Acrylic fabrication questions? I can help! - Page 2

Vert · #26 04/13/2005, 03:45 PM

Heres a question.

What is the minimum diameter you can bend 3/8" acrylic using a metal pipe as the form? How about 1/2"?

Thanks

springerhd · #27 04/14/2005, 07:25 AM

I've probably made it through half of this thread and am starting to think I may finally know enough to attempt my own sump. Dimensions will be 54x20x20 with a water level of 15". I am planning to use a mixture of 75% #4 and 25% #5 which I believe was recommended earlier in this thread.

Can I build this out of 3/8" sides/front/back and 1/4" bottom and partitions inside the sump? How much bracing is recommended? Does the brace need to be made of one large piece with access holes routed out or can scrap pieces be used as cross braces? I'm trying to get the whole thing done out of 2 4x8 sheets, 1 sheet of 3/8" and 1 sheet of 1/4", and as always trying to do it on a budget.

Thanks.
Alex

Vert · #28 04/14/2005, 02:03 PM

What I want to do is put 2 90 degree bends on the front glass to eliminate 2 seams and give the front of the tank a cleaner look. I plan to weld a metal jig that will create 2 90 degree bends at the desired location while holding the plastic square. I am also planning to bend some sheet metal to bow the front of the glass. I think this will create a tank that will look custom, not just 5 or 6 panes of plexiglass.

adrinal · #29 04/14/2005, 03:28 PM

Quote:

Originally posted by Vert
I think this will create a tank that will look custom....

It wont just LOOK custom, it will BE custom.

Simms142 · #30 04/14/2005, 08:30 PM

Do you guys think i will be alright with a sump 23x13x18 out of 1/4. It will have top bracing and baffles all the way up to 15" the longest span from a side to a baffle will be 12"

masterswimmer · #31 04/15/2005, 08:28 AM

Acrylic,
I've got a problem. My tanks been up over a year now. Last night for the first time, I did a bonehead move. Was too close to the substrate, picked up a grain of SD and proceeded to inscribe a 25" long scratch in my acrylic, right at eye level.

I'm so PO'd right now. Can I remove this scratch without any blemish? Does the tank have to be drained to below the scratch? What procedure would you recommend? Thanks for your help,

Russ

Vert · #32 04/16/2005, 03:06 PM

There are numerous items on the market to repair your scratch. Im sure someone here can list some brand names. You do have to drain the tank to make the repair and the results will depend on how deep the scratch.

Acrylics · #33 04/16/2005, 09:10 PM

Masterswimmer, check out a MicroMesh kit at www.micro-surface.com and look for kit # NC78-1. This kit can be used safely in a fully stocked tank. There will be a "dimple" depending on the depth of the scratch.

HTH,

James

masterswimmer · #34 04/16/2005, 10:46 PM

Thank you James

Russ

Fishguru · #35 04/17/2005, 12:20 PM

I personally would like to thank james for all his help here at RC, he is an invaluable member.........Thanks from Everyone...

tonkadawg · #36 04/27/2005, 10:25 AM

Quote:

Originally posted by Acrylics

There are 4 basic ways, those 3 are solvent polishing (not recommended), flame polishing, buffing, and Micro-Mesh. Micro-mesh take more time than any other but yields the best results. It is sanding all the way to 12000 grit sand "paper" and then abrasive creams for the final polish.

Can you expand on this a little please? I am looking to polish the edges of my acrylic after I have cut it. Obviously the best methods for me (I am not a professional) is sanding and then using the creams. What steps for sanding? Is that wet or dry or a combo of both? And what creams should I look for and suggestions on where to find them?

Thanks!

Ehydo · #37 04/27/2005, 10:29 AM

What can I use to clean acrylic for a repair and for adding a baffle?

I use weldon 4 for my joints and 16 to fill gaps.

Acrylics · #38 04/27/2005, 12:05 PM

Quote:

Originally posted by tonkadawg
Can you expand on this a little please? I am looking to polish the edges of my acrylic after I have cut it. Obviously the best methods for me (I am not a professional) is sanding and then using the creams. What steps for sanding? Is that wet or dry or a combo of both? And what creams should I look for and suggestions on where to find them?

Easiest for most is buffing; wet sand to 600-1000 grit then use a bugging wheel attachment for a hand drill to polish and remember to use the buffing compound.
The *best* way is to use the Micro-Mesh as it induces no heat, therefore no unwanted stresses to the material. For this, use the same wet sanding process through 600-1000 grit, then wet sand using Micro-Mesh which goes to 12,000 grit, then an abrasive cream such as Novus 2.

Quote:

Originally posted by Ehydo
What can I use to clean acrylic for a repair and for adding a baffle?

