acrylic / raw material

[slojim]

I would like to try to build some stuff. Was planning on using glass aquariums as the basis for my sump and refugium, but I might try acrylic. For planning purposes, what is acrylic typically sold as? 4x8 sheets or something? In the gulf coast U.S., what might I expect to pay for acrylic, ballpark, and what might I expect to pay (again, ballpark) for a heating strip for bending it? Thanks.

[Vinny Kreyling]

Don't know about your area but generally acrylic can be found in 4x8 sheets or smaller offcuts. Especially @ Home Depot or Lowes. Better to have all the dimensions you need for whatever and have them cut to size. I went with a plastics supplier. Joints should be square for gluing. They can cut them better than I so thats the way I went. Not hard, just water test after building. Bender from usplastics.com. $230.00 - $810.00, or a heat gun for &108.19.
Cut-em & glue-em. Vinny

[nancysnuwave]

Hi Vinny,

Thanks for your posting.. any ideas about cost / square inch (sq foot or whatever) using HomeDepot (etc) to cut to size? Are there better suppliers? Do they carry the 3/8" sheet thicknesses?

Also, what brand glue/what weights (thickness) of cement might be needed?

chris

[slojim]

Thanks, Vinny.
Nancy, HD and Lowes usually do the first one or 2 cuts free, and while they have the equip to cut square, they're not in the business of cutting accurately. That said, with wood they have never been more than 3/16" off for me, which was workable.

[nancysnuwave]

Thanks Vinny, really what I was interested to find was do they have the thicker (read deep water) acrylic (1/4") or (3/8")

[Acrylics]

Originally posted by nancysnuwave
Thanks Vinny, really what I was interested to find was do they have the thicker (read deep water) acrylic (1/4") or (3/8")

Home Depot & Lowes generally do not carry anything thicker than 3/16", sometimes 1/4". 1/8"(3mm) & 3/16(4.5)) are the standards for most home glass needs and that's what they cater to. They won't carry 3/8 - especially in cast material. Look in the yellow pages under plastics to find local distributors, they will cut to size for you and most can cut more accurately & consistently than either Home Depot or Lowes. If you need smaller pieces, try finding a local fabricator. I know I give away pieces that are to small for me to use but others can.

For cement, you can make your own if you want to the lab grade way or simply buy some at your local plastics distributor - should be 'round $5 for a small can of Weld-on 3 or 4. #4 will give you a slightly longer working time. For sealing the joints should you have flaws use Weld-on 40 not Wed-on 16. You can get a small 8oz kit of #40 from your local plastics distributor as well for about $8.

For bending you can make your own strip heater for about $50 which works as well or better than most commercial (read $$$) models - lemme know if you want details on this.

HTH,
James

[slojim]

ohh come on, of course I want details:) I have to figure a bend is a lot less likely to leak than a seam if I can keep it square, so if the price isn't outrageous, I'd rather bend than cut where possible.

[tag007]

Acrylics,

I would be interested in both the "home made" solvent and bending strip heater.

Thanks.

-TAG

[nancysnuwave]

Hi

Thanks for the info.. I am interested in the DIY heat strip thing.

I'm not sure what you mean by the Lab Grade option for cements.. I'm thinking that the Weldon #4 or #3 options should be fine, along w/ the number 40 version?

BTW.. do snap cuts work well enough for construction w/ this?


chris

[Acrylics]

Originally posted by slojim
ohh come on, of course I want details:) I have to figure a bend is a lot less likely to leak than a seam if I can keep it square, so if the price isn't outrageous, I'd rather bend than cut where possible.

Actually, a well glued joint is stronger than a bend but...

Material list for 6" x 48" long strip heater:
1 piece of 3/4" particle board cut into a 6" x 48" strip
2 pieces of 3/4" particle board cut into 2.25" x 48" strips
1 piece 3/4" drywall cut into 6" x 48" strip
2 pieces 3/4" drywall cut into 2.25" x 48" strips
2 1.25" or 1.5" machine screws (1/4 -20 or 10-24 is fine) w/4 nuts & washers
1 coiled ni-chrome wire GE part #WE11X61 available at Johnstone Supply
1 Dimmer switch (cheap 600w variety is fine)
Extra wire (16 ga extension cord is fine
w/ female end cut off and wires stripped.
Particle board: $8
Drywall: $8
Ni-chrome wire: $8
Dimmer switch: $3
Extension cord: 3
Screws: $1-2

Notes: drywall must be cut very clean to assure a clean looking bend.

