Powder Cracks ?

[Guest]

hello everyone its the million and one question guy lol i was coating a set of ragerover sport wheels today silver i gave them all a coat of silver cured them there was sum small imperfections and bits of dirt i didnt like so sanded them nice and smooth i then pre heat them gave them anothr coat of silver and cured them i opened the doors only to find cracks all over the wheels sum wheels worser than others any idea where ive went wrong ? i had this same problem before on that previous question with the wheel that kept turning grey after clear coating it ?

[Guest]

Re: Powder Cracks ?

can you post a pic ? If not, what silver are you using? what was your pretreatment ? what is the substrate ?

[adiemwell]

Re: Powder Cracks ?

i dont have a pic its a valspar powder its called chrome silver i didnt get a chance to clear them this time what do you mean by pre treatment and substrate the wheels were sand blasted , sanded with 80 grit then i out gased them let them cool powderd them silver i then noticed the dirt baked them off i did take them out the oven stratight after they were baked so thewould cool quicker so i could flat the dirt out of them , i fatted the imperfections out pre heat them so they were touchable coated them then one the bake was finisd i checked them and they were all craked ?

[evanscryo]

Re: Powder Cracks ?

if the cracks are fine, like spiderweb, then put them back into the oven for another cycle and see if they go away. When you clear them do so at room temp, not while they are hot. Give this a shot.

[Guest]

Re: Powder Cracks ?

Question about the powder, is that Primid or TGIC ? In Europe most powders are primid or TGIC free powders, not so in the USA...

[adiemwell]

Re: Powder Cracks ?

ill find out tomorro what if they are tgic free ?

[Guest]

Re: Powder Cracks ?

Thank you....primid powders can behave differently than TGIC's

[adiemwell]

Re: Powder Cracks ?

hi heres sum pics of problems iam having theres ones of the cracks that happened theres also like small bubbles i sumtimes get and i recently done sum vw parts and if u like tap it of an object the powders just flakin off or chipping off its like its too brital or something ive seen other powderd parts dun by someone and he showed me it gettin hut of an object and it only marked the colour/dented or scuff it it didnt flake off atall alsosome pics of the powder iam using and the gun settings i allways yous

http://i196.photobucket.com/albums/aa29 ... C00716.jpg

http://i196.photobucket.com/albums/aa29 ... 0715-1.jpg

http://i196.photobucket.com/albums/aa29 ... 0058-1.jpg

http://i196.photobucket.com/albums/aa29 ... 0057-1.jpg

http://i196.photobucket.com/albums/aa29 ... 0056-1.jpg

http://i196.photobucket.com/albums/aa29 ... 0055-1.jpg

http://i196.photobucket.com/albums/aa29 ... 0054-1.jpg

http://i196.photobucket.com/albums/aa29 ... 0018-5.jpg

http://i196.photobucket.com/albums/aa29 ... 0017-5.jpg

http://i196.photobucket.com/albums/aa29 ... 0016-5.jpg

http://i196.photobucket.com/albums/aa29 ... 0015-3.jpg

http://i196.photobucket.com/albums/aa29 ... 0014-4.jpg

http://i196.photobucket.com/albums/aa29 ... 0013-5.jpg

http://i196.photobucket.com/albums/aa29 ... 0012-3.jpg

[Guest]

Re: Powder Cracks ?

Apply coating under normal room temperature conditions.
Avoid excessive build (more than 3 coats).
Apply coating in thin (2-3 mils) coats. This also depends on what your TDS (Tech Data Sheet) reads

Have and use all coating, material, and environment at normal room
temperature conditions.

Avoid excess heat, cold, humidity.

Avoid having the finished product in an environment with extreme
variations in environmental conditions.

[adiemwell]

Re: Powder Cracks ?

what about the chpping off problem ? whats the basic method use would use for coating an alloy i.e sandblast blow off primer or no primer striaght on with the silver cure it then clear coat it ?

[Guest]

Re: Powder Cracks ?

Looks like the part had adhesion problems. I would think pretreatment caused this problem or maybe a contaminate could of gotten on the part. As far as the cracks I would think that it is from the clear not reaching its proper cure time. I had the same issue before with an R&H silver vein that was top coated with a clear. It had many cracks that were real small. It almost looked like spider webs.

Am I close King?

[adiemwell]

Re: Powder Cracks ?

my pre treatent is usually sand blast , blow off, prime , flatnin , base up silver , then laquer see when i powder products the feeling is like hard type this other part someone brought to me that u could let drop without chippng felt like rubber / plastic

[Guest]

Re: Powder Cracks ?

What do you mean then laquer?

[Guest]

Re: Powder Cracks ?

hj, I think he means he wipes down the part with laquer between coats. Course I cant speek for him, but I think thats what he is saying.

[Guest]

Re: Powder Cracks ?

Clear, wow, dont I feel like a tard. So is if spraying laquer over powder? Interesting!