If it's still in sheet form and has not been glued, polished or anything else - you can use denatured alcohol. If it is a "retrofit" job, just use water and allow to dry for a day or so. Acrylic is porous and will absorb moisture so has to be allowed to dry thoroughly else the joints can turn white with many solvents.

HTH,

James

Ehydo · #39 04/27/2005, 03:47 PM

Thanks James

Ruminari · #40 05/04/2005, 12:02 PM

Ok, a couple questions for you acrylic gurus.

I'm making a calcium reactor for my tank. The acrylic shop cut all of the pieces down to 1/8" larger than what I intend on using. So I can route off the edges for glueing. I have been using some scrap pieces with my 3 flute flush trim bit that the acrylic shop gave me as scrap. The only problem is that when I'm running it over my router it ends up being almost kinda bumpy and not smooth. Infact the table saw cut is much smoother than the routed finishing. I'm guessing that it is due to the fact the acrylic is ever so slightly bumping out as I run the acrylic across the table. How do I fix this problem so that I can get smooth cuts? Would using a featherboard work and if so how would I apply it to the router table?

Second - Would it be possible to simply sand down all the edges of the acrylic? My wife and I are contemplating just doing that as the cut sizes of the acrylic would still work for our project. What grit of sand paper could we use for sanding down the edges?

Thanks for your help and suggestions everyone.

Biodragen · #41 05/04/2005, 12:39 PM

Actually the router does a better job and gives you a nicer edge.
Those lines are the gaps of the blades from the bit.
That routered edged is mainly all lines right. That is good and what you expect.
I have used a 100 grit to sand my edges and I have used a razor blade to do the same. I also use a block when sanding the edges.
Thing you need to keep in mind is keeping both of them flat and straight. If you start to go on an angle a bit it will not be a good joint then.

The routering of it gets you closer to a better finish and you can just glue it like that but I take the time to prep a bit more on what I do for projects. I will gett less bubbles and a better joint.

HTH

Ehydo · #42 05/04/2005, 03:13 PM

Are you cutting tubing? I use a miter saw to cut tuning.

Ruminari · #43 05/04/2005, 06:20 PM

Flat sheets, We're making a square reactor.

Ehydo · #44 05/05/2005, 08:35 AM

Just checking.

Biodragen · #45 05/05/2005, 08:38 AM

Try to feed the acrylic a little slower.
The faster you run that bit across it the rougher it will be.

Get a feel for it

trapassi · #46 05/05/2005, 02:09 PM

Hi Acrylic,

A couple of weeks ago, in reply to my question about whether a wall thickness of 1/8" is strong enough with 12" dia cast acrylic tube, you replied:

Quote:

The tube itself is plenty strong, the determining factor is the strength, therefore quality of the bottom glue joint. 1/4" simply has twice the surface area on the ends as 1/8" allowing for ease in getting a stronger bond.

My question: would a groove routed in the base sized to fit the end of the tube be a viable means of strengthening the joint? If so, should I use normal solvent (#4 - fill the groove 1/3 with solvent then insert the tube) or would #40 be better?

Thanks

Acrylics · #47 05/05/2005, 02:43 PM

If you can get a good, "full" joint (entire end surface bonded) , then the grooves won't help. But if nervous about this, then use the #40 in the groove.

HTH,
James

jcaulley · #48 05/05/2005, 03:32 PM

I want to build my own sump. It is going to be 13"L, 8"W, 16"H. This will hold just under 7.5 gallons. How thick should the acrylic be that I get to build this? I was looking at 1/8" cast acrylic sheets. Is $1.91/sqft a decent price for this thickness?

dark8nge1 · #49 05/05/2005, 03:59 PM

I found some crazing long the bottom seam of my 150. It's a 2-3 inch section that's already turned white. I know this is real bad so I was wondering if I could brace it in any way. I have some 3/8" sheets and was thinking of using that. The tank is empty so bracing the joint from the inside shouldnt be a problem.

Ehydo · #50 05/05/2005, 04:21 PM

Quote:

Originally posted by jcaulley
I want to build my own sump. It is going to be 13"L, 8"W, 16"H. This will hold just under 7.5 gallons. How thick should the acrylic be that I get to build this? I was looking at 1/8" cast acrylic sheets. Is $1.91/sqft a decent price for this thickness?

I think that 1/8 inch will bow and I would not trust it. I use .220 inch as a minimum thickness to hold water at 14-18 inches. If I was making an overflow box or a really small box no higher than 2-3 inches I would use 1\8th. It us the 16 high that will put most of the pressure on the box.

I would probably spend about 60 dollars on acrylic for that size box. I also make euro lips on all of my sumps for more support.