learned so far…
a little tooling gel goes a long way.
To apply several cotes of tooling gel before covering it with glass so you have a nice thick layer (lol i started to sand thu it almost on this test peice in one spot)
And letting a layer of resin tack up well on the mold makes layin out the c/f to the curves a lot eiser… (one section wasnt tacked up yet and was a lot more difficult since the c/f just wanted to pull away with any pressuer)
Now i’ve moved on the tha c/f layout… And ya i decided not to bag since i didnt think it would work well with all those curves.
here are some pics from todays fun…
ok today i pulled it from the mold… and being its only one layer of 3k its pertty flexable. but thats ok its only a test… plus if it was not flexable i’n not sure i could of gotten it out of the mold… I used rold release on the mold, 3 layers of it… the flat areas poped off easly but inside the pods was tuff… think in part to having the holes cut for the gauges made it more difficult since the resin kinda ran out of there and bonded to the outside of the mold a little…
Another question, ater i let the mold tack up i applied the c/f (dry) and then wet it out. and i thought i soaked it well but i ended up with some pockes of no resin… looks like it was cause the c/f uplled away from the mold but not sure…
This is about as far as i know what to do. Next would i fill the holes with more resin and bursh on several more coats of resin, building up the finish surface? then sand and polish it?
Here are the pics… since everyone like pics…
What’s rold release? Anyway, congrats on making your first piece. Your problems are very typical and you’ll continue to have them from time to time. The one drawback from letting the first coat gel up and apply your cloth dry is that sometimes you don’t know if the cloth is all the way down or not. You try to push it down but it wouldn’t go any further so you think it’s down all the way. What you didn’t realize is that the cloth couldn’t conform/stretch anymore beyond that point. I normally take a sharp razor blade and score the sharp lines. It cuts up the cloth and allows you to push it further down to the mold surface. As for the holes where the guages go, I’d fill it in with molding clay so that the resin doesn’t seep through and around the mold to create a lock. That’s all I got for now…
Evan
lol… it was a type-o, ment mold release…
So is there no way to fix the problem areas? And yea the next time i do a mold like this i will not have the pod holes in the mold, it was more trouble than its worth…
i have since gone back and added another layer of c/f and it stiffened way up… and now almost all the see thru spots are gone. So all i need to do is find a way to fix the finish.
I plan on mixing up more resin and filling the voids and then painting on several more coats of resin over the finished surface of the piece. Then sanding it as needed… Good idea or really bad one???
BTW thanks Evan for all your help…
Well your ideas aren’t exactly suited for mass production, but it’ll work.
Having the holes in your mold is fine. You can still trim them off before demolding the whole piece. I usually take a utility knife and trim off the edges once the part has gelled up but not fully cured. It cuts like a knife through butter and it saves a lot of dusty trimmings at the end.
What kind of mold release are you using?
yea i did trim most of it when it was gelled, but only on the outside. Thought if i messed thie the inner circles it might mess up… next time i will…
The wax i’m using is this
i only applied 3 coats, so i was a little short i see…
So filling in the holes and brushing on more resin wil work, just not suited if i wanted to turn out more than one relativly quickly…
This being a test part i just want all the experiance i can get from it… In the future if this happens (and it will from time to time you say) i should jsut scrap it and make a new one from the mold?
It all depends, if you think it’s worth doing the refinishing then go ahead. I used to try and salvage those pieces but now I just trash them. I normally get too angry and break them anyway so they’re beyond salvagable. lol j/k
Part all is good. But try using the wax instead of the paste.
lol i know what ya mean… the plug for the mold did not want to come out orignially so my buddie and i figuered heating it up and rapid cool down would pop it free… it did but we also ended up kinda melting the plug…
Well when this batch of c/f and resin that i have it finished i will order new supplys from you, that way you can let me know what will and wont work good…
Luckly the next 2 parts i plan on making are pretty much flat and should be a lot eiser than this… thanks to all the fuss i had trying this one…
oh one last q on this… finishing the part. normally would you just take the part after its molded, and clear coat it, then polish and buff it. or do you need to do any work to the part before the clearcoat?
If you’re going to clear coat it… make sure you scuff off all the mold release that transfered onto your part. I normally don’t clear coat anything unless it’s required. The uv inhibited clear gel coat is shot into the mold before I lay up the part so once it’s out of the mold it’s pretty much done. All I need to do afterward is wet sand and polish if even that. It all depends on what kind of surface finish I have on the mold itself.
oohh… clear gel coat i see…
So you wax, wax, wax, gel coat, c/f, backing. then done…
I had thought about clear gel coat but figuered spraying it may get messy, and wanst sure if i needed a gel coat gun or my regular paint gun would work. And i was worried it would stick to the mold. but i guess the waxing would prevent it… Do you wait till the gelcoat is completely dry to apply the c/f of just till its gelled…
I wait about 20 minutes for it to gel up. I do the “finger print” test which is touching the gel coat with my finger. If it leaves a finger print but doesn’t get on my finger then I know it’s ready for layup. You’ll need a gel coat gun because gel coat is a lot thicker than paint. I actually don’t use wax anymore on my molds. I use a semi-permanent mold release. I just need to treat my mold once and it’s good for multiple pulls. Once I feel that the parts are getting harder and harder to demold then I go back and retreat the mold. I’ll have all of this info once I launch the new supply store. I kind of started building it so you can see it here: www.icancomposites.com but it’s far from finished.