Powder coating tips?

[The Ghoul]

Just picked up a powder coater and will be picking up an electric oven soon (salvation army special).
Any one have tips on process/bake times/ diffrent types of powder?
I am a compleet noob to the process but feel very encouraged by a guy at work that worked in a powder coating shop and seems to know his stuff. I just dont like to get all my info from just one persion, just incase they are full of BS.

[Silver R/T]

you bake it usually at 425 degrees, not sure how long, guess depends on part, how soon it can gain temperature.

[The Ghoul]

oh, It goes by part?
The powder came with a 'suggested bake time'
20minuts @ 350
or
10minuts @ 400
It dosent make much sence to me that it would be dependent on the part, seeing how as its just the surface that needs to get to temp??
But I have been wrong in the past.

[daytonalo]

AS THE OWNER OF A POWDERCOAT BUSINESS YOU ALMOST ANSWERED YOUR OWN QUESTION . FOR EXAMPLE IF YOU POWDERCOAT AN ENGINE BLOCK LIKE I JUST DID THE WHOLE PART HAS TO GET UP TO TEMPERATURE TO MAKE THE POWDER FLOW . IF YOU POWDERCOAT A VALVE COVER IT WILL GET TO TEMPERATURE MORE QUICKLY THAN A ENGINE BLOCK . IF YOU ARE STILL LOST LET ME KNOW .

[The Ghoul]

AS THE OWNER OF A POWDERCOAT BUSINESS YOU ALMOST ANSWERED YOUR OWN QUESTION . FOR EXAMPLE IF YOU POWDERCOAT AN ENGINE BLOCK LIKE I JUST DID THE WHOLE PART HAS TO GET UP TO TEMPERATURE TO MAKE THE POWDER FLOW . IF YOU POWDERCOAT A VALVE COVER IT WILL GET TO TEMPERATURE MORE QUICKLY THAN A ENGINE BLOCK . IF YOU ARE STILL LOST LET ME KNOW .

So let me try to put this in applacation terms, if I understand correctly that is.
If I were to do a big chunk (engine block) I would bake at a lower temp for a longer time to get the part to heat evenly so the melted powder will flow correctly creating a smooth finish. But if its a part with more surface area than mass you can bake at a higher temp for a shorter time and get the same finnish?

Side bar.
I am planing on doing brake componets for my first project and I was wondering If the powder is good to go for the rotors? I initially wanted to just do the hub area but then thought it might bee good to try to get it in the vented center area. Do you think eather of these areas would hold up to the heat of daily driving?
I never get my rotors red hot and would love to avoide the unsightly corosion. 

[daytonalo]

I HOPE THIS SPELLS IT OUT FOR YOU . POWDERCOAT CURES @ 375-400 FOR 10-15 MINUTES AND WONT START TO FLOW UNTIL THE PART ITSELF REACHES THAT TEMP , SO IF YOU THROW A ENGINE BLOCK IN AN OVEN THAT IS PRE-HEATED TO 400 , IT WILL TAKE ABOUT A HALF HOUR TO BRING IT UP TO TEMP . IF YOU THROW A THIN BRACKET IN , IT WILL COME UP TO TEMP MUCH MORE QUICKLY . THE 10-15 CURE TIME ONLY BEGINS AFTER PART IS UP TO TEMP !!!!!!!!!!!!  IF YOU HAVE ANY MORE QUESTIONS MAYBE YOU NEED THE BIG BOOK OF POWDERCOATING

[doctorpimp]

IF YOU HAVE ANY MORE QUESTIONS MAYBE YOU NEED THE BIG BOOK OF POWDERCOATING

Where do you get this book?  What is the title?

[The Ghoul]

I HOPE THIS SPELLS IT OUT FOR YOU . POWDERCOAT CURES @ 375-400 FOR 10-15 MINUTES AND WONT START TO FLOW UNTIL THE PART ITSELF REACHES THAT TEMP , SO IF YOU THROW A ENGINE BLOCK IN AN OVEN THAT IS PRE-HEATED TO 400 , IT WILL TAKE ABOUT A HALF HOUR TO BRING IT UP TO TEMP . IF YOU THROW A THIN BRACKET IN , IT WILL COME UP TO TEMP MUCH MORE QUICKLY . THE 10-15 CURE TIME ONLY BEGINS AFTER PART IS UP TO TEMP !!!!!!!!!!!!  IF YOU HAVE ANY MORE QUESTIONS MAYBE YOU NEED THE BIG BOOK OF POWDERCOATING

ahhh
I see now.
Yes, if you can recomend any books on it Ill definetly check them out.

