Removing rust in frame

[thistle3585]

I have the typical rust on the rear portion of the frame above the shackles. There is some pretty severe holes. I've also looked at a number of repairs documented online, so I have a pretty good idea of the job, but there are a few things that I haven't been able to get a grasp on. How much rust do I need to get out of the inside of the frame before welding reinforcing plates on and what is the best way to get at it? I have a sandblaster at my disposal for getting the outside and whatever I can get on the inside through the holes, just not sure how far I need to go. I am hoping to not remove the body but will drop the gas tank. Is it necessary to remove the shackles or can I work around them? Once I strip the rust out should I prep it with something before welding on new steel plates? I do plan on painting the frame when all is said and done. Any other advice, tips or tricks?

 

[IOPort51]

the effects of the rust on your welds will have a lot to do with the method you use to weld it. Of course you will need sound metal to weld to, if it will fall out when struck with a hammer you really can't weld to it. removing the loose rust with a wire brush should be sufficient for arc/stick welding but could be a bit problematic with MIG/hard wire. What are your plans?

 

[thistle3585]

On the outside of the frame, I was simply going to sand blast it to bare metal. I just wasn't sure what the proper procedure should be on the inside of the frame. There is a lot of mud inside there and I don't know that I can get it out. Once I have the rust removed then a friend is going to arc weld steel plates to either side that extend beyond the rust areas.

 

[IOPort51]

hitting the frame with a hammer could break the dirt loose , I would think.

The only problem I would think would be the dirt absorbing the heat from the in side and , depending on how much organic matter it has in it it may burn. I would do the best I could to remove it from the weld area. the blasting of the weld area will work fine.

watch for brake/ fuel lines!

On the outside of the frame, I was simply going to sand blast it to bare metal. I just wasn't sure what the proper procedure should be on the inside of the frame. There is a lot of mud inside there and I don't know that I can get it out. Once I have the rust removed then a friend is going to arc weld steel plates to either side that extend beyond the rust areas.

 

[PaRenegade]

The rear horns are usually the worst spot for rust. To clean it out well you could cut an access square hole in the rear crossmember at the end of the frame. Then you have direct sight and access to get in there with a vacuum and wire brush. When your done just weld it shut again or plate the whole crossmember for added strength.