saintsnsinners
New member
Oops 1/8".
Acrylic fabrication questions? I can help!
- Thread starter JohnL
- Start date
Floyd R Turbo
Either busy or sleeping
Yeah 1/8" is nothing. What is the material thickness?
saintsnsinners
New member
1/2". dimensions are now 36" x 19" x 8.5".
saintsnsinners
New member
Is there a max tolerance for warping? it has now gone from 1/8" to 1/4". I haven't filled it back up yet. would a center brace help at all?
Floyd R Turbo
Either busy or sleeping
Yes, I would add a center brace.
saintsnsinners
New member
Is there a general guideline as to when bracing or baffles are required to avoid warping?
Floyd R Turbo
Either busy or sleeping
Yes, a perimeter euro is all you need for a 24" tank, then it's a brace every 24". I make rimless frag tanks that are 8" tall 1/2" material and 36 x 24, that's about the limit IMO for 1/2" rimless.
Now that I say that, I look at your info provided and see that your tank is probably 36" long as well and 8" tall, so really a 1/4" bow is not out of the realm of expectation, part of it because the material has warped from normal use, then it will bow a bit upon filling. But that is not a ton of deflection, you would start to see the vertical seams separating long before the tank gave out - if it was well constructed that is, which it sounds like it was (most 40Bs are 3/8" acrylic)
Now that I say that, I look at your info provided and see that your tank is probably 36" long as well and 8" tall, so really a 1/4" bow is not out of the realm of expectation, part of it because the material has warped from normal use, then it will bow a bit upon filling. But that is not a ton of deflection, you would start to see the vertical seams separating long before the tank gave out - if it was well constructed that is, which it sounds like it was (most 40Bs are 3/8" acrylic)
saintsnsinners
New member
I've had water in it all weekend and it hasn't bowed any more. seams look good. it was well built, but it was built with that astari junk. that's why I'm being extra careful.
saintsnsinners
New member
What is the best way to bend small pieces for overflows, probe holders, etc?
saintsnsinners
New member
How can you avoid crazing when flame polishing?
Steveb
Premium Member
Got the triangle in. It doesn't have a cupped back that I can see. I put a steel rule across it and put a flash light back behind the rule, I didn't see any light shine through (between the rule and the triangle).
Floyd R Turbo
Either busy or sleeping
You can use a line heater, but you gotta find one. If the material is thin enough and you don't care about it looking pretty, you can heat it up with a propane torch or a heat gun. If you have to bond the now angled edge, then you will have to sand it as it will bulge out at the bend.
Difficult to avoid, which is why it's better to wet sand and then use a buffer. I use black & decker orbital buffer, just one of the big box store ones, for small jobs and rimless frag tanks, and then I have a high-speed polisher if I need to repair a panel scratch or have something look perfect.
Yep, the USP version looks like an actual right triangle. The one from ePlastics is not, it has a cupped edge so when you put a square on it, only the tips touch. So you're good. Good to know where to get the correct right-triangle rod also.
saintsnsinners
New member
1. What grit of wet sandpaper do you use? I have an orbital buffer and some meguires plastic polish.
2. I want to try bending acrylic for my next build but I don't know how to go about doing it. let's say I want a frag tank 20 x 20 x 8 using 1/4" acrylic. how would I bend the front/sides piece of acrylic so that it remains a perfect square?
3. how can I make a router template for making overflow teeth?
2. I want to try bending acrylic for my next build but I don't know how to go about doing it. let's say I want a frag tank 20 x 20 x 8 using 1/4" acrylic. how would I bend the front/sides piece of acrylic so that it remains a perfect square?
3. how can I make a router template for making overflow teeth?
Floyd R Turbo
Either busy or sleeping
I didn't realize I missed this post, and boy does time fly when you're busy at home & work....
Anyways, after I round edges off with a router I mask off on either side with blue tape then start wet sanding with 800 and as long as that gets things generally smooth and even then 1200, 1500, 1800, 2000. lots of rinsing the paper and rinsing the sanding area during the process (I use a spray bottle with tap water). After than I hit it with the orbital and the Meguiar's Ultra-Cut (105) and that's usually good for corners. At that point you will be able to tell if your sanding job was good enough, because any patterns that didn't get removed from one step to the next will show up. Then you have to go back to those areas and get the scratch out, go through the stages, and polish again (which goes fast for a small area).
I use the sanding block from the micro-mesh kit, it works well. I use the paper from there too, but I also have a lot of sizes available in full sheets from my local woodworking store.
