Powder Coating

Our team is looking into powder coating this year but had a few questions/concerns on how exactly the process worked. First, we were unsure whether to powder coat all the pieces individually or to powder coat the frame as a whole, assembled. I was thinking that if we did the frame as a whole everything would line up and the added dimensions would not be a problem but then (maybe?) the allen keys would not fit in the bolts. On the other hand, if we did it in pieces, I am worried that holes would not line up due to the little thickness. What have other teams done in the past and what is the best solution? Thanks a ton!!! Also any other advice about powder coating would be appreciated :slight_smile:

The end result of Powder coating is very much like paint, and while it adds thickness, it can always be chipped off. I would recommend breaking your robot down into the farthest assembly you feel you might disassemble to. (ie. just your robot frame). As for holes, you can always ream out a hole with a drill bit after it has been coated, and if thickness is a problem a bit of sanding will fix the problem. I would not powder coat over hex screws unless you think you will never take them out. Remember you can always mask off areas you don’t want finished.

The thickness of powder coating depends on a bunch of variables such as partial size, color, etc. typically the range in thickness is between .003 and .005"

Unless you plan on welding your frame, powder coat the individual parts separately. Team 228 has had a sponsor powder coat a bunch of components for us over the past few seasons. We’ve designed our sheet metal frame to assemble using either PEM nuts and button/socket head screws or pop rivets. As long as you design around the proper tolerances, the only thing we’ve ever had to do is bore out the powder coat thickness on any bearing holes.

http://www.team228.org/gallery/102/slideshow/build-season-week-five-_9e0cb-af79f.jpg](http://www.team228.org/media/pictures/view/4806)

We’ve always done our frame in-tact, but it’s also always welded by the sponsor that does the powder-coating.

A word of caution about color choice: if the sponsor purchases a special-order powder and you don’t use all of the powder this year, next year the color will be “off”. As an example, our purple is a specific rich, dark, royal purple at its best. Yet every other year it gets this red-wine tint to it. Usually no one can tell until we put it next to the previous year’s robot.

Seeing as how I worked at a powdercoating shop last year, I think I may be able to answer a few questions. Each company is unique and some smaller companies may have size restrictions on how big the parts can be, as the material needs to be cured in an oven. In addition, the metal is sandblasted (very fine) so the powder will adhere. Like Greg said, any sections you do not want powdercoated will need to be taped off (Duct tape for the sandblasting, and painters tape for the coating).

Now for the screw question:
You won’t be able to fit a standard Allan key into the screw head, you will have to tape off all screw heads. As well if you decide that you want to powdercoat the robot assembled, held together with Allan keys, you will find the powdercoat will chip around the screw hole if you decide to take the screw out. To prevent this you will need to score around the screw head with a sharp knife (safety is important).

Hope this helps.

1726 discovered that painting wood with spray paint, letting it dry, sanding, and painting again leaves a finish that looks almost like powder coating, from a distance.

:slight_smile:

I envy those teams who have their design/build process working so efficiently that they have time to powdercoat their robot!

Thanks! Hopefully we will be able to fit it into our schedule to get it done, right now we r thinking black :slight_smile:

1323 has powdercoated for the past 2 years. Its a really nice deal.

http://www.chiefdelphi.com/forums/showthread.php?t=77120&highlight=powdercoated

We prefer to attach our drivetrain and our mast together.

You had time for 2 coats of paint?:yikes::smiley:

We have a full, welded frame that will be ready for powder coat Sunday night.

The place we are sending it wants it Monday / Tuesday so we will loose two work nights (6 hours). We are trying to decide if it’s worth it vs the time we will miss. (We do have other things that we can do, so it’s not like we will be standing around, but there will be a productivity hit)

Teams that powder coat, some questions for you:

  • How long does it take to get your parts back?
  • When in the season (what week) do your parts go out?
  • Do you do one batch of parts or many?
  • Do any of you coat an assembled welded frame?

Thanks very much!

We have been powder coating for the past few years: it takes around 2-5 days, around week 5 or 6, we do it all in one bundle, and we send our frame welded together and plus all our other smaller parts that we bolt on

Jim,
interesting that you would point that out.
We spend more time stressed over not having enough time to build the robot, then we do the actual powder coating.
We call our build season the 5 week build period because of it and our open house event.

It really does make a difference for the appearance of any bot.

In the past we have been able to get them back in two days, but this year will likely be 4 days due to the shop being busier. We plan to take ours in this coming Monday, or Tuesday at the latest. We usually try to do everything in one batch, although we might need to go for a second round this year. We coat welded frames, but nothing bolted together during coating.

wow! done with your robot already or soon…cant wait to see what you folks have cooked up AGAIN. :slight_smile: