DIY - ACRYLIC BENDING TABLE - (Update 9-28-13)

[charlieram]

I built a small plastic bender a few months ago, not as refined or big as yours and I havn't fully tested it yet, I built it to make gun holsters for my cab...when I get the guns all set up Any way I just used a 12v car battery charger and it worked well enough for me to bend some sanples, thats as far as i got but maybe you could try a truck/car battery charger?

[rablack97]

Ok then, test set # 2

This looked promising, until i opened the package and the knob fell off and the fuse compartment was busted.  However i was able to piece it back together and get it working.  The only problem is at the lowest setting it heats the wire up to the point of failure, I can only leave it on for a few secs and it keeps getting brighter and brighter.  So I'm guessing the lowest voltage output exceeds what the wire can hold up to.



This one was funny, I wired it up and turned it up slowly, nothing happened, a second later the electrcity flowed like water.  Well the wire heated up bright red, snapped, burned the wood on the table, before i could shut it down....Awesomeness



As far as the battery charger goes, i tried one out today, and it wont send juice to the leads unless it senses the voltage from an actual battery, the safety features on this stuff is making this project harder.

Any brands of battery charger recommendations.  If it gets around $60.00-100.00 for a charger I'm better off getting a lab supply or a variac.

It's kinda cool testing what works, so those that are following will know what not to do.  I'll post some photos of what i've done once i find a working power source.

 

[rablack97]

ok found it.......ouch $40.00

HAH, found this at Harbour freight, 9.00...woohoo

[charlieram]

I cant tell you what charger it is cos I'm at work now. All I do know is it was cheap (I'm tight like that , in fact my plastic bender cost no more than £6 ) and so it probably lacks that kind of safety feature! my wire is probably only about 20 inches long.

[rablack97]

I cant tell you what charger it is cos I'm at work now. All I do know is it was cheap (I'm tight like that , in fact my plastic bender cost no more than £6 ) and so it probably lacks that kind of safety feature! my wire is probably only about 20 inches long.

Yeah my wire is almost 40 inches long....

I have a 24v 10amp psu on the way, if that doesnt work, i'm just gonna get a lab power supply or a 5amp variac.

[PL1]

HAH, found this at Harbour freight, 9.00...woohoo

Did you look at this $5 one while you were there?



Have you tried using jumper cables from your car battery?   

12v should give you 660 degrees and draw 5.46A using a 40" nichrome wire.

Another more portable possibility is an Uninterruptible Power Supply (UPS) 12v battery.

Amazon and Interstate Batteries have a number of replacement batteries in the 5-7 AmpHour range for around $20-35 -- should be good for ~50-90 minutes per charge.

They often come with .25" QD connections.


Scott

[rablack97]

Small Update.

Great new the magic PSU is a 24v 10a 240 watt.  It doesnt short and I can control the voltage.  I'll post progress pics this evening and a few bend samples.

I found this out after i purchased the lab PSU, in this hobby, doesnt hurt to have for electronics testing though...

 

[rablack97]

Hello All,

Some major headway....

Ok so i went another route to secure the guide bolts to the frame.

I decided to use brass inserts, I you tubed a cool way to install these things.  Works really well.









FYI, Nichrome wire does not like to be unravelled



I used these connectors and removed the plastic insulators.





Crimped one end to the nichrome wire...like so, just make sure its nice a snug by giving it a few pulls.



This is secured by 2 nuts by sandwiching the connector on the bolt, this pic shows the -ve lead already attached for testing.  This will disappear and is only there for testing purposes only.



I stretched the nichrome wire across the channel, across another guide bolt and attached it to my drag spring.  The drag spring was then pulled and attached to the tension bolt....making up words as i go here.

You see those 2 burn marks, thats what happens when you use AC for power...you get pretty tattoos on your table.



Full view with guide bar and nichrome wire installed...



This is the sweet spot PSU, after 3 attempts.....12v 10a 240 watt, $20.00 ebay.  Simple wiring, 3 prong plug in and 2 alligator leads out.



Look at the pretty laser beam!!!!!!!  I haven't measured the voltage yet, will do so and post later....



Test piece locked and loaded.



I waited about a minute or so and kept lifting the back end until i saw it crease, i unplugged and lifted the back end up to a 90 degree angle roughly, and this is what i got.





Not bad for a first bend, no burning or distortion in the acrylic...I'll probably add a timer as i go along to alert me when its time to bend...

That's all for now...

[CoryBee]

Awesome!

[DaOld Man]

^^^ Agreed!!

Hey rablack97, thanks for that video.
I used some of those inserts on my last build, "A Little Rage" and didn't like the way they installed at all.
I didn't know I was going about it all bass-ackwards!
I thought the slot in the insert was to drive it in with a screwdriver. Had a rough time on a couple of them, on one I had to remove the insert, drill out the hole and re-fill with bondo and start all over again.
I may use these on my latest build "Gayles Jukebox" to fasten the monitor, it looks more attractive now, and I think I have a few left over.