Drill hole on each end of 6" x 48" drywall to accomodate machine screw, screw should slide freely through hole.
Holes should be 1" (or so) from end and centered.
Insert screw through each hole and tighted with washers and nut.
Screw or double face tape 2.25" strips of particle board onto 6" strip such that you have a 1 1/2" gap between.
Screw 6" strip of drywall onto this so that you have a square "tube"
Screw remaining 2.25" drywall strips onto the 6" drywall strip
so that they are flush.
Assembly should now look like 2 channels, drywall channel on top of partical board channel.
Attach one wire (from ext. cord) to one screw and the other wire to
one of the dimmer switch leads.
Attach other dimmer switch lead to remaining screw.
Stretch ni-chrome wire between these two screws.
Screw on washers and nuts to secure wires down.

Done. If I had my camera here I'd post a pic. If ya need one, lemme know.

Coupla things, you do not *have* to use drywall, you can use particle
board in it's place but then you must use an aluminum channel and some
sort of glass or ceramic insulation. If ni-chrome wire touches
aluminum - it will short out the dimmer switch. If ni-chrome wire
touches particle board, you will start burning it causing a formaldahyde gas to be released - this gas is extremely toxic and should be avoided at all costs.
When using, you do not want the wire to be red, if is red - turn it down a little else you'll fry the acrylic quickly.
You can adjust the gap if you like, the gap will be twice the radius
of the bend when acrylic is brought to forming temp.


Disclaimer :-) : This is not a suggestion, just a method of what can be done. This will not be a UL listed heater so use at your own risk. To avaoid electrical danger, never touch wires or screws as these will be hot. Always use in well ventialted area as monomer vapors can be harmful.
Be careful.

Originally posted by tag007
I would be interested in both the "home made" solvent...


The *necessary* ingredients in acrylic solvent are methylene chloride(MC) and acetic acid.
The MC is the chemical doing all the work, the acid actually slows it down, kinda acts like a buffer. Start with a solution of approximately 95% MC and 5% acid. If it doesn't flow well, add a little acid (just a little). If you use too much acid, the joint will look grainy. Weather and mol wt of acrylic will determine how much acid to add but should never reach more than 10%. There are other chemical one can use but these are getting into the haz-mat and are not always easily available.
General rules:
Cast acrylic(high mol wt) requires more acid than extruded(low mol wt).
Cold days require more acid than warm.
These are generalities and there's a little more to it but this should get you going, in time you'll just get a *feel* for it.
BTW, this solvent works well for polycarbonate (Lexan), ABS, and a bunch of other plastics and makes a great primer for PVC.

Hope it makes sense,
James

[drewsterr]

Acrylics,

Can you post a picture of the homeade bender or pm it to me ? Thanks

[Acrylics]

Originally posted by nancysnuwave

I'm not sure what you mean by the Lab Grade option for cements.. I'm thinking that the Weldon #4 or #3 options should be fine, along w/ the number 40 version?

BTW.. do snap cuts work well enough for construction w/ this?


chris

There are those (I'm one of 'em) that like to be in control of how the solvents react and are willing to spend the extra $$ to buy lab grade raw chemicals and formulate our own solvents. Is this necessary? not really but with a few exceptions. For 99.99% of the projects and probably all home projects Weld-on 3,4, and 40 are just fine.

I'd recommend against the snap cut process, but one can make it work especially if you're going to fill with #40 afterwards.

Originally posted by drewsterr
Can you post a picture of the homeade bender or pm it to me ? Thanks

I will bring in the camera tomorrow and post a pic.

James

[H20ENG]

Acrylics,
Just to let you know, you will now be the most popular guy on this site!!:D

I saved the heater out of my old dishwasher to fab a heat strip.
I have a 1000 dimmer for it. How big a channel should I mount the strip in and how far away from the shet should it be?
I am guessing a 1" channel and 3/8 to 1/2" below the surface of the bender to let the heat disperse evenly onto the bend area.
Enlighten us?:cool:
Chris

[Acrylics]

Originally posted by H20ENG
Acrylics,
Just to let you know, you will now be the most popular guy on this site!!:D

I saved the heater out of my old dishwasher to fab a heat strip.
I have a 1000 dimmer for it. How big a channel should I mount the strip in and how far away from the shet should it be?
I am guessing a 1" channel and 3/8 to 1/2" below the surface of the bender to let the heat disperse evenly onto the bend area.
Enlighten us?:cool:
Chris

Generally, the width of the channel will be twice the radius on the outside of the bend. So if you use a 1" channel and are using 1/4" acrylic, you should get a 1/2" radius on th outside and 1/4" radius on the inside. This should work out fine.
If you are using thicker material, widen the gap such that the inside radius is at least the thickness of the material. You really don't want the bend to be much sharper as you'll be stressing the material that much more. Remember when doing this you're stretching the outside while simultaneously compressing the inside, this along with the rapid heating/cooling puts a good deal of stress on the material.

On tight bends like this, 1/2" gap between the material and element should work out just fine. If you are using thicker material, move the element down (or build the sides up) so you don't accidentally fry the material.

I thinx you've pretty much got it down :)

James

[H20ENG]

Thanks! I've built some cheapie benders, but I want to do it right this time.
Should I make the channel width adjustable if possible?

