Just had Frame Sandblasted and...
Thread Starter
Racer
Joined: Oct 2002
Posts: 328
Likes: 0
From: Marlborough MA
Just had Frame Sandblasted and...
I was wondering what people would suggest to keep the rust to a minimum over the next several weeks as I get the seams welded and add gussets.
I don't want to spray a light oil, as it would contaminate the weld area. I could prime the frame and mask all the areas I am going to weld, but that would be a mountain of work. How bad is it to leave the metal bare for 3 weeks? The garage is insulated and has a good vapor barrier. With the cooler weather, I would expect the air to remain relatively dry...
Also, how did people weld up their seams? Did you weld a small section on say the front of the frame, then switch to the back, then maybe to the middle of the frame. That way no one section gets too hot to warp?
Thanks in advance!
I don't want to spray a light oil, as it would contaminate the weld area. I could prime the frame and mask all the areas I am going to weld, but that would be a mountain of work. How bad is it to leave the metal bare for 3 weeks? The garage is insulated and has a good vapor barrier. With the cooler weather, I would expect the air to remain relatively dry...
Also, how did people weld up their seams? Did you weld a small section on say the front of the frame, then switch to the back, then maybe to the middle of the frame. That way no one section gets too hot to warp?
Thanks in advance!
Pro
Joined: Dec 2002
Posts: 560
Likes: 1
From: Mooresville NC
After a frame was dipped in acid, it came back with a coating which protected it for a few months. To get it off we just wash it off with soapy water and it was good to weld/paint. I don't remember want they used back then, should be easier enough to find.
Racer
Joined: Mar 2003
Posts: 268
Likes: 0
From: Mechanicsville VA
I hung mine in an unheated garage in cool dry weather and didn't have much problem. I used POR-15 to cover it about two weeks later.
We did the sandblasting after welding, and only fully welded the seams between the chassis connections- nothing forward of the front (under-engine) crossmember, and nothing behind the differential mount. We did it in stages so we wouldn't warp the frame, though I really don't think that would be a concern.
I still need to weld a clutch cross-shaft mount but will grind the paint off when I do.
We did the sandblasting after welding, and only fully welded the seams between the chassis connections- nothing forward of the front (under-engine) crossmember, and nothing behind the differential mount. We did it in stages so we wouldn't warp the frame, though I really don't think that would be a concern.
I still need to weld a clutch cross-shaft mount but will grind the paint off when I do.
Melting Slicks
Joined: May 2001
Posts: 2,131
Likes: 4
From: May help you? You can sure as hell try!
You could try spraying it with high zinc weld-through primer. Make sure the primer would be compatible with the paint you plan to apply. This way you get two birds with one stone: Anti-corrosion benefit while welding and the frame is prepped to paint in the areas that weren't welded.
Weld through primer might be a bit on the expensive side, though. At least the stuff in spray cans is.
Weld through primer might be a bit on the expensive side, though. At least the stuff in spray cans is.
Le Mans Master
Joined: Jun 2002
Posts: 8,339
Likes: 24
From: I can walk to MA
What do you plan to eventually coat it with ?
Actually, no matter what coating or paint, an acid etch will help.
Use Naval Jelly - or some other Phosphoric acid treatment.
It etches into the surface and converts a thin layer of the steel
(Iron) to iron-phosphate. This layer can protect the metal for
months. It will also wirebrush or sand off easily for clean welds.
The weld-through primer sounds OK - but it will contaminate
the weld. Also, coating with POR15 or similar products - you don't
want primer on the metal - you DO want a phosphoric etch, though.
You'll need the frame outside to wash it off after etching.
When welding the front area of the seams, I just paused between
sections of about 10 inches. This also allows the welder to
cool - staying within the duty cycle of the machine (usually
about 20% - of 10 minutes). Weld 2 minutes - cool for 8.
Actually, no matter what coating or paint, an acid etch will help.
Use Naval Jelly - or some other Phosphoric acid treatment.
It etches into the surface and converts a thin layer of the steel
(Iron) to iron-phosphate. This layer can protect the metal for
months. It will also wirebrush or sand off easily for clean welds.
The weld-through primer sounds OK - but it will contaminate
the weld. Also, coating with POR15 or similar products - you don't
want primer on the metal - you DO want a phosphoric etch, though.
You'll need the frame outside to wash it off after etching.
When welding the front area of the seams, I just paused between
sections of about 10 inches. This also allows the welder to
cool - staying within the duty cycle of the machine (usually
about 20% - of 10 minutes). Weld 2 minutes - cool for 8.
Race Director
Joined: Sep 2004
Posts: 11,874
Likes: 263
From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
Originally Posted by LemansBlue68
You could try spraying it with high zinc weld-through primer. Make sure the primer would be compatible with the paint you plan to apply. This way you get two birds with one stone: Anti-corrosion benefit while welding and the frame is prepped to paint in the areas that weren't welded.
Weld through primer might be a bit on the expensive side, though. At least the stuff in spray cans is.
Weld through primer might be a bit on the expensive side, though. At least the stuff in spray cans is.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Thread Starter
Racer
Joined: Oct 2002
Posts: 328
Likes: 0
From: Marlborough MA
Keeping Rust to a minimum after sandblast
Thanks for all of the replies. I plan on using POR-15 products. I believe the primer is called Metal-ready or something like that.
I plan on getting all the welding done in the next 3-4 weeks, so hopefully the rust will stay to a minimum. I'll look into the phosphoric acid etch coatings in the meantime though.
As for the welding, it sounds like doing a short section of 4-8", then moving on to another area of the frame would be the best. Any more suggestions are of course appreciated.
I plan on getting all the welding done in the next 3-4 weeks, so hopefully the rust will stay to a minimum. I'll look into the phosphoric acid etch coatings in the meantime though.
As for the welding, it sounds like doing a short section of 4-8", then moving on to another area of the frame would be the best. Any more suggestions are of course appreciated.
Race Director
Joined: Sep 2004
Posts: 11,874
Likes: 263
From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
i don't know your welding experience or what you're welding with, but alot of us hopscotch around onthe frame to keep heat down in any particular area and allow us to do alot of welding at once, and then repeatedly go back to the areas.
Thread Starter
Racer
Joined: Oct 2002
Posts: 328
Likes: 0
From: Marlborough MA
Frame Sandblasting
Originally Posted by bobs77vet
i don't know your welding experience or what you're welding with...
