Epoxy mold?

General Composites Discussions Composites Talk
#1

I was looking at the price of tooling gel coat and tooling PER; epoxy doesn’t cost but a dollar more sort to speak for the same amount by volume.

My epoxy costs $35 for 1.5 quarts when mixed

My tooling gel costs $35 for 1 quart.

Tooling PER cost is $20 for 1 quart.

I guess cost isn’t such a big factor in this because i hope to pull many parts with this mold, so quality is key. The mold needs to maintain the plug shape/size exactly or very very close to. Would epoxy create a nice smooth mold surface? Or is it best to lay down a coat of tooling gel coat then once that B-stages or just after B stage switch over to the epoxy? It is a 4 piece mold with many countours. I’ve thought this out in my head for a couple hours and 4 pieces it has to be. How thick should i build the mold? It will be braced with gussets all the way around… about 25 of them. I’d take a picture of this thing, but without showing you 8 different angles picture would be useless.

As for the part, I have decided to use f/g cloth sandwiched between two nice outside layers of 2x2 twill carbon fiber. Money’s running short and this fender is a freebee almost to the customer who is trading me a couple other oem parts for a c/f fender. I am thinking of 3 layers of 3 oz satin cloth for the meat. Vacuum bag procedure after wet lay up.

On another topic/note: does kevlar lay down nice and bond well to c/f cloth? Is it possible to do a sandwich of C/F:kevlar:fiberglass cloth:C/F and have it all bond together nicely? Or is that just looking for a disastrous result?

#2

Instead of tooling gel you use a filled epoxy surface coat.

Or just black tinted epoxy brushed on the plug and wait for it to B stage.

#3

Is the “filled” stuff something i buy to add to the epoxy?
What about black tint? where can i find this stuff online?:slight_smile:

Oh yeah, what is the mixing ratio of both of these addatives?

Another nice thing about using epoxy is the “neighbor factor”. No complaining from neighbors.

edit: fillers as in microspheres and cabosil?

#4

If you are still needing to ask these sort of questions, do you honestly feel you have the know how and experience to make high quality moulds, using costly materials?

Most people would be well advised to learn using cheap materials, and start out on parts where a little shrinkage doesnt really matter.

Finally if you are hoping to go into production with bike fenders, you will find from a commercial perspective, that you are going to make a lot more money using 5 cheap moulds, rather than a single expensive one.

#5

… I wasn’t asking you, and from now on out, my questions are not directed toward you. thank you very much

I’m a nice guy but you just push the wrong buttons. If you’re such an expert Classic leave this forum and start your own classroom.

#6

You will find that when using Epoxy, kelvar will bond extremely well in the middle of a composite piece. I make guards that experience 450 F and have had no delam issues with kevlar in the middle. When it is the outer layer, you may find it delaminating a bit.

#7

Fastrr,
I do the things you are asking everyday. You can laminate any materials you want, glass, cf, kevlar, as long as it’s Vac. bagged with no problems. Keep the materials clean, keep your bare hands and especially coffee off of the materials you are laying up.

As far as epoxy molds. Don’t use cabosil or micro spheres they will not have the proper finish. Use only West system 404 high density filler. It is available at most large boating stores or Aircraft Spruce (1-800-4spruce). As a cheaper alternative with the possibility of poor results you can use very finly crushed lime stone powder. what ever you choose just add to MIXED resin matrix until a peanut butter like thickness (a little thinner I find works better). spread on part just like brushing tooling gel coat. Let b-stage, then add one layer of fine decking glass using THE SAME epoxy as the surface coat. Make sure that you use the same epoxysystem throughout the mold process or bad things will happen. Ask how I know.

The drawback to this method is that you can’t use csm as it is not treated to be used with epoxy. Also this is the most expensive method. However the molds stay dead accurate and yoou can get literally hundreds of pulls from one mold.

Follow these instructions and it will work great for you. I use room temp cure epoxies like Shell DPL and West. I build parts for the Auto Racing industry which need to be light, strong and withstand very high temps. I’ve never had a complaint and some of my customers are very high profile international Sportscar teams.

HTH

CCE

#8

Keep this attitude up Fastrr and you will be banned!