I see you have kept jellies. Did you build a Kreisel tank?
Chris

[Acrylics]

Originally posted by H20ENG
Thanks! I've built some cheapie benders, but I want to do it right this time.
Should I make the channel width adjustable if possible?


If it's not too much trouble and you plan on doing much of this stuff - go for it

I see you have kept jellies. Did you build a Kreisel tank?
Chris

That would be my job :) I kept them for years so I could see where I could make aquarists' jobs easier.

BTW, I'll post the pic (heater) when I get home.

James

[H20ENG]

Cool thanks!
I used to work at a public aquarium, so we had several. I have also modified a few tanks into pseudo kreisels.
We had one kreisel that had a problem with the velocity of the inlet jets. Too high, and it would trap the jellies in a little vortex, too low, and the tank circulation went to pot. Most of the newer designs I've seen have smoother inlet to tank wall transitions.
Got a website?
Chris

[Acrylics]

Originally posted by H20ENG
Cool thanks!
I used to work at a public aquarium, so we had several. I have also modified a few tanks into pseudo kreisels.
We had one kreisel that had a problem with the velocity of the inlet jets. Too high, and it would trap the jellies in a little vortex, too low, and the tank circulation went to pot. Most of the newer designs I've seen have smoother inlet to tank wall transitions.

Boy, that's one old kreisel....
One of the refinements made 14-15 years ago was to make that part beveled to a relatively sharp point to avoid any vortex. The other thing one can do is either go to a single 6mm laminar flow plate rather than the dual 6mm flow plates or simply plug every other hole in the flow plate, this doubles the inlet velocity while keeping the same flow rate - gotsta keep critters off the suction screens.
I guess the above depends entirely on which kreisel design and mfr you got yours from though as we all have different ways of doing things.
Got a website?


Not as yet, we have the the thing designed just not refined.
Should be another coupla weeks 'til we are up and running.

James

[H20ENG]

It was made with 1" acrylic. The "overlap" of the inlet was just radiused with a 1/2" roundover bit. Not sure who made it.
We got a nice pseudo kreisel from living waters in ohio. Its jets were the extruded-cell sheet polyethylene. Worked great. we did have to plug a few holes as you mentioned.

Heres one for you.
After bending, there is a slight lip on the edge perpendicular to where the bend is. What is your method of squaring the piece again for gluing?
I was thinking of a small strip of hardwood with a divot out of it. You could put this lip in the divot, and the rest of the edge would ride flush. Send the whole thing through the router table to trim the edge square.
Help!:)
Chris

[Acrylics]

Originally posted by H20ENG

Heres one for you.
After bending, there is a slight lip on the edge perpendicular to where the bend is. What is your method of squaring the piece again for gluing?
I was thinking of a small strip of hardwood with a divot out of it. You could put this lip in the divot, and the rest of the edge would ride flush. Send the whole thing through the router table to trim the edge square.
Help!:)
Chris

I have an overhead router which I use for this, it is a setup in which the router sits horizontally in the air so you slide the piece on the table under the router bit.
What you are descibing should work if the piece is relatively flat and not too heavy. If you are doing heavy, curved sections the overhead is the easiest way I know of.

http://hometown.aol.com/acrylics/page1.html

Should have two pics, the first for Chris showing what we are doing for inlet and flow plate area. Hope it is fairly clear.

The other is a simple pic of a heater using an aluminum channel and braided fiberglass tape as an insulator. Very quick to make, about 20mins if you have a table saw and costs about $30-40 tops.

HTH,
James

[H20ENG]

Thanks for the pics!
Thats the kind of bender I have built before. It does the thin sheets fine, but needs the dimmer for thicker stock.
Do you use spacer "pins" when gluing capillary style? I use copper wire of different gauge depending on sheet thickness.
I recently built with 1/8", and had to NOT use the pins. The gap was so small, the solvent would not hold the distance between the gap. Had to do it the old fashion way. Squirt it, let sit a bit, then mash it with heavy timbers!:D
What sort of clamping jigs do you use?
Sick of me yet?:rolleyes:
Chris

[Acrylics]

Originally posted by H20ENG

Do you use spacer "pins" when gluing capillary style? I use copper wire of different gauge depending on sheet thickness.


Depends on the thickness and weight of material, but I use stainless steel wire to make a gap for solvent to flow. For material up to 1/4", pins are not necessary if you put high density foam under the piece - just push on the bottom piece a little as the solvent flows. Like you, the wires I use will vary on thickness and area of the glue joint, from about .009" to about .014".

What sort of clamping jigs do you use?

Square jigs usually made of partical board, but sometimes from acrylic, one o' these days I'll post a pic. I like using jigs that are simple and easy. This way I can make different ones on an "as needed" basis w/o wasting much time or expense.


Sick of me yet?:rolleyes:


Nah, not at all :)

James