[PL1]

Looks great.   

Once you add the timer, consider recording these data points on your bends.

 -- Voltage
 -- Temperature (convert voltage to temperature using the calculator Welash posted)
 -- Time the material was heated
 -- Material (if you try anything other than acrylic such as Kydex)
 -- Thickness
 -- General Observations (over/underheated, discoloration, distortion, etc)

Hopefully this data will help you (and anyone following in your footsteps) find the sweet spot for bending different materials/thicknesses.


Scott

[404]

great news. now you can start bending things for my projects 

[rablack97]

LOL....You can scale this project down and DIY man, I plan on using this mostly for CP bends, i just got tired of ruining plexi doing it with a heat gun.

I really like the results.

The final design will be really safe and easy to operate.  For anyone following less than $100.00 cause i've done all the guinea pig purchases.

[404]

LOL....You can scale this project down and DIY man, I plan on using this mostly for CP bends, i just got tired of ruining plexi doing it with a heat gun.

I really like the results.

The final design will be really safe and easy to operate.  For anyone following less than $100.00 cause i've done all the guinea pig purchases.

it was just a joke. I may make one eventually to build some simple enclosures for misc hobby projects. 

[rablack97]

I know man, I know you got the brains to make one these things 

[darthpaul]

Everyone needs one of these, great job.

[rablack97]

Added feet



Secured aluminum channel w/ slightly countersunk screws



Mounted power supply underneath



Hot and negative leads to bolts underneath

 

110v leads to power switch



Here's a short video of it working....



Still need to add volt meter, and digital angle finder...

Thats all for now....

[nordemoniac]

That thing is scary! 

Shouldn't you have some heat protection by the spring and screws?

[sharpfork]

great news. now you can start bending things for my projects 

This is what I was thinking.

rablack97- great to see you follow through with building this thing.  Don't burn your house down.

[Generic Eric]

Any updates?  Have you considered packing a parts list & diagram with instructions? 

[rablack97]

What is it you wanna know?  It works great still to this day, I have no complaints, very useful.

It makes tight radius bends, for a wider radius, this probably isn't the route to go as the element heats a thin strip of the plexi.  PL1 offered some ideas on this in the tread if you wanna entertain that feature.  For the wider, i still resort to the heat gun and clamp weights, which gives you more of a form control benefit.

For my CP's the radius is tight, so it suits me fine

Most folks just commented on it, the parts list is actually throughout the thread.

If your seriously interested in building one, I can compile the list of parts that worked for me.  The design however can be scaled down alot, mine is a bit overkill in regards to width and length, kinda hard to store.

You can use this thread to ask questions and I'll walk you through it....not that hard....

[Generic Eric]

You can use this thread to ask questions and I'll walk you through it....not that hard....

That is kind of you.  Thanks.

TBH.  I'm not building anything until it warms up.  I'd like to make some brochure holders and things for newsletters.

[rablack97]

oh ok, then this will work perfect for you, scale it to half size and you'll be good to go....

Just bump this thread when your ready and i'll help you out....

[Le Chuck]

Great project and good documentation Rablack 

Sure beats the hell out of me with a blow torch and a collection of dowel rods - well, similar results but I'm willing to bet you've got me beat in consistency, that laser beam of hot death is pretty sweet too 

[m1cky69]

Awesome project and im looking at this as we speak. Whats your parts list? I was gonna build a polystyrene cutter few year ago and wondered if the parts I got here will do the job?? I got a dc output power supply that outputs at 24v 2A. And I have some 22 awg wire. Be great if I could use this but dont wanna start knocking together till I know its all ok. The wire would only be about 700mm long as my cp is about 600mm

[wp34]

Somehow I missed this the first time.  I remember you bending acrylic for your Cowboy's mini but just thought you used magic.

Very nice.   

[m1cky69]

Or would it be best to use an old pc power supply using the 12v rail  and have a variable dimmer switch to adjust the power!?

[rablack97]

You need this  psu 24v 10a 240 watt, you can adjust the voltage on the psu....same style you are using now just more power

and you need 20 guage nichrome wire...

I had no luck with the varibale dimmer switches, plus, that PSU is under $20 on ebay, super cheap....

[rablack97]

Somehow I missed this the first time.  I remember you bending acrylic for your Cowboy's mini but just thought you used magic.

Very nice.   

Thanks, man, childsplay compared to your Tron build, which i visit frequently for updates....

[npd1164]

rablack97-   

Okay, i may have missed something, but I see the last post describes successfully using  a "24v 10a 240 watt PSU" ..... but what was the working means to regulate the heat of the wire?   ...or did it end up needing one?

[rablack97]

There PSU is adjustable, you can adjust the heat by turning the voltage on the PSU up or down.  You really just just to turn it up until it glows red, then just leave it alone.