(Topic ID: 221863)

How do I flatten this Bakelite disc?


By RacingPin

1 year ago



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  • 28 posts
  • 13 Pinsiders participating
  • Latest reply 8 months ago by mbwalker
  • Topic is favorited by 4 Pinsiders

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#1 1 year ago

This is from a Gottlieb Queen of Diamonds. It is quite thick and can barely bend it by hand. Like to avoid taking off the number cover if I can. I'm in no rush so any long term process is fine with me.

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Mike V

#3 1 year ago

I would assume since bulb heat warped it that heat and pressure could flatten it. I'd want that plastic separated though. It's obvious it warps at different rates.
I saw a page online that talked about sandwiching between 2 pieces of metal applying medium heat to the metal and letting the weight of the metal flatten the bakelite

Hopefully someone with actual experience will weigh in

#4 1 year ago

Mike I sent a request to add you to the wood rail and em Facebook group. Someone there can help you

nicovolta
ryanclaytor
Can you help Mike?

#5 1 year ago

I thought this was an interesting question and Googled it. One common comment was "is it really Bakelite?"

Here's a link to a pipe forum (e.g. tobacco, not plumbing) discussing bending. Somewhat short, but I thought it had a couple of good comments about shaping (or lack of): http://pipesmagazine.com/forums/topic/bakelite-pipe-stems.

Quoting one posting: "I cannot prove this, but I suspect that what is sold as "Bakelite" is really another type of thermo-forming plastic material. Once Bakelite is shaped by the manufacturer, and cured, it cannot be reshaped or remolded by heating. I could be in error, but I don't think so.

Working with Bakelite can be very difficult. It snaps, easily chips, scratches, cannot be over-flexed, and cannot be bent-to-shape by reheating into all those specialized shapes that are required when fashioning rods and flats into a conventional, pipe stem. True, it can be cut, shaped, and polished, like any other plastic stem material, however, if you lathe-turn a straight rod and then drill it for a draft hole, you'll not be able to heat and bend it into the shape of a pipe stem. It doesn't get soft. It just scorches, and then burns. Smell burnt Bakelite once, and you'll never forget it.

I suspect that if the stem on that pipe in the photo is indeed, Bakelite, it started as a molded stem with that shape, and the draft-hole also had to be molded into that stem. Bakelite cannot be worked, shaped, and then bent, like Vulcanite and acrylics. It can also oxidize over time into unexpected, dull, colors.

Easy way to tell if you have a Bakelite stem....remove the stem from the pipe, heat a needle/pin red-hot, and stick it into the tenon. If the tip of the hot needle melts and enters into the plastic material, it ain't Bakelite....(this test will NOT work with a Delrin tenon). Bakelite also smells like a burnt, electronic circuit-board. It stinks to high heaven! Smells like the burnt handle of an old-fashioned coffee pot.

BTW...I don't think Bakelite is even manufactured anymore. It had its day in the 1920-'40s. Most of the Bakelite that's offered for sale today, is probably surplus, vintage, old stock."

The 'take-away' would be "maybe it's not bakelite?" If you to like keep everything original, I'd be tempted to make a replacement and to keep original just for the sake of keeping it with the machine or to take your time and fix it correctly.

A guy I work with restores old radios which use material that resembles bakelite...I'll get his opinion.

Good luck!

#6 1 year ago

I love to see old machines saved. If you find yourself in a pinch with this I could easily waterjet you out a new disk from Bakelite Phenolic Resin. Wouldn't be that hard to do but I would need you to separate the disks and send me the Bakelite (don't think it is) disk so I could dimension and lay it out in CAD. I have cut G10 for years which is close to the same properties and cuts faster then paper with a 60ksi waterjet. PM me if I can help. FYI, I agree with #mbwalker. I don't think this is true Bakelite as it would burn way easier then deform.

Also, with the number cover removed. That disk Could be saved with a good flat stone type plate and a cautiously used heat element like a torch or heat gun.

The Mod Couple

#7 1 year ago

Interesting as I was thinking this stuff has properties more like masonite but always assumed it was Bakelite. The challenge to get a new part crafted or this easily flattened is the metal fixture in the middle. I don't think that it can come out without destroying it.

