Transparent Derailment Barrier for Fiddleyard

[Harlequin]

2 hours ago, doilum said:

Is it worth trying a wood bit?. I have not had any real problems apart from the bit tending to seize after break through. This may be partly down to a well worn chuck in my cordless and was resolved by having a pair of mole grips on standby.

 

Yes, my preferred supplier says that wood drill bits are OK in polycarbonate:

https://www.cutplasticsheeting.co.uk/product/clear-polycarbonate-sheet/

(click on FAQs)

 

It also says that polycarbonate can be "cold curved" and cautions against heat forming unless the material has been oven dried beforehand. (I haven't tried cold curving yet - you'd instinctively expect it to snap at tighter radii!)

 

Edited May 10, 2021 by Harlequin

[Ian J.]

Acrylic has a tendency to chip, as I understand it from what I've read. Any drill bit that doesn't have a steep enough angle on the point can 'catch' the acrylic and cause chipping, and potential splitting. I think that includes wood bits.

 

As it is I will only be likely using one of the two test pieces I've ordered, which I use depending on how well the different thicknesses of acrylic can cope with being bent round my layout's curved sections. The other piece could be used for testing different drill bits on to see what might or might not work, presuming I don't feel that it could be used somewhere else.

[Harlequin]

Sorry, for some reason I thought you were using polycarbonate.

D'Oh!

 

[doilum]

21 minutes ago, Harlequin said:

Sorry, for some reason I thought you were using polycarbonate.

D'Oh!

 

Likewise. Good luck with acrylic. Can only suggest you make a test piece and see what works for you.

[Ian J.]

5 hours ago, Harlequin said:

Sorry, for some reason I thought you were using polycarbonate.

D'Oh!

 

 

That's probably because in my original post I mentioned that I was looking at polycarbonate because I understood that acrylic scratches easily. However, I've done more research and it appears the acrylic is better. It can be polished, which apparently polycarbonate can't; it's also slightly better transparency, apparently. Polycarbonate's main strength is its strength. Other than that, it seems to have little reason for using it instead of acrylic, so I've decided for acrylic for the test pieces to see how they turn out.

[Graham C]

On 09/05/2021 at 17:18, Ian J. said:

 

I don't believe so. In fact, such a drill might cause even more chipping and/or splitting of the acrylic. The drill for acrylic is as:

 

https://www.amazon.co.uk/Plastic-plexiglass-Polycarbonate-Norseman-BG4600A/dp/B07D1BGH53/ref=sr_1_8?dchild=1&keywords=norseman+drill+bit&qid=1620577015&sr=8-8

 

but that's the U.S. imperial set. I need them in 1mm increments metric. But as @doilum says, I may have to settle for standard metal bits and work up from a very small size to the 5mm hole I'm after.

Alternatively, buy the imperial bits and use 3/16" screws (= 4.6mm, so not far off 5mm)? Looks like those are still fairly readily available?

[ManofKent]

I've drilled acrylic successfully using a dremel  to make a 1mm pilot hole then a step drill bit.

[Ian J.]

10 hours ago, Graham C said:

Alternatively, buy the imperial bits and use 3/16" screws (= 4.6mm, so not far off 5mm)? Looks like those are still fairly readily available?

 

Unfortunately I'm already committed to using 5mm as that the bolts I've got for mounting the barriers to the boards, and the holes have already been drilled into the boards for them.

[Ian J.]

The two test pieces of acrylic arrived late this morning.

 

The 3mm thick piece is a little more resistant to being curved compared to the 2mm, but is perfect otherwise. So I'll use 3mm for straight board sides, and 2mm for the curved boards.

 

Holes were drilled into the 3mm piece using a 1mm metal drill bit initially, then going up in 1mm increments to 5mm. I can't see any chipping in the final holes, so that looks to be a suitable solution and saves me having to try and find the recommended drill bits.

 

A couple of pics of the 3mm test piece in situ. I'm using bolts rather than screws to hold the barrier in place as it's a bit easy for removal for working on the boards, and that will remain the case even once the boards are 'finished'.

 

 

Edited May 14, 2021 by Ian J.

[Ian J.]

A quick addendum.

 

I've received the second batch of 2mm and 3mm cuts of acrylic from my chosen supplier, enough to cover the main operating arrangement and out to a potential 16ft yard/scenic area width.

 

Without it intending as advertising as I'm only a happy customer, the supplier I used was Acrylic Sheet Cut to Size

 

I will be happy to use them again when it comes to the remaining cuts that I have in mind.