The Ford Barn

Royal Ryser · 12-21-2013, 06:17 PM

I think I read someplace that the backside of sheet metal welds should sealed to keep moisture from entering the weld and causing the paint to blister. Anybody have info about that?

What kind of material/product should be used to seal such welds?
Royal

mrtexas · 12-21-2013, 06:32 PM

Epoxy primer is waterproof.

RMR&C · 12-21-2013, 07:10 PM

I use epoxy primer if I can get to them. Mix up a little in a cup and brush it on with a small throw away brush

ford3 · 12-21-2013, 10:11 PM

seam sealer in a tube, it was used to seal the rain gutters on car roofs and seams on the fire wall, get it at paint stores

Bob T · 12-22-2013, 11:38 PM

I try to seal all welded areas from behind. I prefer seam sealer but if the area is difficult to get to I will try to spray undercoat or a similar spray product.

Mike B · 12-23-2013, 12:04 AM

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Moisture can't find it's way through a weld, it can find it's way through an opening in the metal that was not fully welded.

I/e say you are replacing a section of door skin 1inch above the bottom of the door, 6 inches long and 2 inches wide...as you "spot" the weld in and complete the job, after grinding the beads down, you should see no "parting" lines..it should look like one piece of sheet..

If you've accomplished that, the moisture has to work and rust all the way through the metal in order to affect the paint...if say you (third person) got lazy and just tacked the patch in and filled with putty. then yes, moisture can wick through the seams unless filled/covered on the inside.

flatmotor40 · 12-23-2013, 06:38 AM

If you backup your welds it will be flat on the backside like the frt side not rough

flatmotor40 · 12-23-2013, 06:56 AM

I mean if you can't get to the backside or you can used a tube with argon going through and that will back up to help clean up weld.I used a pics of copper that I flattened from a piece of water tubing.Flatten one end and leave the other round for a handle.But I have 2-3 of them

fordor41 · 12-23-2013, 10:53 PM

I always figured if part of some sheet metal rusted, there was a reason why that spot rusted. Usually there're in the same spots in that model line like bottoms of doors from water migrating down past the glass and not getting out the drain holes or behind the front wheel openings at the bottom. I figure anything that will help seal the repair can't hurt. And yes I use seal sealer and undercoat. After 18 years & 125K miles, I finally developed a pin hole in the bottom of the drivers door!

12-21-2013, 06:17 PM	#1
Royal Ryser Senior Member Join Date: May 2010 Location: Colorado Posts: 553	Do you seal welds? I think I read someplace that the backside of sheet metal welds should sealed to keep moisture from entering the weld and causing the paint to blister. Anybody have info about that? What kind of material/product should be used to seal such welds? Royal

12-21-2013, 06:32 PM	#2
mrtexas Senior Member Join Date: May 2010 Location: Sugar Land, TX Posts: 4,395	Re: Do you seal welds? Epoxy primer is waterproof.

12-21-2013, 07:10 PM	#3
RMR&C Senior Member Join Date: May 2010 Location: NW Montana Posts: 131	Re: Do you seal welds? I use epoxy primer if I can get to them. Mix up a little in a cup and brush it on with a small throw away brush

12-21-2013, 10:11 PM	#4
ford3 Senior Member Join Date: Oct 2012 Location: oroville calif. Posts: 1,453	Re: Do you seal welds? seam sealer in a tube, it was used to seal the rain gutters on car roofs and seams on the fire wall, get it at paint stores

12-22-2013, 11:38 PM	#5
Bob T Senior Member Join Date: May 2012 Location: Ontario, Canada Posts: 123	Re: Do you seal welds? I try to seal all welded areas from behind. I prefer seam sealer but if the area is difficult to get to I will try to spray undercoat or a similar spray product.

12-23-2013, 12:04 AM	#6
Mike B Senior Member Join Date: May 2010 Location: Oakdale,Ca Posts: 1,323	Re: Do you seal welds? Sponsored Links (Register now to hide all advertisements) Moisture can't find it's way through a weld, it can find it's way through an opening in the metal that was not fully welded. I/e say you are replacing a section of door skin 1inch above the bottom of the door, 6 inches long and 2 inches wide...as you "spot" the weld in and complete the job, after grinding the beads down, you should see no "parting" lines..it should look like one piece of sheet.. If you've accomplished that, the moisture has to work and rust all the way through the metal in order to affect the paint...if say you (third person) got lazy and just tacked the patch in and filled with putty. then yes, moisture can wick through the seams unless filled/covered on the inside.

12-23-2013, 06:38 AM	#7
flatmotor40 Senior Member Join Date: May 2010 Location: Georgia Posts: 611	Re: Do you seal welds? If you backup your welds it will be flat on the backside like the frt side not rough

12-23-2013, 06:56 AM	#8
flatmotor40 Senior Member Join Date: May 2010 Location: Georgia Posts: 611	Re: Do you seal welds? I mean if you can't get to the backside or you can used a tube with argon going through and that will back up to help clean up weld.I used a pics of copper that I flattened from a piece of water tubing.Flatten one end and leave the other round for a handle.But I have 2-3 of them

12-23-2013, 10:53 PM	#9
fordor41 Senior Member Join Date: Oct 2011 Location: elmira,ny Posts: 1,516	Re: Do you seal welds? I always figured if part of some sheet metal rusted, there was a reason why that spot rusted. Usually there're in the same spots in that model line like bottoms of doors from water migrating down past the glass and not getting out the drain holes or behind the front wheel openings at the bottom. I figure anything that will help seal the repair can't hurt. And yes I use seal sealer and undercoat. After 18 years & 125K miles, I finally developed a pin hole in the bottom of the drivers door!