Tape + CA question

[Brian Tymchak]

I've been cutting lots of parts on the CNC for childrens toys using blue painters tape and CA glue. Holds great. Uses lots of blue tape. Is there any real advantage in using blue tape vs "regular" (beige) masking tape? The regular masking tape is a couple $$ cheaper per roll. I know that regular masking tape can leave a residue but I believe that's more true over time vs 30 minutes on the CNC.

Thanks!

[John TenEyck]

I don't think it matters as long as the tape sticks to the spoilboard but removes cleanly. I bought some generic blue tape in a 6 pack to save a couple of dollars. It would split as I unrolled it more often than not, causing a lot of waste. I went back to the good stuff.

John

[Prashun Patel]

Like John, I buy off-brand blue tape (in different widths) to help with cost. The off brands that I've tried work just fine.

IMHO, blue tape is better than beige because it peels off easier, and leaves less residue. I could remove the regular masking tape residue, but I go through so much blue tape, it'd be a big waste of time.

[Michael Burnside]

If there is an edge to clamp, I use my custom 2-axis, low-profile clamping system 99% of the time. On the rare occasion I'm milling an edgeless job or surfacing, I use X-Fasten 1" double-sided tape. You need a lot less than you think. On say a 12" x 24" job, 4 strips of 4" long on the corners will do the job and the stuff comes of easy.

I'm with John if you want to use tape though. Just get stuff that doesn't disintegrate or split down the middle when you're trying to apply it. Like you said, the residue and staining regular tape can cause is for something that sits overnight or longer.

[Jim Becker]

As long as it sticks and you burnish down both sides before doing the glue dance, it will be fine. Keep in mind that "blue" tape has multiple different versions relatively to how well it adheres. You are best using the version, regardless of color, that has the "traditional" level of stick, rather than the easy peel versions. There should be no issue with the adhesive on your machine or your components because, as you note, it's very short term anyway.

[George Yetka]

I dont see any advantage to using CA/blue tape over double sided tape.

[Jim Becker]

I dont see any advantage to using CA/blue tape over double sided tape.

It can be less expensive, more flexible for sizing, easier to get on the part and machine as a lot of double sided tape gets ornery when you try to keep it flat, easier to break free from the machine and it's a heck of a lot easier to get off the parts than good quality double stick tape. I stopped using double sided tape for anything that isn't intended to be permanent, honestly.

[Brian Tymchak]

It can be less expensive, more flexible for sizing, easier to get on the part and machine as a lot of double sided tape gets ornery when you try to keep it flat, easier to break free from the machine and it's a heck of a lot easier to get off the parts than good quality double stick tape. I stopped using double sided tape for anything that isn't intended to be permanent, honestly.

After seeing the gummy buildup on the bit from the CA and tape, I can't imagine what the bit would look like after tieing into 2 sided tape.

After seeing all the responses from everyone (Thanks!) I ran a job using masking tape and I could find no real difference in any aspect between masking tape and blue tape.

[Michael Burnside]

If you properly secure the workpiece so it can't shift, using low-profile dogs/wedges/etc. then you need very little tape even when using an upcut bit. I rarely use double-sided tape but when I do, if I'm cutting through the material, and again, have no way of clamping it, then I make sure the tape is beneath the actual project. Afterall the tape your bit is grinding into isn't doing you any good anyway.

[Jim Becker]

That's a good point, Michael. I've been using a lot more "lateral support" at this point. Scrap material and the composite fastener gun make that quick and easy, too. That said, when the workpiece material is thin and flexible, one has to use enough tape to avoid too much flexing of that material when the tooling is doing what tooling does, including a slight lifting with an upcut format tool.

[Carl Beckett]

I avoid running bits into tape due to concerns on buildup on the bit. (just me)

I tried various homemade clamps but did not receive joy. I did purchase these clamps which are working well for me (just dont run the bit into them...)

https://www.leevalley.com/en-us/shop...SABEgKzZvD_BwE

Additionally I procured material for a vacuum table - but havent pulled the trigger in part because the pieces I have been running lately are relative small surface area (where tape comes into play). Or to avoid it, I do prefer to leave tabs where feasible.

[Brian Tymchak]

I decided to use tape and CA since the parts I'm cutting are small, 2.5" x 4". I do have to clean the tip of the bit with acetone after each run. I decided to not use tabs on the production runs after seeing how much work it is to remove tabs from the prototypes without splintering/chipping the curved edges. Cutting 600 of these cats for our woodworkers toy drive. These are the stacking cats that Doug Garson posted last December. I thought they would be a perfect CNC project that could run while I'm working on other things. Unfortunately, I got a late start and I'm not sure I'm going to make the late November deadline... ... as I'm only about halfway done cutting and these all have to be sanded.

image_50429441.jpg

[Grant Wilkinson]

I found out the hard way that using very inexpensive beige tape was not the best approach. The thick CA managed to seep through the tape and it was a bear to get the tape off.

I, too, clamp when I can, but I've yet to find a way better than CA/blue to hold down cut outs from the middle of a project. For those projects where the cut out is waste, I would like to try poly nails, but the cost is prohibitive.

To the point that CA/blue is not better than double-sided tape, the price argument is valid. However, for me the bigger question is how do you put sufficient pressure on the double sided tape once you have removed the liner? You can use a J roller when you apply the tape to the project, but once you've pulled the liner, you've lost that option. One benefit of the CA/blue method is that you can firmly stick the tape to both surfaces before gluing them together.

[Jim Becker]

Additionally I procured material for a vacuum table - but havent pulled the trigger in part because the pieces I have been running lately are relative small surface area (where tape comes into play). Or to avoid it, I do prefer to leave tabs where feasible.

I'm glad that you recognize that a vacuum table isn't a good solution for small parts...it's the nature of gravity which is what is at play with a vacuum table. Vacuum fixtures can be used with smaller objects effectively. The thing is, each of these methods require a different kind of vacuum generation system to be optimal for the purpose. Something like a Gast vacuum pump can work well with a vacuum fixture since they develop pretty high pressure with low air volume. A vacuum table kinda needs a vacuum source that can move a lot more air because of the total surface area. I think that Gary Campbell may have online resources that dive into this, if I'm not mistaken.

[Michael Burnside]

I have found a couple of tricks with the vacuum table however. If you leave a skin of 0.005-0.008" at the bottom you can still get good suction/fixturing on batches of small parts. I like skinning instead of tabs because the edge cleanup is super easy with just a bit of hand sanding and you cant even tell. The trick, however, is you should use the spoilboard for z-zero (which I do 99% of the time cuz it's better :P) and you have to have a very accurate tool for setting Z0. The auto/touch probes aren't accurate or repeatable enough if you want a thin skin.

The only tool I use and trust is one of these, which will get you 0.0005-0.001" zero . What is cool is that you can setup WinCNC or Mach 4 to set a custom Z0 with the following command G92Z1. In WinCNC I added a custom button for this task, super easy.

https://www.penntoolco.com/precise-z...hoCGYIQAvD_BwE

I've even setup my job to cut z+0.001" with blue tape underneath and it literally scored the tape but didn't cut through. I know it's expensive, but setting up a job in Vectric to cut Z+0.003 will barely score the spoilboard and will cut clean through. I've done hundreds of jobs this way, it works perfectly and takes seconds to set z0.