VansAirForceForums  
Home > VansAirForceForums

- POSTING RULES
- Donate yearly (please).
- Advertise in here!

- Today's Posts | Insert Pics

  #1  
Old 02-17-2008, 08:08 PM
ecurington ecurington is offline
 
Join Date: Nov 2007
Location: Melbourne Florida
Posts: 111
Default Flush Rivet Advice

I would like some advise on flush riveting. So far mine seem to dimple the skin slightly approximately 1? diameter. They are not that bad but I have seen better. I think my tools are good, mushroom set, good rivet gun etc. I may not be using them properly. I saw a tip on Isham Tools to set flush rivets that I think might be the ticket. It uses a dimpling block to initially set the rivet and then a regular bucking bar to finish setting it. See the link. http://www.planetools.com/Dimpling%20Block.jpg

I do not quite understand how this works. If the hole in the dimpling block is deeper than the rivet then how does it expand the diameter and set the rivet? Or does the dimpling block just push the parts together? Has anyone tried this technique?

Thanks
Eulice Curington
RV-10 Empennage Serial # 40596
Reply With Quote
  #2  
Old 02-17-2008, 10:40 PM
Greg Arehart's Avatar
Greg Arehart Greg Arehart is offline
 
Join Date: Jul 2007
Location: Delta, CO/Atlin, BC
Posts: 2,391
Default

Eulice,

I've never tried the dimpling block so cannot comment there other than that it seems like an unnecessary step. Check your air pressure. I use about 40 psi for AN3 rivets and maybe 60 psi for the AN4 variety. Sometimes slightly less on either if I'm worried about dinging things. Anything more and you are likely to end up with overdriven rivets and dents (but it may also depend on your rivet gun). Make sure your driver is flush against the rivet head before pulling the trigger, and make sure your bucking bar is tight against the back side of the rivet. A common problem is overdriving - you want to pull the trigger just long enough to form a decent shop head, no longer. Most cases this is about 1.5-2 seconds at most. If you're careful, there should be no evidence of the driver on your skins.

Mostly it comes down to trying things out (maybe on some scraps rather than the real stuff) until you get the feel for the best procedure.

cheers,
greg
__________________
Greg Arehart
RV-9B (Big tires) Tipup @AJZ or CYSQ
N 7965A
Reply With Quote
  #3  
Old 02-18-2008, 12:43 AM
pmccoy's Avatar
pmccoy pmccoy is offline
 
Join Date: Jan 2006
Location: Orange County CA
Posts: 646
Default Try Some Paper Protection

I was getting some scuffing on the surface of the skin with my flush rivets. I starting putting some smooth construction paper between the rivet gun and the skin. It worked great. I no longer get any scuffing marks at all. The rivets lines are smooth and clean. As mentioned above, I also do a couple of short quick bursts on the gun, and use the air pressure at pretty low levels.

__________________
_____________
Peter McCoy
RV9A N35PM S/N:91335
First Flight: April 2013
Hobbs: 400 hours after Oshkosh 2017
www.myrv9.com
Reply With Quote
  #4  
Old 02-18-2008, 08:00 AM
airguy's Avatar
airguy airguy is offline
 
Join Date: Oct 2006
Location: Garden City, Tx
Posts: 5,145
Default

I like your paper idea - I have been placing a piece of masking tape over each rivet head and shooting it, and then of course have to remove the tape and put it on the next head. I can reuse the tape for about a dozen rivets before it's shredded, but it takes time to move it. Your method is faster, I believe I'll try it on my VS this week.

The dimpling block simply serves to press-form the rivet and dimpled skin to exactly the right shape, eliminating any irregularity in either the skin dimple or the rivet head, before setting the rivet. It does not contact the bottom of the rivet shank or change it's diameter - the whole point is to make the rivet head shape and the dimple shape "perfect", similar to the idea of matchdrilling.
__________________
Greg Niehues - SEL, IFR, Repairman Cert.
Garden City, TX VAF 2020 dues paid
N16GN flying 700 hrs and counting; IO360, SDS, WWRV200, Dynon HDX, 430W
Built an off-plan RV9A with too much fuel and too much HP. Should drop dead any minute now.

