22 replies to this topic

[Jay Guard]

Most of us know the story of the "Old" Lancer bodies that came in the cardboard boxes. Clearly some of the best of the best in the 60's and early 70's.  But here's the question, did they actually ever go completely out of business or did they somehow hang on and in later years keep making bodies but packaging them in clear bags with a stapled top card?  Does anyone know the story of the later years with the soft packaged bodies?

[Bill from NH]

The bagged Lancer bodies with the black on purple tags were pulled by REHCO off supposedly genuine Lancer molds. How the molds got from CA to OH is a question you might want to ask. I don't have the answer to that, just a guess. Not all the bagged bodies I've had have Lancer's crisp detailing. At least one of the bagged bodies I have was pulled off a mold other than Lancer's, probably Dubro or Dynamic.

[Martin]

Difference between "old" and "new" Lancer?

The difference is quality. That could be partly the molds are worn and the boxed bodies from old were "Butyrate" at least the early ones. This was great for detail. See examples below.  The newer bodies are Polycarbonate, trade name Lexan, which is stronger but gets less detail.

 

This is a good read if you haven't yet Jay.

http://slotblog.net/...hnical-history/

 

Hey Bill

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[Mike Patterson]

Yes, REH acquired the Lancer molds. And, depending on the body, the detail isn't as crisp as it was BITD. I don't know who pulled the REHCo ones. And AFAIK, REH still has the molds (and tons of other stuff).

 

 Lancer body list.pdf   112.82KB   20 downloads

 

Maybe Steve Deiters will chime in. He used to work for Bob.

[Brian Czeiner]

I would be interested in how they got the molds out with so many undercuts. Multi-piece molds or some other technique? Anyone have a picture of a mold?

[Brian Czeiner]

I would be interested in seeing a pic of one of the molds. Were so many undercuts acquired through blow molding or multi piece molds? 

[Martin]

Here are a couple of pics provided by Mr P some time back. I am amazed how good these bodies were BITD.

Also a nice pic (by Rick T) of a Dynamic Lotus 40 showing off the level of detail.

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[Mark Onofri]

I was wondering the same thing myself. I have a " Lancer" cobra, bagged with a black and white stapled label. Fugazi ?

[jimht]

The bagged Lancer bodies with the black on purple tags were pulled by REHCO off supposedly genuine Lancer molds. How the molds got from CA to OH is a question you might want to ask. I don't have the answer to that, just a guess. Not all the bagged bodies I've had have Lancer's crisp detailing. At least one of the bagged bodies I have was pulled off a mold other than Lancer's, probably Dubro or Dynamic.

Bob Haines stopped by the Raceway (in the Seventies, maybe) on the way back (circuitously) from California, said come outside Jim and see what I've got.

 

Opened up the back of the van and inside stacked bottom to top were molds that he had gotten in Cali...Lancer, Dubro, etc.

 

Price sheets I've got around somewhere were made available later but I don't know whether they were actually pulled in quantity or not.

[Brian Czeiner]

Thanks Martin. Looks like a gt-40? 

[Martin]

yes, a MK2. at least the back part.

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[Bill Seitz]

Something to keep in mind is that 60's bodies at least, and maybe into the 70's, were molded in ABS, not polycarbonate. It's always been my opinion that the polycarbonate does not mold to as crisp detail as the ABS bodies did, but the polycarbonate is much sturdier, and I'd rather have it.

[Thom]

I built a vacuform machine based on Gene/ZR1’s recommendations. I can’t get polycarbonate to pull down at all, PETG on the other hand works great. The only thing with PETG is that the thinnest I can find is 0.020. I also modified all my molds to have a vertical nose,tail, and rockers so that I don’t need two part molds,

[Jay Guard]

Thom:

To pull polycarbonate you will need higher temperatures, longer heating time, and higher vacuum compared to almost any other plastic, especially PETG.  And as I'm sure you are aware it will always take a good bit of experimentation to find just the right combination of the aforementioned variables.

 

BTW...Thanks for all of the historical info guys!!

[Thom]

With higher temperatures how does one keep the poly from sagging/drooping into the heat source?

[Jay Guard]

Thom:

On most set-ups the heat source is above the plastic sheet.  During heating the Lexan will droop down and then sort of come back up to nearly flat, that's when it's ready to drop it down onto the mold for the vacuum to form it.  This has to happen quickly with a quite strong vacuum to pull properly.  As I said, it will take a lot of trial and error to get the process just right.  If your heater is below the plastic I'm not sure if it would work well with Lexan.

[Brian Czeiner]

I built a vacuform machine based on Gene/ZR1’s recommendations. I can’t get polycarbonate to pull down at all, PETG on the other hand works great. The only thing with PETG is that the thinnest I can find is 0.020. I also modified all my molds to have a vertical nose,tail, and rockers so that I don’t need two part molds,

 

Vacuum forming is a black art to say the least with it's many variables. I have built several vertical machines with increasingly better designs each time and am about to build another. The two common semi-consistent features are low air volume to move and moving it fast. This will benefit any material. I only need to watch my styrene because holding the vacuum on too long will pull holes through the plastic creating a blow out. I use a foot pedal from Harbor Freight to control the pump. I use a second foot pedal to control the heating too. It's like driving a clutch if you make Brmm Brmm noises. 

 

This next machine will have controlled heating zones like larger industrial machines. Similar to an stove top but next to each other.  I will keep the same pumps but incorporate an all metal frame that will be machined to seal against the plastic instead of using rubber and O-ring seals. They don't hold up well against the repetitive heating and high vacuum cfm. I usually need to replace them every few months. I've found the poly reacts to any small leak using conventional designs. Seals were a must.

[Phil Hackett]

I would be interested in how they got the molds out with so many undercuts. Multi-piece molds or some other technique? Anyone have a picture of a mold?

