Filling-in Holes in C64 Case Advice

[toneburst]

I’ve just been drooling over Jorge’s MBSID

http://www.midibox.org/forum/index.php?topic=5169.0

and

http://www.midibox.org/forum/index.php?topic=5047.msg32059#msg32059

and am thinking of attempting something similar with my SID synth project. Obviously, since I’m not a professional model-maker, I don’t have access to the sort of tools he has, but I’d really like to be able to integrate the front panel into the case as he has done, rather than simply bolting it on to the front. I’d also like to fill in the holes in the back of the case. It doesn’t have to be completely seamless and the colour of the blanking plates isn’t vital, as I’m probably going to end up respraying the whole case anyway.

In terms of tools, I have (or am about to have) a dremel multitool, files and scalpels. Anyone any advice on how I should go about this job? I have several C64 cases I can cannibalise, so I should be able to use the same plastic to cover the holes. Any advice on what glues to use, and on any substance I could use to smooth over joins and maybe create the curve at the bottom of the blanking-plates would be very much appreciated.

I’m thinking maybe I could get Reichelt to create the panel in plexiglass and somehow fit it into the keyboard area of the original C64 Mk.1 case. There’s a groove around the edge of the keyboard, so I thought I could try and cut away the keyboard and fit the new panel into the exact same area… Maybe this is a little ambitious…

Thanks in advance guys,

Alex

http://www.toneburst.net

[Therezin]

The way I’d probably do it is using “plasticard” (think that might be a brand name, basically it’s a sheet of plastic) and a glue called polystyrene cement. This stuff’s basically a kind of glue that welds 2 pieces of plastic together, and it takes quite a lot of force to break it. I’d probably cut the plasticard to the shape of the keyboard cut-out as exactly as i can, then cement it in place. i’d then put some strips of the same stuff over the back of the join, again using poly cement - this should give it some extra strength.

[toneburst]

Cheers Therezin,

I’ll try and track down some of that plasticard then. I remember polystyrene cement from when I used to make model planes when I was a kid!

Thanks again!

Alex

http://www.toneburst.net

[Wilba]

It looked like Jorge did a cool trick to create the grooved borders around sections… using one piece that goes behind the C64’s front panel edge (with cutouts), and then putting smaller pieces on top of that. This not only gets you a front surface that’s at the same level as the original case, but it should be stronger where it joins to the original case, and you could use a stronger or thicker material for the rear layer for strength.

If you’ve got heaps of cases spare, reusing bits of a second case is ideal, that stuff is pretty strong plastic… I guess I’m just suggesting to support the new front panel with something that overlaps it and the edge of the original case’s cutout.

You might want to consider the easier solution of sticking the new plastic panel on top - if you round the edges a bit, and fill gaps with a bit of putty, and spray the lot one colour, it won’t be that noticable and a lot easier to make.

[toneburst]

Hi Wilba!

It looked like Jorge did a cool trick to create the grooved borders around sections… using one piece that goes behind the C64’s front panel edge (with cutouts), and then putting smaller pieces on top of that. This not only gets you a front surface that’s at the same level as the original case, but it should be stronger where it joins to the original case, and you could use a stronger or thicker material for the rear layer for strength.

Ah… makes perfect sense!

I’ve also been thinking about hiding the screws holding the LCD etc. on to the back of the front panel. If I were to do as you suggest, I could screw the boards to the bottom single sheet, then glue the panel fascia over the top. The only problem of course is getting hold of the plastic sheet, and cutting the panel shapes for the front surface without a laser cutter or CNC machine…

If you’ve got heaps of cases spare, reusing bits of a second case is ideal, that stuff is pretty strong plastic… I guess I’m just suggesting to support the new front panel with something that overlaps it and the edge of the original case’s cutout.

Good advice.

You might want to consider the easier solution of sticking the new plastic panel on top - if you round the edges a bit, and fill gaps with a bit of putty, and spray the lot one colour, it won’t be that noticable and a lot easier to make.

I know it’s much easier. I just don’t like the way it looks. Plus, I’m the kind of person who likes to set himself unrealistic targets

What kind of putty do you recommend? I wonder, is there some kind of putty-like substance that will stick to the C64 case, then harden to a surface that can be sanded? I vagually remember something similar from my model-plane-making days, but can’t remember the details…

Cheers again,

Alex

http://www.toneburst.net

[Jaicen]

Personally I think your initial instinct was correct. I’d be inclined to cut away the whole of the front around the rectangular border, then as a Wilba said. glue in a step underneath where you’ve cut, and lay your new panel on top. If you make it slightly smaller than the hole, it will look like the original, if that makes sense?

