Hello CD, I was wondering what you do for your bumper numbers, because the past two years we used nail Polish (we forgot the paint in our shop and had to paint the bumpers in the hotel the day before comp), and we used a paint and a stencil. They have been fine but as a team we would like for it to look nice and clean, so I was wondering how you do your bumpers
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Vinyl stickers are the best (robopromo gives you a coupon in your digital Kit of Parts).
We’ve tried last minute fixes when a whole bumper needed replacing at competition. They are all less than recommended. We’ve tried iron ons but they need to be thin or else they are a snag hazard. Stitch on takes a long time and requires cutting out all of the numbers.
Paint pens are not a good idea. They soak into the materials too much and take many many applications to get semi readable. It’s very obvious and doesn’t look good.
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461 has used adhesive numbers over the years. This year was a little rough (we scrapped off a lot of numbers on the grid by driving in and strafing left and right for alignment).
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Spending my freshmen year in the pits repainting our bumpers with nail polish was an unforgettable experience… and hopefully one to be avoided from here on out 
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Our team uses white insignia cloth, meant for putting numbers and logos on sails. It’s incredibly durable and basically never comes off once you stick it to the bumper fabric. We cut it using a vinyl cutter, but you could do the same thing with a Cricket. That allows you to use any font you like for the numbers, which can make for some nice variations on the standard number designs. To put it on in perfect alignment, you use clear shelf liner, put a strip over the numbers, peel away their backing, and they’re ready to apply. The shelf liner has much less stick than the insignia cloth, so once the numbers are stuck down you can just peel it right off. We also use the red and blue colors for bumper patches, which is much better than duct or gaffer’s tape for patching holes.
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We’ve painted them and used heat transfers.
This last year we used whatever iron-on material a parent had for their Cricut. It lasted two regionals, but started falling off at champs.
I’ve used both commercial (Andymark?) iron on numbers and custom vinyl cut iron on numbers.
There’s absolutely no difference except apparently the font we used one year for the custom vinyl cut numbers somehow turned a 0 into a 4 according to one referee, even though the 0’s look more like D’s. The other regional was fine, and if I recall correctly, championships too.
It’s going to depend on what type of fabric you’re using. If you’re using a smooth, relatively impervious fabric like sail cloth or vx21 I’ve had good results with insignia fabric or molotow paint markers, but the iron on and other paints have come right off. On cordura or other course, absorbent fabrics paint marker will sink in and create faint, blurry numbers, and sticky backed numbers wont bond as well, but iron on numbers will bond really well and thick paints will stick really well.
For sail cloth or technical fabrics:
https://a.co/d/6lZaVgW
For cordura:
https://a.co/d/cj1Iozd
Most iron on anything
This thread has a lot of information on bumper numbers and general bumper construction.
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For our final event of the year (offseason), we used 3d printed bumper numbers. They were around 2 layers of print. We paired with spray adhesive and we played a few matches (defensive role) with some damage. Some pros of doing this was being able to put on new numbers quickly with replacements, it was very quick to do since the 3d printer we use is extremely fast, & we could have lots of replacements on hand. Some cons was they would fall off a bit during matches, and it would be unlikely for them to survive rigorous play. At robots@CNE we used adhesive numbers on our cube bot due to us making new bumpers. Our main bot had sturdier bumpers that were better made. These adhesive sticker numbers fell off constantly and I would not recommend using stickers. Obviously, a stronger adhesive would work better.
Our team has used embroidered numbers for the last several years with great success. We have a couple of parents with embroidery machine capabilities. We just mark a square on the fabric with chalk, then hand it off to them and they embroider them and send them back to us in a couple days.
We used iron-on numbers at the beginning of the season. They were pretty durable, but almost all of them ended up falling off during our competitions. On our second set of bumpers, we used adhesive stickers, which were really bad, to the point where we had to super glue them back on again. Next year, I think we’re just going to spray paint put numbers. It may not be the nicest looking, but at least we won’t need to worry about them falling off.
Everybody does the paint pens backwards. You need to get white cloth and red and blue paint pens.
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