Shrinking Disc Tips and Tricks



All right quiet on the set hi, it’s Wray from ProShaper workshop, we’re doing another shrinking disc video. We got the uh, the jaguar uh e-type nose, lower chin panel uh, because these are so low and there’s curbs and everything these get beat up really bad. And this was the front nose section that we were copying in the aluminum mark is taking all the paint off and then we dipped it in rust, 911 and you can purchase that at our amazon store, which is right in our videos right below you. Just click the link and it brings us to it – brings it to our amazon store. We made a tank and immersed it and the good features of that rust 911 is that it goes in all of the tubes and everything else.


There’s a closed tube inside these structures and the rust can

still be in there if you sandblast it, I’m a very strong auntie sandblaster. I

hate sandblasting on body panels and even worse on sand after they sandblast

that they use an epoxy primer and if you’re doing metal work and you have the

epoxy primer on there, it’s a nightmare. You have to sand it all off before you

can. Even do anything uh that rust 911 will leave a little protection on the

panel so that it won’t humidity rust, it’ll stay pretty clean for a while, and

if you do get a little humidity rust. You just use a little phosphoric acid,

which you can get at Home Depot.


It’s very inexpensive. You spray it on wipe it off dry. It good,

no problem! So here’s the panel and we’ve got a bunch of dents in it. We’ll do

an analysis on the surface and if I was doing this to finish this panel, all at

once, what I would do is break it down into sections.


I got. I have the center section here and then I got these two

wings on the other side. Here and it’s got pretty good access and if you’re gonna

work on a panel like this, my preferred method is to straddle two benches. Now.

You’ve got really good access underneath which you can put your dolly under

there, and the panel will tend to jump around.


So I have a lot of beater bags in the shop people think the

beater bags are only for beating sheet metal on. They come in actually more

utility with a beater bag, just using it as a weight to hold your panels. So I’ve

got four beater bags on here. I circled some of the bad dents, but what I’m

going to do first is just magic marker. This whole thing: I prefer these big

wide magic markers you can get them at Home Depot.


I think that’s the best price around and I prefer this over the

dykem spray, because the dykem spray kind of gums up on the shrinking disc, I’m

going to use the shrinking disc. So, let’s mark this up, it’ll take a few

minutes. You don’t have to be perfect here and I’m just using this as an

indicator to find out where this panel is and how bad it is all right. We got

it all marked up with the magic marker and now we’re going to rub the disc on

it. So, oh look who’s here!


It’s frank! Hey great! Just wishing you a merry Christmas, thank

you, frank and all those metal heads out there in metal land. What are you

doing here right? We’re trying to take the dents out so you’re interrupting the

video, but that’s all right.


This is stupid, volunteer, frank! You call it at first yeah, uh

black magic might color it that way. Uh. I could have gone this way, but in

first grade I like to go up and down rather than side to side to everybody out

there ray and I always go through every day and every day I show up for him so

anyways everyone have a good Holiday: okay, good luck! Getting this

straightened out, we’ll catch!


You guys later have a good Christmas dinner. Bye, frank! All

right, frank has left and now it’s time to pull the shrinking disc out. This is

the 9-inch shrinking this. We make these they’re available on our website.


Proshaper.Com, but before we do it, let me just show you the

proper way to mount it so we’ll take this apart. I get a lot of emails and

calls people asking you know how do you mount the disc properly? Well, this is

an essential agreement here. This is a neck and flange nut.


It’s a 5 8 11 If you’re in a metric country oftentimes, they

don’t have the 5 8 11 thread or spindle thread on the grinders, so they do have

an adapter that will adapt the metric to the American English standard. 5. 8.



So first step is when it’s when it’s all mounted. You want this

to be down in depression and you don’t want the spindle protruding out high

here, because you’re going to run this flat and if the spindle is up, it’s

going to scratch and dig in and everything. So, if that’s a problem, no matter

how you mount it, you just put washes on a 5 8 washers and that’ll change your

position. This is an essential ingredient. This I call this the central hub

support this one I modified by welding, a little ring onto it and turning it to

make it a little deeper.


I don’t make these and I’ve been meaning to make them for a long

time. I think I might start making them because everybody says well: where do

you get these? These usually come when you buy the grinder? This came from Makita

when I bought this grinder and this isn’t too old. It’s only a couple years old

or so, but I found that it worked a little better if I machined it accurately

and I put this little collar on there.


So that goes on like that. Then this is the backing pad. We make

the backing pads and sell them when you buy the shrinking discs. It’s a really

good idea to get a good backing pad and that now creates the support system for

the shrinking disc. So then the shrinking disc goes on and you tighten that up.


