Thread: Some CNC router projects.

Hey Rod,

Great work there very effective and a simple way to have it's own base .

Here is a fluro perspex sign , reverse carved I have just completed. Done in 2 goes on my router , just a matter of repositioning the material in the bed.

That looks really good Rod. Despite your poor photography.

I've never tried bending acrylic. Must give it a go.

Did you paint the etched area of lettering from the back? And if so were you able to wipe off the excess easily without scratching the clear.

Greg

GRS that sign looks very professional.

The lettering stands out well in the coloured acrylic.

I can imagine it would look even better when mounted on a white or light coloured background.

Greg

Gary,
Nice size job and the fluro came up a treat.

Greg,
I have given up trying to get good photos - just point and click. On this one it makes it look like the engraving is too deep and it is merging the engraving but in real life it is like the Vectric graphic.
This one was for mum who is in her eighties and president of a garden club so how could I refuse.
The job was problematic from the start and this is the second version. The problem was me and I couldn't get my act together and when I finally got over all the mistakes I bent the tab the wrong way so it got binned. Second time around it was smooth sailing. Engraving is from the front as I had had enough issues with the first one so simplified it all.
No problem with scratching the perspex as I now use a silicone block (??) that they use for flushing joints. It is perfect as it has a sharp edge and is soft. Once used very little to clean up on the face. See photo.

Just for fun I have included some photos of my heater for bending. My first attempts with a heat gun worked but the bend was too large a radius and I had seen a lot better around. A search of the net provided a heap of videos from Tap Plastic about bending, joining, etc. Well worth a look.
So my solution was to make a very high tech bender using an old bar radiator. The trick is to contain the heat in the bend area so that you can keep the bend radius tight. I flipped the perspex over a couple of times while heating to make sure the middle got the heat without spreading the heat too far down the perspex. The wooden stop bolck was my fence - told you it was high tech.
You need to get the table about 50mm from the bar otherwise it does not heat up quick enough. I used ceramic tiles as I thought they would be able to take the heat and they were in the shed. I put a couple of strip of ally square over the first set of tiles and then laid another set on top. The theory here was to keep the heat out of the top tiles to make sure the heat did not spread too far down the perspex. It sort of worked but probalby need insulation between the tiles ot make it better.
I am rambling on here so have a look at the photos as I peal off each layer and you will be able to work out how I did it. Do you think I should copywrite this?

Originally Posted by rodm

This one is 5mm clear perspex and my photography is hopeless so I am not doing justice to the piece. I have included the design drawing so you can see the detail better. I have combine texture and layering to give an iceberg look. After cutting out the shape I heat then bend the base under forming a stand. A lot quicker than making a wood base and then trying to fix the acrylic to it.

Have you tried going over the edges with a flame to melt the perspex, or were you looking for a rough finish?

Never tried it myself but aparently it works wuite good, just I think if done wrong you would have soot melted into the perspex??

Hi Chris,
I used a cloth buff and the polishing stick for the edges. I once tried a propone torch but blackened the perspex before it melted. The Tap videos say not to use propone. I was thinking of getting mapgas as hiring oxy bottles is a bit of overkill for what I do. In any case polishing on the buff works fine.
Acrylics are great to work with and you do not have to apply a finish like timber.

I have been bending a bit of acrylic lately for some jobs and my crude bender in the post above was past it's use by date.
The ceramic tiles got hot after the first bend and then it was heating too great an area to get tight bends.
So thinking cap on I made a new version and nothing flash but much improved on the jerry built version.
An ally angle frame and 6mm ally plate on top wrapped in four thicknesses of a fire proof blanket. Ally was all sourced from a recycle yard at $3.60 kg. A new bar radiator for the princely sum of $19 finished the set up.
Bent 6mm acrylic sheet no probelms at all.

I can't believe how you churn out projects.

you got some undershots from the side?

Hi Mike
Nothing special with this and excuse my workmanship as it got minimum effort.
Underside view with bracket removed for radiator. The radiator sits in a chamber to contain the heat. Side view shows that a bit better. Idea is to get the bar of the radiator as close as you can to the gap in the top and to keep the gap at the top about 6mm wide.
I should have made the gap adjustable and also fitted a fence so you can butt the perspex up to it but I didn't think it was worth the effort to make. Easy enough to stick a lump of timber on top as a guide.

When you heat the perspex it lifts up slightly and when it is ready to bend it settles flat again. Like an inbuilt gauge. Bending I just do in my hands and then hold it until it is cool enough to keep the bend. A lot of you would have done this sort of thing in school but nothing like this was done while I was at school.

Been quiet on here so I am going to bore you with a job I did this morning.
The sign is cut from aluminum checker plate and backed with a piece of tinted perspex.

It is for a farmers property so the stencil font and checker plate were deliberate design elements. The polished half circle reresents the sun and light coming through the text adds to this theme. Size is about 600 by 370mm

I might set this on a couple or three limestone blocks but it will loose the light effect. If I do I will have a surround so the plate looks insert. My sense of humour wants me to place it on a weathered post with fencing wire tangled around it.

Allan your the farmer on here - any thoughts for mounting? Old piece of cast iron off a machine?

Still thinking of a mounting but for now it is framed with some bar and stainless cap screws to hold it all together. It might end up just being twitched onto the front gate.

Nice job there Rod.

Rod,

It is really a great looking sign, but whatever fixing you use, it has to be done so that you get the effect of the light through the letters.

Seeing that it is for a rural property, why not use the old post and rail fence concept. A (preferably old) fence post at each side with timber rails top and bottom, mortised through the posts. Two fixings at the bottom and one at the top onto the rails.

I have tried to show what I mean with the attached sketch.

Cheers,

Alan

Hi Alan,
I have been thinking of mountings for a couple of weeks and have really been stuck due to the semi circle top. Everything I sketched looked like a toomstone.
Your idea is perfect and the top rail squares it off so it doesn't have that look.
Thanks