Fiberglass

[MandoMan]

Yeah, yeah, another fiberglass help thread. I have read the majority (if not all) of the fiberglass info threads here, but I don't recall seeing answers to some questions I have.

Alright, so first, the moulding. I have an 8 lb bucket of plaster of paris. How much detail can plaster get? I'm going to be casting a homemade Fett helmet using MLC's build-up method if that helps. Also, any suggestions on the wall I have to make around it to have a 2-piece mould? I've read the Studio Creations tutorial about using the clay wall, but that was used on a clay sculpture. Mine will be foam board, cardstock, and bondo.

Now the fiberglassing. The usual order is to brush a few layers of fiberglass resin, lay in the matte, and brush a few more layers of resin in, right? I would be using gelcoat, but layering on a few layers of primer instead of finding and buying gelcoat is a little easier for me. Also, do I just cut a big piece of matte and press it into the mould into all the details, or cut pieces and lay it in?

I think that's about all I need to know. Sorry if I'm just being repetative. I'll figure out the rest when I actually do it.

 

[Hammer of Might]

I don't really have a direct answer, but I wondering If you have a link to MLC's buil-up method? I had it, but lost it somehow.

 

[Darth Fett]

ive used fiberglass a few times. i cut the fiberglass matt into square pieces put them in the fiberglass resin and put the piece into the mold then brush or push the piece into the details. for the plaster i think it gets a lot of detail and should do good for a fett helmet. i hope that helps!

 

[MandoMan]

That helps a lot, thanks! So did you use one square piece, or did you use multiple pieces for one casting? Just want to clarify so I don't mess up. Also, did you brush in the resin first, or did you brush the resin onto the matt and then put the matt into the mould? Thanks alot for the help!

 

[Andromalius]

it's kind of like paper mashaying, mix the resin and then dredge the cloth through the resin and apply to the mold. and use a brush to push the cloth in to the grooves/details of the mold.

 

[Jun Garros Fett]

Hey MandoMan.

I am far from an expert but sent you a PM concerning fiberglassing.

Learned a few things from JD in my visits.
Hope it helps some.

 

[MandoMan]

Awesome, thanks to both of you!

Jun, PMed ya back! Lots of good info!

 

[MandoMan]

Alright, just to get this question out of the way. What if I poured a bottle or two of this over my helmet to mould it:

http://www.craftsetc.com/Store/ShowProduct.aspx?c=65&p=121004

Would that be a stupid thing to do? Just wondering if it's anything like moulding with silicone and if it would be better than plaster, or a complete waste of time. Of course, I'm not even sure if my local Hobby Lobby even stocks it...

 

[Andromalius]

well woodland scenics rubber is most likely for doing rock molds (pouring over rocks ) since the company focuses on model railroading...but unless you think it would be cheaper than traditional methods, i think it might be best to just stick with the traditional prop molding methods.

don't get me wrong it probably would work... but I'd hate to see you ruin your bucket with the stuff (if in a freak accident it didn't work).

but I've never used it for prop casting.....so maybe another helpful TDHer has some experience with using the woodland scenic latex.

good luck.

 

[Hammer of Might]

Hey MandoMan.

I am far from an expert but sent you a PM concerning fiberglassing.

Learned a few things from JD in my visits.
Hope it helps some.

You now have a new PM.

 

[Jun Garros Fett]

Here is a link for some great tips on using fiberglass.

http://www.thedentedhelmet.com/showthread.php?t=12914&highlight=fiberglassing

Hope that helps.


Hammer.. Sent you a PM too.

 

[MandoMan]

Here is a link for some great tips on using fiberglass.

http://www.thedentedhelmet.com/showthread.php?t=12914&highlight=fiberglassing

Yep, that's a good thread.

I'm probably going to just go with a plaster mould. Ronin677's new pics really helped out with putting in keys to line up the mould.

 

[clonesix]

Mandoman,

I didn't read all of the other thread, but it looks like there is some good reading there. It might be wise to review it and a few site like:
http://www.freemansupply.com/
http://www.fibreglast.com/

From what I read in your post, you have made a helmet out of card stock and are now going to mold it and fiberglass the helmet.

First thing I will ask is you model strong enough to withstand the molding process? Plaster is heavy and piling it on can distort the model.

Next I will suggest NOT using plaster of paris. It is the weakest of all the gypsums and will produce a bad mold that can only be used a couple of times. Use Ultracal, or Hydrocal for the mold. It will give a much better surface. If you need to find these, look in your local yellow pages for plaster for a supplier. gypsum molds are very porous and must be sealed, and released very well or the helmet will never come out of the mold without a hammer. More on mold making if needed.

As far as fiberglass, the majority of people use polyester resin with FG. This is fine, and will work but be smelly. Polyester resin has a lingering smell that you should be advised about. I wouldn't want to encase my head in something that pungent. Two options for this are Polyurethane or Epoxy resins. Polyurethane is commenly refferred to as "Resin" by people as it is widely used. Its your choice on material, and the techniques are different for each.