There’s a bug on the thread or something here. What’s going on

here we go there, we go the most grinders have a lock, they just hand, tighten

it. It self-tightens when you use it anyways. So now, when you run these this,

this disc has been around probably two years or more in the shop, see they’ll

run out a little bit like this, not to worry about it, because if it was a

brand new disc, it generally will run a little Cleaner, but that could be still

a fault here in the flange, causing that to do that. It’s not necessarily this

doing it, but it doesn’t mean anything because once you rub it against the way,

you can’t rub it on that, but you rub it on the deck on the panel.


When you rub it on the panel, it smooths it all right out, and

now you have a load on it. These grinders typically run 4500 to 6000 rpm. You

can’t use a buffer, polisher or sander polisher. They don’t have enough rpm.

You need the rpm in order to create the heat.


The secret here is heat and also the fact that you’ve got a nice

flat surface and you’re rotating it. It will highlight all the highs and lows.

So that’s why I put this marker on here to find out what that surface looks

like, like. I said I broke this panel into three sections, this wing, this wing

in the center, and that’s how I would finish the panel out and if it neglected

to mention this no lips of the opening here. That would be another feature that

I’d put a lot of tension into.


So let’s just rub the disc on here and see what kind of surface

we have. So now all of the faults or flaws in the panel are now clearly visible

because the disk wipes off the marker where the highs are and it can’t reach

the low. So all the lows are clearly defined. All the highs or actually good

surface is defined because the disc will hit that marker and kind of scratch it

off a little bit. Now the marker acts as both an indicator of the highs and

lows, but it also acts as a lubricant and without the marker.


If you use right on the steel itself, once in a while you’re

going to see sparks flying, if you see sparks flying, you should stop right

away, because that’s not a good thing at all and what that is you’ve gold. The

panel material from the panel has attached itself to the uh, the disc it’s

galled on there, and then it just keeps scratching everything and it makes more

sparks and makes a big disaster. So this acts as a lubricant. If you have too

much marker on you, you won’t get the heat buildup that you want, so it was

very little heat buildup. This is probably only 140 degrees or so sort of like

sitting your car out in the hot summer day in the parking lot.


It’s not enough to really do the job. You want to be able to get

to uh like 200 and 250 degrees at minimum, and as long as you get steam, which

is 212, then you’ve gotten the job if you see steam you’re in good shape. So

what we’ve done is we’ve got the bad spots all indicated here and there’s quite

a few of them. So well. That mark is not working that well.


Let me get another marker. Let’s see, I got one right here all

right, so I’m taking this blue marker and just kind of identifying all these

spots that didn’t get marked up by the shrinking disc. So you can see this

thing is a horror show it’s got little flaws everywhere. So you take your time

and you pick them out one by one here find where they are circle them and then

your goal is to correct them one by one. So you have basically three

conditions: good surface surfaces that are down and then surfaces that are



The surfaces that are high, we want to bring down with the good

surface level and the surfaces that are low. We want to bring up to the good

surface, so we’ve got to pick these off one at a time and fix them. So this is

a lot of work. This panel uh just fixing this one section, could take couple

three hours or so to get this perfect and then it could be another couple three

hours on either side over here and then maybe another hour here. So the video

we don’t have that much time, I’m just going to show a few little sections

here, we’ll fix them up show the procedure again.


I do have a video on shrinking on me in my YouTube library, but I

think this one will add a few more features since be worthy to watch it all

right. So we’re going to pick off these spots we’ll do two or three of them in

this video. We don’t have to do them all, as I mentioned. So, let’s make this

our first goal here. Uh, if mark can get a close-up of it, we’re going to aim

right for this.


Now we can do uh, dolly uh, no contact with the dolly initially

because we’ll be hitting here, which is uh at a different level than the center

of where that depression is so. This straddles it. The slapper straddles it and

it’s so much better than a hammer, because the hammer is actually hitting right

in the center of where that low spot is, whereas this straddles the whole thing

and we got a nice little universal soap bar dish, soap bar dolly here – and It

has a nice little compound on the top here and we’re basically going to this is

the fulcrum. This is the lever, so we’re levering these little depressions out

and as we hit, we can see the little footprints really well, so we know we’re

on target all right. Can you see those mark?


Is that showing up in the camera? Okay, good, so you can walk

yourself right around really nicely and that came up now uh. If you come up too

much, that’s what the shrinking disc is for you, you, you can err on the side

of being a little a little too much very easily, and that shrinking disc will

just level that, like nothing now, the shrinking disc, you remember, is not A

cure-all, if you’ve got a panel, that’s like uh, a really bad road. That’s all

rutted and everything. That’s not gonna.


