How to design a motorcycle seat // Paul Brodie's Shop 

Mitch does a brilliant job behind the camera. Paul your knowledge and expertise must be second to none.

Groovy background music too, reminiscent of the soundtrack for On Any Sunday. A coincidence? Who knows. Who cares. It's perfect.

My old boss would call it a saber-saw as well. Sure did take me back when I heard you say it. Excellent work!

They were always called jig saws in the Uk I remember my dad obtaining a jig saw attachment to fit on his Bridges drill back in 59 or 60. He cut me out a gun shape from a plank of wood which I promptly broke attacking the orange tree in the back garden.Paul who ever taught you glass work should have shown you how to trim grp with a sharp knife once it reaches the putty stage, so much easier than glass dust every where, also facilitates release.

Thanks Paul and Mitch. My favourite videos are the ones where I think "pfft that'll never work". The very best ones are where I think that a couple of times. This was one of the good ones, I thought "that'll never work" a couple of times.

Always a pleasure to be invited into your shop. Thanks. I have always known that tool as a saber saw.

My dad called it a saber saw sometimes, but back to the video, you are the most even tempered fellow to not totally lose your cool while trying to pop your seat off that mold.

Paul Brodie and Mitchell Nurse you are the best 😁✌️

wow Paul you had me sweating to watching you remove that mould!

To de mold - if the bottom edge I’d the finish shape for the pan cut the excess off flush w/the edge of the pan (a air hack saw w/a metal blade works great) then get some plastic wedges (mold tools) start putting them around the edge , be patient & the part should pop off . Also next time spray the mold w/PVA. You can also use air to help it come off the mold. I think every time I do composites I learn something ( or what not to do real fast 😎). The pan turned out nice !

Zip disks work fine to cut. Vacuum bagging is remarkably easy check out the model aircraft guys. Less resin is good, peel ply helps reduce resin excess. Woven cloth conforms well and is neater to use. Thinner carbon in multiple layers would conform better. But your system produced a nice seat.

That’s the beginning of a Ferrari, Paul. Also, we’ve always called the aforementioned machine a Jigsaw here too but I’m sure it’s a hand held reciprocating detail cutter or some such - like that particulate suit, paper based breathing apparatus, ear defenders, nylon hammer, centimetres, litres, kilometres, phalanges protectors, protruding concentration tongue….

Yep , they were saber saws at my house, too(Sabre trademark name?). Jigsaws were mounted to a table in a fixed position in my mind (cutting jigsaw puzzles anyone?)... The seat on the desert sled photo looks like a BSA Lightning seat. The seat base looks like an old Bultaco fiberglass seat base I have in the garage. Thanks for the very instructive and entertaining vid!

That part put up a fight, think there was a little positive lock going on. I liked the way you got more brutal as time went on, been there done that.

new coffee to hand , here we go.

FLOWS... Nicely with The Tank.. TY Sir.('S...Camera Man Also..lol)

Nice!, and, I’ve always called it a “Sabre Saw”!

The lines on the Cub have to 'flow'??? I've always tried to trim the excess glass off with a cheap pair of Lister bandage scissors when it reaches a leather hard state. But I always use epoxy. It doesn't go off as quickly as polyester. Beautiful work Paul! Thank you (and Mitch!) for having us along.

Your use of hot glue is to my use of duct tape. That looks great. Haven't even thought about Mitch's camera work because it's always spot on and in focus. Your both professional on both sides of the camera, which makes watching your videos enjoyable as instructional. Keep up the great videos.

Big issue is getting the thing *symmetrical.* I think the struggle I saw here was why I went to a thin coating of softened beeswax (toilet gasket) as a mold-coating to make for easier separation.

I prefer to lever the cast and mold apart with a flat tool. As I go I drop in small coins and place popsicle sticks to act as wedges to keep the sections under a separating tension,you can use flat washers. Far easier than bashing away with a mallet. Small moldings like this are ideal for vacuum bagging. I vacuum bag everything these days,using garbage bags. You get no air bubbles ,the lay up follows the contours perfectly and the resin is kept to a minimum. You lay the wetted composite on the mold, put an oversize sheet of plastic film over it ,a thick (2~3mm) layer of paper towels next with the vacuum line on it and then put it in the bag and seal it with tape and connect to a vacuum pump. I put the whole thing in my car on a sunny day and it is cured to the point where it can be removed from the bag , in 3 to 4 hours. If you want to, all the vacuum bagging materials can be bought from composite suppliers.

As always, thanks Paul & Mitch. I think for this project, it should be a Saber-Toothed Tiger Cub Saw. Mitch says "It complains about the music? It puts the bass solo on its skin or it gets the hose again."