With regards to the holes in the back i’d be inlcined just to cut a square piece that will level or just behind the edge of each port. That way you get it neatly blanked without major surgery!

Personally, I’d like someone with access to the tools necessary to think about re-manufacturing cases for us without holes, but given the cost I think it’s unlikely to happen

[toneburst]

Hi Jaicen.

Personally I think your initial instinct was correct. I’d be inclined to cut away the whole of the front around the rectangular border, then as a Wilba said, glue in a step underneath where you’ve cut, and lay your new panel on top. If you make it slightly smaller than the hole, it will look like the original, if that makes sense?

Yep, that makes perfect sense.

Haven’t got my dremel yet, so I’ll leave the cutting for a while. I think I’m actually going to put the working Core and SID modules in a temporary box for the moment- I just got a couple of free samples from Teko so I’ll use one of those for the moment while I work on butchering C64 cases.

With regards to the holes in the back i’d be inlcined just to cut a square piece that will level or just behind the edge of each port. That way you get it neatly blanked without major surgery!

Good plan. If I use sections of plastic from another C64 case, they should be the right thickness to fill the gaps perfectly. The only think that worries me slightly is the fact that the bottom of the Cassette and User Port openings is rounded. I guess I could use some sort of putty to smooth over the bottom of the blanking plate and create the curve, or make it a little longer, so it protrudes at little at the bottom, then sand it to match. The other problem is cutting out the pieces of plastic accurately. Maybe it’s better to cut them a little too big, then sand them to size (thinking out loud here)…

Personally, I’d like someone with access to the tools necessary to think about re-manufacturing cases for us without holes, but given the cost I think it’s unlikely to happen

Yeah, I think you’re right there. The original cases were injection-moulded, of course. Not sure how practical it would be to create something similar using any other technique anyway, and I suspect injection-moulding is a little expensive to setup, for the number of cases MIDIBox builders would need. Having said that, if you can find some rapid-prototyping-type company who will make the kind of thing we want at a reasonable price, them I’d take a couple…

Cheers guys,

Alex

http://www.toneburst.net

[Jaicen]

Original C64 cases were of course injection moulded, but I can’t see that being practical at all for our purposes. The set up costs would be astronomical for even a modest run. If I wa going for expensive, i’d want injection moulded alloy I know of a place that could do that for me in sand cast form, but i’m not sure i’m ready to commit to a project like that!

A cheaper, less robust option woul be to vacuum form the two case halves. It would require some fettling to mate the top and bottoms, but I think that it’s a feasible method and not too costly.

[toneburst]

Hi Jaicen!

Original C64 cases were of course injection moulded, but I can’t see that being practical at all for our purposes. The set up costs would be astronomical for even a modest run.

Absolutely; no point even considering it.

If I was going for expensive, i’d want injection moulded alloy I know of a place that could do that for me in sand cast form, but i’m not sure i’m ready to commit to a project like that!

Why don’t you try it first, and let me know how you get on…

A cheaper, less robust option woul be to vacuum form the two case halves. It would require some fettling to mate the top and bottoms, but I think that it’s a feasible method and not too costly.

I don’t know much about vacuum-forming, though that idea had actually crossed my mind too. I’m not sure how thick it’s possible to make vacuum-formed objects though: I thought you could only use pretty thin plastic sheet. I also seem to remember there’s a fair amount to work involved in accurately cutting the bottom of the sheet once it has been shaped around the form. Having said that, you could potentially make any shape case you wanted this way, so you could make a C64-style case, but with all the right ports etc.

I may be able to get access to a vacuum-forming machine at work, if I talk nicely to the right people. Could take a bit of social-engineering, but might be worth it…

Hmm…

Alex

http://www.toneburst.net

[Mr_modnaR]

you can vacuum form acrylic sheet. the radii between the form and the flat mesh are usually what puts people off, plus you can sometimes get bubbles if you’re a bit over zealous with heating the stuff. if you make the form that you want, then add another inch, you should have enough material to have a clean edge.

funny vacuum forming story: when i was at art college, a girl had brought a change of underwear in her bag, which i stole and vacuum formed onto a sheet of card, which had been printed with her name, and a special offer price on it. it was then pinned to the notice board.

she still hasn’t spoken to me.

[Sasha]

There’s a groove around the edge of the keyboard, so I thought I could try and cut away the keyboard and fit the new panel into the exact same area… Maybe this is a little ambitious…

I done that last night, and today I stubbed on this post and wonderfull Jorge`s C64 mod. That cutout looked to me like good braking guide. I was right. After braking it out with pliers I filed it a bit and sanded. I need more room for keyboard I want to put i C64 Case but hole where was the groove is little bigger than I need.

