VansAirForceForums  
Home > VansAirForceForums

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

- Today's Posts | Insert Pics

  #1  
Old 03-19-2018, 08:16 PM
Bavafa Bavafa is offline
 
Join Date: Oct 2007
Location: Sacramento, CA
Posts: 2,438
Default Drilling the canopy

In drilling the canopy, I used a drill bit for plastic (118 tip) from McMaster with not so good results. When looking at the holes with a magnifying glass from inside, on some of the holes there is a chip on the exit point. (I have deburred the holes which has taken roughly 70-80% of the chip out but not all. From what I can think, here are my options:

1- Deburr more to take all the chip out but it will make a semi (small) countersink on the inside
2- I can use a Plasdrill bit which have had great results with but they are not available in the number sizes and 5/32” would be my next size which makes my current hole of #27 to a 5/32” hole.
3- Don’t be picky and leave it as is
4- Your suggestion
5- Your recommendation


Thanks in advance
__________________
Mehrdad
RV7A - IO360M1B - SOLD
Dues paid
Reply With Quote
  #2  
Old 03-19-2018, 08:32 PM
elev666 elev666 is offline
 
Join Date: Feb 2013
Location: Kincardine Ont,Can
Posts: 77
Default

Mehrdad
It's been a couple years since I did my canopy but my initial holes were all number 40 and then any holes after that you want to have a backer made of wood or UHM , if you need to use one of your regular bits you can dul them by drilling into your concrete floor for 10-15 seconds and the only thing you can use it for now is plexi
Give your glass all the room you can to expand & contract ,,, 2 Of the 4 RVs in my county have cracked canopies rite now , fingers crossed every time I close mine these cold mornings !
__________________
C-GARV RV 6
1946 C85 J3
RV 7 project /IO-360 -200
Dues paid 08/ 17
Reply With Quote
  #3  
Old 03-19-2018, 08:37 PM
RV3Bob RV3Bob is offline
 
Join Date: Jan 2008
Location: Los Altos, Ca.
Posts: 17
Default

Find a scrap piece of canopy. Get a brand new uni bit and practice with it. I have found it works the best. Nice clean hole and it de burrs.



Bob Grigsby. Los Altos. Ca
3B. Close
J3 flying Low and slow. Usually at pattern altitude. Clint at Vetterman wanted to know "why so high?"
Reply With Quote
  #4  
Old 03-19-2018, 08:56 PM
DHeal DHeal is offline
 
Join Date: Sep 2006
Location: Windsor, California
Posts: 721
Default

On my plexiglas and lexan canopies, I generally use a small UniBit for the majority of the holes. Sometimes it results in a hole that is ever so slightly larger than the plans-specified hole -- but that is OK with me since the extra hole clearance provides slightly more room for the expansion/contraction of the plastic material. Another benefit of the UniBit is that you can very carefully use the next larger UniBit drill step to gently chamfer the edges of the hole. As noted above, practice on scrap material to build your confidence and perfect your technique. Also, be sure that the plastic material is warm!
__________________
David Heal - Windsor, CA (near Santa Rosa)
EAA #23982 - EAA Technical Counselor and Flight Advisor; CFI - A&I
RV-12 E-LSA #120496 (SV w/ AP and ADS-B) - N124DH flying since March 2014 - 680+ hours (as of Oct 2018)!
VAF donation through June 2019.
Reply With Quote
  #5  
Old 03-19-2018, 09:21 PM
caapt caapt is offline
 
Join Date: Feb 2013
Location: Pottsboro TX
Posts: 61
Default Make sure the Temperature is warm enough

Plexi does not like to be drilled if it's too cool. Check me on this, but I think 65 degrees is considered a minimum. 85 is better.
__________________
14A Wing Complete!
Tail Complete
Fuse Complete
Engine installed
Reply With Quote
  #6  
Old 03-19-2018, 09:31 PM
flyboy1963's Avatar
flyboy1963 flyboy1963 is offline
 
Join Date: Oct 2008
Location: Lake Country, B.C. Canada
Posts: 2,350
Default make your own bits

if you take the drill size you want ( old and dull is ok) then use a Dremel with an abrasive disc.....put the bit in a vise, get out your reading glasses, and then take the 'rake' out of the bit.
grind the face of the cutting edge completely vertical, in line with the long axis of the bit. Some guys also point the bit like the fancy ones, but it's not entirely necessary.
You now have a milling tool.....much like the unibit.
It will SCRAPE it's way thru the acrylic, and won't 'grab' as you exit.