As for bending acrylic, you need to buy or make a bending jig to get things perfectly square. It's simple enough, my dad has one he uses for making display cases, just 2 pieces of melamine coated boards with a hinge in the middle and a piece of wood on top of each to keep the piece in position (like a "stop block") and clamps on the pieces and then he puts a strip heater on/under the acrylic to heat it up, when it starts to soften you take the heater out and fold the boards to a 90 degree angle. He has a bracket on it so that when it hits 90 degrees it locks in position so he can leave it there as it cools. Takes some practice, and my explanation above it hard to follow I'm sure if you have never seen one but that is the general idea - keep the 2 sides of material on either side of the bend held in place so they don't "twist" as you bend them, and maintain the desired angle after the bend.
As for making and overflow template, I did this using double-stick tape (intertape). Take your template piece, that has one edge routed straight, and place that flat on a table with 1" or so hanging over the edge and clamp it down. Take a long piece that is also straight on one edge and tape it down parallel to the main piece. This is your limit stop, or backstop - meaning, you can't push the router any further than this piece (your router base will hit it). Then take another strip that is square on one corner (or close enough) and place it on top of the template piece, butted up against the limit piece. This is your guide stop. You will be removing and replacing this as you cut each tooth. So you place the guide stop down and run your router along it until it hits the limit stop, then back the router out, move the guide stop 1/2", and repeat. This is done with router in hand with a standard base.
The important point here is to make sure that whenever you use the double-stick tape, you need to remove the masking from all material, and clean the surfaces with denatured alcohol prior to adding the tape and attaching the pieces. When moving the guide stop, usually you can get the piece off and use the same tape for two or maybe three teeth, but eventually there will be enough acrylic dust to diminish it's holding capacity, so you need to replace the tape. If you press it down hard and you can wiggle it, replace the tape. If in doubt, replace it every time - tape is cheap, and you only need to make the template once. Clean off both surfaces after removing tape. For the guide stop I use 2 strips of tape to get better contact. Make the guide strip longer than the template you are taping it to so that you can get leverage to remove it.
You can also use the above to make a small template, say 5-10 teeth, then use that template stuck on top of a longer piece to make a larger template on a router table. Then it's just a matter of lining things up right each time you move the smaller template. Or you can just make a small template and move it several times each time you make an overflow, if you don't make many of them.
I make all my templates out of 3/8" cast material. 1/4" doesn't hold up well with bearings running on them, the teeth can easy snap. Plus 3/8" gives you better bearing contact.
hope that helps
Bud
Anyways, after I round edges off with a router I mask off on either side with blue tape then start wet sanding with 800 and as long as that gets things generally smooth and even then 1200, 1500, 1800, 2000. lots of rinsing the paper and rinsing the sanding area during the process (I use a spray bottle with tap water). After than I hit it with the orbital and the Meguiar's Ultra-Cut (105) and that's usually good for corners. At that point you will be able to tell if your sanding job was good enough, because any patterns that didn't get removed from one step to the next will show up. Then you have to go back to those areas and get the scratch out, go through the stages, and polish again (which goes fast for a small area).
I use the sanding block from the micro-mesh kit, it works well. I use the paper from there too, but I also have a lot of sizes available in full sheets from my local woodworking store.
As for bending acrylic, you need to buy or make a bending jig to get things perfectly square. It's simple enough, my dad has one he uses for making display cases, just 2 pieces of melamine coated boards with a hinge in the middle and a piece of wood on top of each to keep the piece in position (like a "stop block") and clamps on the pieces and then he puts a strip heater on/under the acrylic to heat it up, when it starts to soften you take the heater out and fold the boards to a 90 degree angle. He has a bracket on it so that when it hits 90 degrees it locks in position so he can leave it there as it cools. Takes some practice, and my explanation above it hard to follow I'm sure if you have never seen one but that is the general idea - keep the 2 sides of material on either side of the bend held in place so they don't "twist" as you bend them, and maintain the desired angle after the bend.
As for making and overflow template, I did this using double-stick tape (intertape). Take your template piece, that has one edge routed straight, and place that flat on a table with 1" or so hanging over the edge and clamp it down. Take a long piece that is also straight on one edge and tape it down parallel to the main piece. This is your limit stop, or backstop - meaning, you can't push the router any further than this piece (your router base will hit it). Then take another strip that is square on one corner (or close enough) and place it on top of the template piece, butted up against the limit piece. This is your guide stop. You will be removing and replacing this as you cut each tooth. So you place the guide stop down and run your router along it until it hits the limit stop, then back the router out, move the guide stop 1/2", and repeat. This is done with router in hand with a standard base.
