Acrylic fabrication questions? I can help!

[Acrylics]

James/Acrylics, I know I read somewhere that you mix your own solvent from a few different chemicals. I have access to Methylene chloride solvent from the Chemistry Lab I work in, as well as acetic acid. Was there anything else you include in your mixture? You also gave specific concentrations used. What benefits does mixing give over just using Methylene chloride or putting shavings in to increase viscosity? I just can't find that post.

adding 5-10% acetic acid (99%min) slows the reaction time and allows the solvent to flow better than straight MC. The actual amount you add will vary based on mole wt of the material and atmospheric conditions but just pick somewhere between 5-10% and run with it I also add ethylene dichloride/dichloroethane in varying concentrations but this stuff has become so expensive - hardly worth the price of admission unless you are wanting to do this for a living and doing lots of it.
Personally, I can't find a good use for a thickened solvent; it *can* fill *very* minor flaws in edgework but shouldn't be used to fill gaps or voids - esp if you want it to look nice.

Also, I am building a 15"x15"x13" display from 1/4" plexiglas G with a 2" brace around the top, but not having a good router, they will be 4 separate pieces welded together. Do you think this will be sufficient?

Yeah, not recommended, but from a structural perspective - should be fine. The primary reason for a one piece top is to have a radius in the corners to distribute load better than a single point - as you're doing with 4 strips.

As I don't have easy access to a router, i was planning on sanding with a block and then scraping the edges before using the solvent. What method of bonding would be easiest for a pretty new guy to this. I helped build a few 55 gallon tanks several years ago, but they didn't have to look that good. Should I try to use the wire and pull method? or just go with straight capillary welding?

Definitely use wires IMO. Take a look-see at a thread I did a few years ago called "DIY Tank, Step by step" or something to this effect - should be easily found in search. I've only started 2 or 3 threads so shouldn't be hard to find
Also, unless there is a compelling reason to scrape the edges, I'd omit this step. I don't recommend block sanding pieces all too often so be careful to get a good, flat edge.

HTH,
James

 

[mudskipper1]

Alright, I will check to see if my lab has it, guessing we won't but we shall see. I will try a few different %'s on some scrap and see what works best for me. I have read through that thread before, it is very helpful. I will give it another look at some point before I try this. Thanks for your help!

couple more questions, in order to get the best edge possible from sanding, should I fix the sand paper or the acrylic? I think I read that you should only sand in one direction, but would it be easier to draw the acrylic over the paper more evenly and level? and what grit, 220 is what i remember reading?

 

[Acrylics]

couple more questions, in order to get the best edge possible from sanding, should I fix the sand paper or the acrylic? I think I read that you should only sand in one direction, but would it be easier to draw the acrylic over the paper more evenly and level? and what grit, 220 is what i remember reading?

Personally, I do both depending on the situation. I'd probably recommend fixing the sanpaper to a blockand fix that to the table, then run the acrylic to it, keeping the acrylic flat on the table...hoping this makes sense
I like to glue to the finest edge possible, so maybe a coupla strokes with 320 after the 220/240? It will help 220/240 should get rid of any saw marks, then 320 to prep it for gluing.

HTH,
James

 

[mudskipper1]

Makes perfect sense, Thank you!

 

[vthondaboi]

Ok so I was looking up Marga Cipta and it doesn't seem very popular here. My jpits look really good using the needle and shim method. No crazing after about 6 months either.

So... how do y'all know it won't be a good material to use? When will it fail if it does even?

i was using Chemcast but my go to supplier(Allied Plastics) stopped carrying it, thus the Marga Cipta. Cyro Acrylite is 2x the price while Chemcast at another supplier(Regal Plastics) is 1.7x the price of Allied when they did have it.

Any suggestions?

BTw I'm not building any sumps bigger than 40G and don't do the eurobracing.

 

[jimmyj7090]

Will it work OK to mix and match acrylite FF and plexiglass G?

I need to build a sump and have enough mixed scrap to do it, but not enough to do it all out of one or the other. Would that work OK, or am I better off ordering enough to do it all with one or the other?

thks

 

[kcress]

Hello Acrylics.

