Seat Pan

There’s no place like foam.

So today I finished the seat. It’s not perfect. But it sure is comfortable. And 1,000,000 times better than what was on there (read: a piece of sheet metal and some fun-noodle foam). I started out by tracing (estimating) the hump, and then went to hacking at it with my trusty turkey carving knife. This was 20 bucks at Wal-Mart, and apparently an industry standard. I will warn you…. the thing gets REALLY hot.

I then checked the foam for fitment. I goofed a little, but the good news is.. this stuff is REALLY forgiving. If you cut too much, chances are you can just glue another piece back on and trim it down. After this I glued it down to the seat pan and then started gluing on other pieces to get a good starting shape for the finished product. I used some multi-purpose spray glue. 3M makes some stuff specifically for foam.

After this I started hacking away at it with the electric carving knife of doom until I had a basic blocky shape. Then I picked up with my trusty angle grinder and smoothed the whole thing out. Is there nothing this thing can’t do?

EDIT: It turns out it CAN’T cut an egg in half.

Once I had a smooth shaped seat I sat down and stretched some vinyl over it, stapling it into the wooden frame I’d added to the bottom of the seat pan. Staples will NOT penetrate the resin. Because I’m using one solid piece without cutting/sewing it to fit properly, there are wrinkles. I knew this would happen. I expected it to be worse, in fact. So, there’s a small victory in all of it.

In the end I’m not entirely happy with it. The shape is a little off from my original vision. I will probably pop some staples out and re-shape it a bit to where I want it. The vinyl job I did on it is meant to be temporary, so I can get an idea of how the finished product will look. And I’m glad I did it, as I will be modifying it slightly. Once I find something that I REALLY like, I will be taking it down to an upholstery shop to be covered properly.

Have you bought that angle grinder yet?

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Sunday, May 30th, 2010 BMW Cafe Racer No Comments

Staple Bones

So today I worked on getting a wooden frame built into the bottom of the seat that I will be able to staple to when it comes time to cover it. I started out by measuring out the sticks to fit around the frame of the bike. These are giant paint stirrers from Wal-Mart btw. They were like 30 cents each, and worked well for what I was trying to do.

I taped the pieces to the seat and checked to make sure it fit on the frame properly without rubbing against the wood. I only had to move one of them a fraction of an inch.

After that I went ahead and bolted them to the seat pan. And stood back to admire my handy work.

While I was out at Lowe’s grabbing the bolts for this stage, I also picked up these nifty little plastic wing nut things to mount the seat to to the frame. I figured this would be good for quick removal of the seat without tools should the need arise.

After that I marked the edge of the seat pan with a marker and went to trimming with my trusty angle grinder. The finished product was a clean edged seat pan. Complete with hump, mounting hardware, and a frame for the staples.

It’s not looking too bad. I mean…. It’s not perfect… But I’ve never done this before, so I’m cutting myself some slack. And you should too. Also you should go get an angle grinder.

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Saturday, May 29th, 2010 BMW Cafe Racer No Comments

Don’t Breathe the Resin

So today I made my first attempt at a seat pan. We will see how it turns out. How did i do it you ask? I started with a few simple ingredients.

I started out by taping the area down with painter’s tape.

Then I covered the tape with aluminum duct tape. Like.. REAL duct tape.

I then covered this with a few coats of turtle wax, letting it dry between coats. Finally I threw a layer of fiberglass resin on there and starting laying down fiberglass mat.

I would apply a thin layer of resin and then lay mat over it, building up the layers.

The final layer was a fiberglass cloth, which should give it a little extra strength.

So that’s just going to cure over night. The good news is, the whole setup wasn’t too expensive and it’s not hard to do. Couple of pointers:
- Do this in a well-ventilated area.
- Wear gloves, glasses, and maybe even a little mask to keep some of the fumes out.
- Once you mix the resin with the hardener, keep stirring! It will harden really fast!
- You will notice the resin gets really hot as it hardens. This isn’t really a pointer. Just a noteworthy observation.

Hopefully all I will need to do is trim it and throw some mounting hardware on there and get it to an upholstery shop to get it foamed and covered.

One other thing. I did notice as I was prepping that the rear cowl wasn’t really even. I really like this part of the bike. It looks like an old sportster tank that’s been chopped and welded on. I say welded. I don’t know what else to call it at the moment. You’ll see what I mean in a second. There are a few problems with this thing. For one.. It isn’t straight. Its like the guy didn’t even try to get it on there right. I feel like he cut the piece that covers the hole uneven and just slapped it on. Secondly. The thing is welded to the bike frame. And the welds are ugly. So… I’m going to have to cut it off.. Grind off the old welds and then RE-mount the thing. But properly. So I grabbed a saw and started cutting at that crooked plate so I could straighten the thing out. I then realized I could just bend the plate right off. Thanks to the worst welding I’ve ever seen. Here’s a shot of those sweet welds in action.

So once I ripped that plate off, I was able to straighten it properly and prep it for the seat pan construction. Now I give this guy crap on his welds, but I did like where he was going. I never really considered ripping that old Harley tank off the back of the bike and putting some spiffy fiberglass cafe racer seat setup on there. As a matter of fact. the shape of the tail piece with its side dents was the inspiration for the tank’s shape. I’m excited to get it all done.

Ok. It’s late. Need sleep. Thanks go out to Jon and Kate for their help and moral support today. Goodnight all.

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Friday, May 28th, 2010 BMW Cafe Racer No Comments

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