Bumper numbers

Has anybody ever embroidered their number on their bumpers? What material do you use? Also, what are some good ways to fasten the bumpers to the bot?

We paint our numbers on our bumpers. I know some teams applique their numbers, but I’ve never seen an embroidered set. I’d be afraid that robot contact would cut the threads and ruin the numbers.

Typically, we use bolts through the plywood and into the frame with wingnuts, but it depends on the frame of the drive base.

Years ago my daughter’s team had embroidered bumper numbers, but one of the mom’s had a professional model sewing machine that could do it.

It sounds like you are starting early so paint may be a viable option; however, make sure the paint has enough time to fully dry and that there are no globs of paint that could smear onto other robots. Embroidery sounds like quite the project (at least 8 different sets of numbers), but if you have the time then you could definitely go for it. Keep in mind the requirements for the numbers:

consist of numerals at least 4 in. high, at least 1⁄2 in. in stroke width, and be either white in color or outlined in white

Personally, our team uses iron-on/patch numbers and then stitch them on. Do not get peel and stick numbers as they will rub off during a competition.
Hope the bumper process goes well!

Mike from Robopromo.com here. Helping teams make professional-looking bumpers is what we do. I may have some resources that are helpful for you. We recommend using iron-on vinyl numbers (which won’t come off) and this year we are offering custom-cut numbers to enhance the look of your unique robot.

For attaching bumpers I would recommend using brackets, bolts, and wing nuts. Most teams find this to be a good method. We offer a hardware kit for that on our website also. For a visual on how to use them, reference the end of our “Bumper Fabric Upholstery” video tutorial.

Here is the link to the video:

Iron-On Numbers:

Bumper Hardware Kit:

I recommend using fabric paint for numbers over other methods for several reasons:

  1. Durability and longevity

Painted numbers can peel, scratch, or chip, but this is easily remedied by patching problem areas with more paint and smoothing the surrounding area with an applicator like a sponge or finger. Properly painted numbers are not likely to be damaged to this extent though, as they are bonded to the fabric better than the other two options. Painted numbers are chemically bonded, while the others are mechanically bonded. Iron on are somewhat chemically bonded, but I feel that most iron on adhesion is more mechanical than chemical.

For most teams, iron on is still a decent option. We haven’t tried embroidering, but knowing how much we’ve damaged the bumper fabric itself in the past, I would be weary of my team using embroidery. If you think your team won’t mess up your embroidery, go for it.

  1. Customization

It is easy to create numbers in any font and stroke (and color if you wish) from painting. Simply cut a stencil and apply the paint through the stencil. Custom iron on numbers or embroidered numbers may be more expensive and take time to manufacture.

  1. Easy alignment

Embroidery and iron on methods require that the numbers are applied to the fabric BEFORE attaching the fabric to the bumper assembly. With paint, you have the option to apply the numbers AFTER attaching the fabric to the bumper assembly. I like this option because I don’t have to worry about aligning the fabric perfectly when I put it on the bumper assembly. I can instead focus on a tight, wrinkle free wrap. After the wrap, then stencil can be applied in the perfect position for EVERY bumper, so each side is consistent with the rest.

Aligning the numbers on reversible bumpers is also easier by painting. The other benefit is that paint can fold easier than iron on and embroidered numbers.

  1. Aesthetics

When done right, painted numbers can look just as good as iron on and embroidered numbers. (see pictures)


Here’s a closer look off the field:


You just need to take time to stencil the initial lines and then use masking tape to keep the edges nice and crisp. If there are curves, cut the tape with a razor blade on a separate surface. If you prefer to not use tape, you can print a number onto a sheet of frisket paper and cut it out. Frisket paper is sticky on the back, so it serves as both a stencil and adhesive masking.

We only use our stencil for the light coat of spray paint that goes on the fabric. We then remove the stencil and use the very faint number as the guide for our masking tape. Then we add about five thin layers of fabric paint to make the numbers durable and 100% opaque. One thick layer is not as durable. We don’t apply the paint in strokes, but rather in dabs with sponges to avoid making the numbers “look” painted. It makes for a nice matte and flat finish.

