All MetalShaping

Go Back   All MetalShaping > General Metal Shaping Discussion > Welding Sheet Metal
  Today's Posts Posts for Last 7 Days Posts for Last 14 Days  

Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 11-05-2011, 08:50 PM
kjc kjc is offline
Member
 
Join Date: Sep 2009
Location: SF Bay Area, CA
Posts: 340
Default Gas tacking?

I've always tacked one end, the other end, the middle, then fill in between when I o/a weld.

I noticed recently a post whee Peter T said to tack from one end to the other.
David G does the same thing on his video, of course he manipulates the sheet by hand as he goes which is something I'm not able to do and keep the up-down alignment of the sheets as good as they need to be.

So, how do you tack sheetmetal? One end to the other, or both ends first then fill in the middle, or some other way.

And why?
__________________
Ken
Reply With Quote
  #2  
Old 11-05-2011, 09:22 PM
Marty Comstock's Avatar
Marty Comstock Marty Comstock is offline
Member
 
Join Date: May 2009
Location: East Herkimer NY
Posts: 1,570
Default

I have never tacked any panel in the same manner. Too many variables to give even a rule of thumb, in my opinion.

I look at the entire gap, then tack at where it is touching, or touching with the most force. Then to the next point, so on and so forth, Stretching the tacks or weld only as needed.

Depends on the gap, on wether or not you care about arrangment, on how skilled you are at tacking, on how skilled you are at stretching, all that and so on.

Do what works. For many, following those rules of thumb (tack every inch, high amp/heat tacks, mig tacks, no tacks, etc) work.

What works for you? In what situations does it work?

Marty
__________________
Results = (Effort X Determination2) + Time
Reply With Quote
  #3  
Old 11-06-2011, 09:27 AM
www.kustomgarage.com.au's Avatar
www.kustomgarage.com.au www.kustomgarage.com.au is offline
MetalShaper of the month 06-12, 02-14
 
Join Date: Jul 2011
Location: Melbourne, Australia
Posts: 269
Default

When tacking both ends you are not allowing the joint to expand and contract. When starting at one end and working towards the other, the joint can open and close from the heat when tacking and settle back together, this can help stop the two parts from buckling, as it would if tacked at both ends and proceeding in the middle. As Marty said, there are many variables and it all depends on the preperation and care taken before tacking. All this is important for laying the foundataions for the perfect weld.
__________________
Jamie

www.kustomgarage.com.au
Reply With Quote
  #4  
Old 11-06-2011, 05:01 PM
David Gardiner David Gardiner is offline
MetalShaper of the Month
May 2009, Jan 2012, Dec 2014
 
Join Date: May 2009
Location: England
Posts: 5,325
Default

Tack at one end and work to the other, if you tack in each end and then the middle you will end up with real problems because there is no way of knowing if you have the same amount of metal between the tacks, this will cause bulges in the panel. I weld large lengths using my method. The longest weld I have done like this is about five foot or more.

Marty if you have gaps between your panels you are not using the correct method to mark out and cut your panels so your panels do not fit each other. The method I use enables the two sections to be marked and cut accurately then lined up at exactly the same point as they were marked so they match each other exactly and will tack up perfectly every time.

The sections below were first tacked starting at one end then and working towards the other. Then welded in one go without stopping.



The door below was done in the same way and then dressed out, this is a fairly flat panel so demonstrates that gas welding done in this way can cause little distortion that can then be dressed out.

David
__________________
Metalshaping DVD. www.metalshapingzone.com
Metalshaping with hand tools on youtube
http://www.youtube.com/watch?v=IGElSHzm0q8

All things are possible.
Reply With Quote
  #5  
Old 11-06-2011, 08:38 PM
Overkill Overkill is offline
Member
 
Join Date: May 2009
Location: Cloverdale, CA
Posts: 1,233
Default Video

Here's how Kent White does it:

http://www.youtube.com/watch?v=aF1Srs_e1Aw
__________________
John

Ron Covell, Autofuturist books (Tim Barton/Bill Longyard) and Kent White metalshaping DVD's available, shipped from the US. Contact lane@mountainhouseestate.com for price and availability.
Reply With Quote
  #6  
Old 11-06-2011, 09:41 PM
Peter Tommasini Peter Tommasini is offline
MetalShaper of the Month May 2013, Dec 2013
 
Join Date: Apr 2011
Location: Melbourne,Victoria, Australia
Posts: 7,750
Default

I fully agreed with david and Jamie and I use the same method all the time for welding
Peter
__________________
P.Tommasini

Metalshaping tools and dvds
www.handbuilt.net.au

Metalshaping clip on youtube
http://www.youtube.com/watch?v=WEAh91hodPg

Making Monaro Quarter panel:
http://www.youtube.com/watch?v=KIpOhz0uGRM
Reply With Quote
  #7  
Old 11-06-2011, 10:08 PM
Resto Rod Race Resto Rod Race is offline
Member
 
Join Date: Jul 2011
Location: Launceston, Tasmania, Australia
Posts: 219
Default

Snap, with David G and Peter T. If you take your time to tack it up right it will weld so much easier. But i also see Marty C point of view, sometimes you have to bend the rule of thumb to suit yourself or the situation.
__________________
Adam.

Assumption is the Mother of all Sutff ups.

Resto Rod Race.
Reply With Quote
  #8  
Old 11-08-2011, 03:13 PM
jag2be's Avatar
jag2be jag2be is offline
Member
 
Join Date: Sep 2009
Location: Belgium
Posts: 170
Default

David,

Could you explain about your scribing method for parts.?

Thanks,

Nico


Quote:
Originally Posted by David Gardiner View Post
Tack at one end and work to the other, if you tack in each end and then the middle you will end up with real problems because there is no way of knowing if you have the same amount of metal between the tacks, this will cause bulges in the panel. I weld large lengths using my method. The longest weld I have done like this is about five foot or more.

Marty if you have gaps between your panels you are not using the correct method to mark out and cut your panels so your panels do not fit each other. The method I use enables the two sections to be marked and cut accurately then lined up at exactly the same point as they were marked so they match each other exactly and will tack up perfectly every time.

The sections below were first tacked starting at one end then and working towards the other. Then welded in one go without stopping.



The door below was done in the same way and then dressed out, this is a fairly flat panel so demonstrates that gas welding done in this way can cause little distortion that can then be dressed out.

David
__________________
Nico
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

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

All times are GMT -5. The time now is 04:28 PM.

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.