Seat pan reconstruction?

[Cliff]

Here's the seat from my project.

The bottom pan has surface rust but is solid and intact. The top pan is much more rusted and I could feel soft spots in the metal as I disassembled it. Turns out the top pan is in pretty bad shape.

Here are both sides of the top pan after I sandblasted it.

My build isn't a restoration project, but I'd like to recover and use this seat to honor it's presence as part of the original bike if possible and not just toss it away. My thought is that I could simply put closed cell foam and vinyl or leather over it because those soft elements will still be sandwiched and supported by the bottom pan. But I have no prior experience with this kind of reconstruction and I might just be dreaming in that thought :roll:. Will my idea work and suffice or do I need to give up on this?

As an alternative, I'd also be grateful for any suggestions for a simple reconstruction. I can't weld and have no sheet metal working experience to speak of. Any suggestions as to how I can reconstruct the nose of it and add material to the parts that are rusted out so I can use it?

Thanks for any suggestions.

 

[Walker]

Couple of thoughts on that.

What about a layer of fiberglass cloth over the top pan. Should make it bulletproof.

I've got a few seats to re-do and I'm thinking of using that 1/2" thick carpet padding that kind of looks like thick felt fabric.

 

[Tailwinds]

Ouch! I'm working with a bad seat pan right now too, but yours takes the cake. It usually pains me to discover after I've bought one item that it's not entirely usable and I then have to look for and afford another item to make the first item complete and usable, but it seems that's a theme with working on old bikes.
The reason I mention that is because rather than try to find another seat or seat parts I might be inclined to march right down to Autozone and purchase the fiberglass fabric and resin like Walker recommends and give it a try.

Walker can you give us any more info on that potential seat padding?

 

[Cliff]

Couple of thoughts on that.

What about a layer of fiberglass cloth over the top pan. Should make it bulletproof.

Dig it! Great suggestion Walker, thanks. I'll be off to buy a small fiberglass repair kit .

 

[JLarkin]

I am recovering an identical seat and my outer pan has a few pinholes. That style must have been more prone to rust than most. My other seats have been ok so far. The fiberglass idea is excellent.

Are those square nuts below the springs? Mine were mismatched.

 

[Cliff]

Are those square nuts below the springs? Mine were mismatched.

Yes, hex on top of square nuts on the seat springs, as it was when I got the bike. I've gotten all the nuts loosened and I'm going to put some time into cleaning everything up.

 

[Walker]

I'm just making this up as I go...I bet you could make a dam with clear packing tape over the holes, then paint in some resin. When it cures, remove the tape and then go in with the cloth. Maybe this would be an unnecessary step though? Start with a thin strip of cloth around the outer lip?

 

[Fisch]

Thanks for the info! I just bought one of these for $5 and I know it is going to need some work, but not how much. You have me mentally prepped and fiberglass sounds like a good move.

 

[55ColumbiaBuilt]

..........That style must have been more prone to rust than most. My other seats have been ok so far.

I think what happens is that the seat cover gets a small rip and lets in rainwater. The water is held against the top plate, and the rust follows.

I agree that he fiberglass idea is excellent. I have a seat in similar condition and would like to see the end-result of your project.

 

[55ColumbiaBuilt]

..........That style must have been more prone to rust than most. My other seats have been ok so far.

I think what happens is that the seat cover gets a small rip and lets in rainwater. The water is held against the top plate, and the rust follows.

I agree that the fiberglass idea is excellent. I have a seat in similar condition and would like to see the end-result of your project.

 

[Cliff]

Start with a thin strip of cloth around the outer lip?

I won't have time to work on this until the weekend, but starting with a small patch of cloth over the really compromised areas was how I thought I'd start, and then do a full coverage layer or two of cloth and resin once the base is more solid. The nose portion in particular is very flimsy, and I think it will distort and the possibly not fit well over the bottom pan unless I reinforce the weakened area in its correct shape before covering the entire pan.