If anyone has questions about our process of making perfectly painted numbers, just ask.

We have used paint and the AM heat-seal numbers, and have no complaints with either one. Embroidery sounds great. Use short stitches, to reduce the stress and damage when those bumpers get used for bumping. And of course, some seriously strong thread. Hmmm… can you do embroidery with an opaque monofilament?

For securing, the main thing is that you can switch colors very quickly, and remove and replace reasonably quickly in case you need to get re-weighed. Our rookie year, we used clevis pins and cotter pins, which went in from the bumpers through the chassis; a nightmare. We did “bumper covers” in one color our second year, and were not happy with the appearance of the results; YMMV. Our third year, we had gaps in our bumpers both fore and aft, and secured with four (10-32?) wing nuts. We had four bolts sticking up out of the chassis, dropped the bumpers onto them (which made close contact with the frame perimeter; we had no protruding bolt heads at that altitude), and spun them down. We were double-teamed by defenses in a few matches, but the bumpers stayed in place. This year, we will probably do something similar, but with nylon locking nuts and an electric nut driver (with a hand nut driver in the tool bag as backup!). We will probably have more than just the four bolts to handle the lateral stresses, but only about four nuts to hold the bumpers on.

We’ve done something kinda like what you’re suggesting in the path, though we have a Team mom do it. (Technically the Head Mentor’s wife.) I suppose it more qualifies as sewn on rather than embroidered (Unclear on the differences actually…) but it looks nice and is always readable. It goes onto a kinda thick fabric, but should be doable for most teams.

Yes your bumpers are sewn on like patches, and to get an idea of the difference, our friends from 118 have the best examples I can think of for embroidered bumpers:

(Note that the image below is an example of showcase bumpers, which are not FRC field legal.)

I just want to make sure that you are clear on the difference between iron-on and stick-on numbers. Stick-on numbers are an adhesive that stick to the fabric (which is not recommended) whereas iron-on numbers melts into the fabric when applied properly and is a much better option.

The images of the painted-on numbers above look great, but we painted our numbers on our first year and it looked like we painted them on. Embroidery is a great option if you have access to that.

While I do agree that iron on is a good option, the melting into the fabric of the bumper is still more of a mechanical adhesion, and I’d be happy to be proven otherwise. Iron on is by no means a bad option and is a great number solution for most teams. And yes, I think everyone agrees that peel and stick on is a terrible solution for anyone and there is definitely a distinction. I feel more secure using fabric paint, which can be really difficult to scrape off of fabric due to its chemical composition being made specifically to bond to fabric. Our drivers can be very aggressive with both offense and defense, so this is why this is preferred for our team haha.

If Robopromo can provide numbers in any font, preferrably Bank Gothic, which is what is in the pictures, I’d gladly consider my team ordering and trying your product out!

Sure thing! We can cut any font that you send us or we can do our own styles (pictured on our website). Thanks for your interest.

Oh, and @kyot3, to answer how to fasten the bumpers onto the robot, a pair of t-slots, “backward” bolts, and a pair of wing nuts per bumper are generally the go-to method and fairly simple.

Our team was thinking of using a Cricut to print numbers on white vinyl. We are still coming up with ideas though. It looks pretty inexpensive for the vinyl and we have access to a Cricut machine via a mentor.

What are the rules regarding colors on the numbers for the bumpers.

R28A - 4" tall, .5" stroke and white or outlined in white.


Hasn’t changed in a few years (2012, I think?). Might change next year. Read the manual then too.

Game Manual Section 4.7, BUMPER Rules, R28:

Team numbers must be displayed and positioned on the BUMPERS such that an observer walking
around the perimeter of the ROBOT can unambiguously tell the Team’s number from any point of
view and meet the following additional criteria:
A. consist of numerals at least 4 in. high, at least ½ in. in stroke width, and be either white in
color or outlined in white
B. must not wrap around sharp corners (less than 160 degrees) of the FRAME PERIMETER
*emphasis mine

Blue box for R28 says that the numbers can be split across sections of bumpers but must still be clearly visible and unambiguous.

{and sniped because I took waaayyy too long to type}

I’m pretty sure it was different in 2015.