Lightbox projects

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maplestiltskin
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Lightbox projects

Post by maplestiltskin »

Happy New year to everyone, hope it is a good year for you!

I thought I would post some pics of a couple of projects I did just before the annual festivities. Both were presents for friends. The first is the Harley Davidson logo and the second is the Pittsburgh Steelers logo. Using the Harley Davidson one as an example, the basic concept is as follows;

1. Glue some veneer (figured crown Ash) which will transmit light to a polycarbonate sheet and let it sit until the glue has fully cured. I sand the polycarbonate with 80 grit on BOTH sides, one to promote adhesion and the other to act as a diffuser.
2. Spray a lacquer over the veneer (2 coats), to help it bind together and reduce the risk of it 'popping' off the plastic when machined.
3. Machine a pocket and inlay black dyed poplar veneer (which I bought) for the black bar and shield background.
4.Spray lacquer over the veneer again - 2 coats..
5. Apply a vinyl mask (sign makers vinyl) to the lacquered face once the lacquer has cured completely.
6. Machine out the lettering and any graphics.
7. In the case of this design, I used masking tape to cover up the Harley Davidson lettering.
8. Spray a transparent orange colour (in this case I used Createx Candy2O Grabber Orange) into the areas which are to be orange in the final image. 4 coats were necessary here. This paint is a bit difficult to use as it bleeds and runs but it give a fantastic result. I use Createx bleed checker 4030 to help and then use their auto borne transparent sealer to promote adhesion.
9. Peel off the masking tape and the vinyl mask - I use a Makita heat gun set to 200C (about 390F) to warm the vinyl and soften the glue to aid peeling. This can be a tedious process!
10. Sand the panel flat and then apply finish lacquer.
11. Make a box 100mm (4") deep to house some LED lighting and glue it all together and thats it - well almost, I paint the inside of the box white to reflect the light better!

Both these light boxes use figured crown Ash veneer. The Harley Davidson box is plywood with black poplar veneer applied to all surfaces and finished matt black. The steelers box uses grey Poplar instead, finished satin. The 'steel' ring on the Steelers box was simply painted in using aluminium paint - I ran out of time on this one - it was finished literally about an hour before I gave it to the recipient - phew! The Candy colours I used also ran a bit but it seemed to accentuate the end result so I left it. The Steelers box is 400mm (16") square and the Harley one is 400mm (16") x 350mm (13.8").

As an aside, I only had RGB colour changing LEDs in stock so these signs will change colour but I have not included photos of them as they do not reflect the respective brands (but it is a bit of additional fun!).
Harleyd-1.jpg
Attachments
Harleyd-2.jpg
Steelers-1.jpg
Steelers-2.jpg

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Makingtoothpicks
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Re: Lightbox projects

Post by Makingtoothpicks »

Very creative. They look good. I know you say they where given away. If you make another one could you take a picture
of the unit in the dark to show then lighting effect.

Don

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martin54
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Re: Lightbox projects

Post by martin54 »

As Don says, very creative thanks for sharing. Never really thought about veneer being translucent have you experimented with many different types of veneer ?
I have a box of different veneers maybe time for a little experimenting :lol: :lol:

maplestiltskin
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Re: Lightbox projects

Post by maplestiltskin »

Hi Don and Martin,

Thanks for your kind comments. I find that the lighter veneers like Ash, maple, Birch and even Oak work best but you can get some really cool effects with highly figured woods like Tamo Ash. I have a rather poor picture of the Steelers one in the dark but I have done others. I have done well with a dragon on Tamo Ash - I will upload a couple of shots if I can find them. You will find lighter woods transmit white/yellow/red light but do not transmit green/Blue so you can get some really fantastic effects by playing around. You should try any veneer you can find, the results can be surprising! I test the veneer by shining a flashlight through them to see how they transmit light - especially if you can get one of those LED lights which do red or white light. That way I don't waste veneer and a load of time getting a poor result. My local veneer merchant has got used to me now - to start with I was just a rather weird fellow examining his veneers very closely with a light - and he used to follow me at a distance.... Now he suggests new ones (and usually very expensive) to try....

I hope you do try it out - the results are quite a lot of fun!