Do it. You’re gonna you’ve seen me, use the torch, you’re gonna

torch shrink and straighten it out as best you can. First and get that really

bad stuff out with the torch, the shrinking disc is for the finessing. I use a

shrinking disc for anything. That’s a 1 16 of an inch uh too high or too low,

and anything over.


That is the torch. So some people prefer to torch, but I don’t

think you can do a good as good a job with a torch, as you can with a shrinking

disc, shrinking. This is a really subtle, uh, really great smoothing tool. They

will make glass smooth finishes on your on your surfaces, so that one came out

pretty quick. Now, let’s try this one same process.


You can walk that dolly around easily. Then we got a little

small light one here and then we got one over here. We got one go here to here.

Real important thing is being comfortable too. I’ve got this nice adjustable chair;

adjustable height chair I can get in here.


I got full access all right, so I did a lot of that sentence.

Let me get this other one. Oh we’ve got one over here too, we’ll get those so,

okay, all right! That’s that, let’s uh, I didn’t get them all, but I got a lot

of them in the middle here. We quickly mock this up again and we’ll hit it with

the desk [ Music.


So we saw a little bit of steam there. We had a few little high

spots and that’s feeling a lot better already get that all cooled down. You

can’t do a good analysis of the surface until you get it right at room

temperature, because it’s still swelled a little bit from the heat. We’ll do a

little something a little different now, instead of using the magic marker,

we’ll take the little two inch orbital, make sure that’s nice and dry. Oh, we

still got a considerable little dent there mist and now we have a condition

similar to the magic marker.


It’s the little scratches of the orbits there’s the 80 grit

sandpaper. Now we’re going to take a sanding block and sand across there and

that’ll highlight all those lows. I had a couple sanding blocks. I use this is

a little six-inch Baltic birch really flat plywood. I put stick it paper on and

then this is a piece of aluminum.


I got a piece of, I think. 120. Stick it. I believe. That’s a



Stick it! So let’s try this and we’ll just move it back and

forth, and that should highlight it pretty good. Now the sanding with the

orbital actually leaves the surface a little textured and you can actually feel

it better because of the texture, and you can see it’s pretty rough. We’ve got

a lot to do here, but this is the procedure. How good you get it um!


It’s up to you because you can take like I said a couple hours

at least to take all this dents out here. So let’s take and just rub my hand on

here now so we’ve got a low here. We can mark those lows again: we’ve got a

good low spot there. We have that really bad one over here. So there’s a few

that’ll keep us entertained for a while.


So we’ll get the slapper again get my chair and we’ll slap a

couple of those we’ll go through this cycle and see where we’re at um. I don’t

want to make the video too long, but the perfect. The whole purpose is to show

the procedure and also to show the mounting. Well, let me let me interject here

right now: here’s the five-inch disc that we make. This comes in really handy

on really tight spots, you’re not going to use it as much as the nine.


I much prefer the nine, but the five comes in very handy now. We

don’t make a backing pad for the five inch, because I found that I can buy

these harbor freight plastic ones. I generally don’t like plastic backing pads.

You should inspect it to make sure it doesn’t crack or anything, but I’ve had

really good luck with these and I think they sell them for under five dollars,

sometimes like 3.95 there’s a brand new one with their packaging and it comes

with the nut now.


Their nut is a white metal nut and I really don’t trust that

white metal nut on the big disc, but it seems to work fine on this, so the nuts

sometimes are hard to get. That might be another item that we should be making

is the central hub support for the nine inch and the nut, which would also work

on this too? But people always ask me: where do you get the backing pad for the

five inch and hobby freight makes a really nice one? It’s an expensive one. Now

the condition is low and then high low and then high.


So you’ve got basically like a wave condition. So we have to

undo that wave and that might leave a condition where the panel is up a little

bit, but the shrinking disc, just rubbing on it a little bit will bring it all

down nice and level. So now we just pounded those up. A little bit let’s take

and rub that rubbing block on the sanding block and see if those areas came up

a little bit all right. So you can see that came up there, but not so much over



A few spots where the uh, the slapper and the dolly hit

together, but let’s bring it up a little bit more now, if you hit it lightly

like that and nothing’s happening, then go ahead, increase the amount of hit.

So you just hit a little hotter. We hit that. Let’s see if that came up. Okay,

now you can see those shiny spots starting to appear all the impact points are

showing good.


