Acrylic fabrication questions? I can help!

[RokleM]

Excellent info. I'll let you know how it turns out. My local shop has a lot of acrylic and tons of weld-on, so it's pretty likely I should be able to get the 40 picked up and fixed tomorrow. 40 still require a good 24 hours MINIMUM for a good solid hold or is it shorter/longer?

If I try another like this in the future, I'll likely do it without the channel or at minimum go straight to 40. The reasoning in my head made sense at the time, but I completely understand and agree with why it might have not turned out well.

 

[Acrylics]

For testing in something like you're doing, I'd say a good afternoon of curing should be fine. For max strength, should wait a few days, but for what you're doing - doesn't look like max strength is all that necessary, just a good seal.
Get a small poly bowl, old margerine tub, or similar for mixing. The kit will come with a popsicle stick for stirring, might want to have extras. Don't mix it all up, you can get a few uses out of it. Also try to find a 5cc syringe (no needle) to dispense the 40 without getting sloppy. Don't bother drawing it into the syringe, just pull the plunger out and put the 40 down the top.
Oh, and also eat a Tylenol when you first open the 40, many folks get headaches from the vapors without a respirator, no they're not *that* bad

James

 

[TheGrog]

WOW, tons of great info here guys!! Thanks

Questions that I have not found after reading 40+ pages this morning.

I am planning on building a calcium reactor this weekend. Got all the supplies in and some new tools that I was playing with last night (circle jig, new router bits). Got a tube of #16 as well, my #4 was damaged durring shipping (got a gooey wet package) so have to reorder. Don't know of anyplace in the area that has it so the #16 will have to work.

1. I have a 6" OD acrylic tube with 1/8" walls that is 18" long. Planning on using this with some 1/4" acrylic ends. Is the 1/8" thick tube too thin for a reactor?

2. Next, I am planning on having a flat plate as a cap with multiple holes to seal it to a gasket on the top and use nylon screws to secure it. I plan to tap the bottom plate (the one attached to the acrylic tube) and have the top plate holes untapped for the screws. The plates will be 8" diameter (~1" from tube wall) and 1/4" acrylic sheet. My question is this: how far appart must the holes be to not weaken the acrylic yet provide equal pressure on the two plates to seal it off?

3. I am planning on having tow PVC elbows (threaded) feeding the reactor. One at the top, one at the bottom (upflow design). Not having that large a tap to thread them, what is the best way to attach the PVC to the acrylic? Was thinking of drilling a hole slightly smaller than the threads and screwing it in forcing a thread pattern, then using some #16 to adhere it in place. Better ideas?

4. I also have this idea. What about between the two plates, route a groove in them to seat a large O-ring (rubber or silicone) to seal it off? That would eliminate the large gasket problem. Anyone tried or thought of this?

Thanks for all the help and for the great info!

 

[TheGrog]

Had a new thought, what about putting a groove on the top and bottom ends to the reactor for added support? I have a new circle jig that I think I can make an accurate enough groove to get a tight fit in the tube.

Here is a pic of what I am talking about. The smallest bit I have is 1/4" so there would be 1/8" open space.

Feedback?

 

[Steverino]

Grog: Try that hobby shop in elmhurst downtown, close to the train, with all the radio frequency remote control cars, (it is the street one over west from York, half a block north of the train). I got can of the acrylic glue weldon #4 a month ago.

 

[TheGrog]

<a href=showthread.php?s=&postid=9435097#post9435097 target=_blank>Originally posted</a> by Steverino
Grog: Try that hobby shop in elmhurst downtown, close to the train, with all the radio frequency remote control cars, (it is the street one over west from York, half a block north of the train). I got can of the acrylic glue weldon #4 a month ago.

Thanks! I'll check it out!

 

[RokleM]

TheGrog, in reply to your idea, look at my post just a few up.

 

[Acrylics]

<a href=showthread.php?s=&postid=9434451#post9434451 target=_blank>Originally posted</a> by TheGrog
I am planning on building a calcium reactor this weekend. Got all the supplies in and some new tools that I was playing with last night (circle jig, new router bits). Got a tube of #16 as well, my #4 was damaged durring shipping (got a gooey wet package) so have to reorder. Don't know of anyplace in the area that has it so the #16 will have to work.

Try Laird Plastics in Chicago

1. I have a 6" OD acrylic tube with 1/8" walls that is 18" long. Planning on using this with some 1/4" acrylic ends. Is the 1/8" thick tube too thin for a reactor?

Nope I personally prefer thicker walls for more gluing surface

2. Next, I am planning on having a flat plate as a cap with multiple holes to seal it to a gasket on the top and use nylon screws to secure it. I plan to tap the bottom plate (the one attached to the acrylic tube) and have the top plate holes untapped for the screws. The plates will be 8" diameter (~1" from tube wall) and 1/4" acrylic sheet. My question is this: how far appart must the holes be to not weaken the acrylic yet provide equal pressure on the two plates to seal it off?

About 8 screws, evenly place should do.

3. I am planning on having tow PVC elbows (threaded) feeding the reactor. One at the top, one at the bottom (upflow design). Not having that large a tap to thread them, what is the best way to attach the PVC to the acrylic? Was thinking of drilling a hole slightly smaller than the threads and screwing it in forcing a thread pattern, then using some #16 to adhere it in place. Better ideas?

Just tap the acrylic with a pipe tap, available at any hardware store.

4. I also have this idea. What about between the two plates, route a groove in them to seat a large O-ring (rubber or silicone) to seal it off? That would eliminate the large gasket problem. Anyone tried or thought of this?

