Seat pan repair / Seat Concepts install

[slartidbartfast]

Despite living with it for eight years, the stock seat on my 1100GS has never been very comfortable for more than two or three hours at a time. I aquired a Corbin which has a totally different feel but digs into my thighs at the front and is no better than the stocker after 200 miles - plus it weighs a ton and the pillion seat doesn't fit with it. Based upon the outstanding Seat Concepts seat I installed on my DR350, I have purchased a Seat Concepts kit for the 1100GS.

Rather than tearing apart the perfectly good stock seat, I am trying to use a seat pan that came from a salvaged (underwater) bike. The seat pan was apparently damaged by a Bavarian upholstery gnome's over-zealous use of a trimming knife during assembly and at some subsequent point, the pan split.


Here is the other side with the seat foam removed


I have used a heat gun to soften the plastic and get it more-or-less back into shape but now need to repair the actual split.


Plastic welding seems like the obvious way to go but I do not have any experience and am not sure what material the pan is made from. Do not really want to spend $50 on a hot air welding kit if there's an easier way - or if it is unlikely to work anyway.

Can anyone offer any advice please?

[JimVonBaden]

Stainless steel safety wire sewing and a nice plastic epoxy over the wire. I did something similar to my ST headlight.



For yours I would do closer stitching.

Jim

[slartidbartfast]

Thanks JVB - I hadn't thought of that and I think I'll save it for a last resort. With the seat cover pulled tight, the edge of the pan will be pulled outward so the forces will be trying to bend the plastic along the repaired joint, not pull it apart as with your headlamp. Safety wire stitching seems like a good technique for repairing split fenders and plastic body panels in an emergency (along with liberal use of duct tape, of course!)

[Lomax]

Great job Jim. Your ingenuity really intrigues me some times.

Maybe I should have you hook up my Corbin seat. I think someone got the wires on the switch wrong and the fuze goes pop when I turn it on. Or maybe I just need to spend some time with a meter this weekend.

Marc

[JimVonBaden]

Originally Posted by slartidbartfast

Thanks JVB - I hadn't thought of that and I think I'll save it for a last resort. With the seat cover pulled tight, the edge of the pan will be pulled outward so the forces will be trying to bend the plastic along the repaired joint, not pull it apart as with your headlamp. Safety wire stitching seems like a good technique for repairing split fenders and plastic body panels in an emergency (along with liberal use of duct tape, of course!)

Definitely different stresses on a seat. IMHO, here are few plastic glues/fixes that can handle a lot of constant movement. I would consider a stitch of safety wire combined with your choice of adhesive.

Either way, I am interested in seeing your solution.

Jim

PS Lomax, take a ride in the spring and come on by! I'll buy the first beer!

[slartidbartfast]

Originally Posted by JimVonBaden

Dfiniey differen stresses on a seat. IMHO, here r few lasic glues/ixes hat can handl a lo o constant movemn. I would consider a stich of safety wire combined with r schoice of adhesive...

Been on the sherry this evening Jim? I'd like to buy a vowel please.

[JimVonBaden]

Originally Posted by slartidbartfast

Been on the sherry this evening Jim? I'd like to buy a vowel please.

Argh, my damn keyboard is wireless, and the stupid antenna needs to be practically on top of the keyboard. May as well be wired. Combine that with the crappy typing skills that require me to look at the keys and this is the result!

Jim

[slartidbartfast]

Does anybody know exactly what plastic the seat pan is made from, or how I would tell? These answers seem like a good starting point for figuring out the best substance to apply for repair.

[Lomax]

Originally Posted by JimVonBaden

PS Lomax, take a ride in the spring and come on by! I'll buy the first beer!

That's a hell of a ride for a Beer. hopefully some day I will be able to do things like that.

Marc

[Gillus]

I had to repair a cracked plastic seat pan for a 12GS. I used harbor fright plastic welder, plugs into 110 for heat and uses regulated compressed air to blow it. Then a plastic lid off a gallon milk jug cut in pieces for welding rod and it worked well.

[slartidbartfast]

Originally Posted by Gillus

... a plastic lid off a gallon milk jug cut in pieces for welding rod ...

Just the regular soft plastic from a screwcap? The seat pan on my DR350 looks like polyethylene but the 11xxGS seat is something else. It might be ABS but I'm not sure.

