2005-04-03

4 hours

Today was the day I found out that fibreglass is not my bag…. The stuff truly does suck. Anyways, not to be to discouraging, I learned a lot today. One is, grey primer is easily dissolved by paste wax! The other is fibreglass doesn’t always do what you want it to do.

So, first off, I went to various stores to pick up some supplies, some modelling clay, some brushes, stirrers, mixing cups and some fibreglass cloth. Then, it was off to the hangar for the moment of truth.

I started out by figuring out how the heck I’m gonna get this thing off the form, since it’s practically die locked in all directions. Well, I figured that bit out and made some shut offs for a parting line out of the modelling clay.

Then, I waxed the whole thing up. This was when I discovered valuable lesson number one. Grey primer is crap stuff. It is easily dissolved by the wax paste, and will probably stick quite nicely thank you to the resin. Well, we’ll find out sometime this week when I try to pull the shell off this thing.

Next up was to lay up some glass… I started with the armrest portion… I mixed up five pumps of epoxy and started laying up. Hmm seems easy enough. It’s going on pretty well. Next up, I decided to do the big flat top area that is recessed down a 1/4″, which will hold the throttle quadrant and fuel selector. This was where it all started to go wrong. I couldn’t get the cloth to stay down in the corners and come over and down the sides. I ended up laying tape in the trough part, and then putting a small strip along the ridges at the sides. I really have no idea how this is going to work at this point, and resignation was starting to set in. The first batch was barely used, and it was starting to get sticky where it couldn’t soak into the cloth too well. Time to throw it away.

I mixed up two pumps this time and went about the sides. Got a layer of glass on all over the whole part. Now about this time, I figured it might be easier not to build a mould, and just use the lay ups I’ve done as the actual part. If I break it off the plug, and then lay up from the inside, then sand like mad to get the shape I want again, it might work out.

Another thought that went racing through my mind was to have the whole part made using Selective Laser Sintering in 33% glass filled polyamide (nylon). Trouble is, a part this size would probably cost a couple of grand to have done. Ultimately though, the part would come out a finished article, ready to prime and paint, and it would include all the ribs, cutouts, bosses etc that I would need to make this thing work. Maybe I should make a better CATIA model and send an STL file out for quote. Anybody know any rapid prototyping shops with SLS capability that could do me a deal?!

So, here it is as I left it. 4 hours it took me to get this far, and I’m not confident in how it’s going to turn out. I’ll stop by the hangar on Monday or Tuesday to see how it worked out. Keepin’ me fingers crossed! By the way, the whitish areas aren’t air bubbles, it’s where the grey primer wiped off the part revealing the white undercoat. Grey primer, not exactly suited to this application! It’s funny, the fiberglass is so translucent, you can barely tell there is any on the plug!

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