jfm
Well-Known Member
Pete, mine are 10mm Perspex (milky, as prev advised) plus 3 mm st steel. 125 high.
DIY Illuminated Name letters
- Thread starter PCUK
- Start date
petem
Well-Known Member
Brill, thanks JFM. I'm hoping to have more progress to report later today at which point I'll order the Perspex.
petem
Well-Known Member
OK. Some decent progress to report.
My mate has cut one of the 10mm perspex samples and has channelled a slot for the tape to lie in. It was then encapsulated using some specialist two part potting compound. We used a semi hard one but will probably use a silicon version in the future as it allows the compound to be dug out for repairs (not that we'll be needing repairs but better safe than sorry)
. The potting compound is UV resistant so shouldn't go yellow.
These two images are the perspex without the stainless steel letter on top. You can see that we've now got decent light distribution, particularly at the extremities. Note that the perspex that we used for this test was way more opaque than the one we'll use for real.
Those with a keen eye will notice that some of the LED's are yellowing. I'm not sure why this is but it's happened on some of the LED's that we didn't pot. Hopefully it's a bad batch but I'll take this up with the manufacturer.
And these final two pics show the perspex and stainless together. Consider the opacity of the perspex I think that the next iteration will give the required brightness.
My mate has cut one of the 10mm perspex samples and has channelled a slot for the tape to lie in. It was then encapsulated using some specialist two part potting compound. We used a semi hard one but will probably use a silicon version in the future as it allows the compound to be dug out for repairs (not that we'll be needing repairs but better safe than sorry)
. The potting compound is UV resistant so shouldn't go yellow.
These two images are the perspex without the stainless steel letter on top. You can see that we've now got decent light distribution, particularly at the extremities. Note that the perspex that we used for this test was way more opaque than the one we'll use for real.
Those with a keen eye will notice that some of the LED's are yellowing. I'm not sure why this is but it's happened on some of the LED's that we didn't pot. Hopefully it's a bad batch but I'll take this up with the manufacturer.
And these final two pics show the perspex and stainless together. Consider the opacity of the perspex I think that the next iteration will give the required brightness.
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petem
Well-Known Member
The supplier of the LEDs is pretty mortified by the yellowing of the diodes and is carrying out an investigation / referring the issue to the UK manufacturer. I did wonder if touching the diodes may have caused this but apparently this isn't an issue (as it is for halogen).
Does anyone know if the fitting of backlit lights can cause yellowing of the gelcoat behind the name? Could this be minimized by some kind of barrier layer I wonder? Or is this a non issue.
Does anyone know if the fitting of backlit lights can cause yellowing of the gelcoat behind the name? Could this be minimized by some kind of barrier layer I wonder? Or is this a non issue.
jfm
Well-Known Member
Non issue in my experience. My illum name has been switched on constantly for 3 years or so
petem
Well-Known Member
In response to the requests for pics in my wiring thread, here are some photohs of the latest prototypes...
The original LED bendabble tape that I was using had cut marks every 5cm however I managed to find some that had cut marks every 4cm so this is a potential solution for some job. I also found some pre-wired micro LED modules that I haven't photographed but they will work particularly well for curved letters. I think the minimum stroke thickness I can go down to is around 14mm,
You'll see in the latest prototypes that the LED's are now facing up and towards the back of the LED letter. This seems to have cured the issue of the LED's yellowing. The walls of the channel are now much thinner and this gives a brighter and more even light. In total, the LED's in each letter will produce 330-420lm (these are natural white but warm white, red, yellow, blue and green are available.
The final versions will have white and internal wiring, not the red and black used in the prototypes and of course a proper white sheathed flex.
I've switched over to silicone encapsulation compound which has excellent thermal conductivity, very high operating temperature and can be dug out for repairs. [Note to self, ensure your work surface is perfectly level before using self levelling potting compound!]
I've had to sack my colleague as his home made CNC machine was taking 3 hours to cut each letter. I've found a fantastic local firm that can do the CNC cutting from my artwork (.DXF files), very responsive service and they have a Perspex trade account. Quality is great, particularly the outer edges of the perspex. I was very relieved that the CNC cut perspex was identical in size to the laser cut stainless.
I've also found a lady who can solder the smallest joints. She must have good eye site and a steady hand.
As ever, prototyping is a good fun, and you learn a lot by your mistakes. It's also a really good way to pick suppliers.
