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 Post subject: Re: DIY saddle
PostPosted: Mon Oct 29, 2018 10:16 pm 
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friendly kitty

Joined: Wed Nov 13, 2013 11:38 pm
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Location: Indiana
I would copy the shape of a WTB Pure but add a bit more of a relief in the center section.

Sti, the birthday thread being updated for Nicole was where I got the idea to try making my own. Maybe others will give it a shot, too.


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 Post subject: Re: DIY saddle
PostPosted: Tue Oct 30, 2018 12:01 pm 
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bad kitty!
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Ok, that one is easy, if you already have such a saddle that is.

For the mold, you need cling film, Vaseline, glass fiber mat, polyester, gel coat, and a silicone free release agent.
All of that is readily available from most marine shops.
If you're lucky, you may even find a glass fiber boat repair kit, that has it all. That is however only interesting, if you only plan on making one mold. If you wanna make more, it gets too expensive that way.

If you take a look at the first images of this thread, you see the plug and the mold.
There are two different ways to get there:

1) You make a custom plug of wood/plaster/plastic padding/whatever (positive model), and cast the mold on the plug.

2) You make a negative copy of a saddle you already have (keep padding/no padding in mind), cast a positive in the negative, give the positive proper surface finish, modifications, and so forth, and go to #1.

The actual casting of the carbon is fairly simple, as you need to get 50-50 like this for example:

http://www.fibermaxcomposites.com/shop/ ... l?cPath=36

They even mention Airbus in the description, must be real fantastic :D

Pretty much any wet layup epoxy will do, as long as it's not curing too fast.
Do a wet layup of a few layers, throw in a layer of 50-50 aramid (Kevlar) carbon, to keep your private parts safe in case of a crash or a bad design.
Put a layer of perforated PE film (yes, a plastic bag that you put 100 evenly spread needle holes will do), a layer of the polyester padding you find used for winter coats, and put the whole thing in a plastic bag.
Attach a vacuum cleaner to the bag, allow it to run for a few minutes (watch out you don't overheat the vacuum cleaner).
Seal off the bag, switch off the vacuum cleaner, but keep it in place in case you messed up, leave it to cure. If you have managed to get proper sealed vacuum, you can remove the vacuum cleaner, and throw the setup in the oven to cure. That will allow for much faster cure, and may be beneficial to the final structure, depending how much vacuum you managed to get.

Now you have a carbon shell. Post cure it according to the data sheet of the epoxy (I use one of the $20 mini ovens for this)

The rest is fairly self explanatory I take, counting out that you need to seal the edges, once you're done finishing the shell.
I personally like the titanium frames from old Selle Italia Flite saddles (not the modern fake ones that are claimed to be titanium, the so-called 316Ti, which is stainless steel tubes with 0.0000000001% titanium in the alloy).


Magura :)

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 Post subject: Re: DIY saddle
PostPosted: Tue Oct 30, 2018 7:14 pm 
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friendly kitty

Joined: Wed Nov 13, 2013 11:38 pm
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I can see where you say it takes some time on the first go.
Getting the mounting points for the rails done right will take some work. The seat I want to replace has Ti rails, and the others of that model I have were made with the NiCro rails. Both have lasted well for me.


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 Post subject: Re: DIY saddle
PostPosted: Tue Oct 30, 2018 8:20 pm 
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bad kitty!
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Getting the mounting points right is a walk in the park.
Just mark the mounting points, and use rapid epoxy to fixate the contact points.
Once the epoxy adhesive is cured, laminate a few layers of carbon at each point, vacuum the layup in place.

Magura :)

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 Post subject: Re: DIY saddle
PostPosted: Thu Nov 01, 2018 8:06 pm 
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bad kitty!
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Did I manage to scare you all away?

Magura :thinking:

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 Post subject: Re: DIY saddle
PostPosted: Thu Nov 01, 2018 11:26 pm 
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friendly kitty

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Just late getting online after a full day of driving around town in crappy weather.

I take it the rails are in place during that part of the molding to avoid having to force them in once the lay up is set.


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 Post subject: Re: DIY saddle
PostPosted: Fri Nov 02, 2018 3:12 pm 
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bad kitty!
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Yes, bond the rails in place with rapid epoxy, is what I (not too clearly)tried to convey above.
That part is fairly easy.

