DIY Illuminated Name letters

My colleague has now got his home made CNC machine working, you can see it here https://www.youtube.com/watch?v=PCHzlI_Gack.

He's ordered some 15mm acrylic that will be cut to match a large 3mm edge polished "A" that I had lying around at home. I've ordered 5m of Waterproof LED ribbon in cool white. There are 120 LED's a metre and they can be cut every 3 LED's (so every 25mm).

Plan is to cut out the acrylic then route a channel for the lights to sit in. We're not sure which direction the LED's should face, anyone got and advice on this element?
 
Whitelighter said:
i think LEDs should be placed in the groove face down i.e. towards the SS letter and away from the glue. This will give better diffused light
Click to expand...

+1

but Pete, make sure you sandblast the 15mm edges of the acrylic once cut so that you do get the necessary diffusion to make it acceptable (me thinks)
Well, you can try without sandblasting, but I bet it's going to look 10X better blasted

cheers

V.
 
vas said:
+1

but Pete, make sure you sandblast the 15mm edges of the acrylic once cut so that you do get the necessary diffusion to make it acceptable (me thinks)
Well, you can try without sandblasting, but I bet it's going to look 10X better blasted

cheers

V.
Click to expand...

Hi Vas, the edges will be flame polished with a propane burner. Interestingly, the acrylic is a lot pricier than I was expecting at £40 for a small sheet.

Pete
 
Pete. Not on a PC so struggling a bit with touch typing.
Talked to our resident lighting prof. And he suggests the following:

1. Use narrow beam less (27degrees iirc)
2. Don't place them facing the inbox but facing the outer edge.
3. Do sandblast the edge as the light "escapes" from the inconsistent rough surfaces.
4. Theoretically you got to have consistent and of similar properties on the material that light has to travel. So led, air, acrylic means there is a great deal of loss. Fwiw, you shouldn't really worry as the output of the lads is much greater than needed...

My only concern is that led emitted won't be very uniform with all the point sources unless you sort diffusion really well

Cheers

V
 
vas said:
Pete. Not on a PC so struggling a bit with touch typing.
Talked to our resident lighting prof. And he suggests the following:

1. Use narrow beam less (27degrees iirc)
2. Don't place them facing the inbox but facing the outer edge.
3. Do sandblast the edge as the light "escapes" from the inconsistent rough surfaces.
4. Theoretically you got to have consistent and of similar properties on the material that light has to travel. So led, air, acrylic means there is a great deal of loss. Fwiw, you shouldn't really worry as the output of the lads is much greater than needed...

My only concern is that led emitted won't be very uniform with all the point sources unless you sort diffusion really well

Cheers

V
Click to expand...

Hi Vas,

Thanks for your comments, I'll answer them one by one

1) Most of the LED strips use 3528 diodes which I think have a 120 degrees beam angle.
2) Placing them this way would be loads more work as you'd have to go round the inner and outer perimeters. I'm going to try placing them flat for the prototype and see how bright it is.
3) Looking back in the link that I posted in one of my earlier replies, I see in that project they also sandblasted once they had flame polished the letters. We'll consider this.
4) I think the key here is to get the LED's uniformly spaced. This will be a bit of a challenge as the cut points are only every 25mm.

Incidentally, Volos was on the TV the other day. Looks a really cool place, looks like it has a real maritime culture - I bet you get some excellent fresh fish!

Pete
 
jfm said:
Pete the Perspex needs to be milky. Then mount LEDs as jez said. (No point reinventing what yachtlite already figured out)
Click to expand...

Thanks, agreed with regards the positioning of the LED's. We've ordered clear acrylic but I'll see if we can get it changed.

How do Yachtlite mount the letters? I was thinking VHB to the boat then Glue between Acrylic and stainless. Finally, do YL shape the surface where the letters sit against the boat to stop see sawing?
 
I bought two of those ribbons and they didn't like higher voltages, we are often on shorepower and the 14.3v charging current gradually blew the LED's one by one. Shame to go to all your trouble and that happen so I'd suggest putting a 12v regulator at the switch.
 
Colvic Watson said:
I bought two of those ribbons and they didn't like higher voltages, we are often on shorepower and the 14.3v charging current gradually blew the LED's one by one. Shame to go to all your trouble and that happen so I'd suggest putting a 12v regulator at the switch.
Click to expand...

Yep, totally agree. The regulators are cheap so a no brainer.

Incidentally, when you buy letters from one of the established suppliers, what do you get in the way of regulators, controllers, etc.
 
petem said:
Thanks, agreed with regards the positioning of the LED's. We've ordered clear acrylic but I'll see if we can get it changed.

How do Yachtlite mount the letters? I was thinking VHB to the boat then Glue between Acrylic and stainless. Finally, do YL shape the surface where the letters sit against the boat to stop see sawing?
Click to expand...
It really does need to be milky. I think clear will look rubbish
Yachtlite weld m4 studs on the back of the letters. I know you mentioned witness marks before but if you spin weld and use 3mm steel letters there are no witness marks. There is no glue twixt Perspex and stainless letters - the lights are sealed into the Perspex so there is no need for glue there. There is clear silicone sealer twixt transom and back of the letters, to seal the mount holes
VHB = yuk imho. I wouldn't buy a VHB solution for 2 reasons. First, you will see the thickness of the VHB tape, or a filet of silicone to hide it, yuk, whereas Yachtlite sits hard onto the trnasom. Second, having the letters bolted to the boat is part of the security set up on the boat. It's generally easy to steal a decalled/VHB boat and rename it before you pull into the next fuel berth during your getaway, but it isn't when the letters are bolted on
As for curved transoms Yachtlite will machine anything to order if you send them a file but there was no need on a transom like mine (whose radius is 7.5 metres, with each letter about 200mm wide). You can calculate the rocking horse effect on any online chordal height calculator if you know the curvature and the letter size, and I'd say 0.75mm chordal height (ie 0.75mm gap each side of the letter; maybe even 1mm) is fine
 
Whitelighter said:
I would 'pot' them using a clear silicone - light stip in then fliil the channel with the silicone and flatten off
Click to expand...
Yes that's what Yachtlite do - pot them with some clear stuff, that feels a bit harder than bathroom silicone, and then btw apply a thin w/proof vhb tape over the potting. The acrylic part is therefore waterproof on a free standing basis and the s/s part and the transom play no role in creating the watertightness. This gives yachtlite control over the watertightness

6AC8945C-C047-4AAC-9836-AB21D613C7FF.jpg
 
Well spotted, I put that in to see if anyone was paying attention! Actually, the DIY article that I quoted in an earlier post had this but the backs of the stainless letters should be reflective enough (although, as you know they can be a little dull).

I'm also missing the wires, but I was rather taken with your idea of putting them through plastic studs.
 
Looks good.
1. Gasket is just clear silicone, right? Rubber sheet style gasket won't work
2 And you need tape over the potting silicone to stop it fusing with the gasketting silicone.
3 I wouldn't bother with the bored out stud. Adds loads of cost for no benefit really.
4 I'd want metal not plastic studs for security.
 
You must log in or register to reply here.

Share this page

Top