Thursday, December 30, 2010

Fiberglass: A beginner's guide, the how-to APPLY (pt 2)

 --------------------------PART 2 --------------------------

Ok so now you know the basics and it's on to how to actually do it!  Now that we have all of our supplies we need to set up our work-space and get started!  Don't forget your gloves :)

Step 1:  Prepare base form
  You need a base form made out of something that your fiberglass can stick to.  Unfortunately you can't make it out of anything in the foam family. Why?   Resin melts foam and could let off a toxic gas eek!  So no foam.  So what do you use?  I've used:
  • card stock, for angular objects  
  • plaster wrap cloths, for body parts such as legs, arms etc
  • paper mach, for organic shapes
  •  Any combo from above + random objects that are the shape I need.  (ex. powerade bottle caps for jut out light holders from Samus's suit)

Now we need to determine if we want to leave the base form in or rip it out.  If you leave it in your skin won't be touching the fiberglass but it might get a little tighter than when you originally made it and be heavier.  If you rip the base out after the fiberglass has been formed then you get it lighter, but the inside of the fiberglass my be rough.  So you will have to line it or have something between you and the fiberglass.  If you rip it out make sure that you will be able to get it out.  I know that sounds like common sense but if you have your base out of wood, because your good with woodworking or something of the like, make sure you can get it out by either putting something in-between your base and fiberglass (plastic cling wrap) because you have to be able to rip it out, anything porous, like wood, will have the resin seep into the pores making it near impossible to get it out.

Step 2: Preparing your mat
  When you open up your package of mat it will be folded up in one big long sheet.  That's no good, so we are going to take those scissors and cut strips.  Now the size of your strips depends on the shape.  You can generally have larger square pieces, to be safe no bigger than 5 x 5.  On complex curves I cut skinny rectangles that are a little longer than they are thick. I suggest before you even begin mixing cut an adequate amount of strips.  Think of this as adult paper mache, you don't want to have to go back and cut more mat half way through a batch of resin!  Now put your freshly cut pieces to the side, away from your project and away from where any spare resin my fling onto.

Step 3: Mixing your resin
  In the cap of your fiberglass resin will be a little clear container that says fiberglass hardener.  I know it looks small but trust me it's enough for the whole thing.  Now on your container it will tell you how many drops of hardener per ounce of resin.  The first couple of times you do this measure it out. You don't want it to have too much or too little hardener because it will mess with the curing process.  After measuring for many, many, many batches I was able to start eye-balling it.  If it was for an important piece I still measure it.  Just to be absolutely sure!  First thing you want to pour in is your resin and then your hardener.  Mix it up very good, and you are ready to begin.

Step 4: Applying the mat to your base
  Depending on the temperature, hotter being faster and colder being slower, the amount of work time before it has gelled, or become unworkable, varies.  I would safely say somewhere between 3-5 minutes.  Now you don't want to mix up too much fiberglass resin and risk wasting it!  Remember, you can always make more batches!  So first you take a piece of your mat and hold it up against your base.  Now with your other hand get a glob of the mixed resin and start putting it on your mat.  The goal is to 'soak' your mat in resin, I don't mean actually put your mat into the container with the resin, I mean that is the 'look' we are going for.  Now it is just like paper mache, you take you next piece and layer some part of your second piece over your first piece, I don't mean right on top of, just make sure it is on top of the first piece somewhere. Soak that piece as well and keep going until either 1 of 3 things happen:
1.  Your resin begins to gel.  It will become very thick much like hot taffy, basically it stops being brush-able.
2.  You run out of fiberglass mat.  It happens to the best of us, just take note whether you just didn't cut up enough fiberglass mat or if you ran out.  It's always nice to know how much you use.
3.  You're done. Yay!

Also, to know when you have applied enough mat to be done with your piece depends on how much stress will be on it.  Safe to say no less than 2 but no more than 5.  Patch-work not counting.
  I know that sounds silly but it's true.  When you are applying the resin, sometimes you will notice little air pockets or bubbles. These bubbles will have to be ground down and filled later and compromise the strength of your piece.  So to get rid of them as you go, just 'stab' the bubble with your brush, to get that mat to stick to the resin.  You can also add just a little bit more resin to the tip of your brush to help the stubborn bubbles go away.   If you just can't get it out, you will be able to grind them down and fill them later.  I know it's more work that you didn't want to do, but it's better than having to start the whole piece over...

That's all for part 2!  Now you know how to successfully apply the mat to your base!  In the next part I will discuss how to get it ready for paint!

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