Paper Patterns vs Flexible Shape Patterns

[neilb]

the way it works is he checks the FSP with the part out of arrangement, decides it needs more shape. (it will have more shape if opened up, as we agreed) he then wheels some more. arranges the panel how it should be, then it has too much shape (calls that "tent polling") now he has to remove some shape.

we've all seen it and spoke about it, and for some reason this is supposed to be easier for a novice to learn, but the experienced shaper that fashioned this technique has issues with it.

just watching the guy on the wheel it's clear for a novice like me he doesn't understand what he is doing. watch anyone else on the wheel and each pass is precise and methodical, wheel only where you have to. the wheel is a big cumbersome piece of equipment that needs a precision operator to get the best out of it.

I will agree to disagree with you, I can see you have found a use for this technique and if that works for you, all the best

[joeswamp]

but we just established they are not accurate at all. the only time and this is the only time a FSP can be used is when the part is finished. that is the only time it will fit.

No, I respectfully disagree with that statement. If you take a flat sheet of paper and fit it over a flat sheet of metal, it will fit. If you then bend the flat sheet of metal into a cylinder, the sheet of paper will still fit -- it will wrap around the cylinder.

If I take two metal bowls that nest together, and I squash one bowl into an oval, I can squash the other bowl into an oval and they will still nest together.

The FSP is like the second bowl, it's just not made out of metal.

I believe the problems with FSPs are not theoretical, but practical. FSPs require making lots of small parts that need fitting together later on, which inherently is going to be tough to do (imagine building a single fender out of a dozen independent bucks). The other problem is that it can be hard to know when you've exactly matched the part to the FSP.

on the subject of flipping them inside out. that doesn't work either, as that was discussed on AMS, Kerry himself said he was a dumbass
for not taking profiles of one side of the car to create a buck for the other. his words not mine...

I'll have to re-read that, but the problem may have been related to fitting lots of little parts together, he was building an entire car using FSPs (which is kind of a crazy ambitious use of the method). I do know lots of people have successfully flipped them inside out to make patch panels.

[neilb]

In the end, FSP's are just hyper-accurate paper patterns. Most of the time you don't need this, but there may be times when you do.

but we just established they are not accurate at all. the only time and this is the only time a FSP can be used is when the part is finished. that is the only time it will fit.

on the subject of flipping them inside out. that doesn't work either, as that was discussed on AMS, Kerry himself said he was a dumbass
for not taking profiles of one side of the car to create a buck for the other. his words not mine...

[joeswamp]

after watching wray and watching the video peter put a link to using the traditional way, which seems easier to you?

Sorry, I'm not trying to defend Wray's method as the end-all be-all of metal shaping. Clearly that's not the case -- Wray's method is slower, requires making large parts out of lots of little pieces (which invariably introduces errors, it's like measuring a football pitch with a ruler), and can introduce small errors in the first step that need to be corrected later -- as you point out.

But I do think FSP's are not completely useless, I think they are just another tool to be aware of.

What I believe (and I'm a beginner so take my opinion with a grain of salt) is that FSPs are useful in very specific niche situations. So for instance let's say you need to fabricate a small patch panel but you only have an example from the other side of the car. A flipped FSP + profiles is a quick way to fabricate something without creating a buck.

Wray created his technique because he hates wheeling panels in their final configuration (which may be because he doesn't use full radius anvils). In most of the panels on his Jag nose, his technique wastes time but maybe on the complex one it could save some time, especially for a beginner.

Another example: let's say you're a beginner and want to understand what's going on with something complex, like the front corner of the Jag nose. Whatever method you use to fabricate, the FSP laid out on the table will provide you some insight as to what's going on, it will reveal hidden reverses and areas of stretch that you might have thought were shrinks, due to the extreme bending configuration.

In the end, FSP's are just hyper-accurate paper patterns. Most of the time you don't need this, but there may be times when you do.

[neilb]

When you open the piece up, it will show more shape, but remember this is true with the FSP as well. If you can get the piece to match the FSP, it will always match no matter how you bend it.

it never does though, the whole process is dependent on

If you can get the piece to match the FSP

and that ''if'' is dependent on the shaper knowing what is going on. even the guy that developed this ''technique'' still has issues with it 20 years on. the term flogging a dead horse comes to mind...