The important point here is to make sure that whenever you use the double-stick tape, you need to remove the masking from all material, and clean the surfaces with denatured alcohol prior to adding the tape and attaching the pieces. When moving the guide stop, usually you can get the piece off and use the same tape for two or maybe three teeth, but eventually there will be enough acrylic dust to diminish it's holding capacity, so you need to replace the tape. If you press it down hard and you can wiggle it, replace the tape. If in doubt, replace it every time - tape is cheap, and you only need to make the template once. Clean off both surfaces after removing tape. For the guide stop I use 2 strips of tape to get better contact. Make the guide strip longer than the template you are taping it to so that you can get leverage to remove it.
You can also use the above to make a small template, say 5-10 teeth, then use that template stuck on top of a longer piece to make a larger template on a router table. Then it's just a matter of lining things up right each time you move the smaller template. Or you can just make a small template and move it several times each time you make an overflow, if you don't make many of them.
I make all my templates out of 3/8" cast material. 1/4" doesn't hold up well with bearings running on them, the teeth can easy snap. Plus 3/8" gives you better bearing contact.
hope that helps
Bud
Great job Bud on your continued helpful posts. :thumbsup:
I just wanted to add (for those new to acrylic) that when heat bending acrylic, you need to pay close attention to the area being heated. It can get too hot at the surface and bubble and scorch before it gets pliable. This much depends on your heating set up. I made mine from an old dishwasher drying element bent straight. I have used other methods as well. You may need to keep flipping the piece to distribute the heat evenly through.It can also help to elevate the piece from the heat source to slow the heating.
When you heat bend a piece, the edge will distort and protrude. You then need to trim off this protrusion to make the edge glueable. Do this carefully to avoid any gaps that will make for a bad joint.
One trick I use for edge prep and polishing is to use a razor blade held perpendicular or a cabinet scraper. This only works well for thicker stock where you can keep the scraper flat. Its too easy to get off of square with thinner stock.You can put a nice edge on quickly without too much sanding. Then finish with higher grit and polish.
I just wanted to add (for those new to acrylic) that when heat bending acrylic, you need to pay close attention to the area being heated. It can get too hot at the surface and bubble and scorch before it gets pliable. This much depends on your heating set up. I made mine from an old dishwasher drying element bent straight. I have used other methods as well. You may need to keep flipping the piece to distribute the heat evenly through.It can also help to elevate the piece from the heat source to slow the heating.
When you heat bend a piece, the edge will distort and protrude. You then need to trim off this protrusion to make the edge glueable. Do this carefully to avoid any gaps that will make for a bad joint.
One trick I use for edge prep and polishing is to use a razor blade held perpendicular or a cabinet scraper. This only works well for thicker stock where you can keep the scraper flat. Its too easy to get off of square with thinner stock.You can put a nice edge on quickly without too much sanding. Then finish with higher grit and polish.
Floyd R Turbo
Either busy or sleeping
yes, generally. Acrylite GP used to be on the list as well, now anything under 1" is made in China. But I know a tank builder that uses only that, and it works fine. IIRC he said it bonds like Reynolds, something about needing a bit longer soak time.
I use the generic version of Plex-G for sumps and frag tanks, called PMACS (p-max), same stuff, no print on the mask, made to compete with import cast.
The trade off is it has no warranty. The thing about their warranty is that it is voided the minute you cut it. Verified this myself with Arkema (parent company). So it only does you any good if you buy a lot of their stuff (top 5% consumer or something like that). Other than that I think it's made in the same factory, 25% less cost or thereabouts.
Now for peace of mind you might invest in the G with the printed mask. James wrote up on this thread a while back that he would not consider using PMACS for a display tank.
That being said, I helped a buddy build a 120 tall out of 3/4" and after he set it up he spotted a divot in one of the panes that was definitely a manufacturing defect, not related to construction.
I use the generic version of Plex-G for sumps and frag tanks, called PMACS (p-max), same stuff, no print on the mask, made to compete with import cast.
The trade off is it has no warranty. The thing about their warranty is that it is voided the minute you cut it. Verified this myself with Arkema (parent company). So it only does you any good if you buy a lot of their stuff (top 5% consumer or something like that). Other than that I think it's made in the same factory, 25% less cost or thereabouts.
Now for peace of mind you might invest in the G with the printed mask. James wrote up on this thread a while back that he would not consider using PMACS for a display tank.
That being said, I helped a buddy build a 120 tall out of 3/4" and after he set it up he spotted a divot in one of the panes that was definitely a manufacturing defect, not related to construction.
Floyd R Turbo
Either busy or sleeping
Missed this post before...You could make something like this out of scrap pieces and weldon #16. But it has to support a decent weight, so you would probably want to just do a few simple things like rough cut then scrape with a razor blade, bond together, and then add in little gussets to make sure the joint is strong. Extruded will work for this, 1/4" is probably good, 3/8" is better. I'm thinking though that you can find HOB brackets for stuff like that
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