How well do these work?

[BenWillis]

http://cgi.ebay.com/SHRINKING-DISC-SHRINKER-ENGLISH-WHEEL-PLANISHING_W0QQitemZ7569266312QQcategoryZ633QQrdZ1 QQcmdZViewItem

The rear deck on my Austin Healey Bugeye has several dips in it. The dips all pop back up into place but fall right back in because the metal is stretched. Would this make it easier to shrink the metal and get it close to the original contour so that a skim of filler could be used?

Thanks!

Ben in SC

[MARTINSR]

The problem with the Bug eye is that you have such poor access to that area. Man, I about put my back out doing one years ago. But the shinking disc would work.

The shrinking disc is an amazing tool that does exactly what it advertises to do. It isn't the only way to do it by any means. It is however a way to literally metal finish the car with no filler what so ever. The following URL is to an ebay ad with DVDs with instruction for use of the disc. I recently got this DVD and it is very good. http://cgi.ebay.com/Dent-Repair-and-the-Shrinking-Disc-a-DVD-How-To-Lesson_W0QQitemZ6457851278QQcategoryZ617QQcmdZView Item
After you see the video you can also get the discs from him as well.

I also have a disc, though not this one, one from Sunchaser tools. You can go to http://www.sunchasertools.com/ and see what he has. I also have a video set from Ken (Sunchasers owner) and it has a lot of info on it other than shrinking discs as well.

Brian

[Mooch]

I'm glad to hear that I had ordered one . Never used one but had always wondered how good they would be. I had already ordered the one you put up with the DVD . Thanks Mooch

[keb1]

I have never tried one of these shrinking disk either.
From the description they sound easier & safer than the torch method.
Questions
1 - If I purchase one are they 6" or 8" inch ?
2 - Are they hook/loop or PSA style ?
3 - Should I use a conventiona DA or a small orvit (Airvantage)
type of DA ?
4 - If neither of the tools I listed in question 3
is the proper type .should I use a variable speed buffer ?
5 - Doe Len carry them ?
I need to get rid of an oil canned depression in the rear quarter of my 55 chevy.
It is a new quaarter but oil canned after I welded in the fuel access door.

[MARTINSR]

1. The one I have is 9" I am not certain of other sizes.
2. This is a GRINDING type disc, it is not a sand paper or anything like that.
3. You use a GRINDER, I mean a serious grinder. The one I use is a 15 amp, 5000 RPM monster that will wear you out on a big job. After a while it feels like you have been pumping iron all day. But you need a LOT of torque to get the job done. If you go to the web sites of other companies like Ghiaspecialties you may find other info. But what I know I mostly learned from Ken at Sunchaser tools.
4. Answered
5. Email him and ask, I don't know.

Brian

[MARTINSR]

I need to get rid of an oil canned depression in the rear quarter of my 55 chevy.
It is a new quaarter but oil canned after I welded in the fuel access door.


This may be an over shrinked problem, not a stretched metal issue. It depends on how you welded it in. If you welded and cooled the metal like a lot of people mistakenly do, you could have shrank it.

Brian

[keb1]

That is what I did exactly.
I Mig welded small increments then cooled them with a cool damp rag.
I thought this would lessen warpage.
I can definetly see where it sucked in.
It is an area about 12" diameter.
What is your suggestion to fix it ?

[MARTINSR]

It is hard to say without looking at it. But if you can "planish" the welds with a hammer and dolly or even real close to them you should be able to stretch the metal out a little and lessening the problem.

Remember, you only want to work right where you welded it, or as close as you can get. That area is called the "HAZ" or "Heat Affected Zone". If all you have done up till now is welded it, cooled it, and now the area around it is sunk in, that HAZ is the ONLY place that needs work. At least, within reason the ONLY place. It certainly is the place to start. You need to thin the metal there, stretching it out. So take an area that looks like the least effected and put you dolly behind it and then strike on the metal with the dolly right there, using the "on dolly" technique. That would be, you hit the metal with the hammer with the dolly right behind it, you should hear "ringing" like a bell. This will stretch the metal by thinning it.

Just for clarity, "Off dolly" is putting the dolly behind the metal but say, behind a low spot (low on the out side, on the inside it would be high of course, right where you put the dolly). You strike the metal on the out side with the hammer on the high area surrounding the low area where you have the dolly. You hear a "thud" as you hit because the dolly isn't being hit like with the "on dolly" technique. This actually shrinks the metal.

Brian

[John Kelly]

keb1,

As Brian said you have shrunk the area by welding. Quenching speeds up the shrinkage. You do need to stretch the weld and the small area that turned blue next to it. After that, a shrinking disc would come in handy. Click the link below for an article about welding and the shrinking disc:

http://metalshapers.org/101/jkelly/index.html

The shrinking disc is much more than just an autobody tool. You can remove large bulges in sheet metal, create reverse shapes (think potato chip), fix oilcans, and do perfect metal finishing with it.

You can shrink using a polisher sander with as little as 3000 rpms but the larger grinders with 6000 rpm are faster.

If you buy one of ebay, be sure to purchase from "ewheel" as he is a real metalshaper who has helped the community and made a nice DVD for beginners.... unlike the other guy selling them who simply ripped off the idea from me and "ewheel". I made the first flat (ewheel's idea) shrinking discs with a 90 degree safety flange (my idea), and tested them for safe operation by sharpening to a point, and removing the ridges from a piece of half inch rebar with one, proving that the concept was safe and viable. I do not sell on ebay. I am now making a shallow domed shrinking disc that allows you to reach into valleys and shrink out lumps, or actually make a valley where there wasn't one. The most versatile tool I have.

