::DIY Acrylic Gurus::

[jmt]

Is it feasible to bend a flat peice of say 1/4" acrylic into a smooth trapezoidal shape. If I was to heat it up with a heat gun and then bend.

 

I am making a false back with overflow for my 16ga tank. The tank has smooth edges and I would like the false back to as well.

 

Thanks.

 

-Justin

[CU_Reefer]

I'm not a acrylic guru, in fact I've never even built an acrylic tank, but I do remember hearing that you can make a heat strip out of an old toaster. I think the idea is to soften a straight strip of the acrylic so you can bend it there. The heat gun may just heat one area not a strip long enough to bend. It might work if you move it back and forth.

 

I would be interested to find out as well.

[jmt]

I've been thinking about this, and I think I came up with an idea.

 

Take a peice of pipe and a blowtorch. Heat the pipe up and bend the acrylic across the pipe.

[Undertheradar]

Heres the problem. The temp needed to bend acrylic is enough to burn it on contact and therefore needs to be convected to the acrylic. If the pipe method is used, the acrylic will stick to the pipe...burning it. The heatgun method is very unreliable.

 

The pros have a machine that is rather easy to DIY. It is kind of like a 'break' machine used for bending sheet metal, except that in the area where the acrylic is intended to bend, there is a recessed track/groove where a spiral heating element, like one from a space-heater, is run through from side to side. When used, both sides of the intended piece are clamped down with long locking plates leaving just a few inches in between them for the acrylic to bend along the hinge/heating element that never comes in contact with the acrylic.

 

Or you can use the heat tape detailed in this article as well...

http://www.reefkeeping.com/issues/2002-04/jg/

[1fish2fish]

I have also seen people use an oven and even a microwave. This was to make a curved piece though. You have to be very careful about your temp and watch it pretty closely.

[maroonclown]

From a book with a chapter on welding thermoplastics:

 

welding temp recomendations for acrylic: 575 degrees F.

 

This is hot enough to MELT the base plastic and filler rod. I'd suggest making a few practice bends, the test them for strength. In other words, try to break the bend. If the bend breaks, it has failed. If the material breaks, the bend is good. If it does break, you are either getting it too hot, or not hot enough. Also, I would advise against using an oven to bend it. You just want locallized heat. As in metal, acrylic gets weak when it is heated excessivly. Also, your idea for a blow torch and pipe, is a bad idea. You will have the problem of uneven heating, which will weaken the acrylic. It will also heat more of the acrylic than necessary, also weakening it. Undertheradar's idea is the best way to do it. HTH

[TJG]

I have done minor bends in acrylic under the broiler( on hte lowest rack over a form). Works ok but you have to be carful not to get it too hot or the sheet will start to go white and bubble....

 

 

PS send the wife/gf out for a few hours.... well you know.

[B16A2NR]

I have made acrylic bends under a regular candle flame. Although this has a specific point of heat, a tightly grouped row of candles or a straight line gas flame will work well for longer pieces. Definatly do a few practice runs, start well above the flame and work your way down until you get your bend, the good thing about acrylic is it bends back easier than metal with minimal damage to structural integrity.

[jmt]

I am starting to think that maybe having 2 people is a good idea.

 

How does this sound, since using the oven is not really an option. I am going to make a form of what I want the acrylic shape to look like, out of wood. Then clamp one side of the acrylic to the bottom of the trapezoid shape. While somone heats up the acrylic at the bend point, I will be applying pressure to form the bend. Then clamp it in place and do the next side. After that the whole acrylic sheet is shapened to the wooden form and clamped down, let it dry. Viola, shaped acrylic?

 

Sound good?

 

-Justin

[B16A2NR]

Quite a bit of pressure can be put on the acrylic before it snaps if it is really hot, the downside of getting it that hot is its likely to bubble. Take your time getting it hot, and remember to wipe off the carbon deposits from the flame afterwards.

[maroonclown]

Screw candles, use an oxy-acetylene torch! I still have doubts about even heating with anything but an electric heat source.

[Undertheradar]

why not just buy the HEAT TAPE?!! Its cheap...you know, the stuff used to wrap pipes in cold weather? It isnt some super exclusive acrylic mastering tool...in fact, it's intended use isnt even for acrylic... My gosh, some of you can make this sooo complicated...like trying to reinvent glue or something.

[divemasterdave]

I built this masterpice, and you will build your dream too. I go with the simple things, like spend a little to get a lot!!! The heat tape is the way, and you can use the wood form to aid you in the shaping. Good luck, and have fun.

 

[maroonclown]

Where does one find this heat tape?

[qfour20]

You obviously did not read the EXCELLENT and INFORMATIVE article that wetworx (aka undertheradar) posted.

 

Please read all references in a thread before posting another question.

 

Article is here.

 

-q

[jmt]

I rea dhis article over and over. Since I have access to a heat gun, I figured I'd ask a question to confirm my ideas about going that route. I had no idea that heat tape is readily available. If the heat gun doesn't work out, I will be buying the tape.

 

-Justin

[maroonclown]

jmt, I think he was directing that post at me.