• 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
Cowl Spot Welding Drill Out
#1
Hey Guys,

Can anyone give some advice about drilling out the spot welds on the cowl of my 72. When I drill it goes through the lower cowl and the fire wall flange also. Is this OK. Trying to get through just the upper cowl is hard to do. What is the acceptable practice?

Also what is the best way to get the upper cowl to peel off after drilling? The firewall lip is directly in the way so a flat chisel can't be put into the front seam w/o bending the snot out of the firewall flange.
Chasing Rust
  Reply
#2
are you using a spot weld drill bit?

you don't want to drill straight through the the spot welds you just want to drill out the top of the cowl because when your ready to plug weld the cowl top back to the bottom you need a surface for the plug weld to sit on. when you drill completely through the top and bottom of the cowl you have no base to start the weld pool on to fill the hole back up.

also depending on where you went totally threw both the upper and lower cowl you will have water getting in.

now you can get magnetic copper sheets, you can place that under the bottom cowl where you drilled through completely and the copper will not stick to the weld wire so you can built up a weld pool and then slowly fill the empty space up and then the top will fuse back with the bottom cowl, and you clean up with a grinder so it looks factory again.

another option is cutting out coins of sheet steel to fit into the holes you made then butt welding the seam around the coin to the hole, then grind that flat, put the top of the cowl in place and then plug weld on top of the coin area. this is more labor and you will need to prep the lower cowl to get rid off all incorrect holes on the seams.

basically a spot weld drill bit is sort of like the cutter used when drill out a door to install a knob or a lock its a larger hollow tube with saw teeth, with a drill in the center and you set the depth of the cut, the center drill bit keeps the larger cutter on track. the larger hallow tube cutter then cuts around the spot weld, once your through the top layer of sheet metal you stop, and continue to the next spot weld. when you done the top can be separated from the bottom.

you can use a chisel, or a gasket scrapper or trowel, you just want to separate the seam try not to deform the metal if possible, but its going to happen anyway so don't worry try to get all the spot welds first then you man try working from the windshield frame forward instead of the the front flange back.
[Image: sig.jpg]
  Reply
#3
(01-06-2011, 04:58 PM)72HCODE Wrote: are you using a spot weld drill bit?

you don't want to drill straight through the the spot welds you just want to drill out the top of the cowl because when your ready to plug weld the cowl top back to the bottom you need a surface for the plug weld to sit on. when you drill completely through the top and bottom of the cowl you have no base to start the weld pool on to fill the hole back up.

also depending on where you went totally threw both the upper and lower cowl you will have water getting in.

now you can get magnetic copper sheets, you can place that under the bottom cowl where you drilled through completely and the copper will not stick to the weld wire so you can built up a weld pool and then slowly fill the empty space up and then the top will fuse back with the bottom cowl, and you clean up with a grinder so it looks factory again.

another option is cutting out coins of sheet steel to fit into the holes you made then butt welding the seam around the coin to the hole, then grind that flat, put the top of the cowl in place and then plug weld on top of the coin area. this is more labor and you will need to prep the lower cowl to get rid off all incorrect holes on the seams.

basically a spot weld drill bit is sort of like the cutter used when drill out a door to install a knob or a lock its a larger hollow tube with saw teeth, with a drill in the center and you set the depth of the cut, the center drill bit keeps the larger cutter on track. the larger hallow tube cutter then cuts around the spot weld, once your through the top layer of sheet metal you stop, and continue to the next spot weld. when you done the top can be separated from the bottom.

you can use a chisel, or a gasket scrapper or trowel, you just want to separate the seam try not to deform the metal if possible, but its going to happen anyway so don't worry try to get all the spot welds first then you man try working from the windshield frame forward instead of the the front flange back.

Only drilled 4 out completely through. I am using the 3/8" spot weld drill bit. Looks just like a hole saw. Got it at Harbor Freight. It works good..... too good..lol. I got it. Makes sense what your saying. I knew it wasn't right so I stopped.
Chasing Rust
  Reply
#4
Only drilled 4 out completely through. I am using the 3/8" spot weld drill bit. Looks just like a hole saw. Got it at Harbor Freight. It works good..... too good..lol. I got it. Makes sense what your saying. I knew it wasn't right so I stopped.
[/quote]

Heres how to drill out spot welds & remove the metal as 72 hc stated u can use a spot weld driller or I sometimes use a brad point bit depends on what your doing
http://www.youtube.com/watch?v=WJ_rUEczONM
removing the metal here
http://www.youtube.com/watch?v=tORrwiIdppk
fixing the drill through holes here
http://www.youtube.com/watch?v=ysQMZLT74RA
LOVE OF BEAUTY IS TASTE..THE CREATION OF BEAUTY IS ART
  Reply
#5
(01-06-2011, 06:17 PM)Qcode351mach Wrote: Only drilled 4 out completely through. I am using the 3/8" spot weld drill bit. Looks just like a hole saw. Got it at Harbor Freight. It works good..... too good..lol. I got it. Makes sense what your saying. I knew it wasn't right so I stopped.

