Thread: Joining and Fabricating using Acylic

Here is a fairly cursory treatment of the subject which I found when I was searching for info last year: http://www.practicalsubjects.com/sub...s/working.html

There was also some information posted by Glen Bridger related to a router dust extractor he made:

http://www.woodworkforums.ubeaut.com...&threadid=4912

and

http://www.woodworkforums.ubeaut.com...&threadid=5314

HTH

Thanks for that.

I shall look into it further.

G

Hi Glenn,

Perspex is is an easy material to work with.

Bending:

Firstly to bend it they actually make 'strip heaters' which just heat a narrow strip across the plastic and allows you to make a clean straight bend. However to bend it at home you will have to heat to whole piece in an oven. Set your oven at about 150 degrees and place it on a tray. It only takes a few minutes to heat, just keep checking it, if its too hot it will bubble then melt. You need to wait until its a bit firmer that blu-tac. Once heated take it out and working quickly bend it around a former preferably one which has a male & female profile. Clamp firmly until cool.

The other way is to heat a strip with a blow-torch or hot air gun. Be sure the entire length of the bend area is heated. Rule of thumb; If you have to force it, it isn't hot enough to form.
Using this method you have to be careful to make sure to bend is square and straight.

Depending on the finish you want, one method to ensure a straight bend is to machine a groove (half material thickness) across the perspex. This creates a 'weak spot' and the sheet will bend straight every time.

Glue:

For small jobs Loctite Super glue is ok.
When I was an Instructor at Wagga we used to use a product called 'Weld-on 40', a 2-part polyester glue. If you check the yellow pages I'm sure you could find a suitable glue.

Threading:

You can also 'tap' perspex with standard metal cutting taps. Use coarse series threads because they are a bit deeper and don't tend to bind as much. Use polished brass screws/bolts or black 'Unbrako' allen head bolts for added features.

Hope this helps,

Glen.

I was searching for some information on acrylic and found this thread. Unfortunately the links are useless and the attachments are no longer there (this is why pics should be attached properly ).

Anyway, I went on to search the net so thought I would post a few useful links here.

Working with Acrylic #1
Working with Acrylic #2
Working With Acrylic #3
Working With Acrylic #4
Working with Acrylic - Routing
Notes On Working With Acrylic
Tools for Working with Acrylic

Originally Posted by Glen Bridger

Hi Glenn,

Perspex is is an easy material to work with.

Bending:

Firstly to bend it they actually make 'strip heaters' which just heat a narrow strip across the plastic and allows you to make a clean straight bend. However to bend it at home you will have to heat to whole piece in an oven. Set your oven at about 150 degrees and place it on a tray. It only takes a few minutes to heat, just keep checking it, if its too hot it will bubble then melt. You need to wait until its a bit firmer that blu-tac. Once heated take it out and working quickly bend it around a former preferably one which has a male & female profile. Clamp firmly until cool.

The other way is to heat a strip with a blow-torch or hot air gun. Be sure the entire length of the bend area is heated. Rule of thumb; If you have to force it, it isn't hot enough to form.
Using this method you have to be careful to make sure to bend is square and straight.

Depending on the finish you want, one method to ensure a straight bend is to machine a groove (half material thickness) across the perspex. This creates a 'weak spot' and the sheet will bend straight every time.

Glue:

For small jobs Loctite Super glue is ok.
When I was an Instructor at Wagga we used to use a product called 'Weld-on 40', a 2-part polyester glue. If you check the yellow pages I'm sure you could find a suitable glue.

Threading:

You can also 'tap' perspex with standard metal cutting taps. Use coarse series threads because they are a bit deeper and don't tend to bind as much. Use polished brass screws/bolts or black 'Unbrako' allen head bolts for added features.

Hope this helps,

Glen.

For drilling acrylic,I find forstner bits very good..Brad point drills also work very well .

For tapping, I'd suggest using a pilot drill sized for the root diameter of the screw. Ordinary tap drills are sized for about 65% engagement, which is satisfactory for similar materials in the boy and girl. With dissimilar materials, 100% engagement is stronger.

Joe

Originally Posted by GCP310

Hi All,
I am chasing any past experiences using acryic. I want to build a housing for my video camera using 6mm acrylic and would like to know the ins and outs of this material.

E.g
- what do you use to make watertight joins,what type of adhesive/solvent cement do you use.

- whats the best way to heat it up to bend & shape it.

Thanks for any advise that anyone can share with me.

G

My first bit of advice would be "don't risk your camera", but people say that to me all the time and I go ahead and do "it" anyway.

Our workshop at work has made underwater housings for stuff that has to go between 2 m and >1000 metres deep. The most usual way is for housings to be machined from solid blocks of acrylic or metal since all the joints (even those operating at 2m) eventually fail at some time or other. Some of their gear has to last for 2 years at 3000m deep.

The hardest part will be getting a good seal on the doorway to the enclosure which ideally needs a recessed o-ring type seal and an "even pressure" clamping closure mechanism. I wouldn't bend it since it is very difficult to bend square and this makes joining the other joints difficult.

Before you invest a lot of time in this project I would just see if you could make a small cube out of acylic and tie it to a brick and place it under 2 metres of water for a week and see if your joints are up to scratch.

Just had a thought, an alternative to a strip heater for heating a line for bending, you could use a couple of pieces of cement sheet laid over the acrylic with a small gap in between the two.

Hot air gun or other heat source applied should head just the localised area exposed between the cement sheet pieces.


Cheers.................Sean

Originally Posted by scooter

Just had a thought, an alternative to a strip heater for heating a line for bending, you could use a couple of pieces of cement sheet laid over the acrylic with a small gap in between the two.

Hot air gun or other heat source applied should head just the localised area exposed between the cement sheet pieces.


Cheers.................Sean

That's what I do, except that I use timber and clamp one side in the workbench vice and push against the other side whilst applying heat.

It also helps if you cut the backing timber at half the angle you need so that when they touch each other you have the correct angle. Then put a few clamps on it whilst it cools down and settles.

Peter.

How thick is the acrylic you can bend like that? 1cm?

The acrylic I've used was 8mm thick (because that's the thickness I've got a stash of but I'm sure you can use it for thicker stuff) and I used that method to build my overhead TS guards a picture of my mk1 version is here.

Originally I used that method to bend 10mm aluminum bars for hold downs and these photos show details of it. Bar held between timber in vice. Bar bent. and finished bar


Peter.

Thanks for the info Peter!

Originally Posted by Sturdee

That's what I do, except that I use timber and clamp one side in the workbench vice and push against the other side whilst applying heat.

This sounds familiar.

In 1985 I made an acrylic/plastic bender from galvanized steel plate which could bend sheets up to 1.2 m wide and 8 mm thick. It included water cooled clamps and electric oven strip elements with temperature control. However, even taking things very gently it still slightly buckled the sheets during the bending and they would never be as flat as when they when they were new. The plan was to use the bender to make fan and filter boxes for a laboratory. After I made a couple of boxes this way I stopped using the bender because I found I could achieve close to the same result with a hot air gun that concentrated the heat to a radius of about 1/2" and a couple of bits of wood and G-clamps.

These days I prefer to use 1mm thick polycarbonate to make visible guards etc, mainly because I can get hold of it, it can be cut with tin snips, bent cold and pop rivetted together like sheet metal, and not forgetting that its tough as old boots.

Here's my TS dust collector.


Here's a nose guard I made for a Chainsaw Mill :

BTW that guard vibrated cracked along the bendline after about 3 day long sessions of continuous use and I remade it with extra aluminium rib/bracing which seems to be lasting much longer.