Author Topic: making a custom fiberglass seatpan (Read 9194 times)

paulages · « **on:** February 12, 2006, 11:28:09 PM »

using a wealth of information on the net about fiberglassing, i just made my own seatpan for my CB550F. seemed a couple of people were interested in how i did it, so i thought I'd outline the process i used. i had to improvise here and there, but for the most part all of these processes are out there on the web, explained much better by people who have done this much more. in any case, here's what i did:

i stuffed and taped brown paper bags around the frame in the area where the seatpan would be, and emptied several cans of expandable foam ("great stuff") ***EDIT: DON'T USE THAT PARTICULAR BRAND. FIND ONE THAT IS LABELED AS SANDABLE***into a giant blob larger than, but in the general shape that my seatpan would eventually be. this ensured that my form would be situated exactly where the seat eventually would be, hugging the frame.

then, using an electric breadknife i began carving the shape i wanted. not quite right? fill it back in with more spray foam. once i had it pretty good, and had measured for rough symmetry, i sanded the form...stared at it for way too long, carved a bit more...annoyed my buddies asking if it looked right, sanded some more, drank a few more beers, etc. here was a picture during one of those stares, before i decided it wasn't quite right, and went at it again. the black was just spraypaint, to help me visualize what it would look like finished.

then, once i was happy with the shape i covered the entire thing with aluminum tape. i ended up cutting out the flat section of foam and stretching tape directly across the frame for this part of the mold, so that the pan would mould around the frame perfectly. i used masking tape underneath the aluminum tape on the frame, to ensure that the whole thing would pull off in the event that the pan wouldn't release from the mold easily.

then, after careful masking off the entire bike with plastic garbage bags, i painted on mold release. once that was dry, and SOHC4 member and fellow cb550 rider Southbound had fed me a few beers, i started laying up the glass.

here it is dry, with three layers of fiberglass and a bunch of resin:

with resin body filler:

trimmed up, form removed and ready for more filler and lots of sanding:

EDIT: here it is with the final paint job and upholstery. excuse the wrinkles in the rear of the vinyl. a pro upholsterer i am not...

cben750f0 · « **Reply #1 on:** February 12, 2006, 11:38:02 PM »

dam man that looks great, i think you are gonna have some orders..

keep us posted...peace

KB02 · « **Reply #2 on:** February 13, 2006, 05:09:42 AM »

yeah, that look WAY better than mine!

At least so far anyway.

theunrulychef · « **Reply #3 on:** February 13, 2006, 05:18:04 AM »

Very nice. Your tank is looking really good as well. That's gonna be a really nice ride.

I just did most of the glassing on my seat yesterday, but I used a solid foam plug instead of doing it on the bike. After covering it w/ tape etc, I've been glassing w/ a couple of laminations & putting it in a large trash bag. Then I suck out all of the air using a shop vac (vacuum bagging) until it set. The laminations have been coming out nice & thin (less resin/glass = more strength/weight). I should be done with the seat in the next day or two & I'll be doing the same thing with for a tank, except that I'll be using kevlar fabric & super hard fuel resistant epoxy instead of normal glass & epoxy. I also purchased some micro-spheres (20 micron hollow glass spheres) to mix w/ epoxy for body filler. That should work out well to level everything off.

I got supplies from <a href="http://www.tapplastics.com>www.tapplastics.com[/url] - they've got alot of great stuff.

cbjunkie · « **Reply #4 on:** February 13, 2006, 07:15:09 AM »

paul,
about how thick does the glass have to be to be considered strong enough to stand up to the stresses of sitting and riding? 3-4 layers?

looks really good - i'm posting up some pix of my tank soon which if i may say, looks pretty killer.

coming soon
cbj...

Teach · « **Reply #5 on:** February 13, 2006, 08:53:05 AM »

I've got four layers of 'glass on the tailsection I'm building and it's still somewhat flexible. I plan on going with about 12 or so layers to be on the safe side. By the time I get a couple more layers on it I may change my mind, but for now I'm looking for super-rigid.

ProTeal55 · « **Reply #6 on:** February 13, 2006, 04:54:26 PM »

Great job.
I would buy one

Chris Liston · « **Reply #7 on:** March 23, 2006, 06:09:54 AM »

Quote from: ProTeal55 on February 13, 2006, 04:54:26 PM

Great job.
I would buy one

X2

Jay B · « **Reply #8 on:** March 23, 2006, 06:40:41 AM »

Paul, Fantastic! That's gonna be a sweet ride!!! I've built a soft seat for my 350f using the stock foam cut down and roughly covered to get the look. I'm thinking of making a removable cowl cover for the back, like a Duc Monster. I see Bondo makes a kit for small glassing jobs, seems to have everything you'd need, glass cloth, resin, hardener, etc. For $20 it should be plenty to do a job like mine. Anyone had experiance with these kits, or is there better stuff out there?

paulages · « **Reply #9 on:** March 23, 2006, 09:56:00 AM »

i bought all of my glassing supplies at the local marine supply store. they definitely have kits, but also sell a pretty good variety of fiberglass and supplies, and there are usually experienced glassers there. i would highly recommend buying the self metering pumps that screw onto the top of the resin and hardener bottles. one squirt of each, and mix away. no mismeasuring and ending up with resin that won't set up. they sell several types of fillers that just mix into the same resin.

