Well.. Where to start?
Sorry about not posting yesterday as promised, my bad. I intended to get at it, but the weather didn't co-operate. My back yard is fairly well cushioned against wind, most times, but yesterday wasn't one of those times. Although powder coating is held to the piece by an electrostatic charge, once the leads are off, there's literally nothing keeping it in place that would withstand and significant wind.
Secondly, I'd like to thank Blacky for helping out with a difficult technical question about temperature rise gradients. I appreciate the info. But, damn.. I was hoping for " No worries Chuck, it's X per gram of aluminum per minute on a sliding scale of X per degree of temperature difference... here's what it'd look like plotted on a graph. Hey, I can dream, can't I?
However, the answer that I did get, was, if nothing else, a great shove in the right direction. The buffugly ( or freekin' cool, depending on your taste
) outcome of the first attempt, did have one redeeming factor. It showed that the powder coating is fairly forgiving as to temperature and time. Way more forgiving than I would have expected. Part of the prep process for powder coating is called "off gassing". That's where you toss the rim in and leave it in long enough that all the contaminates that are in the pores of the metal are cooked out, so that they won't cause an issue when the part is in the oven with coating on it. So, I'm going to take the opportunity of having to do what Blacky said, and just use my laser guided infra red $14.00 Ebay, shipped directly in 45 day, guaranteed accurate within 1 degree, temp sensor to chart the temp rise of 1 rim. I'll do my best to minimize the variables. I'll start the oven one hour before putting the rim in, to stabilize the oven's operating temp. Keep the rim in the house for at least four hours before, etc. That should give me a very rough guideline on the warmup temperature.
As the temperature rise of the heated part as a time value is a function of mass and temperature difference, I'll try a second rim with the same methodology, but with one difference. When I actually bake food in an oven, I use a high initial heat to sear. For example, a roast at 350?, put the oven to 425, and then put the roast in and turn it down to 350. I'll try that methodology with a rim. That should accomplish a quicker rise to curing temperature, and, as the rim absorbs the heat from the oven, the lower element won't come on immediately, which should reduce uneven / radiant heating, or over curing. I'll follow the rims temp with the temp gun and see if my hypotheses proves correct.
Moving right along to what I actually did get accomplished, ..
I was a bit pissed at Subaru for there not being anymore fresh factory rims in stock at my local Dealership, so on Sunday afternoon, I rounded up every SVX I could find and we stormed the gates of Subaru Canada's Corporate Headquarters. I wanted an apology, or, failing that, to either confirm or deny the rumours about the 2017 SVX. Unfortunately, they're closed on Sunday, and they have gated security arm post thingys... The SVX has 6.5 inch ground clearance, and they had 8 inch curbs... damn!! It's not that kind of all wheel drive.
Not much point in a protest with nobody to see it, and I forgot to send the press release to the media. Having nothing else to do, I bought this on my way home. Rather than try to get a rim flawless, I'll use this to get an acceptable base to powder coat.
And, because it would seem that I shouldn't have gold Krylon spray painted centers for my rims unless I dig out my platform shoes from the back of my closet. I bought this. I was not going to buy just "black", when, for a couple of bucks more, I could get "Carbon Mist"
I took a rim that was baked to "off gas" it, whipped it with the wire wheel on the die grinder, blew it off with compressed air and painted the high heat on it.... No other prep. The high heat is very, very thin coming out of the can. I picked up one sag before I could even say, " I hope I don't put a sag in this!"..
It came out like this. Yup, you can see the road rash imperfections through the paint, but, it's way closer to the uniform finish than I could have possibly gotten with just the wire brush. Not without spending a considerable amount of time on. If I can get the rim to hold both the "Clear Burgundy" and the clear coat, it should come out very close to what I had in mind when I said " How much could it cost?".
The centers went through the blast cabinet and the gold Krylon came off in less than a minute per center. The "Carbon Mist" came out like this.
Yes, I know, I know.. this is the rim that I still have to strip and redo, but this will give you an idea.
Tomorrow ( Tuesday ) is supposed to be really warm for this time of year.. 20 C.. it'll be windy, but I won't know if the wind will get into the area I work in or not until I get there. I'll either do the powder coating on the prepped rims, or, if weather isn't friendly to that, I'll work on prepping the other rims.
Once again, thanks to all for comments, suggestions, research, etc.. greatly appreciated. I'm still open to comments, suggestions, ideas and creative / constructive criticism, mentoring, outside the box thinking, random thoughts, kudos, whatever..
Oh.. and if anybody knows what the pass code for the gate arm thingys at Subaru Corporate, please share. The kids felt like Mom and Dad had locked them out.