What can you suggest for gluing ceramic plates to the inside back of an acrylic tank?

 

[cherubfish pair]

Hello Acrylics,

Can holes already in a sheet of acrylic be reamed out with a diamond hole saw to make a bigger hole? I will probably only be going from a 1-1/2" hole to a 1-5/8" hole on an acrylic display tank. I'm redoing some plumbing and the bulkhead in this hole is too flimsy so I'd like to go from a standard 3/4" bulkhead to a heavy duty 3/4" bulkhead. I could use a 1-9/16" saw and then a 1-5/8" saw so it won't be such a big increase in hole size? Or do you think one hole saw at 1-5/8" would work. I would probably go metric which is much cheaper with a ~40mm diamond saw and then a ~42mm saw.

 

[madmike]

an holes already in a sheet of acrylic be reamed out with a diamond hole saw to make a bigger hole

You don't want to use a diamond hole saw used for glass on acrylic, it will melt the acrylic. You can use regular wood hole saws or better yet a router would be the best in this situation depending upon where the holes are located.

 

[scbadiver]

Hello there Acrylics. I've been reading through pages of this thread and I think I can do this but I want to be sure. I'm working on a buddie's tank. 80'x30" and 36" deep. 1 inch thick acrylic. Built in center overflow in the back. Due to being improperly supported while it was stored it cracked from the back edge, under the overflow and out into the tank itself across the bottom. I can feel the crack on the bottom outside but not inside. The entire crack is about 12 inches long. Is this reliably repairable in your opinion and if so, what is the best procedure? Thanks for any advice and guidance and for all the time you put into this forum. It IS appreciated.

 

[buck27]

Is it ok to make a 84x24x30 tank out of 1/2" cast with euro bracing? I was going to build it myself but wanted to ask the pros. I have only ever built a 29 gallon but I did it very well and have decided to up the stakes a little with a much larger tank. Any info is appreciated. Thanks guys

buck

 

[noobtothereef]

i would go 3/4" and you will need a center brace, no getting around the center brace on a tank that large unless you go even thicker or the eurobrace would have to be very wide

 

[Acrylics]

Ok so I was looking up Marga Cipta and it doesn't seem very popular here. My jpits look really good using the needle and shim method. No crazing after about 6 months either.

So... how do y'all know it won't be a good material to use?

Seen too many failures over the years..

When will it fail if it does even?.

No telling if or when, maybe it never will, but I don't count on "maybe" - I count on my experiences and what I've seen

i was using Chemcast but my go to supplier(Allied Plastics) stopped carrying it, thus the Marga Cipta. Cyro Acrylite is 2x the price while Chemcast at another supplier(Regal Plastics) is 1.7x the price of Allied when they did have it.

Any suggestions?

BTw I'm not building any sumps bigger than 40G and don't do the eurobracing.

Personally, I don't care about the price of the material. *If* your sump blows and you've got a bunch of saltwater on your carpet, is that $50 you "saved" using cheap material really a savings?

For me and my tanks, it's Polycast and only Polycast..simply the best for our purposes

Will it work OK to mix and match acrylite FF and plexiglass G?

I need to build a sump and have enough mixed scrap to do it, but not enough to do it all out of one or the other. Would that work OK, or am I better off ordering enough to do it all with one or the other?

thks

you can mix if necessary

Hello Acrylics.

What can you suggest for gluing ceramic plates to the inside back of an acrylic tank?

I'd use either silicone (DC 795) or Weld-on 40

Hello Acrylics,

Can holes already in a sheet of acrylic be reamed out with a diamond hole saw to make a bigger hole? I will probably only be going from a 1-1/2" hole to a 1-5/8" hole on an acrylic display tank. I'm redoing some plumbing and the bulkhead in this hole is too flimsy so I'd like to go from a standard 3/4" bulkhead to a heavy duty 3/4" bulkhead. I could use a 1-9/16" saw and then a 1-5/8" saw so it won't be such a big increase in hole size? Or do you think one hole saw at 1-5/8" would work. I would probably go metric which is much cheaper with a ~40mm diamond saw and then a ~42mm saw.