Last edited by airguy : 02-18-2008 at 08:08 AM.
Reply With Quote
  #5  
Old 02-18-2008, 08:34 AM
Rick6a's Avatar
Rick6a Rick6a is offline
 
Join Date: Jan 2005
Location: Lake St. Louis, MO.
Posts: 2,346
Lightbulb Riveting Tape

I prefer to use regular rivet tape to hold a single rivet or a long series of rivets in place and to also protect the alclad from needless marring. You apply the tape so the clear area is over the head of the rivet. The dark green borders contain the adhesive and holds the tape into place on the skin. A roll of tape goes a long way. You can use the same piece of rivet tape over and over again until its adhesive finally gives out.

__________________
Rick Galati
RV6A N307R"Darla!"
RV-8 N308R "LuLu"
EAA Technical Counselor
Reply With Quote
  #6  
Old 02-18-2008, 12:39 PM
ecurington ecurington is offline
 
Join Date: Nov 2007
Location: Melbourne Florida
Posts: 111
Default Thanks for Advise

Thanks to all who replied. I will try to monitor my air pressure more closely. The dimples seemed to be worse on the thin skins of the elevators. I have been using the rivet tape and do not have a marring problem.

Eulice
Reply With Quote
  #7  
Old 02-18-2008, 04:53 PM
nippaero's Avatar
nippaero nippaero is offline
 
Join Date: Mar 2007
Location: Nampa, ID
Posts: 231
Default

I have been using the masking tape method as well. I use the blue painters tape and it seems to come off the flush set easier. I to can get about a dozen rivets set before the tape is shredded. It is a pain but the results are good. I think I will be trying the rivet tape on the wings though. It is probably faster.
__________________
A&P
RV-7 (Sold)
RV-6 (Sold)
1952 Cessna 170B
1947 Aeronca Chief
Reply With Quote
  #8  
Old 02-18-2008, 08:37 PM
JonJay's Avatar
JonJay JonJay is offline
 
Join Date: Jan 2007
Location: Battleground
Posts: 4,348
Default Protection is a waste of time....

..unless you are going to polish your airplane when you are done. If you are going to paint, save yourself the time and move on. Your painter, or you, will go over the entire airframe and scratch the living you know what out of it to prep. Sure, it looks nice hanging on the wall, so if that is important to you....Even if you are going to polish, the small marring from the rivet set will polish right out. I know it does not take much time to apply tape or whatever, but every little step multiplied by hundreds is that much more build time.
As far as there being a uniform dimple about an inch around the rivet, I would wonder if your dimple is not formed properly. It should be nearly impossible to do that on an AN3 rivet without telegraphing the rib or structure below right up through the skin, meaning you are hitting it way to hard. The rivet would be over set also. It sounds like you know what you are doing, so I would check your dies and/or make sure you are getting a good dimple.
__________________
Smart People do Stupid things all the time. I know, I've seen me do'em.

RV6 - Builder/Flying
Bucker Jungmann
Fiat G.46 -(restoration in progress, if I have enough life left in me)
RV1 - Proud Pilot.
Reply With Quote
  #9  
Old 02-19-2008, 06:49 AM
Steve Steve is offline
 
Join Date: Jan 2005
Location: Roy, Utah
Posts: 1,144
Default

I found that using a set with the urethane ring on it (ref Isham's pic in post #1) produced the best looking rivets. Don't force the gun against the work. Hold the gun square to the work with just enough pressue to keep it from sliding around. The bucking bar does most of the actual work.

Steve
Reply With Quote
  #10  
Old 02-19-2008, 09:37 AM
trib trib is offline
 
Join Date: Aug 2005
Location: Virginia Beach, VA
Posts: 474
Thumbs down Get rid of the mushroom!

Take a look at the set pictured in Peter's response and get one of those. The mushroom set is what's causing the dimple. I used a 1" mushroom set for the start of my project and got the same result. The red rubber cup set (from Avery's) completely eliminated the dimple. It's also easier to use as you hold the gun in one hand and then steady it by holding the rubber cup in the other. Much easier!
__________________
Tim Ribble
Virginia Beach
RV-6A (only took 13 years to build )
N621TR In unrestricted operation
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 01:38 AM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.