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Projects Patch welding tips .....

Discussion in 'The Hokey Ass Message Board' started by FAKKY, May 31, 2021.

  1. FAKKY
    Joined: Sep 9, 2016
    Posts: 295

    FAKKY
    Member

    So dug some more to see this area and other areas .....

    Frontside
    [​IMG]

    Backside
    [​IMG]


    Q1) Should I patch it from the rear after cleaning ..... and using a weldable primer on the metal. Then it would be sealed and just a small mount of filler required to smooth out .... or tackle it from front - just worried about metal thickness and curves...

    [​IMG]

    [​IMG]

    That could be a tough weld going straight into the drip edge as well ......
    thoughts on patching over the top with primered metal ....... and thin metal patch and smoothing out with filler.

    Best approach ?
     
  2. squirrel
    Joined: Sep 23, 2004
    Posts: 57,467

    squirrel
    ALLIANCE MEMBER

    You have to cut it back to where there is no pitting on the backside, or else the rust will return.
     
    juan motime, Dino 64, FAKKY and 2 others like this.
  3. as said cut all the rust out, make a new patch to fit the hole tightly, butt weld it and grind it smooth.
     
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  4. Dave Mc
    Joined: Mar 8, 2011
    Posts: 2,764

    Dave Mc
    Member

    Might be the tip of the iceberg ?
     
  5. Get the area clean. Build and shape the patch. Trim the vehicle to fit the patch. it’s easier this way. Butt weld from the outside.
     
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  6. michaelvz51
    Joined: May 24, 2011
    Posts: 868

    michaelvz51
    Member
    from So Cal
    1. HAMB Merc Club

    Agreed on all comments, if you don’t replace the sheet metal and try it the way you explained, you will absolute chase the weld all over as the rusted metal will disintegrate in front of you and the heat from either your torch or mug gun.
    Replace the metal, curves are easier to make than you think.
     
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  7. High quality patch panels for the most popular cars can be purchased from EMS Automotive, or similar suppliers. Cut out all the rust and butt weld. Smaller areas can be fixed with fabricated panels.
     

    Attached Files:

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  8. Ziggster
    Joined: Aug 27, 2018
    Posts: 1,952

    Ziggster
    Member

    Suggest watching a few vids on YT by Fitzees Fabrications. By far the best and most practical on body patch panel repair.
     
  9. dave 62 pb
    Joined: Nov 5, 2013
    Posts: 252

    dave 62 pb
    Member

    I am in the process of cutting out all the rot in my trunk , It would have been easier to replace the whole trunk floor but they are not available for 59 Edsel , well not over here in the UK
    Here are some of the patch panels I have made using home made jigs DSC_4313.JPG DSC_4325.JPG
     

    Attached Files:

  10. b-body-bob
    Joined: Apr 23, 2011
    Posts: 620

    b-body-bob
    Member

    If I understand what you're describing there, I did something similar on an OT car, but only in a couple of places where it doesn't matter. I also cut out all the rust before doing it. Yes the holes consolidated into one big hole, but that's what it will do eventually anyway. Best to cut it out yourself and save some headaches welding the patch in.
     
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  11. 1ton
    Joined: Dec 3, 2010
    Posts: 714

    1ton
    Member

    All good answers above. Of course you could do it the asshole way. That is to fill the voids with expanding foam. Shape the foam to the proper contour then skimcoat with bondo and sand smooth. I honestly saw a guy doing this to flip OT POS cars. At first I laughed my ass off and then bitched the guy out for being such a prick
     
  12. Boneyard51
    Joined: Dec 10, 2017
    Posts: 6,556

    Boneyard51
    Member

    But, you can chase rust all the way to the other side of the vehicle! Sometimes you have to compromise a little and quit when you find solid enough metal to weld to, even though there may be a little rust. Or find a total replacement panel.








    Bones
     
  13. squirrel
    Joined: Sep 23, 2004
    Posts: 57,467

    squirrel
    ALLIANCE MEMBER

    the lower panel he's working on, probably has a line where the rust mostly stops. Those old suburbans and panel trucks trapped dirt in the bottom of the quarters, and it caused the rust over time. After you clean out the dirt, you'll see a line where the rust stops...just cut it above that line
     
  14. As has been mentioned... remove all bad metal until you get to clean, non-rusted, non-pitted metal. Failure to do that will lead to more work later on as well as fighting blow-throughs when attempting to weld you patch in. Simply said, you can't weld to rust.

    It would also be extremely beneficial to treat all exposed metal with some sort of rust converter once you open it up. Trust me on that one!
     
  15. FAKKY
    Joined: Sep 9, 2016
    Posts: 295

    FAKKY
    Member

    Thanks guys ...... makes sense I guess Im just sure I've seen guys do a panel over the top in areas where access was harder. Primered on backside.

    The lower sectiojn shouldnt be too bad for a full? cutout and shape .... not sure about the roof going into that drop edge though. Would you just cut out the metal to a shape then try and get something to fit and shape with clecos ? tack welding and shaping further along the way ?
     