[hoobatech]

High Performance Powder Coating. - The latest advances in powder & equipment. In depth info. 325-page hardcover by Bob Utech. Published by SME.
Handbook: Practical Guide to Powder Coating. Folkerman, Haegeman, Porro, etc, Paint Research Association (UK, phone 44-81-977-4427 fax 44-81-943-4705).1992
Powder Coating, The Complete Finishers Handbook. Powder Coating Institute (phone 703-684-1770, fax -1771), 2nd ed. 1997

theres a few good links 

[doctorpimp]

Thanks!
My friend is starting a small Powder Coating business and those will be invaluable to him.

[The Ghoul]

First attempt.
The mask lines arnt all that clean but good enough for rotors.
There are some patches where it didnt take but I was planning on doing a second 'coat' any how.
I am happy and I cant wate to try it out on something that I dont need to mask.

[The Ghoul]

Second coat turned out great!!!
Some of the flat surfaces ended up with 'dimples' that are only visible with direct side light. I wonder if this is because I baked it too long? Or if I didnt bake it long enough?
Eather way I am very happy with it and cant wate to do the rest of the stuff!

[BigBlockSam]

IF YOU HAVE ANY MORE QUESTIONS MAYBE YOU NEED THE BIG BOOK OF POWDERCOATING   

   your a pisser Larry

[Bandit72]

i work for B&W truck beds, and we powder coat black parts (pin block for the town 'n stow) at 425 degrees...grey parts are at 340 degrees and i don't recall what white parts are at...it depends on the thickness of the metal i guess (like others have said)

[The Ghoul]

i work for B&W truck beds, and we powder coat black parts (pin block for the town 'n stow) at 425 degrees...grey parts are at 340 degrees and i don't recall what white parts are at...it depends on the thickness of the metal i guess (like others have said)

Is it possible to over bake them.
EX. If I bake a part at 450 for an hour what would happen? Will it bubble and run? Or will it combust?
The reason that I ask is I baked the second coat at 450 for 30 minutes and got one maybe two 'dimples' per rotor but I checked in on them at the 20 minute mark and they were there. Was this because the base layer liquefied in that one area before the surrounding area or because it baked to the boiling point and bubbled up? Or was it because of too thick of a second coat.
(sorry I still have not picked up that book yet, its on my to-do list)

I guess what I want to know is what will I see if it bakes too long?

[Bandit72]

i'm sure you CAN overbake them, but i've never experienced it...the "dimples" i would have to say would be caused by something on the metal under the powder that got hot and expanded...but i'm not claiming to be an expert by any means...

[The Ghoul]

i'm sure you CAN overbake them, but i've never experienced it...the "dimples" i would have to say would be caused by something on the metal under the powder that got hot and expanded...but i'm not claiming to be an expert by any means...

Thats what my guess would have been but this did not occure on the first coat but the second. I am wondering if there was a bit of water that got onto the surface?

[plum500]

I wouldn't think water would cause a problem a problem like that, I would think it (in any amount small enough to go unnoticed) would evap quick enough not cause anything that severe, or even more of a spattered/small bubbled effect -- but I'm no expert, just guessing -- looks more like a greasy impurity to me... dunno... but again, I'm no expert, just watching this thread to learn...

cheers

[The Ghoul]

I wouldn't think water would cause a problem a problem like that, I would think it (in any amount small enough to go unnoticed) would evap quick enough not cause anything that severe, or even more of a spattered/small bubbled effect -- but I'm no expert, just guessing -- looks more like a greasy impurity to me... dunno... but again, I'm no expert, just watching this thread to learn...

cheers

Yeah your right.
The water would have evaporated far before the powder would start to melt.
It just seemed to me the longer I baked it the more it began to even out.
I am almost sure its either from oil (from handling it because I wiped it down with tack cloth before 'dusting' it so it wasn't a glob of grease), or from the base layer melting in before the top coat. Ill see if I get a similar issue with the caliper brackets.

[Rack]

You think maybe it was an air bubble that got trapped under the powder before you put it in the oven? Seems highly unlikely but you never know.


I ordered the powder coating kit from EastwoodCo two days ago. I plan on doing a lot of this stuff in the near future (probably even to stuff that won't need it  ). Any suggestions for a fellow first time powder coater?


I'll be sure and post pics of my "work" when I'm done as well. Hope my first try goes as well as yours.