[MsLizVt]

Originally Posted by slartidbartfast

Does anybody know exactly what plastic the seat pan is made from, or how I would tell? These answers seem like a good starting point for figuring out the best substance to apply for repair.

Slartidbartfast, hi!

If you have a moment to look at the back of your seat, you should find a bunch of numbers, some look like part numbers. But there should be one number that looks like this > PP + 20% TALK <. That means PolyPropylene, plus twenty percent talc added in for substance and strength.

PolyProylene is a thermoplastic, which means it can be heated up again and it'll flow and bond. Harder plastics are most likely Thermosets, which means they can't just be heated up and flow, they have to be bonded. My guess is that Jim's headlight bucket is a thermoset, which means his mechanical and glue bond was probably the best option. It could have been welded, but it would have been a project.

PP is common in household stuff, including bottles and containers. Most of the time you can tell on almost any bottle or container by looking for a symbol that might be a triangle with a number and then letters. For instance, look at your milk bottle, there should be a number 2, for number 2 plastic, the most common in household use, and HDPE, which is High Density PolyEthylene, different than PP. I'm not sure what the cap is, but there's a good chance it's PP. Soda bottles are different, they are number 1 plastic, PolyEthylene Terephthalate, PET.

Actually, here you go. Bottle Caps

As Gillus mentioned, you can just cut up pieces of bottle caps and melt them into the cracks. The key to welding plastic is the same as welding steel or aluminum, it's the preparation of the joint. Most of the time, you'd like to have a V groove that would be easy to fill, in this case, because the seat material is so thin, you might have to just wing it as best as possible.

Gillus is right, a Harbor Frieght plastic welder would do the trick. They also come with a selection of plastic rods of all different types of material. Another option, and if this is your only plastic project, is to use a good soldering gun that has a flat tip, which often come with the soldering gun. You would heat and add plastic, heat, and add. It helps to have something on the back side of where your welding to keep the welding material from melting away.

Another method that usually works pretty well is two part epoxies. Not all of them will work with PP, because PP generally is pretty flexible. Check the epoxy to make sure it'll work with PP. My best suggestion for using epoxy would be the rough up the surface, cut out a piece of wire mesh screen, spread out the epoxy, lay in the screen, coat with more epoxy. Do both sides for best strength. You can sand it down after, if you wish, but it's under the seat, my guess is you want function, not fashion.

You could also find some sort of sheet of plastic, and to be honest, I would even use a milk jug, to put over the epoxy and wire screen/mesh, doing this on both sides, and then clamping it all. That might be overkill, but whatever works. For what it's worth, laundry detergent bottles are thicker.

How's that for a start? Questions?

Enjoy,




Liz

[JimVonBaden]

Liz,

Every time you post you impress me more and more! Great info!

Jim

[MsLizVt]

Slart*, hi!

Was just trying to think of anything that has PP in it that you could canibalize.

Apparently white products, as they are called, like the plastics inside refrigerators and plastic on coffee makers, are PP, or some form of it. There will always (I think) be a recycle mark on the plastic, in this case a triangle with the number 5, and PP somewhere near by. Here's a link.

http://www.thedailygreen.com/green-h...460321#slide-5

Interesting that they have straws in there as PP. Those would make good little welding sticks. Ketchup bottles, syrup bottles, medicine bottles, and bottle caps.

Liz

... is one of the leading suppliers of specialty polypropylene (PP) resins to the white goods industry ... high quality materials that meet the toughest requirements, including high impact and temperature resistance, high stiffness and strong aesthetic properties.


Today appliances have become part of our daily life ...


Some typical appliance applications include:

• Large appliances (white goods): Washing machines, dishwashers, fridges , freezers, dryers and air-conditioners
• Small appliances: Vacuum cleaners, coffee makers, ventilators, microwave ovens, power tools, water kettles, steam irons, toasters, rice-cookers, tea -makers, water heaters, motor housings, consumer electronics, other household and personal care products

[MsLizVt]

Some links of interest:






http://www.ehow.com/how_6404382_glue...e-plastic.html

http://www.ehow.com/how_5932276_repa...utm_source=ask

http://www.ehow.com/how_5882700_repa...-gas-tank.html

http://www.urethanesupply.com/Bumper...art/step3b.php

http://en.wikipedia.org/wiki/Polypropylene