Can I use masking tape in the laser cutter to avoid surface burns? And any suggestions for a good child friendly finish for laser ply?

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#1

Hi, current project is making these trophies for my kid’s football team

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IMG_9107.jpg3024×4032 2.69 MB

The classic problem of surface burning, particularly on the underside is especially acute as the pieces are quite small and its quite difficult to sand such small pieces (not just small but also thin, I can’t afford to lose much wood). I’m not talking about the edges here but actual surface damage (you can see on the inner leg in this picture).

I have read one solution is to add a layer of masking tape to the surface of the wood before you cut it - makes sense but I wanted to check a couple of things with this group:

  • is that safe - to cut masking tape in the laser cutter?
  • if so, will I need special settings to cover cutting through that as well as the material beneath? I’m not really advanced enough to make my own settings and tend to use other people’s existing ones.

As a separate question, I would like to finish these in a way thats fairly easy to achieve and would be ok for kids to be touching. I have read beeswax as a suggestion? Would people agree with that?

Any advice welcome as ever.

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Latest project - 16 tiger trophies
#2

Masking tape should be fine, it is thin, so I wouldn’t expect to have to change the settings to get through it. There seem to be 3 ways to avoid the reflections that are all highlighted in this video:

Basically if you are have too much excess power it will reflect a lot, so option 1 is to dial the settings (speed/power) in until you comfortably cut through but not much more to minimise the reflections. If you are using other peoples settings they are likely not optimal or are too high.

Option 2 is add a buffer

Option 3 is the masking tape

Some experimentation with all 3 and you should find something that works for you!

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#3

There should be a roll of masking tape on the laser shelf which is there for members to use (If it’s been used up let me know and i’ll order some more).

My first thoughts on how to finish the trophies (which look great btw) - have you considered wood stains?
The best stains to uses on the Ply are gel stains (water based stains soak in too much revealing too many of the plywood layers)

#4

Thank you very much! This is great. The buffer approach is interesting, I might try that. I had another similar idea to simply place another piece of waste wood beneath the one you want to cut, the same way you would when drilling through wood to avoid blowout. It would be a bit wasteful but seems like it would stop the reflections as the laser wouldn’t be able to get all the way through and reflect back. Have you ever tried that?

#5

Thank you! I spotted that roll and wondered if thats what it was for. Appreciate that. I’ll try these different approaches.

I thought about staining but I always seem to do a terrible job of it (blotchy) but I’ve never tried gel stains so will give it a go. Have you used them and if so do you have tips on the best way to apply? Brush/rag etc. Sorry for a cheeky follow up question…

#6

That should work just the same, if the piece is large (which it looks like it is for the trophy) just using little pieces to support it likely wouldn’t work well as it would sag. So your idea is probably better, maybe just use a large off cut from the free bin, so no extra cost and will likely support your actual sheet better.

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#7

I use them quite a bit - brush some on the wood, let if sit for a few moments before wiping it away, reapplying when needed.

I find water based stains are blotchy on ply, hence me discovering gel stains :slight_smile:

You can stain a sheet of wood, make sure it’s dry, masking tape it and then laser cut the pieces

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#8

yes maybe my problem is I’ve always used water based ones

“You can stain a sheet of wood, make sure it’s dry, masking tape it and then laser cut the pieces”

ah, amazing, I hadn’t thought of that, thank you

#9

Great - thank you!

#10

When I was cutting card with the laser cutter, I could avoid the marks by placing a sacrificial piece of paper under it which would suffer the marks leaving my card unmarked. Nice and simple. Haven’t tried it with other materials.

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#11

I usually just sand with the orbital sander and finish with danish oil (we have some by the glue in the woodshop). If using danish oil, please remember to dispose of rags correctly.

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#12

Hey Martyn, would you know the best place to get the gel stains, I had a Google and I only listed water based?

#13

I’ve purchased from the below in the past :slight_smile:

https://www.woodoc.biz/collections/decor/products/woodoc-gel-stain
and
https://www.ebay.co.uk/itm/262488127177

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#14

Thank you!

#15

Hi, I thought I’d report on my experiments last night for others benefit.

The buffer approach didn’t really work, it might have even been worse, a solid board behind the piece was better but still somehow a lot of burn made its way through.

Masking tape was the best by far, I did it on both sides for one piece and the pieces came out perfectly clean which is very satisfying. For cutting that is. I don’t think its worth it for engraving. It was slightly cleaner around the engraving but the slight difference in surface between wood and tape (especially if there were any bumps) meant the engraving was not as crisp, it even skipped over certain parts of the design (I’m sure you could fix that by adjusting settings but thats beyond my expertise or inclination). It also created a crazy amount of work for me getting all the tape off afterwards. With pretty small text, trying to get tiny leftover pieces out of the negative space of letters like ‘A’ and ‘B’ was not worth it. So my approach going forward will be:

  • cutting - tape it
  • engraving - light sanding afterwards

@Martyn_Thomas I’m afraid the tape technique worked so well I used the rest of the tape that was there so you might want to order some more. Sorry, I will bring my own next time.

I have also ordered some Gel stains to experiment and will report back. I won’t receive them in time for this particular match but if they get through to the next round I’ll take the trophies up a gear into full colour!

Thanks for all advice. This is such a great forum.

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#16

Don’t worry - I’ll order some more for the space :slight_smile:

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#17

As @danielbenton mentioned, I have also had good luck with a piece of paper. Never had it catch fire, probably because of the wood or plastic next to it and the fact that it’s on the underside. Check with your folks there to make sure they’re OK with that. Masking tape might be better for small parts because it keeps them from flying around once they are cut from the sheet, unless you’re using enough power to also cut through that as well.

This same problem occurs with acrylic, but worse. You can also get re-deposition of vaporized plastic that sticks to the top surface. So make sure you leave the masking that comes already on it when you buy it. This is a little problematic when engraving or cutting the outlines of letters. You get a bunch of little bits you have to scrape off individually. I just use a fingernail (mine) to gently scrape them off. Also, a brush under running water can be used to clean out the crud that accumulates in the engraved area.

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