[The Ghoul]

You think maybe it was an air bubble that got trapped under the powder before you put it in the oven? Seems highly unlikely but you never know.


I ordered the powder coating kit from EastwoodCo two days ago. I plan on doing a lot of this stuff in the near future (probably even to stuff that won't need it  ). Any suggestions for a fellow first time powder coater?


I'll be sure and post pics of my "work" when I'm done as well. Hope my first try goes as well as yours.

The powder goes on very fine so it would almost be impossible for a bubble to get stuck under it.

Here are tips I have learned so far.
-Don't bake it in your home oven, you will never get the smell out.
-Make sure to wear long pants, long sleeves, a hat, and a dust mask when to apply it (that powder will get every where).
-Powder coat hates sticking to any thing smooth so rough up the surface by sand blasting, sanding, ect... before applying it.
-Make sure after you bake it once you reapply masks and powder coat it again. Out of the 4 parts I have done so far there isn't a single one that have full coverage the first coat. On all most all of them I accidentally brushed ageist them and wiped some of the powder off of.
-What ever you don't want powder coated (threads, sealing surfaces ect..) mask off before you 'dust' it with powder coat and remove ALL of the masking material before baking.
-Those 'coding label' "dots" are great for masking off threads, are self adhesive and are only about $1.75 for a pack of 300.
-Make sure that you don't brush ageist the part after its been dusted but before its been baked. The  powder static electrically adheres to the surface so it is incredibly easy to brush off.
-After you 'dust' the part; use an air gun with the same pressure setting for the powder coater (10 psi ish) to lightly spray off the part. This will reveal the areas that the 'overspray' hit but the powder didn't stick to. It also sprays off the very loose powder so it wont be too thick.
-Have a clean rag handy and a steady hand because no matter how well you mask some powder will get where you don't want it so you have to wipe it off before you bake it.
-Reclaiming it is more work than its worth when you don't have a spray booth. So far I have done 2 coats on the 4 rotors, and one coat on the 4 caliper hangers and have only used about ¾ of a pound of powder.

That's about all I got so far just remember, powder goes every where, it builds up thick so you don't want it where tolerances are important (threads, bolt holes ect...) and take your time to clean the part of overspray before baking it.

[Rack]

Great tips, Ghoul.


I need to go find myself a cheap oven.

[The Ghoul]

Great tips, Ghoul.


I need to go find myself a cheap oven.

http://www.craigslist.org/
Its a free classifieds website so you find all the people that want to get rid of the stuff but don't want to throw it out. I found an electric one for $75. Its a standard electric house oven, so its big enough to do stuff like rotors, upper control arms, center links, rims, bumper braces, steering knuckles, brake calipers, drums, rotors, valve covers, oil pans, trans pans, the millions of crappy little brackets and braces  ect, ect, ect.....

You see how the investment will soon pay for its self.

I also highly recommend that if you have the means get a sand blaster, either a cabinet or an open air. I have a 30 gallon stand up compressor running an open air sand blaster and it works well for me. I do reclaim the abrasive because its easy to do . basically just sweep out your shop floor, cover every thing you don't want sandy with plastic, sand blast, shake off all the plastic, sweep the abrasive to the middle of the floor, and sift it through a screen, then deposit it back into a bucket.

Here is how I justified it in my mind, and some one please point out if my shop price is off.
Shop to do the stuff:                                   $800 easy.

Getting yourself set up:
Powder coating machine                     $80
Oven                                                     $75
Powder $20/2lbs Approximately 20lbs =      $200
Sand blaster                                      $100
Media for sand blaster                                      $50
Total              $505

All of this is based on the parts that could be baked in a conventional oven. I excluded all the big stuff ( drive shaft, front bumper cross supports, k member, ext.) because either of the options would require them to be done at a shop.

With my love for cars I figured that even if I didn't save money on the impreza stuff (why I initially picked it up) I sure as hell would on the charger, and if not that then the next one , or the next one... ect...
Easy choice to make for some on in there mid 20's. Like I said before I have never been reluctant to spend money on tools or education.

[Rack]

I agree 100% about spending money on tools.


I plan on buying/restoring a Cuda after I do the charger so these tools will be used plenty.


I won't be getting a blast cabinet, but I do want to get a sand blaster. I'm also looking into having a rotisierre built, but so far most people in my town have never even heard of one. So that'll take some time, unfortunately.


I plan on powder coating anything that'll fit in the oven I purchase, plus finding someone with a big enough oven to powder coat the things that don't fit. A restaurant just burned down here a few weeks ago, maybe they'll sell me their burned up oven cheap.


Where did you get your sand blaster and how much did it cost?

[The Ghoul]

I agree 100% about spending money on tools.


I plan on buying/restoring a Cuda after I do the charger so these tools will be used plenty.


I won't be getting a blast cabinet, but I do want to get a sand blaster. I'm also looking into having a rotisierre built, but so far most people in my town have never even heard of one. So that'll take some time, unfortunately.


I plan on powder coating anything that'll fit in the oven I purchase, plus finding someone with a big enough oven to powder coat the things that don't fit. A restaurant just burned down here a few weeks ago, maybe they'll sell me their burned up oven cheap.


Where did you get your sand blaster and how much did it cost?

this is the exact one I have.
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=34202
I think I payed $120 out the door for it at there store.
abrasive makes a world of differance for these. I started off trying to use sand that was too fine and it jambed all the time. Now I use some stuff thats more coarse and it works out great.

[Rack]

Looked in the classifieds today and found a "double" oven (regular oven on the bottom, stove, and then a smaller oven on top) for $100.


Haven't plugged it in yet but it looks like it's in good shape. I have to clear out my dryer so I can have room to plug the oven in. If it doesn't work it probably won't take much to fix it. Looks very solid.


Now I just have to wait for the powder coating equipment to get here and I can start experimenting.

[Drop Top]

When Powder Coating. Just like paint you can get it too thick and it will become a run. That picture looks like maybe a drip from the gun. Like a bit of powder droped onto it somehow. You do know that when you recoat something. Your not suposed to bake the first coat all the way entill its cured, don't you? If you did cure it out before the next/2nd coat. Then it might be a bubble where it didn't stick to the first layer.

Here is a tip. Next time you do a set of rotors. Dont wast time tapeing them off. After you have coated them. Take them to a place that turns rotors and have them turned just enough to get rid of the coating. Just be careful not to blast the surface area with your blaster. I have done this a number of times. Costs around here range from $5 to $10 a piece.

[The Ghoul]

When Powder Coating. Just like paint you can get it too thick and it will become a run. That picture looks like maybe a drip from the gun. Like a bit of powder droped onto it somehow. You do know that when you recoat something. Your not suposed to bake the first coat all the way entill its cured, don't you? If you did cure it out before the next/2nd coat. Then it might be a bubble where it didn't stick to the first layer.

Here is a tip. Next time you do a set of rotors. Dont wast time tapeing them off. After you have coated them. Take them to a place that turns rotors and have them turned just enough to get rid of the coating. Just be careful not to blast the surface area with your blaster. I have done this a number of times. Costs around here range from $5 to $10 a piece.

I was paranoied that the centers of the rotors would get to hot and melt the coating so I wanted to keep it to just the center.
Sounds great though.
So do you just bake the first coat untill it smooths out?
or
Do you just lightly bake it to the point where there is just a lot of little 'blobs'?

Well eather way my brakes are finaly done and I am very happy with the results!
Both looks and function!

Next project is that old set of keystone clasics that came on my charger 

[Rack]

Great job, Ghoul! Looks freakin' awesome!


Can't wait to get my powder coating kit so I can try this stuff out.

[daytonalo]

WHEN WE POWDERCOAT ANY CAR PART WE CLEAN THEN BLAST IT THEN , HERES THE KEY STEP , IT'S CALLED OUTGASING . THIS IS THOSE PIMPLES OR LUMPS , TO REDUCE THE CHANCE OF OUTGASING YOU NEED TO HANG CLEANED AND BLASTED PART IN THE OVEN AND BRING PART TO 400 FOR ONE HOUR , REMOVE THEN LET COOL TO UNDER 100 DEGREES THEN YOU READY TO POWDERCOAT . I TRY NEVER TO COAT A PART HOT BECAUSE IT WILL PILE ON TOO MUCH POWDER AND BE PRONE TO CHIPPING. LARRY

[new_red_67]

12 years ago, I started a polyurethane molding business and tried to use a regular electric oven for R & D.  Knowing the particular material I was dealing with required a tight temperature range for the urethane to cure properly I put a lab grade thermometer in the oven.  After monitoring its cycles for several hours, I was shocked to discover the "on cycle" would overshoot the target temp by 77 deg and undershoot as much as 49 degrees.

Knowing that all electric home ovens (except the new digital types) overshoot and undershoot as bad or worse than mine did, I'd need to know how sensitive the powdercoating material is to these temp swings or if it matters at all.  Just a thought.