Here are two albums that will give you an idea of what you can accomplish with a shrinking disc:

http://allshops.org/cgi-bin/community/communityalbums.cgi?action=openalbum&albumid=9980124046566

http://allshops.org/cgi-bin/community/communityalbums.cgi?action=openalbum&albumid=9980121727059

John www.ghiaspecialties.com

[Len]

John
I see that you sell the shrinking disk for $50., but is there anything else a person must purchase to use it? I see other sites that sell a "kit" that cost a lot more money that contains backing plates etc. If a person already has a polisher can they just purchase a shrinking disk without all the extra items?

[John Kelly]

Hi Len,

All that is required is a standard sanding disc back up pad and spindle nut. I have used the ones that came with my grinder, and the ones (Makita?) that home depot sells. They both work fine. No extra backing pads are necessary...a lot of that stuff is pure hype.

For some uneditted video of shrinking disc use, click on the link below and scroll down to "misc video downloads"

http://metalshapers.org/101/index.shtml

John www.ghiaspecialties.com

[BenWillis]

The demos and photos all show a convex surface where there is a hump so to speak. What about a panel on a car where the oil can is concave? How can I use one of these to shooth the surface out or should I use another tool?

Thanks!

Ben

[John Kelly]

Hi Ben,

Besides a flat disc, I make a crowned shrinking disc that will work in concaved areas...but you might want to consider propping the panel out so that it won't pop in and then use a shrinking disc so that you are working with the metal nearer where it needs to be. You will better know where to shrink this way. If you shrink in the valley created by an oilcan, there is no guarantee that you will not be working against yourself.

Oil cans are often hard to read if you have not raised and smoothed every low spot around the area of major damage to make sure your surface flow is good in all directions. You need a certain amount of tension in the panel to hold its shape. Shrinking helps get back the tension or firmness that was lost by stretching.

John www.ghiaspecialties.com

[keb1]

I agree-It seems that the shrinking disk are a better process for lowering and spreading a raised area.
-
For my situation..........
I can easily get behind the oil canned depression of my quarter panel.
What if I added a 2nd piece of sheet metal to "thicken" the metal in this area.
Would that help ?
If it would help,
Should I use an adhesive or tack weld it in ?
-
I am hesitant to purchase the shrinking disk,
thinking I would rather try other methods first.
I am scared that I will only aggravate the problem by making the area
thinner.
-
When I return on the 23rd (must leave town on buisness)
I will attach photos of affected area.

[John Kelly]

Hi Keb1,

The shrinking disc does not make the metal thinner. It does not remove any metal. It generates heat shrinking through friction. It actually makes the metal slightly thicker where you use it. Here is an album in which I shrank the same small area about 50 times to see what would happen to the bulge I stretched in a 20 gage fender. The results are pretty spectacular:

http://allshops.org/cgi-bin/community/communityalbums.cgi?action=openalbum&albumid=9980124046566

I look forward to your photos. There lots better ways than doubling up the panel to keep it from oil canning.

John www.ghiaspecialties.com

[BenWillis]

It looks like Keb and I have a dual thread going on here. No problem though!

I'f I can post a few pics could you tell me the best way to proceed? As I mentioned this is a 1960 Ausint Healey Bugeye and the oil canning is on the rear deck. Since this is one of the sexier parts of the car this panel has to be RIGHT!

Ben

[John Kelly]

Hi Ben,

Pictures would be nice. I'm sure there are more than a few of us willing to take a stab at it. I will be away from my computer tomorrow, but will check back when I return.

John www.ghiaspecialties.com

[BenWillis]

Thanks John!

Ben

[keb1]

Didn't mean to step on you Ben Willis.
I just thought that we had more or less the same problem.
I will send photos of mine on the 23rd.
(must leave today for out of town assignment).

[BenWillis]

Not a problem Keb. I enjoy starting these long threads :)

I took a few pictures but you cant see the areas I'm talking about clearly so I dont think I'll post them. The panel actualy looks pretty straight in the pics, go figure.

Ben

[BenWillis]

Ok I decided to post the pics because I'm not sure what to do.

http://www.tri-countyrc.com/galleries/bug_gallery/Lumps/index.html

The whole rear deck needs attention for it to be smooth. Any suggestions?



Thanks!

Ben in SC

[John Kelly]

Hi Ben,

Try a guide coat and sanding a little to highlite the low spots. Then we will be able to see what is going on a little better. It looks like you need to use a hammer and dolly, or better yet, a slapper and dolly to smooth the areas that are lumpy before even considering using a shrinking disc or chasing an oilcan around. The panel should be in bare metal before going too far with metalwork....in the meantime, guide coat and sand...then more pictures! If you have never done a guide coat, someone can explain that pretty easily....just shout.

John www.ghiaspecialties.com

[keb1]

On Christmas no less.
Here are my first attempts and attaching photos.
Hope you can see the problem.
Will a shrinking disk hel ?
Had to wet surface down as I previously shot it with PPG DLP90LF
and bythe way...Happy New Year

[BenWillis]

I dont see any pics Keb.

[keb1]

With a lot of help from Len here are some photos.http://autobodystore.com/images/post/keb1.jpg

By the way.............
Happy New Year to everyone

[John Kelly]

Sorry I missed this earlier...that looks like a low sopt that needs to be bumped out and smoothed before worrying about oilcanning.

Cool car! Same vintage as me...

John www.ghiaspecialties.com