Acrylic fabrication questions? I can help!
- Thread starter JohnL
- Start date
nothing to speak of. You might notice a little if you placed a straight-edge on it, but only 1/16" or so.
James
What is the quality of the Acrylite GP 1.25 cast acrylic? Do they carry Polycast in 1" thickness in black? Haven't really seen it listed on any sites. Would it also be possible to use vinyl or window tint to black out panels? Could it be used on the inside of the panel vs. the outside? I'm asking do to the fact of running an external overflow box, and you'd still be able to see into the overflow box from the front of the tank.
noplay180
New member
Hello I have been reading through this great thread and saw that chemcast acrylic has a bad rep. I have already purchased this prior to discovering this thread should I try to get another type of acrylic or should I just use the chemcast. I am building a sump 48x24x16 with 4 baffles all in 3/8. Please Help
I can't say anything about the new GP in 1.25".. historically, it's been good, but I only use Polycast these days so honestly don't know. Since my livelihood is on the line, I don't take chances and they haven't sent me any to play with. I do know it's made in Germany and imported here, but that's really about all I know of it nowadays.
Polycast does make 1" black, but it isn't stocked many places unless the distributor has a local customer that uses it regularly. I know it's kept in stock for me at my branch, and I'm sure at branches local to other tank builders: Vegas, Phoenix, and LA would be examples of such.
I've see window tinting used on the outside of tanks, but not the inside. As for vinyl, I don't know. I just use solid black acrylic. But there's no law that says you can't silicone 1/4" to the inside of a tank wall
It's got a bad rep from me due to what I've seen of it; the number of tanks I've replaced due to catastrophic failures..
As for whether you should use it or not - I cannot say. That choice is completely up to you. I can only say *I* will not use it for tanks, nor recommend it for any pressure vessel. Does this mean it *will* fail? certainly not.. I'm fairly certain the failure rate is pretty low, but high compared to Polycast.. just for whatever that's worth
James
noobtothereef
New member
Hey james, do you have a chart or anything like that that figures in forces of water pressure at different depths? Im trying to figure the statics loads that will be placed on the tank walls, does any tank builder use information like this? Or is it just an expierience thing and know whats needed from trial and error etc?
Weld-on 4 will be fine.
Water pressure itself is only a small part of what is determining thickness. We determine material thickness based on deflection rates. If deflection is within reason, then water pressure itself is inherently accounted for. Water pressure is the same whether the tank is 1" long or 50' long, it's the span on that pressure that is important and determines deflection, bracing, thickness, etc..
For example, a tank 1" x 1" by 120" tall can be made from 1/8" acrylic with no bracing.. but widen that out - not so much
James
noobtothereef
New member
Weld-on 4 will be fine.
Water pressure itself is only a small part of what is determining thickness. We determine material thickness based on deflection rates. If deflection is within reason, then water pressure itself is inherently accounted for. Water pressure is the same whether the tank is 1" long or 50' long, it's the span on that pressure that is important and determines deflection, bracing, thickness, etc..
For example, a tank 1" x 1" by 120" tall can be made from 1/8" acrylic with no bracing.. but widen that out - not so much
James
I think i may abandon the idea of the bullnose part, the problem area seems to be where the bullnose meets the flat side panel,(the end of the radius) I think its just going to want to bow to much, i may just go a rectangle with a step on the end. With the bullnose i agree that it would have to be 2" thick or better. Plus going this route i will still achieve the deep stepped end but not have the need to cast the seam of the bullnose and the sides together. Now just if i could find 72"x144" sheets of 1.5" anywhere..... Doesnt seem to be a popular size...
When i put this together the second to last piece will be the "L" bottom, when i route the side panels to the "L", i am going to radius that inside corner of the "L", when you route 1.5" like this, do you cut this off with a saw first and then route with a flush bit? I dont see cutting the 1.5" with a flush bit in 1 pass, I could use a non flush bit and route it in multiple passes with a jig to leave excess material to route up flush to the bottom panels, how does this sound?
Last question i would like to strengthen the seams on the bottom with a "triangle" shaped material like many do on theyre inside corners, how is this done? After putting a seam together it seems that i always have a bit of "squish" of material come out of the joint when i remove the pins and place the panels together, i dont see how i could put a perfectly square piece in that corner as its inside corner will interfere with the "squish", would i sand off just enough on that inside corner to clear the "squish" to allow it to sit flush and then hold it out with pins on either side and then use capilary/wo4 and fill and then remove pins? I need to make this optically perfect as this will be on the front visible corners. Would i be better off casting these in place instead? As if there would be any voids in the corner piece wo4 isnt meant for filling these areas
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noobtothereef
New member
will the bottom and top of this need to be 1.5" as well?
james, this is not a diy question but would like your opinions.
i just bought a used tenacor acrylic tank from a LFS used and when i placed the tank on a flat surface, the tank does not sit flush. the tank is wobbly and it seems as though there is 1/8-1/4 space in one corner when three sides of the tank touch the surface.
am i asking for trouble with this tank. it is a small tank about 24x18x24.
your opinion is greatly appreciated.
i just bought a used tenacor acrylic tank from a LFS used and when i placed the tank on a flat surface, the tank does not sit flush. the tank is wobbly and it seems as though there is 1/8-1/4 space in one corner when three sides of the tank touch the surface.
am i asking for trouble with this tank. it is a small tank about 24x18x24.
your opinion is greatly appreciated.
