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Discussion Starter · #1 ·
Hi All,

One of our customers has ageing galvanized structure , it is a water splash slide at an amusement park. The structure is very similar to the one shown below.
We are going to use cold galvanizing spray to coat it.There are many areas which have corrosion this includes some sheets, under track areas portions of the supporting metal pillars, almost all the fasteners.

we plant to use rust converter to reclaim the corroded areas and then coat it with zinc rich spray

What surface prepration do you suggest ?
1) Sand blasting can not be done because it is an amusement park , where hundreds of people come every day.
2) we are suggesting a scaffold structure so that men can reach varios corners of the structure.

Does any one have prior experience ??

regards
Sanjay

 

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Needle gun heavy rust
soft pad grind with 36-80 grit discs
Vacuum blast
contain scaffolded work areas with shrink wrap while surface prep is underway in case heavy metals present and it keeps debris from contaminating other areas of the park.
 

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Just be aware that rust converter's does not actually convert rust to anything. It will still corrode. You really need to have a specialist look at it for proper corrosion control measures. If the fasteners are heavily corroded, think about it? Do you really want to put a band-aid on it and let your kids get on it? The corrosion needs to be removed and fasteners that have substantial metal loss replaced with new fasteners to be safe. Give me a call if you would like to discuss more. 205-717-0292
 

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I think painter213 has some good advice concerning this slide.

I could understand how re coating the entire structure could far exceed any practical costs to repair just the corroded areas, but safety has to be a priority here.

If you were to approach it as a maintenance repair, abrasive blasting will still give you the best surface preparation before application of organic or inorganic zinc. these coatings are designed to be applied directly to prepared steel without any barriers, including rust converters.

As painter213 suggested, a professional structural engineer who is experienced in corrosion control should be consulted so the correct assessment can be made.
 

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Great point Ben and CA
If it is to be assumed then you need a structrual steel engineer type specialist and not just a corrosion control specilist,if you really want to be on the safe side.
these places usually have daily and mandatory inspections as a SOP but you never know.
 

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Discussion Starter · #7 ·
thanks , further questions

Thanks a lot CApainter, ibsocal ,painter213 :thumbsup:
,Really appreciate your inputs.

1) Safety, is to be given priority !! will do that, infact have talked to the customer , will call a profesional structural engineer get each and every fasterner and critical part checked ,replace them if necessary, and will coat only after that.

2) How can i Differenciate between
a)Inorganic and organic coatings, i am going to use spray cans ,
b)how do I judge the quality by spraying , i have two suppliers to choose from. any suggestions?

3) Rust Converter and then spray coating
or
just roughening and spray coating?

4) Zinc galvanizing gives a matte finish, any sugeestions to make it look lustorous, shiny ??

thanks
Sanjay
 

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Your pointless using a cold galvanizing over a rust converter. Unless you have a direct metal contact, the cold galvanizing will do nothing for protection. And the spray can is going to be about the useless coating in the first place. Not trying to come down on you but you have to use a product with a high zinc content and you have to have a clean rust free surface. If your going to erect scaffold, go ahead and tent it and use dust collection an abrasive blast the corrosion areas and do it right. As far as the difference in organic and inorganic zinc. The difference is how it is carried. A inorganic would be as a zinc silicate and a organic zinc would be a zinc filled epoxy. A rust converter does not actually converts rust to anything but puts a hard shell over it that will eventually fall off in a few months in a corrosive environment. Stay away from them is my suggestion.
 

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Thanks for the thread. From now on, I will always do my homework on any amusement parks I consider bringing my boy to.

Sounds like you need a specialist to help you out here, as it sounds like you have no experience with this type of work.
 

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Discussion Starter · #11 ·
reply to painter213's post

And the spray can is going to be about the useless coating in the first place. Not trying to come down on you but you have to use a product with a high zinc content and you have to have a clean rust free surface.
The spray i refer to is a zinch rich galvanizing compound spray can,
it is going to high zinc content surely.
 

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Correct. Zinc in a can is useless sir. You have to have a high zinc content for good protection and you will never get that from a spray can. If it did then you could never get it out of the can. Someone is trying to sell you snake oil in a can. Think about it. How many painters do you see painting bridges and water tanks with spray cans? Maybe only the 16 year olds wanting to get there girlfriends attention. But really, cold galv in a spray can will not last one year before showing corrosion again. The zinc would be gone in a few months. Do you really even understand corrosion and how zinc is used to combat it? Zinc corrodes, so you have to apply a high solids coating with a large volume of zinc to make it last. Give me a call tomorrow afternoon and we can talk more about the subject. Free consultation. This is what I do for a living. www.abbottcoatinginspections.com
 

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painter213 said:
Correct. Zinc in a can is useless sir. You have to have a high zinc content for good protection and you will never get that from a spray can. If it did then you could never get it out of the can. Someone is trying to sell you snake oil in a can. Think about it. How many painters do you see painting bridges and water tanks with spray cans? Maybe only the 16 year olds wanting to get there girlfriends attention. But really, cold galv in a spray can will not last one year before showing corrosion again. The zinc would be gone in a few months. Do you really even understand corrosion and how zinc is used to combat it? Zinc corrodes, so you have to apply a high solids coating with a large volume of zinc to make it last. Give me a call tomorrow afternoon and we can talk more about the subject. Free consultation. This is what I do for a living. www.abbottcoatinginspections.com
So true, crazy to even mention zinc in a can.

Two processes need to be understood and that is 1) effective catholic protection which can only be achieved though correct conductivity with the metal. A problem with rusted galvanized metal is that this is nearly impossible to achieve. As the old corroded galvanising scales like a a crusty skin and the corrosion will be even worse then you think when you get past (if you get past) the old galvanising. That is why ships are not made from galvanized metal. 2) anodic passavation, this will only be effective if the coating is compatible with the catholic protection.

I think it is great that painter 213 is offering support, it sounds like he knows his stuff. Perhaps you should give him a call.
 

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painter213 said:
Your pointless using a cold galvanizing over a rust converter. Unless you have a direct metal contact, the cold galvanizing will do nothing for protection. And the spray can is going to be about the useless coating in the first place. Not trying to come down on you but you have to use a product with a high zinc content and you have to have a clean rust free surface. If your going to erect scaffold, go ahead and tent it and use dust collection an abrasive blast the corrosion areas and do it right. As far as the difference in organic and inorganic zinc. The difference is how it is carried. A inorganic would be as a zinc silicate and a organic zinc would be a zinc filled epoxy. A rust converter does not actually converts rust to anything but puts a hard shell over it that will eventually fall off in a few months in a corrosive environment. Stay away from them is my suggestion.
Man, so true.
 

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sanjayb,

The implications of an improper application are too serious for someone on the internet to guide you through such a critical job as this amusement park ride. Your cautiousness should be an indicator that you are not fully confident to do this job, and therefore you should consult an expert in your area to guide you.

Good luck.
 

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sanjay,

I offered for you to give me a call but apparently you didn't think that was important. Not sure where your from or what line of work your in, but I'm pretty sure it's not in corrosion control systems. There are several good ways to go about this project if your customer is willing to pay the price. If not the all the band-aids in the world will never last long and the final outcome would not be good. I am a coatings professional and I'm picky about what projects bares my name on them. If the customer doesn't want to do the job the right way, then I move on to a customer that does. I stay pretty busy with work too. Good advise here on the board so you can really either take it or leave it.
 
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