Magura :)

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 Post subject: Re: DIY saddle
PostPosted: Fri Nov 02, 2018 10:11 pm 
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friendly kitty

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Now I need to gather up the stuff I need and see what kind of building skills I have. I figure this will take me most of the winter to complete since I have two other projects going that should take a week or so each, and have been working at them since May.

Once I get the core of the seat done deciding how to cover it might be the hardest or easiest part. I will either take the approach that my butt doesn't care and get a rejected piece of purple leather or get picky and try to match colors of the bike. I don't know what might be durable enough, but I thought I would check with an auto upholstery place a friend used for his car seat repair.


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 Post subject: Re: DIY saddle
PostPosted: Fri Nov 02, 2018 10:35 pm 
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bad kitty!
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Auto upholstery shops are great places for sourcing such materials. Mostly a six-pack will give you access to the leftover box.
I've in the past been subscribing to "my ass has no eyes", and just used random leather to cover the composite, in the name of safety.
Today I take it a bit further, but due to creative perception of colors (color blind), nobody else seems to be all that impressed anyhow.
As for the time involved, there's a limit, as the majority of the processes includes something that's curing.


Magura ;)

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 Post subject: Re: DIY saddle
PostPosted: Sat Nov 03, 2018 3:31 am 
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friendly kitty

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I'm sure it would be a terrible idea, but instead of using a foam layer put in a thin gel pad where my sit bones contact the seat. Kind of like they put in the heel of some shoe insoles. Pedaling around the bikes that came into the shop I worked at with gel seats I know the big ones feel good but they are heavy, huge and would likely suck after 15 minutes.


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 Post subject: Re: DIY saddle
PostPosted: Sat Nov 03, 2018 10:18 am 
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bad kitty!
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In my humble experience, padding is a band-aid for not having the right saddle shape.
Padding puts pressure on soft tissue as well, where you sure don't want it.
My best saddles are in fact just bare composites, or composites covered with leather.

The bad news?
It takes a few attempts to make the perfect saddle for yourself.

The good news?
If you start making your own saddles, you have a chance of achieving the perfect saddle for you.
If you keep buying saddles, odds are it will never happen.

Magura :)

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 Post subject: Re: DIY saddle
PostPosted: Sat Nov 03, 2018 10:18 pm 
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friendly kitty

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I might go for covered/unpadded, as I mentioned it doesn't seem to matter much after a few minutes of riding. Bare composite would be fine if it isn't too sticky or slippery when wet or dry.

One of the seat sellers has you sit on a piece of cardboard to see where the sit bones put pressure to help choose the width. I may use that method to see better where it is on my favorite seat that I want to model this from. Use that info to make the center channel wider/deeper since there is soft tissue contact there. The hole in the underside does nothing unless I am more forward on the nose of the seat. I will be moving that more to the middle of the area where I make contact.


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 Post subject: Re: DIY saddle
PostPosted: Sat Nov 03, 2018 10:58 pm 
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bad kitty!
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A very old trick, used by race car drivers, to make custom seats, is to fill a bag with polystyrene balls, sit down on it in the position you think is right for you, and draw a vacuum from the bag, so it holds the shape once you stand up.
That way you get at least a "wet finger in the wind" idea, about how your behind is constructed.
Throw in a bit of anatomy study, and you have a pretty good idea about the direction to take.

The polystyrene ball bag allows you to measure with reasonable accuracy, if you cast a positive.
One done, don't forget to mount ears on the positive, and give it to someone you don't like much.

Magura :D

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 Post subject: Re: DIY saddle
PostPosted: Sat Nov 03, 2018 10:59 pm 
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bad kitty!
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Bare composite is exclusively for dry weather rides. I'm not sure I'd use a bare composite saddle on a MTB neither.
For a road bike it's great.

Magura :)

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 Post subject: Re: DIY saddle
PostPosted: Sat Nov 03, 2018 11:15 pm 
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bad kitty!
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Take a look at the Selle Italia Flite Evolution.
That should give you a fair hint about how it's done, counting out that they bolted the frame in, in the front end, that I wouldn't do.
The Flite Evolution 2, is a great example of how not to do it. Note the Kevlar going all the way to the edge, so you have to cut it to shape the shell.
Never do that :D

Magura :)


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 Post subject: Re: DIY saddle
PostPosted: Sun Nov 04, 2018 2:30 pm 
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friendly kitty

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Keep the Kevlar within the edges so the ends are covered in the epoxy is what I take from the "how not to do it" on the Flight saddle. Do the same for the glass mat as well?