Heres how to drill out spot welds & remove the metal as 72 hc stated u can use a spot weld driller or I sometimes use a brad point bit depends on what your doing
http://www.youtube.com/watch?v=WJ_rUEczONM
removing the metal here
http://www.youtube.com/watch?v=tORrwiIdppk
fixing the drill through holes here
http://www.youtube.com/watch?v=ysQMZLT74RA
[/quote]

Thanks.. The copper piece of metal attached to the open hole is what 72HCode was talking about. I need to do this when its time to button up the cowl. Good stuff. Gives me more confidence seeing it. Thanks for all your help.
Chasing Rust
  Reply
#6
Great vids Qcode. Smile
My garage http://www.7173mustangs.com/forum-garage...rxt_uid=40

73 mach 1 351c 4v cc ported, torker2, 750 edelbrock,C6.
73 fastback 351c 2v,performer intake,600 edelbrock,fmx, 325 trac-lok.
  Reply
#7
Excellent work... thanks for sharing. I'll be looking to remove my upper cowl and maybe replace the right pillar on mine. Seeing this kind of work kind of helps me get over my fear a little. Can you reference the rust preventative you are using?

  Reply
#8
(01-07-2011, 07:44 PM)71_badmach Wrote: Excellent work... thanks for sharing. I'll be looking to remove my upper cowl and maybe replace the right pillar on mine. Seeing this kind of work kind of helps me get over my fear a little. Can you reference the rust preventative you are using?
Thanks ! Heres the products used
http://www.youtube.com/watch?v=B48YKmsadJ4
LOVE OF BEAUTY IS TASTE..THE CREATION OF BEAUTY IS ART
  Reply
#9
great work Qcode351mach!!! you're putting a lot of love into that mach1 of yours. keep up the good work.

best regards from vienna
abudi
  Reply
#10
(01-10-2011, 07:22 AM)canadian_red_maple_leaf Wrote: great work Qcode351mach!!! you're putting a lot of love into that mach1 of yours. keep up the good work.

best regards from vienna
abudi
Abudi..Thanks ! Yes lots of love ! The reason being is this car is very special to me...It's the first car I ever bought..I've owned it since 1979 ! Alot of history & sentimental value ! Met my wife (of 24 years) with that car & we shared lots of good memories with that car( Ya gotta admit these cars are chick magnets! at least back in the day & it snagged the love of my life & soul mate, Interesting story I will post up one day but it was all about "do you want to take a ride in my mustang") I don't know who's more excited to see it done Her or Me ! and it helps that she is so supportive .. thanks for subscribing to my you tube channel. I think you be impressed when you see it done !

Scott

LOVE OF BEAUTY IS TASTE..THE CREATION OF BEAUTY IS ART
  Reply


Possibly Related Threads...
Thread Author Replies Views Last Post
  COWL VENT GRILLES Kevin J 8 399 12-01-2016, 03:14 PM
Last Post: mustang7173
  Cowl Rust Repair Step-by-Step 69 Rustang 10 3,738 01-15-2015, 05:26 PM
Last Post: Duncan Mach72
  Replacing a rusty cowl panel downwardspiral 7 4,739 08-18-2014, 04:51 PM
Last Post: Paul113
  Under dash - Cowl tube removal pulling my hair out matrixx 2 930 09-24-2013, 05:46 AM
Last Post: Qcode351mach
  Heater Box to cowl seal kcmash 3 1,094 08-14-2013, 01:43 PM
Last Post: kcmash
  '72 cowl vent cover Danno 7 1,743 03-29-2013, 06:08 AM
Last Post: don29163
  Cowl Vents aero3113 10 1,446 02-13-2013, 01:10 PM
Last Post: OMS
  Cougar cowl turtle5353 4 769 10-25-2012, 08:53 PM
Last Post: shgrrttn



Users browsing this thread: 1 Guest(s)