Question No more double sided tape for fixturing???

Ok, It's hard to admit but maybe we have to learn something from guitars manufacturers...

As you know, double sided tape is spongy, sticky, and moving 'cause of its consistency and... damn! It's extremely hard to remove!
I've discovered this videos and I want to share them with you. No idea if the trick works, I still didn't try it. But folks... it's intriguing!

Ingredients: simple masking tape + cyanoacrylate glue + cyanoacrylate glue accelerator

Look at that:
The greatest luthiers trick of all - down with double sided tape!
Or this:
A Secure CNC Mounting Technique - NO DOUBLE SIDED TAPE!

Let me know if some of you get some result from the above technique.

About the first video I posted: if you have no patience then jump to minute 7:00

Too much work for an easy task IMHO. You're exchanging double tape for homemade double tape. I don't see the benefits at all.

I just screw the piece and after some months I change the spoil board. That's all.

jvalencia wrote: Too much work for an easy task IMHO.

jvalencia, it depends on your particular needs.

For example I have to mill special antireflex lexan (a very rigid material) with good precision. If not firmly hold it starts chattering/vibrating like a crazy horse with a rocket in the ass.
Since the material is (really) highly costing I have no margin to add screws around the border of my shapes. This would mean to throw away 30-40% of it due of the particular size-format of the board they sell. This is unacceptable for me.
Also I cannot make holes inside the shape and screw it.

In another case/project, I could make holes inside the shapes but they would be so close to the border that the milling bit would crash against the screw's head...

So, as you can see, double sided tape is not an option in my case.

Last consideration.
A "glued" board has another advantage: you don't need to create tabs to keep the shape in place until the end of the milling session. When cutting those tabs (i.e. with a sharp knife) there is an high risk to create scratches on the surface if the material is very brittle (i.e. plexiglass) and throw away your work.

P.S: to remove a professional 3M double side tape I saw people so desperate to put the piece in the oven to detach that sticky thing.

I'm still waiting for the spray activator that I've ordered by post. Nevertheless, I made some experiments without it.

My main concern was about ABS/Polycarbonate materials: can the cyanoacrylate of the glue go trough the masking tape and damage sensible plastic surface? How can a paper-based tape stop it???

So, to avoid the risk above, I bought a plastic masking tape (the one used for car painting) but the result was a disaster. The super glue doesn't stick to it. Adhesive power is close to zero.
After this experience I remembered something you can read on any label on the super glue bottle: "not recommended for PP and PVC surfaces".

The experiment

So I moved to simple tape-based masking tape. I bought a TESA "classic" at the Hornbach store in Munich:




After I've attached a 75x150mmm HARD-PVC panel to a board made of Lexan using the methods proposed in the videos (again, without spray activator).
As you know, the cyanoacrylate is extremely aggressive against polycarbonate. So a single micro-drop would damage it irreparably.

I was really skeptic about the possibility of the tape to protect the surface from the glue, but... it does!
Look at the photo below, there you can see the rear face of the Lexan panel with the PVC board sticked on the other side.
The glue didn't passed through the tape at all. The panel is absolutely clear and untouched.

Detaching the PVC panel from the board is 10-20 times easier than with double sided tape. Just apply a little force and help yourself with the unglued tabs of tape coming out from the sides.
As you can see, the super glue spreads out in a very uniform way.




Next, you have to detach the "tape" from the PVC panel. Super extra fast and easy!

MDF board

I was thinking that it's easy for the masking tape to adhere to a super flat and perfect surface like a board of Lexan/Polycarbonate. So, I was extremely skeptic about using a MDF board. The surface of MDF is rough and raw when compared to Lexan so I was sure that the adhesive power of the paper masking tape would result greatly reduced. Well... I was wrong. You can apply all your brutal force and the attached panel would not move of one tenth of millimeter! Seems soldered to the surface!

As before, just a little 2 mm strip of super glue does the job:

What about contact adhesive? It's easy to remove with your fingers by rubbing it.

Or even put your double sided tape between the masking tape!

Well, if your material is that damn expensive, why don't you invest in a vaccuum pad?
Its worth the money at the end.

Did - made a small one for pcb's out of scrap bits and pieces. Only cost was a decent vacuum pump!!!! Can mill/engrave 0.010" tracks accurately.

Well, even a vaccuum pump is not needed.
I run mine with the same vaccuum cleaner which I use for the suction.
Works like a charm, I can lift the whole vaccuum pad by grabbing the piece on it.

DerRoy wrote: Well, if your material is that damn expensive, why don't you invest in a vaccuum pad?
Its worth the money at the end.

The advice/suggestion I posted is for anybody that doesn't need to produce/mill a lot of parts per month and is looking for a straightforward/cheap solution.

In my case, I'm thinking about a vacuum pump since long time, but for now I don't want to do such economic investment. I'm still in the prototyping phase.

peterg1000 wrote: Or even put your double sided tape between the masking tape!

Uh Oh!
That's a smart ideaaaaaa!

I have to investigate about that.
The main drawback could be the total thickness of those 2 layers: 2 x masker tape + 1 x double sided tape....
In fact, the main advantage of the super-glue solution is the absolute low-thickness of the materials sandwich:

Tesla masking tape +
Super-glue +
Tesla masking tape =

---

0.2 mm
(or 2/10 of 1 mm)

As you can imagine, the "ideal" double sided tape is the one with zero thickness, so transversal/lateral forces generated by the milling bit moving horizontally will not move the piece 'cause of the leverage effect.

In you use double sided tape, you need just warm Water 40-50*C.
You put in your fixed Material, now you can remove it easy.

Stefan

I've just measured masking tape alone and 2 layers of masking plus double sided tape. Each turn out to be 0.0045" +- .0002" - i.e. 0.114mm.

Double sided is branded "Diall" from B&Q in UK - it's not the spongy type of course. It doesn't stick at all well when warmed.

Peter

Sure a vaccum pad costs some money, but it is still worth it.
I got mine from EBay for abt. 45€ (300x200) and as I mentioned before, I use my standard vaccuum cleaner to run it.

Not that expensive at the end.

The only thing I modified was to connect two suction hoses directly and not using one line with a T-Connecter. This creater a better vaccuum as you have a higher Air-flow.

But of course you can also use your Stepcraft to make your own. There are a lot of examples shown in this forum. Makes it even cheaper.

DerRoy wrote: Sure a vaccum pad costs some money, but it is still worth it.
I got mine from EBay for abt. 45€ (300x200) and as I mentioned before, I use my standard vaccuum cleaner to run it.

Very interesting...
But I've read somewhere that using a standard vaccuum cleaner is dangerous 'cause you can overheat it. Furthermore, running a vacuum pump/cleaner is very noisy! It makes more noise than the machine itself.

peterg1000 wrote: I've just measured masking tape alone and 2 layers of masking plus double sided tape. Each turn out to be 0.0045" +- .0002" - i.e. 0.114mm.

Double sided is branded "Diall" from B&Q in UK - it's not the spongy type of course. It doesn't stick at all well when warmed.

Peter

0.114 mm is damn good!
Did you try to use it between two layers of masking tape? I'm curious about this solution.

Warming the part could be a solution, but you need to buy a (reliable) oven and manage the part until it remains hot. If it gets cold you have to put it the oven again and start again the cycle.
So, more tools and more complications IMHO.