Steel Structures Repair

[babdoc]

Dear All!

Currently I'm working in a project in wich I've to repair some steel structures from a HV Substation. I've to remove the zinc coating from these structures and then galvanize them again. Prior to the galvanization process it is possible to cover/seal some of the holes of the structures (see an example in attached, where you can see some structures with holes that I need to cover/seal)?

I'm sorry if I'm saying any nonsense, but this is not my area.

Thank you in advanced.

 

[mk3223]

Not clear what you try to cover/seal, and why?
Assumed that you want to re-coat the hot-dip galvanized steel after the repair, correct?
For repair work, apply the proper cold galvanizing coating material on these holes.

 

[babdoc]

Hi mk3223!

Yes, I want to re-coat the hot-dip galvanized steel after the repair.

You see the holes in the structures in the picture that I've attached? My client want this holes covered/sealed in a proper way.

For what I understand, you said that in the repair stage this holes can be sealed with cold galvanizing material? It's that correct? Then after the repair works re-coat the hot-dip galvanized process.

I did not know that there was a product capable of sealing these holes, I thought in my ignorance that these holes had to be covered through some process involving welding.

Thankx

 

[david339933]

No, cold galvanizing is used on repairs to avoid re-galvanizing the entire structure. It comes in a spray can....applied just like spray paint.....google "cold galvanizing".

 

[gtaw]

If you are talking about the drilled holes, they would require a welded repair that would definitely disrupt someone's day. Distortion, possible weld defects, disturbed HDG, etc. It is probably best to leave the holes as is if they are already HDG.

Best regards - Al

 

[mk3223]

IMHO, the drilled holes on the HDG steel, which not to be used, may be covered with silicone, if desired.

 

[dik]

It is likely most economical to re-do the sub station and recycle the existing as 'scrap'. This will give you the best 'end product'.

If you want to reuse the existing steel it is a matter of dismantling it, noting how everything goes together. There may be months between tear down and re-assemble. Hopefully there are 'member stamps' on the individual pieces, else, you have more work. Parts can be repaired by welding and the pieces re-dipped and re-assembled. You need good drawings and perhaps existing shop drawings. It's a chore.

Alternatively, you can lightly sandblast affected parts and use a zinc rich primer or epoxy to effect a repair; it will not be as durable as a HDG approach, but, will be much less costly. It's a matter of discussing this with a coating supplier to use the right product.

I would not recommend filling holes with silicone; there is a good chance pockets will remain that will trap water and cause further corrosion.

Dik

 

[gtaw]

If the holes are not being used, why not place a galvanize bolt in the hole, snug tighten, and walk away if there is an objection to an open hole?

Best regards - Al

 

[dik]

As long as there's a hole in the backing material.