2005 Frame Rust Spot / Just got it sandblasted / exterior plate or cutout?
 

Would you cut out the frame or just weld an exterior plate? This look to be less than 8 inches in length but I talked to a fab guy today who is busy with King of the Hammers preparation so it'll be a couple of weeks till he can work on it. This is near the engine and this part of the frame is double walled. If this spot was on a single wall part of the frame I think it'd rusted all the way through..I just had it sandblasted today and was underneath it tonight and am not sure what to do. Thoughts?

I've been researching Eastwood products as well for the interior of the frame. I know this damage is not like the folks in the NorthEast but I am concerned.

Personally, I would cut it out and patch with fresh metal.

Nice prep! If your fab guy has frame experience, I would likely go with what he suggests. My thought would be to plate it rather than be cutting on the frame - could weaken it. Then I would treat the interior of that frame member with Woolwax (and perhaps the others as well) and prime/paint the exterior of the repair. Could then treat exterior with Woolwax if you want.

I have an '03 with a spot exactly like that on my frame. I sanded around it, wire brushed, primed and painted. Not sure that's the best route but what I did.

How bad was your frame compared to this one?

Under passenger door a hole about 10" long by 2" wide rusted through on the bottom of frame rail from where the A/C condensation would collect and drip on floor, I had that patched and another hole in inside of frame same general area patched for $1000. The inside of frame has considerable rust debris but the driver side externally is good except for lots of surface rust which I have sanded/wire brushed primed and painted. I bought it used in December 2012 w/72K miles and it had been an Ohio car I think, I'm in Chicago area so it's seen it's share of salt. Rear axle hsg also needed sand/prime/paint as well as front rad support.

First thing I'd do is see if I could punch through the other layer with a hammer and chisel. It kinda looks to me like you will be able to as it looks flaky. To me rust is a cancer so I would cut it all the way back to solid metal then make a plate that fits inside the hole.

^^^^This what I would do also, if you don't get rid of all the rust or as much as you can it will come back in the same area.

Upon yall's recommendation that it was I did tonight and with a punch I am near certain I was able to punch through the other side on the interior of the frame. I talked with a mechanic buddy from my hometown and I'm gonna go with the overkill solution. I think what I am gonna have done is to cut out, then weld the interior with a plate but it'll probably be 2 strips welded together, then have a plate welded flush with the outside of the frame, and then have an external plate welded over that.

I went ahead and ordered a couple of cans of Eastwood internal frame coating. I think what I'll do after the weld job is complete is to flush the frame with water to get out any debris and then air chuck it at every available entry on the frame. Then, I'll apply the internal frame coating paint and do my best to not think about this issue ever again. I will post pictures in a couple of weeks of the weld job.

Does anybody see any issues with my proposed method of repair?

Often in these cases rust is kind like an iceberg with the outer skin being the water level. The deeper into the metal you get the larger the rust area like how an iceberg gets bigger under water. Your plan sounds good but I would not bother with the 3rd external plate. If it's welded properly it will be stronger than original with the inner and flat layer and will look nicer. If the last layer is beveled so you can get a layer of weld deep and then another layer on top of that you can ground the weld flat and make it look good. If you are concerned that the weld will weaken the frame then you can do a fish plate to spread out the weld area. These are boxed frames so they are quite strong unlike what you'd have with similar rust on C-channel. My 2 cents.

This great feedback. Thanks. I'll post pictures in a couple of weeks with the results of the effort.

I did some frame patching (in my build thread) due to the a/c condensation line.

In the spot pictured, I would cut out and patch the area, then utilized a fish plate.

Used Eastwood internal frame coating before, I did the same as your plan - flushed the frame as thoroughly as possible with a garden hose, even took it to a carwash and got the wand into openings with the soapy setting. I could have done even more cleaning at home squirting some Dawn into the frame openings then following up with another thorough garden hose flush, then follow up with some kind of pre-paint cleaner like Eastwood offers.

I got tired of being soaking wet and stopped short of really thoroughly cleaning the frame and crossmembers internally, applying pre-paint cleaner, went to the internal frame coating and it seemed to adhere very well. Eastwood makes a good product, have at it.

Get a couple more cans and get into the radiator crossmember and the other crossmembers along the frame, spare carrier. I believe Eastwood recommends two coats, I used one coat. A smart guy, not me, would mask over some of the frame openings to prevent drippage, I believe Eastwood recommends that also.

Eye/face/head protection, gloves, long sleeves/overalls is a must. That stuff is nasty to get off when it gets on your skin. The 360 degree spray head popped out of one of the frame holes and laid a stripe of it along the side of my face.

HINT: uncoil the spray hose and lay it out straight over a house furnace duct for a day until it loses the "coil" it wants to stay in. Much easier to slide it into the various frame openings. Best of luck to you.

Thanks for the comment. I looked up fish plate and will talk to my welder fab guy about considering this method. I'll post pics when complete.