We got a little uh canyon in here low spots. The important

factor is, I have either using the magic marker as the highlighter, and sometimes

I actually prefer the little orbital sander, but to see it really good. You

need a light behind you, so if you’ve got the light behind you, it shows up so

much better. So, let’s just focus the attention on those two little spots. The

rest are going to be the same procedure, but you’ve watched those come up as I

hit them with the dolly and the slapper.


So now, let’s um, we don’t want to hit it with the shrinking

disc in those spots without some lubricant there, so we’ll put the magic marker

on and then we’ll sand it again and then sand it with the orbital sander and

then sand it with the with The sanding block and see what kind of progress we

made here so I’m putting the knocker on as a lubricant and I’m going to bring

the disc onto until it gets hot enough, so it gets steamed there’s a little bit

of steam there cool that down. Oh, that’s feeling a lot better. There was a

ridge in there before what generally happens is when you get a dent going in a

dent going in here. It causes a ridge to form which feels like a high spot,

which it sort of is it’s sort of been manipulated up by the lows which were

punched into it. These z-types really take a lot of abuse on this little chin

panel, because they’re so low this one’s actually a pretty good one, there’s a

little bit of rust over in the corner here I’ll replace some of the metal, but

the rest of its pretty good and We dipped it so nice that all the rust

internally and all the little cage nuts that are on the other side and

everything all cleaned out really thoroughly, and that wouldn’t happen.


If you sand blasted, I’m really on an anti-sandblast kick. I use

the sandblast at my grandfather’s restoration shop when I was just a kid and I

know how much damage sandblasting can cause to refrain from sandblasting paint,

remover and chemical rust. Remover. That’s the way to go. I just lost my

sandblasting audience.


People that are professional sandblasters are not watching me

now, I’m sure it’s funny. When you have strong statements on anything, you lose

half your audience. You got to be really mellow in today’s world. So what will

happen here is if you want to achieve perfection, you’re going to go through

many cycles. It could be four or five cycles before we’re done here, where,

when I sand that, with that sanding block you’re going to see nothing but nice

smooth surfaces because you’re going to get full contact, you can see right now

this is shown up here.


This is like a little low spot there and there’s a multitude of

little spots now we’ll chase them one more time and then we’ll call this video

finish it. So the object is for you to get the procedure down and every time

you cycle through here. This this panel gets smoother and smoother. You know

it’s almost crazy. Now that a good uh fill prime would do that.


It’s a little bit lower here, but a fill prime and blocking

would uh smooth that out beautifully. But there is a nice sense of

satisfaction. Taking a panel, that’s all beat up and then smoothing it nice,

and then you know you don’t have to frosted with bondo. Anybody can put bondo

on not everybody can smooth a panel on I’ve done a lot of bondo work in my

life. I’D never want to do bondo work again.


I lost all the bondo audience now all right, that’s feeling a

lot nicer, we’ll give it a little more magic marker hit it with the disc again,

even the disc, the magic marker flows over it. Nicer now, because it’s a nice

smooth surface, you might have saw our spark right here, there’s a little lip,

that’s high and I hit it with the disc and it caused a little spark. Abrasion

spark. So let’s hit that with the soapy water. What kind of soap just uh I use Palmolive

or any kitchen dishwashing the heavy concentrated dishwashing so as I’m rubbing

my hand with the soapy water on it.


This is smoothly sliding right over really nice there’s a few

semi-perceptible right here. That seems to be a little ridge right here. I

might have to hit it with the disc a little harder but um. That’s actually

pretty nice now, but there’ll be flaws. There they’ll you’ll never get it

absolutely perfect, but you can get it so that you just have to use a little

bit of fill prime block it and I think it’ll be as good as factory even stuff

from the factory is pretty flawed.


If you took a brand new car off the line and subjected it to the

same type of sanding block you’re going to find flaws in it, so now we hit it

with the sander again, you can hear that sliding across now you get a nice

swishing, sound They’re just smoothly swishing over it, it’ll still show some

lows and some highs, but they’re more and more subtle now, so that was the

little bit of a ridge there that that’ll have to probably be shrunk down or it

might get absorbed once they pound. The surrounding area up a little bit and

now we’ve got a situation where I can barely perceive any low here. But it’s

showing a low here and here and we’ve got that high right here, but it’s

feeling really nice. I think the video has done its job, so I hope you uh can

fully understand how that shrinking disc works and how it mounts and don’t

forget you can get them at www. Proshaper.


om appreciated we’ve making them for 20 years. We sell them all

over the world. We call them the smooth and safe style shrinking disc, made out

of stainless steel. We make them out of thicker stainless than some of the

other people that have copied my design. So, thank you for watching its ray

from pro shaper.


Merry Christmas.


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