Cheers,

Warren
Attachments
Steelers-3.jpg
Dragon-3.jpg
Dragon-2.jpg

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Xxray
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Re: Lightbox projects

Post by Xxray »

Nice work - By " polycarbonate sheet", do you mean plexiglas/acrylic ?
Doug

maplestiltskin
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Re: Lightbox projects

Post by maplestiltskin »

I use polycarbonate not plexiglass or acrylic. The reason is twofold. First, normal cast acrylic or plexiglass varies in thickness by up to 10% or more across its surface - not great for accurate v-carving if you are doing any fine detail like the dragonfly attached. The alternative its extruded acrylic which is way more expensive but much more dimensionally consistent. Problem is, acrylic has a very poor fire rating.. Polycarbonate has a very good fire rating - it basically is pretty safe and is about the same price, if a little more than extruded acrylic. I am not sure of the trade names for polycarbonate round the world but an internet search for polycarbonate sheet should give you what you need. I use 10mm thick material to get the impression of depth from the V-carving..hope this helps.
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Dragonfly-2.jpg

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Makingtoothpicks
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Re: Lightbox projects

Post by Makingtoothpicks »

Thank you for the added pictures. I see how the blue does not
transmit well. I am going to have to try this it looks great

Don

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Re: Lightbox projects

Post by LittleGreyMan »

Happy new year to all.

Very interesting and nice job, Warren. Thanks for sharing.

In your explanation for the material choice, you mixed up price of cast and extruded PMMA (plexiglass is a trade mark, PMMA is the right chemical designation). Extruded PMMA is cheaper: it's a continuous process, at the opposite of casting.

Both are more expensive than polycarbonate here.

They have better optical properties than polycarbonate: transparency is higher (but polycarbonate has the same transparency as glass, which is not bad at all), it can be polished, but the most important thing is they don't yellow with time and UV.

For machining, PMMA is the best material, especially cast PMMA. But you're absolutely right for thickness variations and the Vcarving issue, unless you have a machine with a floating head. Cast PMMA gives excellent results with etching techniques, in this case with a pressure tool you don't care of thickness variations.

Why are you concerned by fire rating with LED lightning? Polycarbonate is way better than PMMA in this domain, but it shouldn't be an issue in this case.
Best regards

Didier

W7 - Aspire 8.517

maplestiltskin
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Re: Lightbox projects

Post by maplestiltskin »

Hi LittleGrey man,

I was very intrigued by your comments on cast vs. extruded pricing and I have discovered that this is my particular supplier where extruded is a non stock item and therefore they charge more - I use them for a range of other materials as well so it has always been 'convenient' - but perhaps not for much longer.... It has been a couple of years since I ordered these materials and a quick online search yielded the following:

1. Extruded acrylic 1m x 1m x 10mm, £86.35
2. Cast acrylic 1m x 1m x10mm, £106.28
3. Polycarbonate 1m x 1m x 10mm, £133.22

Prices have certainly gone up in the last two years!

As to the fire rating, I have done some work with a hotel chain and some retail outlets and their fire safety standards are such that acrylic in any form is not permitted in any fixtures or fittings (or lights, lamps, etc...), especially if there is any electricity near it, no matter how remote the chances of ignition...But I agree that acrylic is easier to machine and for a project like these light boxes fire ratings are less of an issue. I simply default to polycarbonate so I don't have two materials in stock. That said, for smaller one-off non commercial projects extruded acrylic is probably the best choice as you have already indicated. On a purely personal note I also find the smell of the acrylic monomer which is released when cutting acrylic very unpleasant. If I do cut it (usually coloured material), it is usually my cue to grab a cup of tea and watch from a distance.

The UV issue you also raise I think is less of an issue as the wood veneer will most likely be affected long before the plastic, although I use a lacquer with anti-UV additives incorporated to reduce the impact as much as possible. Despite that nothing will last forever...

LittleGreyMan
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Re: Lightbox projects

Post by LittleGreyMan »

Thanks for the feedback, Warren.

All this makes sense. It demonstrates the "best" material is just a matter of context and constraints.

Forget all I wrote about prices. Like you, I had old prices in mind. I double-checked the prices with several suppliers and have no more opinion!
Best regards

Didier

W7 - Aspire 8.517

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