Sorry,

I've gotten a little behind in posting my progress. I'll try not to get too far behind.

<u>Step 7</u>:

Once the initial thinned layer of epoxy has set up, we can get to the fun stuff. Next, mix microballoons into the resin and use this filler material to fill in and smooth out sharp edges in the mold. Each type of cloth has its own idiosyncracies, but most fiberglass cloth will conform pretty well to compound curves (this is why it is such a popular choice for scale construction these days), but it definitely has its limitations. It does notconform tosharp corners well. Especiallywith the type of "hand-layup" construction methods I am detailing in this thread. It would do better under the pressure of vacuum bagging, but that requires specialized equipment and a whole other learning curve that I haven't gotten to, yet; and, some that I have talked to state that they still have serious problems with the cloth laying down in the corners. I've learned to stop fighting it and just radius the corners and fill in (at least partially) other details with microballoons and resin.

As microballoons are added to the resin, it becomes more opaque. The higher the microballoons to resin ratio the: 1) lighterthe filler material becomes, 2) the easier to sand it becomes, 3) the thicker the mixture becomes, 4) the more delicate it becomes. (And vice-versa.) Different ratios have different uses in the process. More viscous mixes are better for flowing easier into- andfilling in- sharp edges (such as the thinnest parts of a wing fillet), but the mold must be supported such that the mixture stays where you want it until it jsut starts to cure. Somewhat thicker mixes are better for holding the shape of radiused corners. I've read that a ketchup consistency is good, but have found that if you want the mix to stay where you put it reasonably well, while having the filler still be workable, (It is going to settle on you somewhat. Just accept it. You are never going to totally override gravity!) get itto a consistency where it behavesalmost more like merangue(I hope you guys are cooks out there, or that analagy won't help at all). In other words, it will almost tend to hold stiff peaks, only very slowly settling under its own weight slightly. I included a picture to demonstrate what this might look like. Realize that some applications will require thinner mixes that this. You just have to play around with it and see what happens. If it is too thin for your application, slowlymix inmore microballoons. If it is too thick, add more resin.

. . . OH yeah,did I mention that:
1. I recommend that you always wear gloves when working with epoxy. Research has shown that excessive skin contact leads to an allergic reaction to epoxy (I believe that this is withworking professionalswho have much more exposure to these chemicals that most of us hobbyists; but why take the chance when clean up is so much faster and convenient. Like whenyouhave to answer the phone continuously because: thewifekeeps calling to remind you about stuff on the "honey-do" list .. .and all your friends keep calling to find out how the project is going, and want to know when you are going to get more posted on the fabrication process. . . and you have to keep taking pictures and don't want to get epoxy all over your expensive camera . . . trust me and just wear the gloves, already!

2.It is a good idea to thoroughly mix your resin first, before adding any other fillers.

3. Then pour a little of the resinin another cup. This has two benefits. First,the shallower the resin level, thelonger the pot life (working time); and, second, this wayyou have extra resin to thin down your mix ifyou get to aggressivewith the ratio of microballoons.