CB an many other pros are on here to help out newbies but I won’t stand for you calling them names! Nor telling them to leave and start their own forum. No you own this one? NOT!

#9

its kinda true, if sm1 gives an opn. take it to the best of their knowledge. even if it hurts, absorb what is said and either explore what they said or ignore it.

i agree thou, for many years… (4 yrs) ive been using epoxy for molds + surface tooling. well it costs WAY to much for what a mold is, + u cant spray it… per + gel coat works the same at a much lower costs. on the parts themselves, well then thats where you can explore using epoxy.

#10

I Don’t know Fastrr and I don’t condone his treatment of Classicbike. It is difficult to get real answers on the web. I think what Fastrr was trying to express was that he is able to make the judgement as to wether epoxy or PER would be suitable price wise. It is frustrating when people won’t answer your question and tangents get started. But we must play nice in the sandbox or…NO SANDBOX!!

#11

This is one of the only messages boards where things are civil and questions don’t degrade into name calling. Full of good info. and smart composites experts. I would be at least a full year behind where i am right now if I had not absorbed the info on this forum. As soon as you start resorting to name calling, learning goes down the shitter. The original comment was callous but the response was un-necessary.

#12

cce, What is fine decking glass?

By the way, what teams do you do work for? I do work for Wayne Taylor racing and Sigalsport Daytona Prottype teams.

#13

I think me and Classic will do just fine if he stops his rude behavior. I’ve met plenty of English people online and none have the poor attitude of him.

Thanks CCE, I appreciate the good advice.

And no Werks i don’t think it’s my forum. Why you stick up for this guy I don’t know, after he dogs me and dogs me with rude comments.

#14

Like Ricky Bobby?

Seriously though. You ever use epoxy tooling clay? If so how did you like it?

#15

I wonder why my providing helpful and accurate advice is felt to be rude in any way?

I am not sure if FastRR has any sort of skills, but I if he has, how he would feel if someone who was very much a newcomer to his area of expertise, decided they would be able to pretty much side step any sort of learning of the said skill, and to be on the same level as he was, after flicking through a couple of books, and making a few posts on internet forums?

#16

ive never seen Classic’s replies to any of my post offensive but more informative on his view of what i do. this is what forums are all about! =)

#17

OK, lots of questions:

Fine decking cloth is 2oz. to 5oz. fiberglass. It comes in several weavs but usually satin. I think it is a surfboard term, no, I’ve never built a surfboard. I use it to prevent print through on molds. You know, as a first layer into the b-staged surface coat.

I prefer to keep my clients confidential but I will say that I do supply a global catalog company from which many types of GT cars can be constructed. I have done work for several GT teams and a few prototype teams. I have constructed undertray diffusers, wings, hoods, trunks, infact entire cars from Elvas to Spitfires to Hyundai rally cars, Porsche GT cars, Corvette TA cars to Argo Mazdas and Lola b2k40’s. The list goes on and on.

I have used epoxy tooling clay but only once many years ago. I remember it being very expensive and not having much success. It can not be used as a surface coat as far as I know.

Hope that helps.

CCE

#18

I ordered some tooling PER from FibreGlast and they had backordered it on me, so I figured i may never get the stuff since i ordered it three weeks ago. Well today i did get a courtesy email letting me know they billed me for it and are shipping it today. Guess that solves what i will be using for this mold and the next few.

So West Systems epoxy isn’t compatible with other brands of epoxy? Who does WestSystems buy their epoxy from ( Dow, Shell)? Someone may have already said, but this is a long thread so i will have to scroll up and read more.

And my sincere appologies for the name calling. Luisn is right if I don’t agree with someone elses opinions i can just ignore it.

I did order some “surfboard” f/g cloth… 3.2 ounce. I’m hoping it will drape nicely without much bridging. I’d also like to use some of 1.5oz CSM i have on hand for this mold. Later on I will experiment with epoxy molds, so the info isn’t waisted.:slight_smile:

#19

Gougeon Brothers manufactures West System. The reason for using the same resin throughout the mold construction is that not all epoxies are the same. Some amine blush quite a bit. Making secondary bonds with unlike epoxy resin will cause subsequent layers to not bond well.

CCE

#20

ohh yeah amine blush, I forgot for a moment about that.