Now it's true as you say that there will always be errors, but that's because it's hard to *perfectly* match the part to the FSP. So any error you make in the first (wheeling) step eventually shows up in the final fit to the profiles.

if that is the case, then why continue to work making errors that you know will be there?

like i've said before if this is how you work and wish to continue, fine crack on. i would like to see an end to this conversation as it's going nowhere, it seems to be more of excuses of errors in the process, rather than the process of making a panel quicker and simpler, why re-invent the wheel when it's already round?

[neilb]

after watching wray and watching the video peter put a link to using the traditional way, which seems easier to you?

[joeswamp]

and that is why you wheel holding the material in the shape it should be. wheeling like he does will always have errors. because when you open the shape up, it will show more shape than it did "out of arrangement" that is a simple fact of physics you can't change

When you open the piece up, it will show more shape, but remember this is true with the FSP as well. If you can get the piece to match the FSP, it will always match no matter how you bend it. Remember that the FSP is an accurate model of the sheet metal part, just with zero bending stiffness.

As an aside -- it's sort of interesting to make an FSP of a weird part and then manipulate it on a table. You see things like reverses that you didn't know were there. I think Wray shows this in his first video (the most complex part of the Jag nose).

Now it's true as you say that there will always be errors, but that's because it's hard to *perfectly* match the part to the FSP. So any error you make in the first (wheeling) step eventually shows up in the final fit to the profiles. So practically this method doesn't entirely eliminate wheeling the piece in its final shape, but it does minimize it.

[neilb]

and that is why you wheel holding the material in the shape it should be. wheeling like he does will always have errors. because when you open the shape up, it will show more shape than it did "out of arrangement" that is a simple fact of physics you can't change

[joeswamp]

this is what I said about contradicting himself, the FSP should have told him what was wrong, not coming up with some stupid term for a f#ck up. my apologies for quoting Gordon Ramsey but the guy makes my shit itch lol

So recall what he's doing is wheeling a part until it fits the FSP, and then bending the part until it fits the profiles. He spends a bunch of time bending the piece laterally to fit the transverse profiles. Since the part seemed to fit the FSP, it should then automatically fit the longitudinal profile. It doesn't, it's a bit off. So he checks the FSP and realizes that it wasn't an exact fit, there's a high spot where he wheeled a bit too much, so some correction will be required.

To me, reading the FSP and seeing if it's a good fit is the primary skill required for this method. Wray uses techniques of tapping it with his fingers and he talks about taping the edges down and shooting some air under the FSP to see where it doesn't fit.

how can you tell if it's due to bending or wheeling? even that quote is contradictory...

That's the whole point of the method -- the FSP has no strength in bending but doesn't stretch in any direction, so essentially it's a copy of the part in fabric. If the FSP fits, then only bending to the profiles should be required to make the part. In this case, he bent to match the transverse profiles and the logitudinal one didn't fit, and he saw using the FSP where he messed up.

After watching Peter's wheeling video, I've wondered if Wray developed this technique because he uses very stiff wheels with flats and thus requires very flat pieces to wheel effectively without lines. He strongly prefers to wheel parts in that barrel arrangement.

[neilb]

It can be tough to judge the fit of the FSP, especially when you're in the final stages. But it is nice for a beginner to be able to distinguish whether the poor fit is due to wheeling or bending.

how can you tell if it's due to bending or wheeling? even that quote is contradictory...

[neilb]

this is what I said about contradicting himself, the FSP should have told him what was wrong, not coming up with some stupid term for a f#ck up. my apologies for quoting Gordon Ramsey but the guy makes my shit itch lol

[joeswamp]

I do understand that Peter is not a fan of the FSP but I've never seen an explanation as to what's wrong with the method. Is it that it wastes time? Produces poor quality results? Too limited in application?

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Joe further more to your question above take a look at our friend making the scoop on the Jag bonnet ...then take a good look at the two ends where the two pieces needs to be welded together... do you see what has happen ? The two ends are diving down like crazy (it's about 1 inch ?)...and that is because the stupid idea of the flexible patterns '' tells him '' to put more shape where really it's NOT NEEDED ! There for the two pieces are too full in the middle and dive down at the two ends ..then take a look at the overall length profile.... and that tell you the same thing........ too full all over .it would need a lot of unnecessary work to set it right ...... when simply he could have used the profiles from the existing bonnet place them in the right place and check the shape wile he was shaping the two panels the right way ...AGAIN .... no need for the flexible pattern. which is time consuming and a waste of time.
I as a client.... would not happy to pay for all that time spent in making it in two pieces + weld them together, there for more work involved , when it should only take about 6 hours to make all in one piece and that goes for the front piece as well .......................
I simply can not understand his way of working and doing things ??
Peter T.