Personally, I'd use a router with a 1/16" rabbet bit, and then clean up with a pattern bit. This will increase the hole size by 1/8"

HTH,
James

 

[Acrylics]

Hello there Acrylics. I've been reading through pages of this thread and I think I can do this but I want to be sure. I'm working on a buddie's tank. 80'x30" and 36" deep. 1 inch thick acrylic. Built in center overflow in the back. Due to being improperly supported while it was stored it cracked from the back edge, under the overflow and out into the tank itself across the bottom. I can feel the crack on the bottom outside but not inside. The entire crack is about 12 inches long. Is this reliably repairable in your opinion and if so, what is the best procedure? Thanks for any advice and guidance and for all the time you put into this forum. It IS appreciated.

Not even gonna touch this without seeing it, far too many variables. FWIW I sincerely doubt it cracked due to it being improperly supported during storage. A well made tank can be hung by a eurobrace alone or just stretched between two sawhorses for storage. There is another issue somewhere, I can just about promise that.

Is it ok to make a 84x24x30 tank out of 1/2" cast with euro bracing? I was going to build it myself but wanted to ask the pros. I have only ever built a 29 gallon but I did it very well and have decided to up the stakes a little with a much larger tank. Any info is appreciated. Thanks guys

buck

I agree with noob on this; 3/4" at a minimum depending on the width of the bracing and number of crossbraces.

HTH,
James

 

[cherubfish pair]

Personally, I'd use a router with a 1/16" rabbet bit, and then clean up with a pattern bit. This will increase the hole size by 1/8"

Thank you!

 

[kcress]

Ditto James.

 

[noobtothereef]

does anybody know a supplier for acrylite gp in 1" thickness with 72"x120" sheet sizes? or even 48"x120" sheet sizes, everybody local thinks im crazy for a 120" length, it can also be polycast

 

[noobtothereef]

Hello there Acrylics. I've been reading through pages of this thread and I think I can do this but I want to be sure. I'm working on a buddie's tank. 80'x30" and 36" deep. 1 inch thick acrylic. Built in center overflow in the back. Due to being improperly supported while it was stored it cracked from the back edge, under the overflow and out into the tank itself across the bottom. I can feel the crack on the bottom outside but not inside. The entire crack is about 12 inches long. Is this reliably repairable in your opinion and if so, what is the best procedure? Thanks for any advice and guidance and for all the time you put into this forum. It IS appreciated.

Im sure its some sort of stress crack, if it were mine first i would drill a 1/4" hole trhough the bottom at each end of the crack, then take a die grinder on low speed and "v" out the crack, then take weld on and cast the "v'd" crack and holes, somebody will have to chime in on which weld on, i think 40, then i would take a piece of 3/8" acrylic larger then the entire repaired area and bond it over that area just for a second failsafe, make sure the patch goes past the ends of the crack by at least a couple of inches, the bad thing that it goes under the overflow so im not sure of the best repair, maybe just bond an overlay on each side of the overflow where the crack is present and seal it religiously with weld-on 40..... i am no expert , but that is ALOT of water to leak out while your gone at work...

 

[vthondaboi]

Ok so I picked up some 1/4 cell cast acrylic last month from a supplier and they said it was Polycast. It came in a plain brown paper mask. Is this how it normally comes?

Just curious if they just wanted to tell me a brand that I wanted to hear...

 

[noobtothereef]

Acrylics, have you ever done butt joints in thick acrylic? Im contemplating building a bull-nose , i cannot find 120" material at a reasonable price, price per square foot skyrockets over 96" for some reason, i have a shop in town that has an oven to bake the sheet for me and i can build the form for it, so if i go bullnose i can utilize 3-96" sheets , but that brings into the equasion 2 butt joints, i have never done a butt joint but im assuming its as easy as routering roughly a 20-30 degree angle in the pieces being joined and also spacing it .030 and placing a backer and then casting the gap and overfilling to avoid shrinkage, then sand and polish the area? Since the sheet will be drape formed it will have been heated, will this cause crazing during the casting and bonding process?