If you are going with polyester resin, you need to add 2 more components: Cabosil (thickener) and milled fiber (powdered fiberglass). You make paste with these. Paste fills in all the detail and helps round the sharp corners of the mold. THESE ARE DANGEROUS MATERIALS You MUST wear a respirator! cabosil is light and fluffy, it will float around and you do NOT want it in your lungs!

Fiberglass comes in cloth and matt and is given by onces per sq foot. Two layers of 1.5 OZ matt will work for a helmet. HINT: you will have a better finish if you put in one layer of 1.5 oz matt, and one layer of 10oz cloth. You are much less likely to get a FG splinter from the smooth cloth than from the matt. Remember: your head is going into this thing.

So you have a two part mold. You lay the fiberglass into the halves separately. Make sure the glass and resin extend beyond the edge of the mold. When the resin has set-up, its known as the "Gel" state and you can run a utilty knife along the edge of the mold to trim off the excess glass. Then you can put the two halves of the mold together and apply a small strip of fiberglass (and resin) to the seam. Once cured, the helmet will come out in one piece.

I hope that helps.

 

[MandoMan]

Well, if plaster isn't a good idea, then how does a fiberglass mould work? I think MLC made his helmet out of cardstock and made a fiberglass mould. Plus it looks like he had a ridge with holes for bolts to line up better. I'd love to know how to do this, and if I could do it with Bondo brand fiberglass resin?

 

[Hammer of Might]

Mandoman,

I didn't read all of the other thread, but it looks like there is some good reading there. It might be wise to review it and a few site like:
http://www.freemansupply.com/
http://www.fibreglast.com/

From what I read in your post, you have made a helmet out of card stock and are now going to mold it and fiberglass the helmet.

First thing I will ask is you model strong enough to withstand the molding process? Plaster is heavy and piling it on can distort the model.

Next I will suggest NOT using plaster of paris. It is the weakest of all the gypsums and will produce a bad mold that can only be used a couple of times. Use Ultracal, or Hydrocal for the mold. It will give a much better surface. If you need to find these, look in your local yellow pages for plaster for a supplier. gypsum molds are very porous and must be sealed, and released very well or the helmet will never come out of the mold without a hammer. More on mold making if needed.

As far as fiberglass, the majority of people use polyester resin with FG. This is fine, and will work but be smelly. Polyester resin has a lingering smell that you should be advised about. I wouldn't want to encase my head in something that pungent. Two options for this are Polyurethane or Epoxy resins. Polyurethane is commenly refferred to as "Resin" by people as it is widely used. Its your choice on material, and the techniques are different for each.

If you are going with polyester resin, you need to add 2 more components: Cabosil (thickener) and milled fiber (powdered fiberglass). You make paste with these. Paste fills in all the detail and helps round the sharp corners of the mold. THESE ARE DANGEROUS MATERIALS You MUST wear a respirator! cabosil is light and fluffy, it will float around and you do NOT want it in your lungs!

Fiberglass comes in cloth and matt and is given by onces per sq foot. Two layers of 1.5 OZ matt will work for a helmet. HINT: you will have a better finish if you put in one layer of 1.5 oz matt, and one layer of 10oz cloth. You are much less likely to get a FG splinter from the smooth cloth than from the matt. Remember: your head is going into this thing.

So you have a two part mold. You lay the fiberglass into the halves separately. Make sure the glass and resin extend beyond the edge of the mold. When the resin has set-up, its known as the "Gel" state and you can run a utilty knife along the edge of the mold to trim off the excess glass. Then you can put the two halves of the mold together and apply a small strip of fiberglass (and resin) to the seam. Once cured, the helmet will come out in one piece.

I hope that helps.

dang! you saved some time there. thanks.

 

[clonesix]

Well, if plaster isn't a good idea, then how does a fiberglass mould work? I think MLC made his helmet out of cardstock and made a fiberglass mould. Plus it looks like he had a ridge with holes for bolts to line up better. I'd love to know how to do this, and if I could do it with Bondo brand fiberglass resin?

Whoa, I said plaster of paris is a bad idea. Plaster of paris is too soft for molds. Go to www.usgypsum.com to learn more about different types of plaster.

Plaster is cheap and its easy to work with. It is also not as toxic as polyester resin. It wouldn't be a bad idea to make a few "test molds" before risking your prized fett helmet that you just spent all that time on. If you build yourself a 1/2 sized fett helmet, (accuracy non-issue) you could make a practice mold if it at very little cost, but you would learn a lot from the experience. You can even practice your hand at fiberglass before tackling the big project.

Good molds don't happen by accident; they come from practice and experience.

A fiberglass mold would use the same principles, but is a lot more work. Try the plaster mold first and a fiberglass one after you have worked with the material for a few trys.

 

[Dha Syntir]

How about the latex (I believe anyway) stuff they use all the time on the Discovery Channel show "Mythbusters?" I've seen them use a liquid stuff which after a while hardens into a soft and flexible mold. Would something like that work for your purposes, or is it too expensive to use for this type of application? Just a thought.