The molds were/are in multiple pieces. They are keyed so there's no misalignment when reassembling it for the next "pull". So, after the plastic is pulled you remove the main section so the "end" pieces can be pulled out of the "undercut"...(the proper word escapes me right now....)

[Mark Onofri]

Seems like several of you have experience in vacuforming. I built one in shop class when I was 12. Made a few molds then, found out girls were funner and never used it.
I'm curious if it is beneficial to have a vacuum tank equal in displacement to the vacuum chamber. It seems like it would give a (almost) instantaneous reaction ?

[Brian Czeiner]

Seems like several of you have experience in vacuforming. I built one in shop class when I was 12. Made a few molds then, found out girls were funner and never used it.
I'm curious if it is beneficial to have a vacuum tank equal in displacement to the vacuum chamber. It seems like it would give a (almost) instantaneous reaction ?

 

When building a machine you don't make a large vacuum chamber. Mine is literally the thickness of some window screen at just under 12" x 7". I arrived from that dimension to get the most product from a 4' x 8' sheet of plastic.  A single 3cfm pump from Harbor Freight works fine if using a short hose. I use a foot pedal and start the pump before dropping the plastic. Though my next machine will have the option of a second vacuum pump. I've found a few degrees in the building from winter to summer can change the cooling time of the plastic. It's only spit seconds but it matters with polycarbonate. This just my experience, there is no wrong or right way as long as the results are satisfactory.

 

 

If you have a large chamber, then a tank would probably be beneficial. The type of plastic you are forming matters too. Poly cools very very fast as opposed to PETG or styrene.

[Mark Onofri]

Brian,
I would think that any vacuum chamber would be beneficial. You wouldn't have to wait until the pump reached the desired negative pressure. Just my opinion.

[Brian Czeiner]

Brian,
I would think that any vacuum chamber would be beneficial. You wouldn't have to wait until the pump reached the desired negative pressure. Just my opinion.

Maybe we have a difference in the definition of a Vacuum chamber? I think what you are talking about is an additional vacuum tank which could be preset to a negative pressure. I don't use one of those on either of my machines.

 

My definition of a vacuum chamber is the actual space under the platen where you place the mold. The larger that volume of air is, the more air you must move before actually pulling down the plastic before it cools. If your chamber is paper thin, it drastically reduces this issue. I believe Gene's design uses blue tape for the chamber thickness. Mine is metal window screen.

I may have to start the pump a second before dropping the plastic, but using foot controls there isn't any problem. It leaves my hands free to run the slide. You can see my machine in this video link.  Turn the volume down.

 

https://www.facebook...069653053138423

 

If you notice, the styrene is down on the mold before I turn the pump on. This is to prevent a blowout because the styrene cools slower. Polycarbonate is just the opposite. I start the pump before dropping the plastic to get the air moving before hand. It's about the timing. Using an additional tank, you still have the same problem of pulling air through the hoses before it reaches the chamber and effects the soft plastic. The tank loses vacuum pressure towards the end of the pull when its needed the most to create a tight detailed pull. If you raise the tank pressure, you risk a blowout by pulling plastic down into one of your platen holes while the plastic is the softest.  A pump will stay consistent or even increase pressure up to it's specs.

Using a pump and tank, the pump would have to move the tank air along with increasing pressure. Which isn't happening because you increase the volume of air needed to be moved during the production process. That could easily be resolve in the design to close the tank in mid pull. My feeling on that is more stuff to do creates more variables in the short time span of vacuum forming. There is the cost of the tank to consider when decent pumps are relatively cheap. A 3cfm pump like the type I use, is about $140 at Harbor Freight. Don't forget additional space needed for the tank. Space is always at a premium in a hobby room.

You can see my pump in the video is located just behind the machine reducing the length of tubing required and reducing the volume of air that needs moving. The flexible tubing will be replaced with hard pipe on the next design. 

 

I have a second small commercial machine from Vaquform. It has a two pump system where it initially pulls a large volume of air when you drop the plastic then turns on a second pump for stronger pressure. You can hear the shift of the second pump in this video.   https://youtu.be/VqonYbYQTyc          

 

I don't recommend this machine, unless you have no possible way of building one. The purchase price is staggering for a hobbyist. Mine was $1400 a few years ago. The plastic sheet is an irregular size creating a higher initial material cost and an extreme amount of wasted material.  I have tried pulling multiple bodies on it but it creates one thin side between the two body molds. Worst of all, is how hot the clamping frame gets when doing multiple pulls. We wear gloves when using this machine. Even then, there are times we have to let it cool. I have had little success pulling thin polycarbonate because of the hesitation of the two stage vacuum pump at the crucial moments of cooling. It works great on styrene so I use it for our shallow interior molds.

On the up side, the even heating of material is perfect. I need to replicate this on my next machine. I may take it a step further to control each zone of heating. We will see.

 

Then there is mold design with vent holes. But that is another variable we could discuss some other time. All of these variables combine into the voodoo of vacuum forming. I sum it up as vacuum forming can't be taught, but it can be learned. There just isn't an absolute answer at the hobbyist level.

 

These are my opinions based on the thousands of bodies and interiors I've pulled.  Yet there are plenty of videos out there that would refute these claims. I'm sure the key to good results comes from moving the volume of air quickly from under the mold. Whether you accomplish this with a reservoir tank or high cfm pump is really irrelevant as long as the final product is satisfactory.

[Gene/ZR1]

Lotus 40 with deep undercuts

2 part mold

 

As far as a vacuum pump, this one does it all, no issues. 12CFM-2 STAGE

Robinair (15424) CoolTech Vacuum Pump - 2-Stage, 93 liters/minute

 

enjoy, g