Didn’t realize you’d have that much trouble de-molding your part. Wish I’d have said something the other day. In my boat factory days we used air to de-mold our parts. We had a satellite air tank that stood about 16 feet tall with a dump valve attached to a 4 or 5 inch rubber hose. Using Delrin wedges like you we’d separate the edge and push in the flattened end of the rubber hose. It took two guys to hold the hose and someone to control the dump valve. It was always a good time when new guys would hire in because we’d get to watch as the hose would blow out and put them on their asses. Back to your seat pan,you need some 3/8,1/2 and 3/4 inch flexible plastic air line depending upon the area of the part you’re de-molding. Along with the line a ball valve and compression fittings for whatever size hose you’re using.. I’ve made a couple of portable units for my buddies that have chopper guns and work on parts outside. They were nothing more than a portable air tank and one inch brass ball valve,empty propane tanks work just as well with a handle welded on. Also excellent for blowing tires onto the bead when you’re working with tubeless stuff. As far as the plastic line I mentioned,most auto supplies have it in stock as it’s used for tractor trailer brakes and air ride systems. Again great video and great camera work from Mitch. 👍

Wow Paul, that was finicky work! And yes, Mitch does a great job, and editing video so it flows organically is also a finicky job - you are both well matched for the project!

The seat shown in the desert sled photo was a Bates Cross Country saddle, or clone thereof. Seemed to be the choice on most of the desert rigs.

My first recollections were a sabre saw...I go with the flow now and call it a jigsaw😅

I've seen guys use compressed air to separate the mold/plug.

You guys are a two man team. Paul's video and editing, oh and music, are critical and accomplished perfectly.

You had a good workout then Paul lol It was good to leave in the difficulties you had removing the Mould it just shows that the pros have problems too, good Video 👍

I don't make a lot of comments, but... Sabersaw is like Skilsaw, or Sawzall (now known as circular saws and reciprocating saw, respectively), they all have other names when made by someone else, but they were so significant of an improvement to tools that the name of the original was used for those that came after it - which is a great segue into a tool you really need, which was made by Porter Cable alone for many years though without a catchy name the Oscillating Tool (Mitch, being a woodworker, may have one). Its a much better tool than your angle grinder, to cut pieces from their moulds (*and a million other precision jobs). I also rarely ever give "how to" advice, to a content creator, but I do have a fair bit of experience with almost everything done in this episode... there are a few things I'd have done differently, so that I struggled much less than you did, here. One, the BIG one, polyvinyl-acetate (PVA) mould release agent. You spray it over the final wax coat, it dries pretty quickly, and it makes the mould let go of the part so much more easily *I wouldn't even pretend consider casting a body panel without it! Two, I'd make the mould much stouter, with some bracing inside to hold its shape while thermo-cycling, and to provide a way to pull on it ...the two moved around, together, as you pulled and hit it *I'd also have considered skirting to mould to keep the part from closing over the edge of the mould ...but that's a whole 'nother kettle of fish, and wasn't conducive to the way you mocked up the form. And lastly, given the mould had no skirts, I'd have used an oscillating tool to trim the part all the way around, save for a tab at the back to push/pull on (*coinciding with a good handle on the mould). I don't regularly hammer small parts out of a mould. :P

I’ve always known it as a jigsaw in Australia. Hope Mitch and yourself enjoyed your coffees 👍

Oscillating saws do a real good job of cutting fiberglass or carbon, plus they don´t throw up dust.

Mitch does do a good job.

Hey Paul, great stuff as always! Just a few thoughts , PVA release agent is your friend as others have noted, also , what I use, this is just me - widdershins as they say - 1/2" electrical plastic conduit , bout 12" long, heat the end with a heat gun and flatten in the vice , then grind a gentle curve , not unlike the shape of a spoon ,and a little taper to it. then once you've got an aperture you can simple drive it in slightly and it displaces the mould from the casting. Make a couple of them and the whole trick just parts, usually a little light banging on the release section is all it takes spring it loose. The spring being the whole idea. While you're here , maybe before you get ahead of yourself as i sometimes do , to fasten the cover , some kind of split rivet drilled through from the outside before you close it all up , basically same idea as my previous note , if you're careful you could counter sink any head and just a pply a spot of bondo to glue it in. As to cutting , i cut no mask, no paintsuit , no gloves - I use a garden sprayer set to a fine mist which I spray over the blade and area while i'm cutting, The mist pulls the dust down and cools the blade at the same time , obviously one has to exercise care but I've never had an issue and that with a 230V grinder. As to seat shaping - an idea that i use that works well , especially when one needs a dense hard seat , like a racebike for instance - I lay up a couple of layers of Sondor foam(Probably a brand name here) might be called something else, i think it's EVA , anyway , it's the black stuff , same as the excercise mats are made of , which can be shaped / sculpted with a grinder and a P80 grinding disk. You do however have to work gently and gradually lest you end up with gouges but it makes a really nice seat that takes a cover beautifully especially if you want to do it in one piece - no seams. I'll shut up now! Sorry for the chapter n verse , I just like sharing knowledge and ideas!! Have a good one!!

