UH-18: Shaping foam for the nose

Second part on the foam nose job.

This is the variac UH uses. Mine is bigger but totally unprotected electrically, and it's not at the shop so I use theirs. Mine makes me a bit nervous because you have to watch what wires you're touching.

Another attempt to show what I'm going to do. The bow will rest on each wood side and cut off all the foam that sticks up above that.
Not visible in this sequence is that I added some battery cables before putting in the piece of foam over the battery box. They're household 2/0 wire, which is huge but I think necessary. The plan calls for 4 guage, but that's the normal car wire. The voltage drop when you start it has to be terrible.

And here it's done. The whole thing is about an inch thick, and in several pieces. You don't want to have epoxy where the wire is going to go. This is only filler to hold fiberglass up. It's also structually strong for when you sit on the nose to work on the lift fan.

I used blocks of wood to space the wire up a bit. This is after the fact, trying to show what happened. The nose will be rounder there, so I don't want to wire directly between the nose and the duct.

Now there's a lot of sanding. You see the "little johnson" sander there, I started with the "big johnson" sander. That's a 1x6 about 3 or 4 feet long with handles on the back, and a huge belt sander belt screwed to it.
The idea is to round the foam off so it looks like you want it to. I'm going to increase the radius of the duct here a bit, so the white foam actually meets the duct some distance above the glass. This process is long and tedious, and I cheated with an orbital sander too.

Now adding pour foam to fill in near the duct. The holes that are not covered by white foam, I just stuck a piece of white foam in there and foamed around it. The white foam keeps the liquid foam from dripping through. I had to use several pours, which is a much better idea than trying to get it all in the right spot right away. This is a fast process.

You can see a piece of 1/8 plywood (I'm not really using that piece. I'm using a longer piece the same width. This one was here to help just in case I needed it.) and a piece of plastic. You pour the foam onto the spot you want it to be, drop the plastic on there and press in with the wood. This particular foam gets big bubbles in it if you don't compress it as it hardens.

Do whatever it takes to shape it. In my case that meant sanding and even sawing the foam off. I don't like the smell this foam makes when you hot wire it, it gives me an instant headache even though the place is fairly well ventilated.

I'm done for today, but not done with the nose. There's more filling to do and much more sanding.

I dropped a bottle of invisible ink on there and now it's gone.
Really, I just gots some 3-wheeled casters to stick under the craft so it can roll. This is really convenient for the UH guys and for me, since it's no longer a big production to roll it out of the way, or over to a different work space. It's behind the gray tarp.

	This is the variac UH uses. Mine is bigger but totally unprotected electrically, and it's not at the shop so I use theirs. Mine makes me a bit nervous because you have to watch what wires you're touching.
	Another attempt to show what I'm going to do. The bow will rest on each wood side and cut off all the foam that sticks up above that. Not visible in this sequence is that I added some battery cables before putting in the piece of foam over the battery box. They're household 2/0 wire, which is huge but I think necessary. The plan calls for 4 guage, but that's the normal car wire. The voltage drop when you start it has to be terrible.
	And here it's done. The whole thing is about an inch thick, and in several pieces. You don't want to have epoxy where the wire is going to go. This is only filler to hold fiberglass up. It's also structually strong for when you sit on the nose to work on the lift fan.
	I used blocks of wood to space the wire up a bit. This is after the fact, trying to show what happened. The nose will be rounder there, so I don't want to wire directly between the nose and the duct.
	Now there's a lot of sanding. You see the "little johnson" sander there, I started with the "big johnson" sander. That's a 1x6 about 3 or 4 feet long with handles on the back, and a huge belt sander belt screwed to it. The idea is to round the foam off so it looks like you want it to. I'm going to increase the radius of the duct here a bit, so the white foam actually meets the duct some distance above the glass. This process is long and tedious, and I cheated with an orbital sander too.
	Now adding pour foam to fill in near the duct. The holes that are not covered by white foam, I just stuck a piece of white foam in there and foamed around it. The white foam keeps the liquid foam from dripping through. I had to use several pours, which is a much better idea than trying to get it all in the right spot right away. This is a fast process.
	You can see a piece of 1/8 plywood (I'm not really using that piece. I'm using a longer piece the same width. This one was here to help just in case I needed it.) and a piece of plastic. You pour the foam onto the spot you want it to be, drop the plastic on there and press in with the wood. This particular foam gets big bubbles in it if you don't compress it as it hardens.
	Do whatever it takes to shape it. In my case that meant sanding and even sawing the foam off. I don't like the smell this foam makes when you hot wire it, it gives me an instant headache even though the place is fairly well ventilated.
	I'm done for today, but not done with the nose. There's more filling to do and much more sanding.
	I dropped a bottle of invisible ink on there and now it's gone. Really, I just gots some 3-wheeled casters to stick under the craft so it can roll. This is really convenient for the UH guys and for me, since it's no longer a big production to roll it out of the way, or over to a different work space. It's behind the gray tarp.