I know I am asking a lot of questions for something I won't get to for a month or so but it helps with planning and learning before I start.


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 Post subject: Re: DIY saddle
PostPosted: Sun Nov 04, 2018 2:39 pm 
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bad kitty!
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That goes just for Kevlar, as it's a bitch to cut and sand.
Glass is just like carbon to cut.
Not that I'd use glass for the saddle itself, given the low cost of carbon.

Magura :)

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 Post subject: Re: DIY saddle
PostPosted: Mon Nov 05, 2018 1:11 am 
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friendly kitty

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Started shopping. Looks like this site is the one I have found that doesn't require me to buy 10 yards.

https://compositeenvisions.com/carbon-fiber-lmfg-stabilized-fabric-2x2-twill-3k-206-31gsm-6-1oz-50-1541.html


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 Post subject: Re: DIY saddle
PostPosted: Tue Nov 06, 2018 12:14 am 
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bad kitty!
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I'll ask Drew Diller if he would be interested in supplying kits.
That would be the easy solution.
Didn't think of that till now.

Magura :)

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 Post subject: Re: DIY saddle
PostPosted: Tue Nov 06, 2018 2:09 am 
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friendly kitty

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I haven't got supplies fully priced out, but it looks like it would be around $100 US. There would be a lot of left over carbon and carbon/aramid mat left which I might be able to use for repairing and updating my bike travel case instead of using Kydex.


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 Post subject: Re: DIY saddle
PostPosted: Wed Nov 07, 2018 9:34 pm 
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friendly kitty

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Magura wrote:
I'll ask Drew Diller if he would be interested in supplying kits.
That would be the easy solution.
Didn't think of that till now.

Magura :)


Please do look into that option. Making one that has what's needed to create the mold and plug would be great, too.


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 Post subject: Re: DIY saddle
PostPosted: Wed Nov 07, 2018 9:58 pm 
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bad kitty!
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I just got back home a couple of hours ago, so didn't ask him till now.
He's having a look at this thread ASAP, and then we can take it from there.
My thought behind, was as much to make sure all raw materials are compatible and so forth.

Magura :)

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 Post subject: Re: DIY saddle
PostPosted: Thu Nov 08, 2018 1:21 am 
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friendly kitty

Joined: Wed Nov 13, 2013 11:38 pm
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That's a good thing. I am learning, but I can see where buying the wrong stuff won't end well. Hate to be the guy with the parts that never cure. (Was going to end that with "harden up" instead of cure, but read it first.)


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 Post subject: Re: DIY saddle
PostPosted: Wed Dec 05, 2018 11:48 pm 
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lurkin' kitty

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Hey. I'm sorry for my VERY slow reply. If you want the excuses, it's a boring story.

I need a few things to move forward on this idea of me parting out some raw supplies. It is fair to say I'm cautious almost to the point of cowardice.

First, I want to make my own saddle. Haven't done that yet. I have certain ... physical needs that make me more like an old guy than a middle aged guy, so I have my own incentive for making a custom fiber saddle.

Second, I want to talk to my liability insurance provider. Strangely, they are unresponsive these days, which gives me concerns that are larger than custom saddles. Chicken or the egg kinda thing. It does seem to me that a bunch of businesses that I normally rely on have friggin clocked out for the year.

Let's see what January brings.

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 Post subject: Re: DIY saddle
PostPosted: Thu Dec 06, 2018 5:56 pm 
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friendly kitty

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Hi Drew. A followup in January is great since I have a couple of projects I need to complete before taking this on.
I would be happy with a product listing, or a buy this/ don't buy this, and which supplier to use or avoid list if you have that. No reason to bind you in liability. With the amounts available from online suppliers I doubt there will be excess material left once a few practice lay ups are done.
With the time Magura has spent leading me, and from researching on my own, I think I have enough information to start hands-on learning once I have the right materials to work with.


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