Mike V

#8 1 year ago
Quoted from RacingPin:

Interesting as I was thinking this stuff has properties more like masonite but always assumed it was Bakelite. The challenge to get a new part crafted or this easily flattened is the metal fixture in the middle. I don't think that it can come out without destroying it.
Mike V

Looks to me like you could carefully drill out the rivets from the Bakelite side, then remove the middle collar with an Allen wrench, and the whole thing should then come apart into three pieces....unless I’m missing something?

#9 1 year ago
Quoted from AUKraut:

Looks to me like you could carefully drill out the rivets from the Bakelite side, then remove the middle collar with an Allen wrench, and the whole thing should then come apart into three pieces....unless I’m missing something?

The Allen head screw fastens the collar to a shaft which I already removed. The collar is two pieces of metal sandwiched together. It can't be removed without destroying something

Mike V

#10 1 year ago
Quoted from RacingPin:

The Allen head screw fastens the collar to a shaft which I already removed. The collar is two pieces of metal sandwiched together. It can't be removed without destroying something
Mike V

Mike,

So if you did try to flatten this (assuming it's not Bakelite), would you drill out the rivets on the number disc and try to flatten the brown disc and number disc separately? Or try to do both at the same time?

#11 1 year ago
Quoted from mbwalker:

Mike,
So if you did try to flatten this (assuming it's not Bakelite), would you drill out the rivets on the number disc and try to flatten the brown disc and number disc separately? Or try to do both at the same time?

Your comment about the metal pieces...looks like they are squished together?

#12 1 year ago

Interesting update:

Steve Young from PBR saw this thread and asked me to give him a call so did just that. He says that it is not actually Bakelite but a Bakelite/resin fiber 'lasagna' of sorts.

His advice for flattening it was to separate the plastic light shield wet the board a touch and rig a jig to hold it flat. Since he never tried it he had no guidelines as to how long or exactly how much force to apply.

He did give some insight into additional discs that were used through the years as I enquired about possibly using one from a Dodge City. He as usual had all the answers and several NOS ones to give me some info. Turns out all the contact points are different on each ones and the later versions mount differently. He did say that the later ones light shields didn't do the same destruction as mine since they used different material at that point.

So I'm going to rig the jig and let it sit for 2 weeks and report back ..

Mike V

#13 1 year ago
Quoted from RacingPin:

Steve Young from PBR saw this thread

Wait, Steve reads Pinside?

#14 1 year ago

Mike,
so if that fails, (and i hope it works!) Maybe you could cut away the outer part of it, with the holes, and save the center ( it seems fairly flat)

That way you would still have the contacts and hub intact, and then make the outer portion of the ring from aluminum sheet and rivet it to the "bakelite"

What size are the holes for each card? I might have some punches the right size.

What is up with the extra rivet on the inside near the "8"? See any reason for that?

Bob

#15 1 year ago
Quoted from SirScott:

Wait, Steve reads Pinside?

Why wouldn't he, he's in the business...

#16 1 year ago

I ran this by the gent at work that restore old radios, and his comments were the same as the pipe comments and PBR (that it's likely not true bakelite). He also mentioned the trick similar to the hot needle test. Lots of alternatives to Bakelite from when it was invented to the 50's. Sounds like if it was 'Bakelite'...it wouldn't have warped in the first place.

Steve's comments were the icing on the cake tho. Good for him replying to this thread.

I would think some minimal heat would be needed (heat lamp?) to make it slightly pliable - but probably goes w/o saying...the slower the better (like the 2 wks you mentioned).

Keep us posted on progress, please. And pics too!

#17 1 year ago
Quoted from BobLangelius:

Mike,
so if that fails, (and i hope it works!) Maybe you could cut away the outer part of it, with the holes, and save the center ( it seems fairly flat)
That way you would still have the contacts and hub intact, and then make the outer portion

Funny .. I was thinking along the same lines. If it fails cut the warped outer ring off and then find one from a Dodge City that Steve said most likely would still be flat. Cut the inner ring away from that but leave a slight overlap and fasten those together.

Mike V

#18 1 year ago
Quoted from mbwalker:

I would think some minimal heat would be needed (heat lamp?) to make it slightly pliable - but probably goes w/o saying...the slower the better (like the 2 wks you mentioned).
Keep us posted on progress, please. And pics too!

