About Dimpling

Lee Jordan · #1 08-25-2005, 07:06 PM

Hello,

I received my practice kit from Vans and I seem to be missing some basic building theory about dimpling. I have two flat sheets of aluminum that I need to rivet together. These sheets are going to be held by 12 flush rivets. I need to dimple the top sheet so that the rivet will sit flush. The problem I get is after I dimple this sheet, the two sheets no longer lay flat against each other.

The dimple protrudes through the bottom of the sheet preventing the second sheet from laying flush. There are 12 little humps on the bottom of the top sheet. The rivets fit great, nice and flush on the top side. When I rivet the two sheets together you can see a gap between the two sheets because the dimpling is holding them apart.

I tried differing amounts of pressure when dimpling, but any less of a force causes the rivet to not sit flush.

Am I supposed to dimple both sheets?

thanks,
Lee

rv6builder48138 · #2 08-25-2005, 07:17 PM

Quote:

Originally Posted by Lee Jordan

Hello,

I received my practice kit from Vans and I seem to be missing some basic building theory about dimpling. I have two flat sheets of aluminum that I need to rivet together. These sheets are going to be held by 12 flush rivets. I need to dimple the top sheet so that the rivet will sit flush. The problem I get is after I dimple this sheet, the two sheets no longer lay flat against each other.

The dimple protrudes through the bottom of the sheet preventing the second sheet from laying flush. There are 12 little humps on the bottom of the top sheet. The rivets fit great, nice and flush on the top side. When I rivet the two sheets together you can see a gap between the two sheets because the dimpling is holding them apart.

I tried differing amounts of pressure when dimpling, but any less of a force causes the rivet to not sit flush.

Am I supposed to dimple both sheets?

thanks,
Lee

Lee: you're exactly correct, you have to dimple both sheets. Make sure that before you dimple the holes, that you deburr them (go easy on the deburring, you just want to knock off the rough bits at the edges of the holes).

Are you an EAA member? If so, go to their web site at www.eaa.org and check out the articles on building. Lots of good hints, they are in the member's section. John

DeltaRomeo · #3 08-25-2005, 07:21 PM

Yep. Dimple 'em both. Reference page 22 of http://www.vansaircraft.com/pdf/materials.pdf (middle right of the page).

Best,

Lee Jordan · #4 08-25-2005, 07:36 PM

Thank you sirs. It appears that my dimpler will be the center piece of my work-bench =)

Lee

alpinelakespilot2000 · #5 08-25-2005, 10:31 PM

From my own experience, I would highly recommend a build class. They will teach you much about the basics that will allow you to get started with confidence--dimpling, riveting, deburring, bending, etc. You still learn much later, but I can't imagine not having started from a class. They are relatively cheap and short in duration (1-2 days) and a lot of fun. I guarantee you'll enjoy building more after them.

Also, I'm not sure about the quality of the practice kit instructions, but my build instructor told me to rip them up and just look at the drawings. Not terribly bad advice given what you'll be dealing with in terms of written instructions as you get into your kit. I was almost horrified when he told me to do that. Now I just laugh because he summed up the value of the instructions that (on some days) seems very true. Thus, don't count on Van's to hold your hands through the instruction process--again, a build class will help you learn what to do, almost intuitively, from just the drawings and a QUICK glance through the written instructions.

I would also affirm the value of the articles in EAA's Homebuilders Corner

Good luck.

Steve

mgomez · #6 08-26-2005, 05:53 AM

Yup, dimple them both. If the bottom piece is too thick to dimple (> 0.040" or so), you have to countersink it (cut a conical pocket with a tool you put in your drill).

The SportAir workshop will teach you all this stuff for $300 and a weekend. I strongly recommend it. In my case, it paid for itself in replacement parts I didn't have to buy.

Martin

tomsrv · #7 08-26-2005, 07:05 AM

I don't know where you are located but our next class is October 15 and 16 and we have 4 slots available. We are located at Rostraver Airport (KFWQ) in Belle Vernon PA. Check our our website: www.wparvbuilders.nstemp.com

Come spend the weekend with us and let us take the mystery out of sheet metal for you!

Nickie Emery

TShort · #8 08-26-2005, 07:21 AM

DO IT!

I can't say enough good things about Tom and Nickie's class - it will answer all of your questions about metal work.
Figuring out all that stuff on your own, while possible, won't be nearly as easy as getting some good hands on experience in Tom's shop (not to mention Nickie's food!)

Thomas
-8 Wings

Hwood · #9 08-26-2005, 07:38 AM

Perhaps you can find a builder near you that has a project underway. The learning curve from "hanging out and helping" is exponential. I would be really surprised to hear of a builder who didn't want the help or company. Personally, I'm tired of talking to Winston, my dog.

Alexander's school in Griffin is also outstanding. Tha was my route for the empennage.

Hwood

N941WR · #10 08-26-2005, 07:55 AM

The guys and gals in the chapter will be more than willing to help you get over the learning curve. They will also help keep you motivated and moving forward with your kit.

Check out the Things to Consider page on my web site. If you scroll down (the book marks aren't working right) you will find a note about dimpling tables. They are a big help in keeping the skins looking good.

One other tip, when dimpling, just wack the thing, don't tap the c-frame a bunch of times to make your dimple. This keeps you from cold working the aluminum and makes a better dimple.

Good luck and ejoy the process, you will soon find yourself feeling lost if you can't spend an hour or two a day working on your plane.