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-   -   White fluffy powder/salt forming at seams. (http://www.sculpture.net/community/showthread.php?t=3713)

Jackson Jarvis 09-30-2006 04:31 PM

White fluffy powder/salt forming at seams.
 
Problem - A white fluffy powder/salt is forming at the weld seams on a new metal statue a day after each rain. We would like to eliminate this problem.

Background - We have a new metal statue of a bull in our garden. He was a gift from a client. I believe he is either bronze or brass and is made of several cast pieces welded together. He was then powder coat painted.

Each time it rains, a day later when everything has dried out a white powder which looks like some kind of salt is forming fluffy deposits along all the weld seams.

Does anyone know what this white powder is and whether it might be toxic?

We would also like to know how to get rid of it permanently.

My guess is to turn the statue upside down and open a hole in the bottom. Then fill it with water and let it stand overnight to dissolve the "salt" or what ever it is. Then pour out the water and repeat once or twice until the statue is clean inside. But I am sure this is a known problem and there is a preferred method to take care of it.

Thanks in advance. Please email answers directly to me at Jackson.Jarvis@CIR2.Com as well as post them here. Thanks again.

iowasculptor 09-30-2006 05:08 PM

Re: White fluffy powder/salt forming at seams.
 
Can you post a pic of it, that might help us get a better idea of what it is or what is happening.
Matt

iowasculptor 09-30-2006 05:15 PM

Re: White fluffy powder/salt forming at seams.
 
check this link out it might answer some of your questions

http://w3.gsa.gov/web/p/hptp.nsf/035...6?OpenDocument

Good Luck.
Matt

iowasculptor 10-01-2006 08:49 AM

Re: White fluffy powder/salt forming at seams.
 
Well I talked to a friend of mine who used to have a powdercoating company. Here is what he said. Your sculpture is probably not bronze, I was thinking this too since I don't know anyone who would powdercoat over bronze, it doesn't make sense to spend the money on bronze and then cover it up. So assuming that, he stated that the filler metal on the welds was probably a different metal than the rest of the sculpture and what you have is a reaction between two different metals. There is no salt inside your sculpture. When these metals react (rust, oxidize) they create this white powder. The rain or water would cause this reaction to happen each time, Its kind of like when your car gets a little rust on it, each time it rains or gets wet it rusts a little more. To fix it??? keep it out of the water, seal it up good, put a sealant on it, you could spray it with a clear coat, this would need to be reapplied every year or so.
Hope this helps
Matt

EJB 10-01-2006 10:47 AM

Re: White fluffy powder/salt forming at seams.
 
A picture would greatly help the many knowledgeable folks here help determine the source of your problem. I would go along with the dissimilar metals theory and Iowasculptor's suggestion of sealing the piece from moisture. If your 'salt' formations are 'fluffy', that sounds like a condition particular to aluminum. I can't recall ever encountering a powder coated bronze but it is possible I suppose. If you are not getting orange rust as well it is likely not steel but wouldn't hurt to give it the magnet test. If the problem lies in the welding, brazing or soldering alloy, the cost effective remedy again is sealing out moisture. Powder coating has the potential to be corrupted and might need to be redone.

Ries 10-01-2006 12:53 PM

Re: White fluffy powder/salt forming at seams.
 
I am also guessing its cast aluminum, welded together, then powdercoated, probably quick and dirty by a production line type process.
Alumium will oxidize and make white powdery fluff, particularly where its kinda sloppily welded together with some pinholes that will hold moisture.
Then, powdercoating aluminum is particularly tricky, and seldom done right- it must be sandblasted first, then baked before spraying, particularly castings, as the castings have lots of small imperfections that hold moisture. If not baked at 500 or so for at least an hour, the powder almost never holds up.
In addition, powdercoating is a particularly poor outdoor finish- its cheap and quick to apply, but doesnt hold up long outside- it color fades, peels, and crazes very easily. Sunlight and rain, and especially salt air, accelerate these processes.
If it was my sculpture, and I liked it, I would have it sandblasted, then painted with a 2 part epoxy paint by a professional shop, assuming it was worth the money.
This is the only painted finish I have seen that holds up on metal outdoors for any period of time.

RWJR 10-02-2006 02:16 PM

Re: White fluffy powder/salt forming at seams.
 
I have seen this happen with a joint that is brazed with a fluxed brass rod. It can look clean but after alittle moisture get to it "fluff" pops out. Probably have to clean and recoat it. picture would help

fused 10-02-2006 02:43 PM

Re: White fluffy powder/salt forming at seams.
 
As RWJR said, it may be a steel sculpture with brazed joints. If a borax flux was used and not cleaned after joining parts (chip off clear brittle remnants and scrub with warm water) it may re-emmerge later. Usually as a crusty white extrusion that is not toxic, just a nuisance. Chip it off, wash with warm water and a bristle brush, then seal with a clearcoat and wax. Eventually it will run it's course and not occur again.

BMBourgoyne 10-02-2006 04:46 PM

Re: White fluffy powder/salt forming at seams.
 
Could it be gypsum core material left inside leaching out with moisture (assuming it is indeed bronze)?

Can you see metal anywhere to confirm whether it is aluminum or bronze (on the bottom perhaps)?

Can you see inside the sculpture?

just a guess.
bmb

nep75 10-02-2006 05:40 PM

Re: White fluffy powder/salt forming at seams.
 
It could be brass which it was brazed with a flux. I like the flux idea - but it could be anything from aluminum to brazed steel. Let us know!
~ N

jimmart 01-07-2014 09:23 PM

Re: White fluffy powder/salt forming at seams.
 
I'm having this problem also. Can people advise on the best way to seal the large brass sculpture? Borax has been leeching out several weeks, can't wait anymore, need to ship! What type of clear coat? What type of wax? (Best for sealing out moisture/sealing in borax)? Heat surface first?
Thank you.

jimmart 01-07-2014 09:39 PM

Re: White fluffy powder/salt forming at seams.
 
1 Attachment(s)
Also, just a thought I'd like advise from the experts here; I was thinking maybe this type of thinner mixed with wax (Italian product called Extra Lux) for granite/marble, might actually seal better than normal Renaissance wax?
Though it's for stone not brass, I was thinking it might be a better sealant.
Anyone have any experience?

raspero 01-09-2014 05:24 PM

Re: White fluffy powder/salt forming at seams.
 
If you cover up borax flux with a sealer it will still be there working away. It will rear its ugly head soon, and you will have an unhappy customer. You need to get the borax out of there first. If the piece is small try boiling it in a tub of water.

I have read of other ways to get borax out but I have not used them.

Richard

jimmart 01-14-2014 06:26 PM

Re: White fluffy powder/salt forming at seams.
 
Thanks very much Richard. I'm willing to try anything. Customer is waiting and getting anxious/testy...
The pieces are large, about 5-6 feet tall.
Can you tell me what you have read about other ways to get the borax out?
Thanks again.

RWJR 01-14-2014 09:37 PM

Re: White fluffy powder/salt forming at seams.
 
Take it to a radiator shop and see if they think it should be dipped in an acid bath, they may recognize the fluff. Of course you need to neutralize the acid after the dip and refinish / patina . The flux residue is on the inside and seeps out thru pin hole.


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