I"m really impressed that you stayed cheerful the whole time you were wrestling the pan off the mold. If I was doing that, it would have been a whole pile of yelling and cursing. 😂 That's a really interesting and amazingly straightforward process for getting the pan and seat contours right. That saddle's going to look great. Mitch gets props too, absolutely - editing a bunch of raw video together into something that's interesting, engaging, and maintains pace, is a serious skill.

Speaking of camera work... 15:05 that hoop is perfectly aligned with the rim in the background. Nice!

I call it both, I think Porter cable or Skill called it the saber saw if I remember correctly.

The jig is up. I grew up knowing it as a saber saw. Today, I call it both names. I have always thought of a bench mounted say with a small table that uses a scroll type of blade is a jig saw. I blame the people in marketing for the confusion.

Harmonize, dang it! Harmonize!

I love what you eye see's! This is a great example of solidifying your vision in wire form. We always called that type of saw a saber saw, but we're old. Great video and great choice of music to go with it.

I remember it as a Sabre saw and slowly being transitioned to Jig saw.

Anyone else out there notice at 15:05 how that first arched wire to form seat hump is the exact radius to match the front rim of the Aermacchi on the lift behind him? Yes folks, he is that good.

We always drilled a small hole through the mold that we would shoot a blast of air into with a nozzle. Pops them right off.

oh, man, i like how you do the symmetry of the seat with these wires and hot-glue, excellent job, very professional work

Jig saw in Australia Awesome work Mitch You do ok to Paul 👍

Uses polyvinyl alcohol as a release agent. You just spray a little water in between and it releases automatically.

Jeeeesss, i,m itching just watching you, lol

I was was taught to cut the excess off with a knife when it was “green” so only part set. Very easy if you judge it right

Feels like John Britten building his entire bike with wires.

Like My FATHER, when I work around guys I can always tell when they call things by the old Timey-name (I'm 53yrs old myself) But guys now call them ZIP TIES, old guys call them Tye-Wraps? Same as Jig Saw/Sabre Saw I suppose? Dad always called it Sabre saw, and so do I ..... I typically De-mold parts like that with compressed air- Youre fighting that seat pan so much because it has NO pattern-draft, in fact, it has the opposite of that as the sides curl around - very tough to de-mold THAT SHAPE of seat is known as a "Bum Stop" because the bump at the back stops your BUM from sliding off the back when you gas it! Hahaha

My dad, who worked in construction in the 1920s, called it a saber saw. A jig saw is what folks now call a scroll saw.

My dad called them a sabre saw and i did too for a while. Now i just call it a jig saw...LOL but then again I'm 46. I still use things like a yankee twist drill and other odd items. I have really enjoyed this build. I just found you about a month or so ago and you have a lot of great knowledge. Keep up the good work, one RU-vidr to another ...

that's looking great, my weekly dose of Paul and Mitch brought a difficult week to a positive end, thanks guys!

What a lovely camera angle, the wireframe of the seat hump matches with the rim of the motorcycle behind. Great eye Mitch 👌

On a new mould, its always a good idea to use PVA as well as wax for the first few pulls. Without PVA the first pulls can be very difficult and mean part or mould gets damaged.

Really enjoy your videos I grew up calling it a saber saw we would say jig saw for what I would call a scroll saw today

Here is a useful note on hot glue. You can debond it almost instantly and even break it down into mush with isopropyl alcohol (99%).

Some boat builders fibreglass into the female mould compressed air fittings and smooth over the opening of the fitting with plasticine before laying the fibreglass into the female mould. Does not take much pressure to pop out a 12m hull. For trimming the chopped strand overhanging the edges of the female mould, I use a air hacksaw using a trimmed short length of hacksaw blade to the length I need, reduce the height of the blade by half and put a bull nose round on the end using the belt sander attachment on the bench grinder. I use air tools working with fibreglass, air tools are cheap, fibreglass ruins electric tools.

Fun game of whack-a-mold :)

I cut all that excess off while it's still soft, after it hardens trim down to the edge, then sneak a wedge in and blow with compressed air. Any run over onto the inside will make it hard to separate. When I do my gel coat, I coat the top of the edge of the mold also, so when trimming it gives you a guide to see, so that you don't cut down the mold. The seat pan itself looks like it's the perfect size to be the seat.

Thats going to look fantastic...but working with fibreglass looks like a right pain!

when cuttting fiberglass, esp. in situ, I use mostly an "alternating saw" , which also makes much less dust compared to a rotating saw (Fein is a top quality brand around here, but intermediate brands such as Bosch work just as well for laminated)

Hi Paul & Mitch, Great episode! The wire form should really help your upholsterer. Looking good! I was happy to see you wearing the safety equipment today - especially cutting on fiberglass. I always called it a sabersaw, too. Mine was a hand-me-down, with no speed control-just On/Off.

