My first try at a seat. What do you think?

jmcelhan

jmcelhan

New Member
Thanks to the videos by Herm Narisco's at DCC, and all the posts here on DTT, I decided to try making my own seat. This is the first time I've tried anything like this so it promised to be an adventure.

First I got the foam blocks from Micheals. They also had a can of 3M spray adhesive right there on the shelf so I figured, "Hey, that's convenient. I'll use that stuff to glue the blocks together." Unfortunately the 3M product was crap so I had to head back out to Home Depot to get some LocTite.

Anyway, here's how it started:

Untitled by jmcelhan, on Flickr

My next step was to file out the bottom so It sat a little lower on the frame. After that I drew the rough shape with a marker and started carving. Here's what I ended up with:

Untitled by jmcelhan, on Flickr


Untitled by jmcelhan, on Flickr

Folowing the steps from Herm's video, I started taping and used some coax cable to form the outer ridge.

Untitled by jmcelhan, on Flickr


Untitled by jmcelhan, on Flickr


Now the fun part. I haven't done much with fiberglass, just enough to know that I hate the stuff. Still, after covering the mold with some turtle wax, I laid down a couple layers of the fiberglass cloth and resin.

Untitled by jmcelhan, on Flickr

After letting it sit for a couple of hours, I cut it loose and pulled out the mold, which to my surprise, came out in one piece. Unfortunately, this is also where I made a bit of a mistake. First, I probably should have put at least on more layer of cloth or mat down on the initial shell. Second, I probably should have let it cure over night. Why? Because the initial shell was a little too flimsy and ended up bowing out a little on the bottom near the seat area and bowing in a little on the bottom near hump area. Not a huge deal, it'll just require some extra sanding and some extra bondo to get straightened out.

Anyway, here's what the she first looked like on the frame:

Untitled by jmcelhan, on Flickr


Untitled by jmcelhan, on Flickr

The next evening, I started beefing up the structure from the inside. I ended up putting about 3 more layers of matt and resin on the inside. After it cured for 24 hours, that thing was hard as a rock. So I started in on the initial sanding.

Here's what it looked like after the first round on 80 grit.

Untitled by jmcelhan, on Flickr

It's hard to see but the inside edge around outer ridge got filled in a little with resin so I had a hard time cleaning that out. I think I'll have to go back around it again with the dremmel to get it just right. Anyway, there's a lot more sanding to go. Ugh...

Finally, last night I trimmed up the bottom and mocked it up in the frame again. I'm going to have it sitting about a quarter inch to a half inch lower, but you get the idea:

Untitled by jmcelhan, on Flickr

And here's one more with the vintage looking 6V brake light I'm going to eventually install. This is also the reason I went with a flat back hump rather than a more conical shape.

Untitled by jmcelhan, on Flickr


So if you've made it this far, thanks for looking. I'm hoping some of you will have a little advice for me. For instance. how much sanding do you normally do before smoothing it out with the body filler? Any other tips are more than welcome. I see a lot more sanding in my future....

Thanks again!
 
You should sand and sand until you are at a point where any given low spots will only need 1/8" or less of body filler .... ( a body man would tell you a max of 1/16" )
 
with a tank shaped like yours, i would have just made a mold of of the back half of the tank, and then made a plug from the mold, that's what I did. Because then your hump is almost a perfect match of your tank, sanding should be minimal since it should be close to the same condition as your tank.

Carving up the foam is fun, but you may have overlooked a much simpler method.

I know you want to mount that taillight on the back of your seat, but I think shaping your seat to accommodate a tail light is going to detract from the overall profile of the bike. You could cut and french that tail light into a contour with some effort.

Sorry if you weren't really looking for criticism

As for sanding... i like to do a quick shitty rattle-can paint job on parts, almost like a guide coat to see how i'm doing, especially working on fiberglass parts. It will give you a good indication of how smooth something actually is.
 
jsharpphoto said:
with a tank shaped like yours, i would have just made a mold of of the back half of the tank, and then made a plug from the mold, that's what I did. Because then your hump is almost a perfect match of your tank, sanding should be minimal since it should be close to the same condition as your tank.

Carving up the foam is fun, but you may have overlooked a much simpler method.

