www.TK560.com

[CrazyFool]

Hi all. First time poster noob with and urgent question... of course!

My boss found out that I (theoretically) "know" how to vacuum form mold plastic letters for his business signs... and all heck broke loose. He ordered me to build a vacuforming machine IMMEDIATELY because his business is about to go under due to the fact that he was sued by a previous vendor and forced to cover up a large portion of his business signs (that contain a trademarked word owned by the vendor). But the borded over signs have been killing his business and he can't afford to have new signs professionally made. It's truly a do or die situation.

Enter my goofy arse.

I foolishly said, "Heck, we can make new plastic letters ourselves!" Famous last words.

I could go on and on about what happened and maybe I can fill you all in as the story unfolds but let's just say, I haven't had much sleep the last 7 days and I've been scouring this forum.

My goals:
1. Build a 2 ft x 4 ft vacuforming machine.
2. Make 12 plastic letters (each letter aprox. 15" x 19") for each of 7 stores for a total of 84 letters. Fortunately, the letter shapes are fairly simple, and raised only about 1 1/2". Unfortunately they must be pulled with 1/8" acrylic 'Sign White'. I have two 5.5 hp shop vacs and a compressor to do this. I know 1/8" is really thick but I don't need fine detail and... I have no choice. The new letters must match some existing letters that will remain. The other, older, existing letters that will be kept are all made from 1/8" sign white acrylic. It's what most businesses use in their signs.
3. Keep my boss from losing his business and me from losing my job

Where I'm at in the story:
1. All parts for 2 x 4 machine purchased. Everything is ready to put together (nichrome wire, posts, hardibacker, etc).
2. My design will be a 2 x 4 forming surface with the single hole design, except in my case I plan to have two 1 1/2" holes so that I can make a jig for the machine and use it later as a 2'x2' for smaller molds. I have two 5.5 hp shop vacs (one for each hole) and a compressor for the high vacuum pull. I don't really have time to fiddle with making a water heater tank type high vacuum system, so I'm hoping the compressor alone is enough for now.

My questions:
Q: I can't seem to find on this forum anywhere where the exact dimensions of a 2 x 2 forming surface are mentioned. At first I thought the 24" x 24" was the measurement of the outside of the holding frame ("the entire machine") then I saw the oven calculator suggesting that the oven is 28" x 28" and the forming surface of the table is a 'few inches less depending on angle of convection oven walls and their height'. (Starts to get headache.) So I assumed for the sake of argument that the forming surface was in fact 24" x 24" but then... I saw the site owner's photos and counted the 1"x1" squares he drew on his metal forming surface... and they added up to a lot less than 24"x24". (Head really hurting.) Can someone please point me in the right direction here? What exactly are the measurements for a 2'x2' machine?? (Sobs turn into giggles turn into Stephen King 'hackles').

My offer:
I'm not sure what I can offer for you help. I am certainly willing to buy any and all books (even multiple copies) for any authors and to support this site however I can. But right now time is killing me. I don't have time for any more reading. I have to start nailing the sucker together and fire it up.

I'm sorry for writing a book here on my first post. But tonight I begin putting the machine together and I'm trying to get any answers I can between now and then.

Thanks in advance for any and all advice. Primarily I am concerned now with the dimensions of the machine's forming table surface (that I assume should match the opening 'mouth' of the oven).

Sincerely,
CrazyFool

PS My machine is an over/under design due to the largeness of 4'x2'.

PSS THANKS YOU GUYS. THIS SITE IS INCREDIBLE!! Seriously.

[CrazyFool]

I should add (being as this is a SW site after all) that I once had over 30 storm troopers and was Darth Vader and Luke Skywalker for Halloween, although it was cold outside on Vader night and the stupid eye pieces kept fogging up so I had to push the helmet back and look out the neck hole. Man was I upset for a long time about that! Kind of ruins the effect if YKWIM.

Umm... and my 2'x4' machine will have two 2'x2' ovens to simplify wiring and keep them on different breakers.

BTW, several members here have awesome videos and I truly thank you for posting them. Here is a non-member video I found on UTube that is pretty inspirational. Simple design. High school kids. And a BIG, THICK pull using nothing more than two 5.5hp shop vacs.

http://www.youtube.com/watch?v=skNfOIbFWmk

[ANH trooper]

Basically the size of your platen should be 1/2" on all sides less than the inner dimensions of your holding frames. So, if your outside frames measure 48" x 24" and you are using 1" square tubing, your platen should measure 45" x 21".

The reason for the oven being bigger than your frames in to ensure the plastic is heated correctly. The plastic is harder to heat at the edges unless your oven area is bigger than the actual sheet. This is why most ovens have extra ring around the perimeter of the coils so the edges are hotter, making the plastic sheet heat more evenly.

[CrazyFool]

ANH trooper,

Thank you very much. I have few questions for you (or anyone) if can spare a minute.

1. Is my drawing of your comments correct?
2. In this example what exactly would the dimensions of the opening of my oven be?
3. What would the dimensions of the 'bottom' of my oven be (the surface that my ceramic posts and nichrome wire are attached to).. 52"x28" ?
4. How tall should the sides of my oven be?

I apologize for all the questions and I appreciate your help very much.

CF

PS Is the goal of the TJ 2x2 design to have a platen that is 21"x21"???

[ahillworks]

That looks correct. To keep it simple always remember the oven has to be bigger than the table. I do not have dimensions posted but if it helps I have pictures of my former. Now granted its not working right now do to the oven was not finished. But when I had some basic toaster oven elements in it it did work the first few times. So mine is smaller but its based on the same standards. I hope it does help a little. http://r-cdrifting.com/album/thumbnails.php?album=9

[Fredo]

These posts may also be helpful. Read harley guys posts page 9 May 12 07. If your really pressed for time the Proto might be the way to go. Read Chris Lees post Feb 3 08. He did a really fast build on that machine...........Fredo

[CrazyFool]

Thanks ahillworks & Fredo. I will re-read your posts after I get back from Mother's Day festivities. I will be there biting my nails and pretending to have fun!

