Advice on Making a Foam Layer for a IBM Model F 4704 107-key

[Wingpad]

I am in a bit of an awkward situation with my Model F 4704. I sent my plate off to be powder-coated by a third party so now I do not have a template to cut out replacement foam for the keyboard. I can think of few solutions for this:

• Hand-Trace a new template with a thin sharpie marker hoping things line up
• Attempt to scan my barrel plate and print a scale copy of it to put on top of my foam when punching out holes (less practical since the spacing could be eschewed due to the bend in the plate)
• Find a pre-made layout file to just print and lay over my foam (perhaps even to just try and laser cut it?)
• Spray some sort of temporary paint on the barrel plate with a piece of foam behind it to make a template

Any advice on this matter would be appreciated, perhaps even for knowledge on a temporary paint I could use for these purposes. I attempted the first option and it went quite slowly... plus, in the end my results were not great

Oh, and just as an FYI, do not powder coat your plate unless it is a thin coating... these barrels are going to be a tight (but doable) squeeze! I have a 5/8" hole puncher already, so I'm set on that front as well.

[pr0ximity]

When I replaced the foam on mine I went with the "spraypaint the barrel plate with foam underneath" option to create a pattern.

However, some of the resulting marks weren't very clear (blue paint on black foam ) so I lined up the barrel plate again and made a mark in the middle of each hole in the barrel plate on the foam. Since every cutout is the same size, it was easy enough to use those as guiding marks to line up the hole punch I used. I should think you could do the same if the holes you're attempting to cut aren't super precise (for example I did not cut notches for the ridge on each barrel, I used a larger punch to accommodate the ridge).

[fohat]

That is a tough position.

After doing it many times, I have devised a few tricks but they all involve spray paint.

With 1/6" (1.5mm) art foam and a sharp punch, it is easy to cut 2 mats at once, so the one on the bottom could be the same color as the paint. You can also spray paint a white piece of paper instead of the mat directly, and even re-use it for future cuts, I have done it but it is not as easy as it might seem.

In any case, the key is keeping the mat or paper tight against the under side of the plate when you spray.

After the fact, in your position I think that I would go the paper route, and use a pencil instead of a Sharpie so that you don't mess up the powder coat job. A folded towel underneath might help keep the paper pressed snug against the curvature of the plate.

[chzel]

Didn't wcass make templates for the 4704's? On mobile now, but I'll search later

[alienman82]

removed.

[Parak]

I use a roper whitney xx punch, sticky backed paper, and wcass's template. Print template to paper, stick to foam, punch out holes. Disadvantage is that said paper doesn't always release cleanly, but using it as an extra layer doesn't really hurt things either.

[Spaceman1200]

keyboards-f2/replacement-foam-mat-for-i ... ml#wrapper

Had it bookmarked, Use the F122 Template and just forgo the top section.
This is the foam i have, But due to a hand injury i have yet to use it
https://www.mcmaster.com/#catalog/122/3605/=159n04f

[Wingpad]

keyboards-f2/replacement-foam-mat-for-i ... ml#wrapper

Had it bookmarked, Use the F122 Template and just forgo the top section.
This is the foam i have, But due to a hand injury i have yet to use it
https://www.mcmaster.com/#catalog/122/3605/=159n04f

Thanks for this link, I searched around a bit but wasn't able to find the link. This will definitely get me started! I have a ton of this foam sitting around, I just have to get to cutting it

As for the chalk paint, I considered it but it doesn't seem like it's as temporary as I'd hope. I've read things about it sticking to powder-coated surfaces and leaving "permanent" marks that don't wash off...

[alienman82]

removed.

[lot_lizard]

Just an offer... send it to me and I will laser cut it against WCass's template. You would have shipping back covered already with other ventures. I need to look at his templates, but as long as they are SVG, or the PDF is using .001 inch for the lines when generated (hair line), it would work well. I haven't looked at the 4704 version he has out there yet.

EDIT: even if you decide to cut yourself, it will give you options... and it lets us know the 4704 template is good for others in the cutter for the future

[Wingpad]

Just an offer... send it to me and I will laser cut it against WCass's template. You would have shipping back covered already with other ventures. I need to look at his templates, but as long as they are SVG, or the PDF is using .001 inch for the lines when generated (hair line), it would work well. I haven't looked at the 4704 version he has out there yet.

I can definitely send you some foam to experiment with too, I still have a huge roll of it sitting around. I will probably take some off of it to experiment with at the school's laser cutter, though. If I don't set it on fire, I'll post results

I'm planning to look into it tomorrow, between the badges GB and finals 'tis a busy season for me.

[lot_lizard]

Not sure the grade or composition of the foam you are using, but if it's neoprene, and not the "ozone safe" variety... It will emit hydrogen chloride fumes when it vaporizes. The ozone safe version still does as well, but much less (on paper). You would have to run a lot of it to damage the machine, but the school might be picky. Do make sure it is vented to the outside though or a fire might be the least of your worries

[wcass]

I think I only published PDF versions of the templates. I would be happy to share DXF format for anyone interested.

[Spaceman1200]

i wouldn't mind having a dxf of them. Can't hurt to have it in multiple formats. I'm sure others can use them as well for playing around with laser cut replacement mats