  16. FAKKY
    Joined: Sep 9, 2016
    Posts: 295

    FAKKY
    Member

    Just saw his methond on fitting overlapped metal to a butt weld .... *doh* - feel like a idiot they way I chase big gaps :)
     
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  17. 6sally6
    Joined: Feb 16, 2014
    Posts: 2,645

    6sally6
    Member

    Don't get the mind set to ...build-it-back-better-than-new! You're just removing rusty metal and replacing with good metal.
    Do you plan to just 'park it out side in the weather, when you finish?'....I didn't think so.
    Gonna drive it to work in the snow and slush?.......Didn't think so.
    Are you even gonna drive it if it 'looks-like-rain'....didn't think so.

    Cut out the bad (big patches are easier to weld & fill than several tiny ones) replace with good.
    I would try and save the drip rail area and cut back the rot leaving yourself plenty of room to weld
    Try not to have any/many 90 degree edges.
    Before you cut it out get the patch metal into the general shape of the area you're removing.
    Tack and hammer......No long runs of weld beads. Tack...then cool and make next tack BEHIND your previous one(not in front of the previous one.)Back step it.
    Cooling with compressed air or a wet rag will help with warping.
    You are gonna needs some body filler to make it right (just not a gob a 1/2 inch thick!!!)
    Butt welds are best butt........harder to get right.
    All bondo ain't the same. Use the kind that won't absorb water.
    Enjoy it........remember, it's a hobby...it's suppose to be fun.
    6sally6
     
  18. FAKKY
    Joined: Sep 9, 2016
    Posts: 295

    FAKKY
    Member

    So ...... found more damage ....... keeping in mind what @6sally6 said above ... which I think is good advice.
    WHy does everyone? recommend butt welding ... versus lap welding with overlapping patch panbel...
    I ask for 3 reasons

    1) Easier
    2) Your generally not getting to the reverse side anyway so its raw metal or often at best partially primered
    3) - this guy does it professionally - yet lap joints



    Dont want to take teh easy route just because its easier ... but dont want to go through the pain if I dont need to:)
     
  19. That video is hack work at its finest. There are numerous reasons not to do lap joints. You can't get any warping out after the fact, they provide a perfect place for moisture to sit and create further corrosion down the road and two layers of metal will expand and contract at a different rates than a single layer so you have a very good change of the repair showing up later through the paint.
     
  20. FAKKY
    Joined: Sep 9, 2016
    Posts: 295

    FAKKY
    Member

    ^^ All of which make sense .......
    But if a guy that does it for a living uses that approach (obviously not show car) .... assuming he doesnt want the warranty work ... so must last right ?

    I think 80% of it I can get the panels aligned clsoe enough to tig ....... but the other 20% ..... wondering if I can a good enough fitup .... better to bondo or better to lap etc ...
     
  21. Lots of people do shitty quality work for a living. Doesn't make it the right way to do something. I wouldn't pay that guy a dime to work on my wheel barrow.
     
  22. Mike Colemire
    Joined: May 18, 2013
    Posts: 1,431

    Mike Colemire
    Member

    If you lap it moisture will get between the lap plus it's harder to finish out. It'll need more filler. One of the best tips here, and there are many, is to cut the patch and then trace around it and cut the area, I use a marker and then a scribe and then use a thin, 1/16 cutting wheel. It's a lot easier fine tuning the patch to fit than it is welding a gap.
     
  23. FAKKY
    Joined: Sep 9, 2016
    Posts: 295

    FAKKY
    Member

    Ha ha :)
     
  24. FAKKY
    Joined: Sep 9, 2016
    Posts: 295

    FAKKY
    Member

    Not sure 100% follow .....
     
  25. FAKKY
    Joined: Sep 9, 2016
    Posts: 295

    FAKKY
    Member

    oh i think it get it now ...... cut the patch .... push up against the truck .... and trace it out and cut that way
     
  26. safetythird
    Joined: Feb 26, 2014
    Posts: 292

    safetythird
    Member

    I've always made a slightly oversized patch, and then I either tack it in place of rivet it, then cut through both the patch and the panel underneath. Then I separate the two and the hole is the same size as the patch.

    YMMV.
     
  27. squirrel
    Joined: Sep 23, 2004
    Posts: 57,467

    squirrel
    ALLIANCE MEMBER

    qft...again...just a reminder, what he's working on here.
     
  28. Holy freaking ship.
    I was doing crap like that in my teens on my first car. Then I started learning how to do stuff.
     
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  29. Lap welding Vs butt welding.
    For me, butt welding is easier. A lot less mud work.
    I will make patterns. Yes, multiple if a body line is involved.
    Make the part. If the pattern is accurate and you faithfully follow that pattern, it’ll work.
    Fit the pattern and scribe around it. Make reference marks across both the patch and panel being repaired.
    I will rough cut within 1/4 inch of the scribe line. Then use aviation shears to cut against the scribe line. Line up reference marks and weld.
    By not lapping over, the weld distortion is easier to remove.
    It’s easier to metal finish and eliminates the possibility of a shadow line in the future.
     
    Last edited: Jun 7, 2021
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  30. Fortunateson
    Joined: Apr 30, 2012
    Posts: 5,530

    Fortunateson
    Member

    Wow, Fitzee would NOT approve! On the other hand he makes me look a lot better...

    I heard too much "good enough" and "close enough". I thought this guy was a pro?
     
    Last edited: Jun 9, 2021

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