Help with casting Jason Hocks?

[Little Fett]

So I thought I'd try my hand in the hock business, so I sculpted, and casted in silicone a basic Jason part 3 hockey mask. I'm pretty happy with the glossy texture. Ok, hard part done right? Maybe not:angry.

I tried making my first cast using one piece of fiberglass cloth; applying resin, cloth, resin to the inside of the mold. all pretty simple. the resin kinda pooled in the nose area, but otherwise it looked pretty good.....until I pulled it.

I found bubbles had gotten between the cloth and the mold, leaving large craters in the finished mask. Also, some areas came out totally clear and flimsy, despite having cloth and resin just the same as the other areas :confused.

I then tried using cut pieces of cloth (same resin, cloth, resin application), which improved the problem, but didn't solve it. I still had bubbles and the same weird clear areas.

I'm using Elmers fiberglass resin and woven fiberglass cloth. What am I doing wrong??

 

[ob1al]

You can't use one big piece of FG cloth, as you have discovered. You'd have to chop it up into much smaller pieces and carefully lay that inside the mask.

I don't know what Elmers resin is, but you could consider a different product - a nice polyester resin meant for casting rather than laminating, for a nicer finish.

 

[Little Fett]

You can't use one big piece of FG cloth, as you have discovered. You'd have to chop it up into much smaller pieces and carefully lay that inside the mask.

I don't know what Elmers resin is, but you could consider a different product - a nice polyester resin meant for casting rather than laminating, for a nicer finish.

mmmkay, thanks for the advice, man! Any idea where I could get polyester resin?

 

[Kyle138]

I would try some Smooth On: Smooth Cast 320

 

[Little Fett]

Here's the stuff I tried using.

 

[Voodoo13]

I'd use smooth-On Rebound 25 with a shell of plasti-paste for your mold and then either smooth cast 300 or 385 depending on how hard you plan on using the final product.

 

[Bowelrock]

You can glass in one piece you don't need to do a bunch of small parts.. You really wanna watch how much of your curing agent you use, Less will give your more work time. The trick with Glassing is to use as little resin as possible. You only want your cloth to absorb the resin. Not over saturate it.

 

[exoray]

Google and Youtube fiberglass layup and watch some videos you need lots more practice The big issue I see is it appears you tried to get by with one layer of fabric, and you also didn't devote the time to getting the bubbles out of the layup...

Beyond that you also should consider some type of gelcoat in the mold initially, it has it's own issues but one you master that you will get a clean casting...

Also I have no clue how you did it but get some disposable 'chip' brushes the cheap white bristle wood handled brushes... Using the brush push and stipple the fabric and resin into the mold while forcing and working out all the air pockets... Working out the trapped air is simply something you will gain with experience...

And I'm not quite sure why some are suggesting casting resin for fiberglass layup, that is an entirely different technique and application...

 

[Ozymandius]

The stuff you are using will work just fine, you just need to learn how to work with the material.

First step is to do your first layer with resin alone. Brush on a thin layer and keep brushing it back out of the low areas as it will pool at the bottom (as you've so discovered).

Second step is to start adding your cloth. It should be cut it into small sections about 4 inches square (you may need even smaller pieces for the complex curves). I find it helps to pre-resin the cloth on a palatte (scrap cardboard works just fine) and then place it where you want it. Don't try to do it all at once, but rather do small sections about the size of your outstretched hand. Continue to work the area you've just layed with dabbing motions of your brush to get the cloth to lay flat and work out the bubbles. The cloth will likely want to rise back up and create new bubbles, so you will have to concentrate in that one area until it kicks.

Third, when laying up complex curves like the eyes, nose, etc: don't try to cover all the curves with a single piece of cloth. Instead use a seperate scrap of cloth for each curve. Ex: One piece for the top of the eye, a second piece for the bottom of the eye. One for the left side of the nose, one for the right, and a third for the bottom. etc.

Repeat as needed until you have the thickness you want.

Your finished cast will still be rough due to the grade of resin, but it will be something that can be easily cleaned up with a little spot putty and sanding. To get a really clean surface you'd want to use gel coat, but that is probably more expense and time than you want for your first project.

Oz

 

[Holluba]

I made one of these many years ago and the process that I used was quite similar to what people have already suggested, though I do have a few extra little tips that may be of help to you.

First off, with the waxed mould itself, I gently warmed it before applying the gelcoat. GRP doesn't like the moulds to be too cold as it delays the curing process and it's at this point that issue can arise.

I tinted the gel coat to a different colour than the mould for one simple reason, contrast. Doing this will help you immediately spot areas that you've missed and will also highlight air bubbles - which you can quickly brush out. In many cases, I wait until the applied gel has almost gone off in the mould to the point where I can just about leave a finger print in it, then I apply a second safety coating of gel and wait for that to go tacky.

Now goes on a layer of "chopped strand" - that's basically the matting, but chopped into little bits of less than 1/4" (6mm) in length, you can buy this as ready chopped. Tinted matting resin on top of that and tap the whole surface to ensure that the strands are laying flat. This stuff saves you a lot of work and heart ache because already you are preventing air bubbles from being cast into the surface layer of your casting and you have a hassle free layer of matting already added to the entire inner surface.

Once this layer is tacky, you can start to apply your matting cloth, gently adhering it to the tacky resin from the previous layer, this helps in the long run as things can't move out of place when you start to apply the resin to your matting.

What I did for something so small was to tear the matting into managable sections. Tearing it also gives the matting a feathered edge that not only allows you to blend it into the matting around it, but leaves it with enough flex to sit comfortably around contours. If you have a straight edge cut, the material will act against such contours of the mask and will crease in on itself to create pockets for the air to get trapped into.

More resin gets applied to this layer. If you want, you can do another layer of torn matting for extra wall thickness to your mask, once the previous layer is tacky.

The reason I don't let each layer fully cure before the next is applied is very simple, you get a better adhesion doing it this way and it also makes the whole laying up process very quick. I can finish a mask casting (on a good warm day) in just a few hours and have it popped from the mould all ready for trimming. Using this method, I have never had a mis-cast, nor any air bubbles.

You say that you had very flimsy, transparent areas in your casting. This suggests to me that the resin and catalyst weren't thoroughly mixed, it seems that you've got pockets of severely under catalysed resin. You really have to be thorough at that stage, I mix mine in a bucket stirring clockwise in a spiral movement, then do this anti clockwise, then up and down and finally left to right - just to be absolutely sure that everything is mixed equally.

Holluba

 

[Little Fett]

Thanks for all the help guys!