I searched the forum for my question but no luck. Here goes I made a styrofoam negitive of the proton pack can I use automotive fiberglass and resin to make my pack? I have also made other foam molds for the other parts and wood molds for the wand body. Also can I use the auto Resin with out the fiberglass for making diecast parts?
Can you post some pictures of what you have done? It would help to see how the molds are made and which specific foam you used to make them.
All my molds are made of styrofoam. Except for the wand its a styrofoam and mdf mixed construction.
Okay, are you being generic or specific when you say styrofoam.
“…the word styrofoam is often incorrectly used as a generic term for expanded polystyrene foam, such as disposable coffee cups, coolers, or cushioning material in packaging, which are typically white and are made of expanded polystyrene beads. This is different from the extruded polystyrene used for Styrofoam insulation. The polystyrene foam used for craft applications, which can be identified by its roughness and by the fact that it “crunches” when cut, is moderately soluble in many organic solvents, cyanoacrylate, and the propellants and solvents of spray paint, and is not specifically identified as expanded or extruded.”
If you used the craft application type, then you will have to coat it with something to keep it from melting.
Pictures of the molds would have been helpful to see how much undercutting they have. You might be able to use something other than auto resin to make your cast, but without more information coming from you, this is just a “what if” thread.
Polyester Resin, the standard automotive fiberglass resin found in most hardware stores, will eat foam. If you buy epoxy resin it won’t eat foam but you’ll probably get only one pull from your mold as it will break during demolding and it’s much more expensive.
The only reason to make a mold for a pack is if you want a bunch of them. If you just want one or two, or even three, it’s much more economical to scratchbuild or buy a shell.
Sorry for the lack of pictures but my only real web access is from my cell. The styrofoam I am refering to is white packing style. I only used it cause thats what I had on hand. I am still new at this so I dont mind remaking my molds just yet.
Its gonna get eaten away by the resin.
I had wanted to make 5 pack shells from my mold. I am still new at this so I was unsure of how to do things. I do want to keep cost down thats why I was trying not to buy the shells and only buy what I had to. I like all the shells out there but I like to try my hand at new things all the time.
Try making the buck out of wood, Or start with PC’s paper pack. I would look at the other build threads, such as Alkaline and bigi71’s. I think they use a buck and what not.
You can scratchbuild a pack out of aproximately $20 worth of foamcore, $30 worth of MDF or $40 worth of styrene depending on the level of durablility you want and what tools you have access to. Your biggest expense will be the time involved and that all depends on how accurate you want them to be.
Well I would like to have a pack that will last a long time and be sturdy. Thats why I wanted to build my pack out of fiberglass.
If you coat the foam in 3-4 coats of wood glue, you’ll be OK. I usually coat foam parts in glue then use bondo to make it all smooth before casting. Just make sure the part is fully covered in glue or bondo will eat away at the foam just like resin. Sometimes I think its more work then just starting with wood to begin with, but if you already have it modeled in foam your half way there.
Okay now thats something I can do. Thanks alkaline. Now for my final part of my original question do I need to put fiberglass in resin when making resin parts?
It’s completely relative to what it is you’re trying to do and what materials you’re working with.
If you’re talking about a pack shell then yes, it’s a really good idea to use fiberglass. You don’t HAVE to but the final product will be heavy, brittle, more expensive and take a long time to make if you don’t.
No, not typically. Some resin parts will be solid, like the bumper, because its just easier to do so. So you really cant lay fiberglass into the part. Other parts, like the ion arm, should have a 3/8" - 1/4" wall thickness depending on the resin you choose. Most resins ship with some sort of documentation stating what the optimal part thickness should be. I would consult that or shoot the manufacturer an email telling them what you plan to do. Most of the time they are very helpful.
ps ^ what Jack said about the shell.
There is no way you are going to get 5 pulls from a styrofoam mold. That sounds like a one-pull-tops deal.
Wait, yea I just re read that. You made the Negative out of foam? As in a cavity? Not so much why on earth but HOW on earth did you do that haha? I’m guessing you meant to say you made the positive?
Well I work in a tool and die shop and I am a cnc operator at the Shop. We have an old machine that cant do more than electrods any more so I asked if I could use it to cut a cavity in some foam. Then I wrote the cnc program to cut the pack out as a cavity.
Well unless you make one for each cast I don’t think you will get more than one pull from it. The process sounds cool, but you would probably be better off making a positive, smoothing it out, then molding it.
As he has gone about thisbackwards, he could cast his packs out of Silicone or Urethane Liquid Rubber. There are brushable kinds available. Should be able to pull them out without busting the mold. A wire frame or some other kind of blocking for the inside would help them keep their shape.