The rear piece might be diving down because it's not quite done, as he bends the sides down more I believe it might flatten out.

As for the front piece, he does talk a little about how he screwed up and overwheeled the center. But the FSP helps to illustrate this, he calls the phenomenon "tent-poling." See this excerpt:

https://youtu.be/nWovrphMkgA?t=3103

It can be tough to judge the fit of the FSP, especially when you're in the final stages. But it is nice for a beginner to be able to distinguish whether the poor fit is due to wheeling or bending.

I also agree that it would have been better to make this hump out of one piece. I believe that's the biggest limitation of the "wheel first bend later" approach -- if your pieces are big and have a lot of locked in shape it can be very difficult to bend them. Hence you must use smaller pieces and weld them together.

[cliffrod]

Without a proper rigid support, any flexible pattern has limitations. With paper patterns, the folds, creases and wrinkles capture & preserve specific information about how a flat sheet of metal must be changed to create that shape. The entire point of the FSP approach is to create a smooth pattern that conveys none of this action information. Why willingly discard such information? Paper patterns cost less, provide more information and are faster to make. My first post on this thread covered a lot of this information,

An experienced expert might be able to achieve some level of success with an FSP, just like a real chef can use an professionally useless cooking gadget (marketed to non-professionals) & make it look like a magical solution for your lack of kitchen expertise at home. With my extensive culinary training & background, I could make a lot more money demonstration & selling such crap to homemakers and wannabe chefs than cutting stone. I've turned down opportunities to do that. Never did it because IMHO it would be dishonest- simply about selling product & not about developing true expertise.

There are larger issues that are similar to issues in my stone work with flexible patterns/molds, rigid support of these flexible molds for accurate use, precisely where a specific dimension needs to occur & how it relates to other such specific dimensions. Lots of casual art people do it wrong all the time, know no better and are not willing to learn the proper method because it isn't simple. They berate people like me when I correctly evaluate their shortcomings. so I don't waste my time on them, their art/sculpture groups, forums, etc. No need to type a book about it on here, but glad to talk about it off group.

If you want to be like them, just do (use a paper pattern) like the real Masters do. That's why we're here.

[RockHillWill]

This is why I quite trying to use the FSP's. I was attending one of the earlier hosts of a metal meet in Alabama. This gentleman was building an aluminum bodied car and had made a FSP of one of the rear fenders, then cut that large pattern into smaller ones and gave them out to some of the attendees, and I received one of them. The next day when trying to assemble that rear fender, none of the pieces fit the other ones well enough to be able to weld together. Each of them fit the FSP, but not each other.

[Peter Tommasini]

[QUOTE=joeswamp;n845]I do understand that Peter is not a fan of the FSP but I've never seen an explanation as to what's wrong with the method. Is it that it wastes time? Produces poor quality results? Too limited in application?

.................................................. .................................................. .................................................. .................................................. .................................................. ......................

Joe further more to your question above take a look at our friend making the scoop on the Jag bonnet ...then take a good look at the two ends where the two pieces needs to be welded together... do you see what has happen ? The two ends are diving down like crazy (it's about 1 inch ?)...and that is because the stupid idea of the flexible patterns '' tells him '' to put more shape where really it's NOT NEEDED ! There for the two pieces are too full in the middle and dive down at the two ends ..then take a look at the overall length profile.... and that tell you the same thing........ too full all over .it would need a lot of unnecessary work to set it right ...... when simply he could have used the profiles from the existing bonnet place them in the right place and check the shape wile he was shaping the two panels the right way ...AGAIN .... no need for the flexible pattern. which is time consuming and a waste of time.
I as a client.... would not happy to pay for all that time spent in making it in two pieces + weld them together, there for more work involved , when it should only take about 6 hours to make all in one piece and that goes for the front piece as well .......................
I simply can not understand his way of working and doing things ??
Peter T.