I have a 4x2x2 acrylic tank that has a center overflow drilled in the bottom. I can't use the holes in the bottom, so I need to cover them.
I know I'll have to bond a piece of acrylic over it, any tips on what to use/how to do that? I'll also need to drill the back for new bulkheads...what should I use?
Thanks for the help!
Colin
I know I'll have to bond a piece of acrylic over it, any tips on what to use/how to do that? I'll also need to drill the back for new bulkheads...what should I use?
Thanks for the help!
Colin
bioload
Having moments of clarity
Can't believe this is the first time I'm seeing this tread.......Great Work!
Working on a few media reactors at the moment 6"OD 1/8" wall. I'm currently using a router to prep the edges for welding to the base and flanges.
A bit tedious, and requires several passes to get it flat.....Just wondering if anyone has some tips to get this done. I'm finding this way requires a VERY steady hand.
Here are some pics of the process I used for my skimmer
Working on a few media reactors at the moment 6"OD 1/8" wall. I'm currently using a router to prep the edges for welding to the base and flanges.
A bit tedious, and requires several passes to get it flat.....Just wondering if anyone has some tips to get this done. I'm finding this way requires a VERY steady hand.
Here are some pics of the process I used for my skimmer
Reynolds Polymers in Grand Junction, CO has 6' x 15' sheets made, industry termed "RPG Asia." However, all joints with this material must be cast as it doesn't solvent bond well at all.
Personally? I use a router and mulch it out, but several passes with a final finish pass is just fine.
Don't bother IMO. Provided you do well on the joints, this won't help at all and may actually hurt as it further stresses the material. If you really wish, then cast it in place when you glue the bottom on (assuming RPG Asia material)
Generally no, but the top depends on your bracing scheme. The bottom can be thinner though I wouldn't go any thinner than 1" (personally)
James
More than likely was originally on a stand without a truly flat deck or a very thin one. Over time the bottom bowed down into a "bubble".. nothing you can do about it without replacing the bottom which is not advised on a tank this small/inexpensive unless you want to do it for "culture"
James
just get pieces of say 3/8" or 1/2" that will overlap the holes by 1/2" or so and glue it on using solvent or (IMO) just silicone them down. Spooge a bunch of silicone on the piece(s) and slap them down over the holes. Smush it around a little and wait for the silicone to cure. It's what I do on my personal tanks. If you want it permanent, glue the piece(s) down with Weld-on 4 using wires or pins, you can use Weld-on 16 or 40 and follow the silicone instructions above.
For the holes in back, any hole saw will work fine. Just drill away; do not stop the saw in the hole, use a 50:50 solution of Palmolive and water as lube/coolant, and use this liberally. Use firm pressure but not too hard, keep medium speed - don't try to race through it.
James
Where your level is as a fence, use a fence that is at least as tall as the tube (6"+ in this case) The fence must be perfectly perpendicular to the work surface for this to work properly.
...or omit the routing by taping 220 and then 320 sandpaper to a flat table and sand the ends flat. Use the 220 to get it flat and 320 to prep for gluing. Only sand in one direction as human hands/arms tends to pivot the piece if sanding back on forth.
Other option is to chuck them up in a lathe if you have one
HTH,
James
More info on why I had asked about laminating thinner material to thicker material. The idea would be to overlay an 1/8" piece over a 1" thick clear piece to avoid the expense of buying a full sheet of black. The laminated piece would be the back wall of the tank blocking out the overflow. That was my intention for wanting to know.
Painting isn't really an option due to the overflow being external, so the water would be in contact with the paint.
Painting isn't really an option due to the overflow being external, so the water would be in contact with the paint.
If I want it permanent, do I use Weld-on 4 with wires/pins OR Weld-on 16 (or 40)? Or is that a two part process?
Sorry...total acrylic newb.
Colin
dlp211
New member
I have an internal glass overflow box that I want to black out and the consensus was to us a piece of black acrylic. The only problem is that the overflow is a coast to coast and I need to figure out how to affix the acrylic to the glass.
So far I have thought of using rare earth magnets, fabricating a lip that could latch to the glass, superglue or epoxy.
I would prefer to affix the acrylic directly to the glass with magnets being my second favorite option. I really don't want to fabricate a lip just because of the length 65" and the very slim width 3/8".
Thanks for the help.
So far I have thought of using rare earth magnets, fabricating a lip that could latch to the glass, superglue or epoxy.
I would prefer to affix the acrylic directly to the glass with magnets being my second favorite option. I really don't want to fabricate a lip just because of the length 65" and the very slim width 3/8".
Thanks for the help.