 

[Fisch]

Start with a thin strip of cloth around the outer lip?

I won't have time to work on this until the weekend, but starting with a small patch of cloth over the really compromised areas was how I thought I'd start, and then do a full coverage layer or two of cloth and resin once the base is more solid. The nose portion in particular is very flimsy, and I think it will distort and the possibly not fit well over the bottom pan unless I reinforce the weakened area in its correct shape before covering the entire pan.

A thought might be to get some spray foam insulation too. The kind that expands. Grease the underside of the pan with a cooking spray like Pam (as a release agent). Squirt in some foam on the underside, aim for the problem spots. GO easy it really expands!

Let the foam expand through the holes.

Once dry you should be able to trim off the extra foam on the top, and then sand it into the shape of the seat again.

Then use the fiberglass on the top side.

Once finished the foam can probably be removed pretty easy from where the cooking spray was. Might be a bit of extra cleanup where the holes were, but it is all on the bottom side anyway.

When I get my seat, if it is as bad as yours I will try this!

 

[highship]

Ever work with JB Weld?

 

[Fisch]

Ever work with JB Weld?

I actually repaired some little holes in the rockerpanels of my 71 Datsun Truck with JB. I pushed a bit of screen through the hole then loaded it up, once dry sanded to shape. Has held up for a year so far.

 

[Cliff]

Ever work with JB Weld?

I actually repaired some little holes in the rockerpanels of my 71 Datsun Truck with JB. I pushed a bit of screen through the hole then loaded it up, once dry sanded to shape. Has held up for a year so far.

I haven't worked with JB Weld, so I went to their web site after reading this idea and found their JB Stik product: http://jbweld.net/products/jbstik.php. This looks interesting and promising to me. In thinking about covering the top pan with fiberglass, it occurred to me that it might not flex enough to accommodate the thickness of the vinyl/leather cover when sandwiched between the two seat pans. I think I will try modeling JB Stik in and around the affected areas of the top pan and use the bottom pan as a press during the initial forming stage to get the shape and relief of the top pan right.

 

[Walker]

When cured, JB will be hard as a rock too.

 

[highship]

I sugested it because I thought it might give you a little more structural integrity on the nose. Once cured it can be ground or filed down.

 

[Cliff]

Did some work

I spent some time repairing my seat pan using JB Weld Stik. I'd never used the product, so there was a bit of a learning curve for the modeling technique. I finally realized I could freehand mold it best if my fingers were wet once I started applying it to the pan. The reconstruction isn't perfect, but it's Rat-ready I think .

Here's the inner surface of the top pan with the JB Weld molded on and prior to grinding

And now the outer surface, also prior to grinding

Here's the outer surface after I showed it no mercy with the Dremel

And finally, the inner pan set inside of the top pan

Like I said not perfect, but OK and much better...good enough to recover and use. The rust seen on the inner surface of the top pan showed up after I sandblasted it and then wiped it down with some isopropyl alcohol. I need to blast it lightly again and shoot some primer on it quickly next time.

 

[someguy83]

After you reblast it, spray it down with a product called THE MUST FOR RUST. It is made by KRUD KUTTER. Works great for rust prevention. What
I usually do is spray it well and allow to dry. I do not rinse it with water like the directions say cuz it doesn't make sense to add water to something that has in the past had an issue with rust. Instead take a scotch brite pad and rub it down, then tack off the surface. I found if this is not done you will have little air bubbles appear in your paint, but the scotch brite breaks those bubbles that are unseen prior to priming. This has had great success in the past when prepping parts and especially the 100 year old clawfoot bathtubs that I work on daily (the outsides are raw cast iron and very porous allowing for some NASTY rust to grow).

 

[55ColumbiaBuilt]

For what it's worth. I know you are not powder coating the seat pan, but get this. There is a high metal content to JB Weld, and the product takes powder just like the metal component it is applied to. Just so you know.......