As other's have said, be sure you have a good, solid backup, and just go right into it so the hole in the acrylic is a nice cylinder.

smart to test, test, test before doing the real thing.
You'll know by the sound..... the rpm.... and pressure ....and speed of cut that makes nice curlies, and those that don't!
__________________
Perry Y.
RV-9a - SOLD!....
kinda missing it!
Lake Country, BC

....paid up til Nov. 2018
Reply With Quote
  #7  
Old 03-19-2018, 10:59 PM
Bavafa Bavafa is offline
 
Join Date: Oct 2007
Location: Sacramento, CA
Posts: 2,438
Default

Lots of good advise, none applies to my situation as I have already drilled it and honestly the chip is so small that can not be seen without a naked eye.

I have done the backing it with a piece of wood method when is possible, the canopy is backed by its frame and not possible to back it with a piece of wood. Also a uni-bit will not work with thick material unless you don't care about the size. If one is OK with going to a slightly larger size hole, I highly recommend a Plasdrill, you can get it at skygeek or Tap plastic. It works very nicely.

http://www.skygeek.com/craftics-1106...SABEgIJ9fD_BwE
__________________
Mehrdad
RV7A - IO360M1B - SOLD
Dues paid
Reply With Quote
  #8  
Old 03-20-2018, 06:23 AM
BillL BillL is offline
 
Join Date: Sep 2007
Location: Central IL
Posts: 4,450
Default

Quote:
Originally Posted by caapt View Post
Plexi does not like to be drilled if it's too cool. Check me on this, but I think 65 degrees is considered a minimum. 85 is better.
They don't like hot either, so, when drilling many holes, the bit gets hot. Just dipping the bit in a cup of water before drilling provides enough lubrication and cooling to make a much cleaner hole. I discovered this when drilling dozens in plexiglass for a different project. It made a significant difference.

BTW - I use the Avery bits that look more like these.

__________________
Bill

RV-7
1st Flight 1-27-18
Phase II 8-3-18
Reply With Quote
  #9  
Old 03-20-2018, 06:07 PM
Stockmanreef Stockmanreef is offline
 
Join Date: Nov 2012
Location: Midland, mi
Posts: 584
Default

I plan to buy permagrit 100 degree counter sinkers to counter sink. They might be able to clean up the hole edge if used carefully.

Go to this site for drill bits of all numbered sizes for plastic. I just bought some.
https://www.abbeon.com

Just a thought, since I have not yet done this step.

I emailed vans about scrap plexiglass. I got an call from the canopy manufacturer and 3 days later I have scrap plexiglass. I just had to pay shipping.

good luck.
__________________
Ken Stockman
Midland, MI
EAA Chapter 1093 member


RV-14 (serial number 140073)
N73XP (at least that # reserved now)
Reply With Quote
  #10  
Old 03-20-2018, 06:15 PM
Scott Hersha Scott Hersha is offline
 
Join Date: Jan 2005
Location: Cincinnati, OH
Posts: 899
Default

Mehrdad,
I think you need to get all of the chipped areas out of the holes you've drilled. A chip is a stress riser, and under the right conditions of temperature and load near the hole, it will crack. If additional countersinking won't get rid of the chip, you'll need to drill a larger hole with a clean cut. Countersink this hole, make it smooth, and if it's larger than the head of the installed rivet - not to worry.... use a countersunk washer to capture the rivet head and spread the load out to the hole. I made all my drilled holes in my canopy 2X the diameter of the rivet shank to allow movement. Not only countersinking, but polishing all cut and countersunk edges in the plexiglass will reduce stress riser areas, and allow easier movement with temperature changes. Make sure you use soft pull rivets for canopy installation if you are using rivets for attachment - not the best plexiglas attachment method by the way. You can't regulate the pull on the rivet, and even 'soft pull' rivets pull too tightly.
__________________
SH
RV-8
Cincinnati, OH/KHAO
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 11:44 PM.


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.