Pete
The original LED bendabble tape that I was using had cut marks every 5cm however I managed to find some that had cut marks every 4cm so this is a potential solution for some job. I also found some pre-wired micro LED modules that I haven't photographed but they will work particularly well for curved letters. I think the minimum stroke thickness I can go down to is around 14mm,
You'll see in the latest prototypes that the LED's are now facing up and towards the back of the LED letter. This seems to have cured the issue of the LED's yellowing. The walls of the channel are now much thinner and this gives a brighter and more even light. In total, the LED's in each letter will produce 330-420lm (these are natural white but warm white, red, yellow, blue and green are available.
The final versions will have white and internal wiring, not the red and black used in the prototypes and of course a proper white sheathed flex.
I've switched over to silicone encapsulation compound which has excellent thermal conductivity, very high operating temperature and can be dug out for repairs. [Note to self, ensure your work surface is perfectly level before using self levelling potting compound!]
I've had to sack my colleague as his home made CNC machine was taking 3 hours to cut each letter. I've found a fantastic local firm that can do the CNC cutting from my artwork (.DXF files), very responsive service and they have a Perspex trade account. Quality is great, particularly the outer edges of the perspex. I was very relieved that the CNC cut perspex was identical in size to the laser cut stainless.
I've also found a lady who can solder the smallest joints. She must have good eye site and a steady hand.
As ever, prototyping is a good fun, and you learn a lot by your mistakes. It's also a really good way to pick suppliers.
Pete
Croftie
Well-Known Member
Great stuff Pete, this project is really coming on
jrudge
Well-Known Member
The more likely issue is that the gelcoat behind the letter remains pristine and the rest continues to oxidise / UV degrade.
PCUK
Well-Known Member
What machine is used to cut the perspex - a cnc router?
Sorry if this has already been covered!
Sorry if this has already been covered!
petem
Well-Known Member
These prototypes were CNC cut.
You can cut the outlines using a laser but the channels (aka troughs) have to be cut on a CNC machine. The CNC router uses a vacuum to hold the material down so the channels have to be cut before the outlines and therefore you need to find a shop that does both laser and CNC.
petem
Well-Known Member
Pete, mine are 10mm Perspex (milky, as prev advised) plus 3 mm st steel. 125 high.
John, there's something interesting about your letters. As you must be aware, when you CNC cut letters, you cannot get a true inner right angle due to the drill bit being round. The more acute the angle is, the bigger the problem is. You don't get the same issue when cutting with a laser as the bean of light is very narrow.
Unless I'm mistaken, your name is made using the 911 Porscha font. In the image above, which I think is an 'M' on its side next to an 'H' (or 'T'), where the cross bar of the 'H' joins the upright the inner corner looks to have been rounded (the font has this as a right angle). The end result being that the perspex and the stainless are a perfect match.
It had already occurred to me to make the same modification to the artwork before having the letter cut so I'm pleased that my thinking appears to be correct.
jfm
Well-Known Member
Hi Pete. Yes the upper part of that photo is a C on its side, and the lower half is H on its side. As you say, the internal 90 degree corners have been rounded. I think that is a modification to the true font (which as you say is Porscha - not sure of spelling) done I guess by Yachtlite, to match the cutting tool as you say. I'm happy with it.
Incidentally, I also modified the font myself: I had the M custom stretched to about 120% of the width that it was in the standard font, because I thought it looked too narrow relative to the A. The vertical line in the middle of the M makes it look narrower than the A if you make both letters the exact same width.
So my point is that Yachtite aren't averse to modifying fonts!
Incidentally, I also modified the font myself: I had the M custom stretched to about 120% of the width that it was in the standard font, because I thought it looked too narrow relative to the A. The vertical line in the middle of the M makes it look narrower than the A if you make both letters the exact same width.
So my point is that Yachtite aren't averse to modifying fonts!
jfm
Well-Known Member
Ps sorry for slow replying to PMs. Crazy busy at moment and little time for forum!
petem
Well-Known Member
Excellent - thanks.
That font is deliberately called Porscha, to avoid a Trade Mark I guess. I agree, fonts shouldn't be sacrosanct - it's perfectly acceptable to make sympathetic alterations or even derive a new font from them (subject to copyright restrictions of course). For example, if I was to stretch your 'M', I would stretch the cross bars and leave the verticals the original width. Otherwise you end up with different width verticals which would look a mess. But I'm sure you already know that!
petem
Well-Known Member
No worries, I appreciate you're a busy man.
jfm
Well-Known Member
That's what I did! We cut and shut the crossbars a la stretch limo, as opposed to stretching the whole M sideways as you would with an image on your computer screen