After I read how Jorge (my new idol) did it I am going to try the chloroform technique. I used chloroform for melting acrylic for making acrylic glue, but I never tought I could mix acrylic with C64 ABS case. I had idea of plugging the holes with fiberglass, but I dont like that material for fine job like this (dirty, sticky..) Now, I cant wait to try choloform melted acrylic. :D. I know the result could be great. I don`t need the original C64 colour so I will glue anny colour of acrylic I have at hand, but first I need to lasercut/engrave it. I strongly advise laser cutting/engraving for anny MB project since it will cut the cost down alot! And every expres stamp making service have laser machine. Cutting subpanel and pannel + engraving pannel for my Traktor controller (http://www.midibox.org/forum/index.php?topic=7008.0) costed me just 12 EUR! (without material - Rowmark Texture Black: http://www.rowmark.com/laser/Textures/textures.asp)

[toneburst]

you can vacuum form acrylic sheet. the radii between the form and the flat mesh are usually what puts people off, plus you can sometimes get bubbles if you’re a bit over zealous with heating the stuff. if you make the form that you want, then add another inch, you should have enough material to have a clean edge.

I seee. Then once the two halves have been cut, you have to add some sort of ‘lip’ I guess, so the halves fit together.

funny vacuum forming story: when i was at art college, a girl had brought a change of underwear in her bag, which i stole and vacuum formed onto a sheet of card, which had been printed with her name, and a special offer price on it. it was then pinned to the notice board.

Lol- cruel, cruel…

But funny

That cutout looked to me like good braking guide. I was right. After braking it out with pliers I filed it a bit and sanded.

So you managed to break the keyboard section around the line? That’s cool; I will give that a try on my spare case.

Now, I cant wait to try choloform melted acrylic. :D. I know the result could be great.

Keep us informed on how it goes

Make sure you don’t fall asleep while you’re working on it though…

And every expres stamp making service have laser machine. Cutting subpanel and pannel + engraving pannel for my Traktor controller (http://www.midibox.org/forum/index.php?topic=7008.0) costed me just 12 EUR! (without material - Rowmark Texture Black: http://www.rowmark.com/laser/Textures/textures.asp)

This IS intriguing. I’ll definitely check this out!

Cheers again guys!

Alex

http://www.toneburst.net

[Mr_modnaR]

I seee. Then once the two halves have been cut, you have to add some sort of ‘lip’ I guess, so the halves fit together.

well, if you use thick enough acrylic, that should suffice, but you could also add a thin strip round the inner edge of either shell. make it overlap the shell’s edge, and it will locate in the other half.

[Sasha]

Keep us informed on how it goes

Make sure you don’t fall asleep while you’re working on it though…

I get home late tonight so I didnt needed chloroform to fall asleap. I havent got chance to do all experiments but I do manage to melt acrylic. It seams it needs much more chloroform than acrylic. I does that earlier in smaller quantity so it wasnt noticable that much. Today Ill glue a piece of acrylic on the ABS and, if it dries, Il try to sand it down to see how smooth transition I can get. Too bad I dont have a camera at hand, still waiting for my Canon S3IS ;) Should come till the end of the week. I have few roling projects Id like to document. Hear you

[Sasha]

At last some immages of my holes filling…

This is how it looks from inside. Piece of blue acrylic is glued to the C64 case apliing the gell like chloroform melted acrylic. I dont know how the hell inside of Jorges case looks so clean, but it doesent matter because it is hidden.

This is how it looks after some sanding with coarse sand paper.

And this is how it looks after some sanding with fine sand paper. It needs some minor crack filling and it is ready to be painted.

I must say that the C64 case plastic is just great for fine sanding. It feels just like woods.

The blue acrylic filling seams stick really great with C64 case.

[toneburst]

Nice job!

What did you use to cut out the blanking plates Sasa?

Alex

http://www.toneburst.net

[Sasha]

You will laugh now, but I used hacksaw without piece for holding it because I didn`t have it at hand. Precission is  really not so important because melted acrylic fill all holes. If some are missed they are easily to fill later.

[Sasha]

Here you can see finished bottom part. It is sprayed with primer and mat black paint. I am pretty satisfied with result. Currently there is no anny hole except those two for MIDI in/out since I don`t know yet what I am going to use this case for.  

The top part is just fine cuted and sanded. It is waiting for the acrylic panel which is going to be united to it using same technique. This is it for now. I`ll post more images, but I need to decide first what should I put in it. 

[Mr_modnaR]

wow, that’s come out really well sasa, i’m impressed!!

[Sasha]

Thanks Modnar, but I still dream about Jorges mod. What a beautyfull case, and what a pro work. I would really like to hear some more expert advices from him. I`m sure he can give tons of advices. Jooorgee..?