SEM Rust-seal and welding |
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SEM Rust-seal and welding |
Wes V |
Mar 21 2008, 08:50 AM
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#1
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Member Group: Members Posts: 482 Joined: 11-October 07 From: Los angeles Member No.: 8,211 |
I'm addressing rust issues and came upon an problem that I'm unsure about.
The top surface of the longtudinal, under the (removed) battery tray, had a lot of surface rust but is solid. After light sanding and wire brushing I treated the surface with SEM Rust-seal (39308). This is a rust "converter" that turns the rust into a permanent black coating. The product works great and as advertised, however I think it leads to the problem I'm having. I want to weld an additional coverplate over this area and fabricated one using 18 gauge plate steel and drilled 1/4" holes in it for welding. A light coat of 3M weld-through was sprayed on both the long and metal plate. When I try to mig weld up the holes, attaching the plate to the long, I get a great looking weld that doesn't attach to the metal of the "long" at all!!! I even tried scratching off any form of paint (in the holes) with a dental pick. So, two things come to mind. It may be that the SEM is preventing the weld. It could also be that 1/4" holes are too small. Most of the SEM coating can be removed with Aircraft paint stripper (dang, what a messy job) Wes Vann |
Wilhelm |
Mar 21 2008, 09:25 AM
Post
#2
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Member Group: Members Posts: 408 Joined: 7-September 07 From: Hooterville, OR Member No.: 8,088 Region Association: None |
I'm addressing rust issues and came upon an problem that I'm unsure about. The top surface of the longtudinal, under the (removed) battery tray, had a lot of surface rust but is solid. After light sanding and wire brushing I treated the surface with SEM Rust-seal (39308). This is a rust "converter" that turns the rust into a permanent black coating. The product works great and as advertised, however I think it leads to the problem I'm having. I want to weld an additional coverplate over this area and fabricated one using 18 gauge plate steel and drilled 1/4" holes in it for welding. A light coat of 3M weld-through was sprayed on both the long and metal plate. When I try to mig weld up the holes, attaching the plate to the long, I get a great looking weld that doesn't attach to the metal of the "long" at all!!! I even tried scratching off any form of paint (in the holes) with a dental pick. So, two things come to mind. It may be that the SEM is preventing the weld. It could also be that 1/4" holes are too small. Most of the SEM coating can be removed with Aircraft paint stripper (dang, what a messy job) Wes Vann Take a white metal marking pen and mark through your plates spot weld holes onto the longitudinal. Pop the plate off. Then take a small grinder or even a dremel and sand down the white marks on the longitudinal to bare metal. Now you'll be welding a clean surface. Likely a lot less mess than stripper. |
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