I know you want to mount that taillight on the back of your seat, but I think shaping your seat to accommodate a tail light is going to detract from the overall profile of the bike. You could cut and french that tail light into a contour with some effort.

Sorry if you weren't really looking for criticism
Click to expand...

Those are all good points. I never considered using my tank. Ah well, that's why I'm here to learn new things. I have to admit that in the pictures the hump looks a little larger that it should. I think it's because the whole seat is sitting higher on the frame than it will when I'm done. As far as the tail light, the plan is to cut a hole and place the light inside the seat so that only the bezel is protruding. I'm also planning to take the original tail light/license plate mount and attach it to the inside of the hump. That'll give me a way to secure both the tail light and the license plate below. The tail like also has a license plate light so the plate will be lit.

Anyway, I'm pretty far into it now, so I'm just going to keep plugging away to see what I end up with. Thanks for the advice and opinions.
 
I think you have done a great job for your first try, and should keep going with the sanding and finish it off and paint.

As you go make a list of the things you forgot, could have done better, or just want to change.

Then afterwards when you have the time/patience/money you can make V2.0, referring back to your list.
 
Thanks everyone. I tried a v2.0 this week and it was a total disaster. Working with the mat is a lot harder. So I've decided to just repair the defects in the original. I'll have some pictures up next week as I'm hoping to finish it up.
 
Great first attempt! I'll be sure to take some notes from this when the time comes for me to make my seat. Thanks for sharing!
 
DeanJ said:
You should sand and sand until you are at a point where any given low spots will only need 1/8" or less of body filler .... ( a body man would tell you a max of 1/16" )
Click to expand...

I agree with dean(im a bodyman) what i would do honestly is:

I would take filler to it and get it exactly how you want it and wrap it in cling wrap. then i would lay 2-3 layers of fiber on and make a mold. and then i would let it cure and do the same thing but inside of your mold. once you have done this you will have a seat pan that requires very little body work and you have a mold for your next bike if you do one. just my .02 i like things to be difficult sometimes though
 
CutNup said:
I agree with dean(im a bodyman) what i would do honestly is:

I would take filler to it and get it exactly how you want it and wrap it in cling wrap. then i would lay 2-3 layers of fiber on and make a mold. and then i would let it cure and do the same thing but inside of your mold. once you have done this you will have a seat pan that requires very little body work and you have a mold for your next bike if you do one. just my .02 i like things to be difficult sometimes though
Click to expand...
This is not the correct way to do a mold. Once your seat is perfect you would use a mold release agent on the seat and start laying glass right over it. You want the mold to be perfect so the part that comes out of it needs no ore than primer and block sanding. I don't think you can cover your seat with cling wrap and not have any creases in that will need to be fixed on every seat that come out of the mold. Once you have a mold all you need is to spray in the gel coat and then back that with glass.
 
To go with 01's post, you'd want your mold to be tooling gel. Build your plug, get it perfect, wax it, spray it with tooling gel, lay glass on it. Pop it off, trim it, wetsand it out to 1200 or so. Then, you're ready to build parts.
 
I personally would have gone with a smaller hump more symmetric to the tank, but I totally understand wanting to match it up to that light (which is awesome). Either way, I applaud your work+ would like to try myself on my next build.
 
dtrader said:
I personally would have gone with a smaller hump more symmetric to the tank, but I totally understand wanting to match it up to that light (which is awesome). Either way, I applaud your work+ would like to try myself on my next build.
Click to expand...

+1
Also, if I understand epoxy, I think one of the objectives is to rough-up the otherwise smooth surface of the epoxy so that it will accept paint...unless of course you are just making a plug. In which case smooth-as-a-baby's-bottom is the call. :)
 
So I've made some more progress. After additional fiberglass work, some body filler, and tons of sanding, I finally got to something I could work with.
ugevuba5.jpg


So I decided to fit the tail light.

u9ereqy7.jpg


Once that was done, I shot it with a coat of primer.

gujunuhu.jpg


ybu5e3a7.jpg


I still have some pinholes and scratches so I'll be using some finishing putty to fill them. Then I'll sand again and spray another light coat if primer and see where I'm at after that.

Here's a pick with it just sitting on the frame. Getting closer to paint one day at a time.

2emuzu3y.jpg


ynejema8.jpg


It's no professional job, but I'm no professional so I'm still proud of it.
 
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