After listening to Steve and him mentioning that an NOS from that era he had was warped the same way led me to think heat isn't necessary though I guess it could speed it up but it is an unknown variable that could damage it.

Since this is a back burner project that I'm collecting parts for I have time on my side so we'll try the jig and report back

Mike V

#19 1 year ago

I guessing the heat from the original incandescent lamp(s) caused it to warp in the first place? If so, I'd use LEDs in that area to eliminate the heat so it doesn't happen again. Only say that since some guys keep everything original...including the incandescent bulbs. Just food for thought.

Sure sounds like this might have a happy ending.

#20 1 year ago

I believe that disc is made of phenolic material. Basically, the granddaddy of laminate materials. I have a hunch you're screwed, but you may want to try something the record community uses. Two plates of 1/4" thick glass and the sun. You'll have to have the plates made to accommodate the studs and wires (a hole in the center of the glass), but any good glass shop can do that for you. I also think you need to separate the two different materials.
For a record, 20 - 3- minutes in the sun, then a cool down period inside with a weight on the top works great! No clue what your "heatup time" would be.
Good luck! I'll be watching, as I'm curious as can be!
Jim

#21 1 year ago

If it some kind of multi ply, could it be soaked in hot water?

After removing the warped plastics. Put into hot water, let it soak until it gets soft. Create some way to press it until it was dry. It might change color, it could de-laminate and fall apart. Not really sure. No guarantees expressed or implied.

#22 1 year ago
Quoted from mojonitro:

I believe that disc is made of phenolic material. Basically, the granddaddy of laminate materials. I have a hunch you're screwed, but you may want to try something the record community uses. Two plates of 1/4" thick glass and the sun. You'll have to have the plates made to accommodate the studs and wires (a hole in the center of the glass), but any good glass shop can do that for you. I also think you need to separate the two different materials.
For a record, 20 - 3- minutes in the sun, then a cool down period inside with a weight on the top works great! No clue what your "heatup time" would be.
Good luck! I'll be watching, as I'm curious as can be!
Jim

Jim,

Good comment. But if heat (albeit from an incandescent bulb) gradually warped it over decades in the first place, couldn't the same, low level heat (i.e. the sun, heat lamp), also be used to return it to the original shape if clamped? I could be full of it (not the first time and not the last) - just asking. I'm an optimist, not a pessimist.

Whatever caused it to warp in the first place, I'd duplicate the same to help it return to the original shape.

Mark

#23 1 year ago
Quoted from mbwalker:

Jim,
Good comment. But if heat (albeit from an incandescent bulb) gradually warped it over decades in the first place, couldn't the same, low level heat (i.e. the sun, heat lamp), also be used to return it to the original shape if clamped? I could be full of it (not the first time and not the last) - just asking. I'm an optimist, not a pessimist.
Whatever caused it to warp in the first place, I'd duplicate the same to help it return to the original shape.
Mark

According to Steve Young his NOS ones warped the same way. They were never exposed to incandescent bulbs. The plastic light shield simply shrinks and takes the base with it since those early ones are unstable. I figure I'll go safe first.

Mike V

1 month later
#24 1 year ago

Any updates on this?

#25 1 year ago

Old guitar pickguards keep shrinking until they either crack the screws or lift the finish from the guitar.

I have a feeling that you will end up having to make a bunch of reproductions with a CNC mill, Lasercutter or Waterjet machine.

#26 1 year ago

Here is an update:

I had to source a hard ring to mount the disc on. I used a ventilation cover with the center knocked out. I proceeded to drill out only the outer rivets and attached 5 clamps. One each on the spot were rivets were removed.

This was done only a two days ago and haven't dared to check it yet. Will report back in two weeks now.

Mike V

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3 months later
#27 8 months ago

Update:

I checked it at two weeks with minimal change. Let it go for another 6 weeks and it is as good as this jig good do:

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Though not ‘flat’ at least the ‘wobble’ look is gone when it is spun. Also not the rivet holes don’t line up anymore because the plastic has shrunk as noted earlier.

Looking for a thin metal ring to screw in place to further smooth the spin. Will report back if I can find one.

Mike V

#28 8 months ago

Good to see an update about this...had forgotten about it.

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