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lightice Samba Member
Joined: December 14, 2012 Posts: 599
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Posted: Wed May 07, 2014 6:33 am Post subject: Weld through primer for bus tophat/cross member/outrigger |
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I searched around and found locally I have this available:
http://aervoe.com/paints_coatings/Cold-Galvanize-Coating-93-Zinc-Rich-7006.html
Has anyone used this product before?
How is the adhesion to other paint? Assuming I want to paint the exterior facing sections of the I beams and crossmember sections.
I am going to be replacing all the crossmembers, I sections, top hats, outriggers and jack points in my bus and would want to ensure that rust doesn't come back and eat them up again.
I understand that once welding and final painting is done, I should pump some good quality cavity wax into the crossmember sections. |
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Chubber Samba Member
Joined: November 12, 2003 Posts: 334 Location: Clermont, Central Florida
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Posted: Mon Jun 02, 2014 9:14 pm Post subject: |
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It's good at what it says, but it suffers from two problems:
1) It's porous, so water will go right through it.
2) It's adhesion is very low, so bits of it will dust off, like chalk.
So, yes, put some on for any seam that might be "pinched" or hidden when welding. But it needs to be completely sanded and painted once welding is done to remove the loose stuff and seal it against the elements. _________________ Chubber
'71 Deluxe 7 Passenger Bus (Resto thread)
'72 Fastback
'74 Super Beetle Convertible (Sold) |
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theKbStockpiler Samba Member
Joined: July 07, 2012 Posts: 2316 Location: Rust Belt
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Posted: Tue Jun 03, 2014 10:46 am Post subject: |
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If you can't use weldable primer in a blind spot,it would then serve no purpose. What would be the point? _________________ My beetle is not competing with your beetle. I have the yellow beetle in my town. There is a red one, a green one ......
Use all safety devices including a mask. |
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Chubber Samba Member
Joined: November 12, 2003 Posts: 334 Location: Clermont, Central Florida
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Posted: Tue Jun 03, 2014 11:19 am Post subject: |
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theKbStockpiler wrote: |
If you can't use weldable primer in a blind spot,it would then serve no purpose. What would be the point? |
It's good when you have a lap joint you need to weld through with a spot weld or weld around with a plug or seam weld that would normally burn off regular paint, plus the primer doesn't boil out and prevent a good weld like regular primer would. It also prevents rust from spreading so quickly if the paint does get scratched through. It keeps the rust from creeping under the paint so quickly.
Just don't fill a rocker panel with just weldable primer and expect it to stay rust-free.
If I sand and clean sheet metal, then spray it with just weld-through primer, I expect it to start rusting through the primer after about 3 months of exposure to the elements. Better than nothing, but not really a sealant.
Remember, it's called weld-through "primer" for a reason. It's not paint. _________________ Chubber
'71 Deluxe 7 Passenger Bus (Resto thread)
'72 Fastback
'74 Super Beetle Convertible (Sold) |
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theKbStockpiler Samba Member
Joined: July 07, 2012 Posts: 2316 Location: Rust Belt
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Posted: Tue Jun 03, 2014 4:11 pm Post subject: |
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I'm not a butt weld believer so I always use lap joints (panel flanger) to hold panels on. Until lately , I have not heard of weldable zinc primer so if I could not get behind a panel to seal it afterwards I would use high temp paint on it. It works to some degree. I'll do some test on similar products to see if they work before trying it on a project.
Thanks for the info! _________________ My beetle is not competing with your beetle. I have the yellow beetle in my town. There is a red one, a green one ......
Use all safety devices including a mask. |
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lightice Samba Member
Joined: December 14, 2012 Posts: 599
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Posted: Fri Jun 06, 2014 1:40 am Post subject: |
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Problem is I can't find a 'weld thru primer' in Malaysia, and this product sells per carton here so 'testing' isn't exactly economical.
I'd try to source further and see if I can find a suitable weld through primer. |
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Chubber Samba Member
Joined: November 12, 2003 Posts: 334 Location: Clermont, Central Florida
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Posted: Fri Jun 06, 2014 6:04 am Post subject: |
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lightice wrote: |
Problem is I can't find a 'weld thru primer' in Malaysia, and this product sells per carton here so 'testing' isn't exactly economical.
I'd try to source further and see if I can find a suitable weld through primer. |
If you can't find zinc primer, it's nearly as good to do a wash with dilute phosphoric acid to convert the flash rust near the welds, let dry completely and just prime.
Everyone should also realize that welding the zinc primer also releases gasses that aren't friendly to your lungs, so be sure to get plenty of ventilation when doing a lot of welding with it. It was really designed for spot welding, most MIG welding needs a cleaner surface to get a good weld. _________________ Chubber
'71 Deluxe 7 Passenger Bus (Resto thread)
'72 Fastback
'74 Super Beetle Convertible (Sold) |
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lightice Samba Member
Joined: December 14, 2012 Posts: 599
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Posted: Fri Aug 15, 2014 9:08 pm Post subject: |
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As an update, I am still unable to get weld thru primer.
We use mostly gas welding, and I got a water based rust converter that is direct to metal and ready for primer or other coating(cavity wax). |
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