i didn't answer before because i was waiting for it to fully harden up, but i only laid three layers of glass and it's pretty rigid. after i finished sanding and mudding the outside, i just spread more resin filler on the inside and it's very hard. i'll probably lay one more layer on the bottom to embed the mounting hardware.

cbjunkie · « **Reply #10 on:** March 23, 2006, 11:53:22 AM »

looking sweet man - i have completed the first mock-up seat base but as of now i'm not happy with the way it turned out - i'll be re-doing this step before beginning the fiberglass step.

just getting started on it gave me lots of ideas - thanks for the encouragement and inspiration.

junkie out.

paulages · « **Reply #11 on:** March 23, 2006, 12:17:59 PM »

are you gonna start again from scratch? when i overcut or didn't like something, i just squirted a bunch more foam all over it.

cbjunkie · « **Reply #12 on:** March 23, 2006, 12:29:24 PM »

i'm going a slightly different route - i'm not laying it on directly on the frame as you did - i'm making a "negative" of the underside using a combination of 1" polystyrene and "The Stuff".

i have a tricky wrap under from the pan that becomes the rear fender and my taillight is mounted inside the piece - will mount up underneath the cross brace and the seat pan is going to form a cowl over the top of it...it doesn't work very well explaining it with words - i'll send some photos when i get it further along.

i'm pretty sure it will work - now that i have one mock-up already i thought of a better way to do it all in one piece - that's why i'm starting over.

i'll post some pics...

Terry in Australia · « **Reply #13 on:** March 23, 2006, 12:39:01 PM »

Very nice mate, I wouldn't mind a 'glass seat, but as I've got a NOS 32 litre aluminum tank for my racer project, I'll make a matching alloy seat/electrics box and just polish it. Cheers, Terry.

dodge · « **Reply #14 on:** March 23, 2006, 01:20:28 PM »

can i just say your work is truly insirational , i have been toying with the idea of customising my bike for about a year , then last week , my bike was knocked over by a joy rider , knacked certain parts of the bike , completely mashed my custom paint job , so i was pissed for a while , then put the bike in the shed and just stared at it for about 3 hours , listening to nirvarna , with quite a few beers , reminising , antways the point was sorry , cut the backend away lose the panels put a cheery bomb can on it and get rid of the stock front end ,

your front end is awesome , the fibre seat is exactly how i invisiged it on mine , and the tank , i love a bike when you need to stretch over the tank , awesome ,

firstly , how did you get round the hanldebar mounting , using risers

? ,
secondley , how is the seat going to be mounted to the frame

for access to the battery

thirdley, rear light mounting how will you acieve that is the hole or ready there or you gota cut the fibreglass

the exandlable foam brilliant i was going to use chicken wire and filler to make the form

post more picks please

In Awe dodge

cbjunkie · « **Reply #15 on:** March 23, 2006, 01:27:46 PM »

yeah paul! will you marry me?

ProTeal55 · « **Reply #16 on:** March 23, 2006, 01:55:13 PM »

I want part of this...........

paulages · « **Reply #17 on:** March 23, 2006, 07:55:30 PM »

sorry cbj, i'm already married to this damn bike project!

paulages · « **Reply #18 on:** March 23, 2006, 08:02:43 PM »

dodge,

haven't made the seat mount yet, but i was thinking of glassing a flat bar to the bottom that ties in to the original hinge on the frame. i left that on purpose when i stripped the frame, just in case. as for the taillight, i'll probably just go with something small that will just bolt through the panel on the back of the pan. i have a couple laying around that aren't quite right, but would mount that way.

the seat pan sits above the original turn signal mounts because i like having the frame showing.

not sure about your handlebar question...i just installed a set of clubmans on the stock front end. i would like to have lowered it a few inches to match the lower rear with the 16" tire, but the bars already bottom out on the top of the fork tubes.

Terry in Australia · « **Reply #19 on:** March 23, 2006, 09:11:52 PM »

Quote from: cbjunkie on March 23, 2006, 01:27:46 PM

yeah paul! will you marry me?

Fag!

cbjunkie · « **Reply #20 on:** March 24, 2006, 04:54:04 AM »

ha-ha Cheers!!!

...feeling lucky, Terry?

ProTeal55 · « **Reply #21 on:** March 24, 2006, 07:01:44 AM »

Quote from: paulages on March 23, 2006, 08:02:43 PM

.i just installed a set of clubmans on the stock front end. i would like to have lowered it a few inches to match the lower rear with the 16" tire, but the bars already bottom out on the top of the fork tubes.

Paul--->
You can solve this issue by internally-lowering the front-end 1'' or so. Mine will be 1'' lower from stock, to equal out the 1'' added by the new 21'' front wheel. Should look sweet when all is said & done. Not as killer as your bike , but hopefully close

Terry in Australia · « **Reply #22 on:** March 24, 2006, 01:14:44 PM »

Quote from: cbjunkie on March 24, 2006, 04:54:04 AM

ha-ha Cheers!!!

...feeling lucky, Terry?

Er............... no?

cbjunkie · « **Reply #23 on:** March 24, 2006, 02:05:12 PM »

terry, you crack me up, man...

paulages · « **Reply #24 on:** March 24, 2006, 02:17:35 PM »

terry,
me thinks thou does protest too much...??

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Author Topic: making a custom fiberglass seatpan (Read 9194 times)

theunrulychef

Teach

dodge