This is the standard method

The groove idea is used by many people, but the groove provides no support to the tube. The tube, being round, is very strong as stress is distributed to a roughly infinite number of points. If you want to fill the groove with weld-on 40 then it's fine but don't count on it for "support", the tube won't need it.

HTH,
James

 

[RokleM]

Local place had weld-on 40 btw, but only in the 16 oz container. I'm trying to figure out how much of this to use and how to measure it. The "component b" container doesn't state how much is actually in the container.

I have have some 5 ml syringes I can use for measuring.


If I'm reading this correctly, I should be able to use 4 full syringes (20 ml) of the A plus 1ml of the B and that should be the correct mixture. Do you think this will be enough to do the trick? Should I double the amount just to make sure I have enough (was going to seal top and bottom just to make sure)? Any issues using the syringes to do the measuring for initial mixing?

 

[Acrylics]

Shouldn't need that much, 5ml total should do the trick but prolly mix about double that to make it easier. BTW, there's no magic to the ratio, esp in small amounts, 10:1 to 20:1 should be good. FWIW, WO42 is the same stuff but in a 10:1 ratio.
I guess I'd say mix whatever you are most comfortable with, if mixing 20ml is easier, then it'll be fine - no worries

James

 

[RokleM]

I JUST completed mixing and applying. It's very easy to work with, and the syringe made it very easy to mix. That 16oz container will last me quite some time. A little goes a long way.

I applied it as I would caulk, at an angle, making a little 3/16th wide or so 45 degree angle along the entire seam. Hopefully some sinks in there, and what doesn't should make a nice boarder on the outside.

You're right about the smell though. I did it in my garage with the door open, and had to walk out a few times. VERY potent.

I'll wait about 15 min and see if it's hard enough to flip the unit over and do the other side (depending if the mixture hasn't hardened inside the syringe yet). If not, I'll mix up a small batch later.

Very cool stuff.

 

[Acrylics]

If the first side has skinned enough to flip over, you can pretty much count on mixing another batch. Pot life is about 10 minutes or so.

James

 

[RokleM]

I think I'm ok. The first skinned over very well and I had already sucked what else I needed into the syringe. Only the tip of the syringe had skinned over

So, I got both sides. I'll give it a good 6 hours at least to dry, then test (non pressure) later tonight to see if it worked. The way it seals, as long as it doesn't shrink drastically during the process, I can't imagine it not working.

Once again, thanks.

 

[TheGrog]

IN BUSINESS!!!!

Found my #4 at the local hobby shop.....on sale too!!! Got enough to last for about 5 years now!!!

Saw the taps at a local hardware store. Looked in 3 stores before I found them at an Ace. Cost $29 for the size I need!!!:eek1: Think I can get them cheaper elsewhere??

Started cutting acrylic today!! My circle jig only goes up to 7-1/2" so I fashoned one out of a peice of plywood and mounted it to my router table. Took a few pics so I will post them later. Worked like a charm!! Got PERFECT 8" circle cuts for the top parts and the bottom. Edges nice and smooth too!

Then problems arose. When cutting out the inside of one of the top circle peices, the 1/4" router bit shattered and a peice of shrapnel imbeded itself in my shoulder!!! No major damage and nothing a little dermabond couldn't seal (yes I really am a doctor...surgical resident at that). The bad part was I am at a standstill until I get a new router bit. Good thing it is a Craftsman so I just bring it in and get a new one!!!

Well, back at it tomorrow and Sunday! I am taking plenty of pics so I will post a journal when done!

Thanks for all the help and suggestions. I am sure I will have more as time goes on!!!

 

[RokleM]

James (Acrylics) you are the man! I let it dry a bit, and it's currently hooked up to my system passing water No leaks at all this point. I'll probably shut it off tonight and run it again during the day tomorrow just to make sure it's all good. It's passing MAYBE 20 GPH at this point, just a little slow flow.

 

[Acrylics]

Glad it worked for ya Eric

 

[woz9683]

James, or anyone else. Do you have any guidelines on thickness of acrylic when cylinders are involved? Maybe, 5-6 feet tall, and 14" OD for a protein skimmer, would 1/4" tube still be okay? What if it got up to 24" OD?

 

[Acrylics]

1/4" should be fine for the 14" tube, and in theory - fine for the 24" tube as well as stress is distributed to an infinite number of points. In practice though, I like use thicker walls for the 24" tube when I can. The weakest spot will be the joint between the tube and pan (bottom), so I like to have more surface area there, not *necessary* but makes ya "feel" better about it.
FWIW, Reynolds is the only company to make 24" tube in 1/2" wall. CSHyde and Spartech wouldn't do it for me a few yrs ago - they'll only go to 1/4" wall on the 24".

HTH,
James

 

[RokleM]

<a href=showthread.php?s=&postid=9447910#post9447910 target=_blank>Originally posted</a> by woz9683
James, or anyone else. Do you have any guidelines on thickness of acrylic when cylinders are involved? Maybe, 5-6 feet tall, and 14" OD for a protein skimmer, would 1/4" tube still be okay? What if it got up to 24" OD?

You'll need to sell your car to buy that :eek1: :eek1: :lol:

Good luck. I would love to see the pictures as you start working.

 

[woz9683]

Run a search for Spazz + Skimmer and you'll find plenty to ogle. I will be working on one that's about 14" over the next month or two in all my free time (when I should be sleeping - my neighbors love me). For some reason I decided to form the riser cone first, and I'm building a form for it at the moment. If all goes well I will be putting up a thread about it sometime soon, I'll make sure I take plenty of pictures.