Rigor,

   Thanks for the question!  Let's try a few different ideas to look into:

   Let's start with the brake clean.  Most cleaners like that are petro based, so they tend to leave an "oily" film.  You could try MEK or another solvent.  Because of your issues, there's a part of me that believes the powder simply didn't bond to the metal.  You did blast the parts, so you do have an etch.  That being said, it sounds like something impeded the bonding.

   Next, it may be the powder.  I don't know what powder you used, where you purchased it, anything like that.  I would investigate to make certain that it was a high temp powder.

  Finally, how long did you bake the parts?  If you did under-cure the parts, the powder will be brittle, which would explain the spider web effect.  

  Try to look at it this way:  powder that chips easily tends to point to a problem with the cure.  Powder that peels off in large flakes most often indicates pretreatment and prep issues.

  Hope this helps!

Joey

The powder i got came from caswell, Hi-temp gloss black ,does not say on can but think its tgi.Will try to find a better cleaner,alchool based.

Cure temp is 450f and time is 20 mins witch i did, in a house oven.As far as the flaking its small chips and rubbes off easily.

  Actually, you should always clean the part after the out gassing.  The out gas process opens the pores and drives die release contaminants, oils, etc to the surface.  In this case, you are doing the right thing.

  I have nothing at all against Caswell or other companies that don't manufacture powder.  They serve a nitch in the market by buying powders and re packaging them by the pound or whatever for the consumer.  There are a few of these companies that are very reputable and what you ask for is what you are getting.  I would, however, NEVER buy from some others that sell on e-bay because they aren't really giving you quality product.  They are giving you reclaim powders and such and selling them as brand new virgin material.

  When you see that the powder is a "silicone", it's not the same thing as the silicone we normally speak of.  It's more of a verbiage thing used in the industry.  No worries here.

 Because the powder isn't coming off in larger flakes, I don't think it's in the pretreatment.  Because it rubs off so easily, I do think it's in the cure.  450 degrees at 20 minutes may be what the Technical Data Sheet says, but that is at PEAK METAL TEMPERATURE.  Therefore, once the metal hits 450, you would stay there for 22 min.  Home ovens are tricky because they don't have the proper airflow to really cure a part uniformly (also, they aren't exactly legal because of the lack of exhaust but they will work and are great for beginners).  My best guess would be that you should have cured that part for closer to 40 minutes to be safe.  Remember, under-cure is brittle and it's always best to over-cure.

  Hope that helps!  Let us know what happens when you bake for the longer cycle.

Thanx for the info will try the longer cure time on the weekend hopefully.One more thing ,i know that there is different temps and cure times forsome powders,for example, gloss black will say cure at 375 for 15 mins or 325 for 30 mins, does this also apply for high temp powders. Just wondering if i can lower temp and increase cure time for high temp powder? BTW thanx again for the insight.

Thank you Joey for your help will try the longer cure time not sure when ill get to it but when i get it done i will let you know on results.

Thanx again.