Saber saw is a trademark brand name owned by Craftsman...like Skil saw for circular saw or Kleenex/facial tissue

Mine is a "Junk saw " I got it at KMart in 76. It is KMart brand and the original cord is about 10 inches long , a California safety features " supposed to keep you from sawing through the cord .I know makes no sense because you can't use it without a extensions cord . Ok I got up and looked at my saw it is labeled Saber saw. I have also seen Scrolling saws, similar designs except they have a knob on top above the blade that rotates the blade so you can turn the cut without swinging the entire saw body . Used one at work .

We're about the same age. I got a job in a tool shop in 1973. We sold Bosch (Scintilla) jigsaws, Holz-Her jigsaws and Millers Falls sabre saws. I think MF spelled it "saber". I have the impression it was a trademark of Millers Falls/Ingersol Rand Corp. Millers Falls did that American thing of moving the factory somewhere else (Greenfield, Massachusetts?) and then went out of business. Holz-Her got bought out by Festo (Festool). You can still buy a Bosch jigsaw,and it no longer costs a couple of months wages but it ain't made in Switzerland any more. So it goes... A mate of mine had a factory making fibreglass baths and handbasins. He would blow the bath off the mould with compressed air. It made a helluva pop but didn't damage the finish.

Inspirational. Thank you.

Both Paul. Saber saw and Jig saw.

I like the TIG glueing at the end 😂

great teamwork, just like the dynamic duo, now i can`t wait for the next exciting instalment! Paul, the side stand on my tiger cub broke the other day, I`d stopped to fill up, and it just keeled over but I caught it , part of the braze had come away from the tube, I can weld it,, I hope.

About time we met Mitch

Yes, jigsaw. A sabresaw has a long free floating reciprocating blade?? Seat looks a little thick/high in the middle, but maybe it will be more comfortable like that. Thanks guys.

Diretamente do Brasil! VOCÊ É O CARA!!! ESPETACULAR a sua tecnica!!!!!

Thanks again Paul and Mitch. Another very enjoyable production. Can't wait to see the seat finished. I think Mitch needs to film the upholstery getting done. 😎

Paul u are Legend ✌️

Brodie Brilliance once again, but am I the only one feeling itchy?

I still call them saber saws. (Still have my Dad’s all metal one, I won’t use without thick gloves)

Very cool.

That's awesome....

When I worked at a fiberglass maufacur before the fiberglass fully kicked off got fully hardened we cut off with a razor blade.

Watching you skin that mold made every part of my skin itch.

The top corners look a little sharp, 90 degrees, a bigger radius might be more comfortable. Mitch is a pro, looks great.

A jigsaw has the steerable blade axis and/or very narrow blade depth. Sabersaw has basically scaled down Sawzall blades and a longer stroke

Abpout the separation, if you ever find yourself in that situation, use some air from an air compressor, you can drill a tiny hole in the middle, stick the air compressor gun to separate the foils and then close back the hole

Amazing , as always .

i use the air compressor and stick the gun between the mould and the "product" toreleasethe part from the mold.

I’m with you Paul, it will always be Saber Saw.

Look at Mitch the master videographer. 15:08 he set the shot up so perfect the aluminum welding wire radius is concentric to the front wheel of the aermacchi motorcycle a few feet behind it. Very nice. The bass solo kicks ass too.

Hi Paul, my first encounter that saw was in early 80's as a handyman in South East Asia, we all call it Jig saw , I don't know if it has any other name in my region. : )

Mould separation was a bit..mmm but the end result is really nice.

GAD - Glue Aided Design

When you started bending the aluminium rods I started having flashbacks to delboys garage busa build !!

Yes, always known as jigsaws in the UK. Seat base beautifully done Paul! KRT Framework just put up a vacuum alternative… interesting different process from another meticulous and talented fabricator - worth checking out. Looking forward to seeing the seat upholstered… hope the side profile won’t look too chunky against bike contours.

Oh the things I could learn from this man. I would love to be his neighbor.

Paul . You shouldn't have that mutch troubles. Try DUPONT TEFLON RELICE AGENT it works

Mitch, Amazing job! , pretty interesting video, I have not seen tho whole process of building a seat before

@15:05 , the way the hoop lines up with the wheel in the background

Mitch is not only the operator, but also video editor). Am I right? Nice work, as always! Stay safe!

Vibrating multisaw works great for cutting fibreglass and very little dust! For me thats a jigsaw, a sabresaw has a longer blade and comes straight out of the front of the machine :-)

I think sabre saw was a brand but the jig saw is more a description of what it was used for. Another great video using wire forms was the basis of early 3d cad modelling.