[jegner]

Here is what I did. I knew I wanted to use 24x24 plastic. So I made my holding frames, out of 3/4 inch square tubing, with an outside dimension of 24x24. Then, made my platen 21.5x21.5 inches. This allows the holding frame to be larger than the forming area, and ensure a good seal when forming. Basically it's 24 inches minus the thickness of the 3/4 inch tubing, then some space, about 3/4 of an inch. This could be less or more depending on your needs.

I have to ask, why a 4-foot long machine?

Jim

[ANH trooper]

1. Yes your drawing is correct. If you were to use 3/4" tubing for your frames, your platen would be 45.5" x 21.5". As long as you have rougly 1/2" gap all the way around you will be fine.

2. The opening of your oven would depend on if you are having an over/under or flip/flop table. For an over/under your oven opening will be 51" x 27" and for a flip/flop it will be 46" x 22".

3. Your oven base no matter what design you have should be 51" x 27". Basically 3" wider and longer than your holding frames (1.5" wider on all sides)

4. For an over/under you should really have the oven walls at least 3" lower than your holding frames to hold in more heat while the plastic softens. For a flip/flop I am not too sure. A 4' x 2' sheet of plastic is going to sag more I would imagine, so better to have more height I would think. They usually have 3" for a 2' x 2', so I would think a minimum of 6" but I am only guessing on this. I can't see any problems myself as the heat rises, so it will hit the plastic even if you had it 12" high. You could make the oven walls something like this, with a 3" tapered section and a 3" straight section which would allow more sag.

[CrazyFool]

jegner,

Hi, and thanks. All of the letters I will be making are 18" in length or less, but the company logo is 19.5" in length and... 30" in width (so I couldn't manage it with a 2x2). I thought about a 2x3 but doing a double 2x2 sounds easier, considering that so many people have done a 2x2 with wiring and all. Time is a HUGE factor so I just didn't want to get into fiddling with a 2x3.

ANH trooper,

Thanks. I appreciate the figures. I don't recall seeing a photo of an over/under with oven sides that came down past the frames. Do you happen to know of a photo like that?

CF

PS I'm going to start putting the thing together right now. I'll post some pictures hopefully by Monday night.

Oh...! I almost forgot. My frames are 1"x1" aluminum. Can someone please tell me how tall (high) my platen should be? I have no idea. Thank you.

[CrazyFool]

Just taking a break from construction for a sec...

Still totally bewildered as to how 'tall' my platen should be. I guess it's not rocket science but I would like to 'cut once' if YKWIM. This project has given me the perfect excuse to buy a bunch of neat little tools I always put off buying. Picked up a scroll saw. They sure are interesting. Can't wait to try it out.

YOU MIGHT WANT TO REMEMBER THIS (or on my end ... maybe not!) but if I get some help here I could be a source of help to others down the road. I happen to own a Roland MDX-40. It is the same machine that sculpted Darth Vader's new helmet for the last SW film. If you know what I'm talking about, then you know the potential.

CF

[Jr Branham]

Crazy,
Doug Walsh (kayaker?)is a poster here. He has a great set of plans. I built one, see if the video will show for ya.
If time is important, perhaps you can get one of the board members to pull your stuff for the time being. And build your machine at a leisurely pace and enjoy it while you build. Good Luck.

Jr. B

http://s216.photobucket.com/albums/cc81/teambranham/?action=view&current=MOV00715.flv

[ANH trooper]

Here's an old pic of my oven. It now has the hardibacker on the sides to insulate the heat but you can see how the oven walls come down lower than the holding frames.

Your platen should be about 1/2" higher than your plastic when your frames hit the deck. So, if you are using 1" aluminium frames, your platen should be at least 1.5" tall.

I am using 3/4" frames and my platen is level with the tops of my frames, but this is not essential.

Make sure that your platen has slightly rounded corners so the hot plastic can grip it. I have read that it can lose seal with sharp corners and also metal platens are best. I have a wooden platen at the moment and am not getting a 100% seal, so I am on the lookout for a metal platen

[CrazyFool]

Jr Branham,

That is a very inspirational video. Boy, that setup is sweet. I like the sounds too. It even sounds cool. If I can't even pull a 1 3/8" high letter 'I' with my rig I may HAVE to ask someone for forming services. lol

Trooper,

That is exactly what I was looking for. Thanks a lot!! I have an MDF platen at the moment and if my setup works I may have faith to run to the metal shop for a better platen (and better frames). My aluminum frames even at 1"x1" seem a little 'soft'. We'll see.

Back to work... now was that measure once and cut twice or.......

CF

[CrazyFool]

Here are a couple shots of my quick and dirty rig before I get back to work. Should have more photos tomorrow. You might be thinking, "Did he read Jack & The Bean Stalk too many times as a kid?" lol My purpose for putting the oven so high is so that I can stand comfortably and watch the plastic sag level, without having to bend over and twist my neck to look up. If you see any serious problem with doing this please let me know. Thanks.

The blue letter 'L' is one of the old letters I will (hopefully) be replacing on my employer's business signs. It has a draw of about 1 3/8" and no real complexity. I am hoping to pull pieces just like this with two 5.5 hp shop vacs. I may not add a second 'high vacuum' source yet if two shop vacs do the trick. My understanding is that high vacuum is mostly for high detail or very slow cooling plastic.







CF