Acrylic fabrication questions? I can help!

[Floyd R Turbo]

Thanks for the answer. Do you think is too thin even though it will technically be 14" tall (there is a drain that does not allow more than that)?

better, but it's still going to bow quite a bit IMO. This is usually not a major problem as long as your fabrication techniques are good. Bond your baffles in at the same time as your end panels (i.e. bond all to front, flip, bond all to back one at a time) instead of after the fact because you have to treat the baffles as structural joints so the bond can't be a capillary weld (weak)

Also it's not just a matter of bowing. There is a formula that has to do with water pressure (on the bottom joint) that drives panel thickness. 14" is pushing it IMO

EDIT: that being said you see eshopps sumps 16" tall made out of 3/16" all the time. It doesn't mean it's right to build it to the minimum though. I've sen those cheap sumps crazed all over the joints because of it. There's a reason they are cheap/inexpensive.

 

[Floyd R Turbo]

could 1/4" be used to do a 48" x 12" x 12" display? I would do a euro brace, If not could it do a 36" x 12" x 12" Would probably only fill to 10.5 to 11"

It's not so much a matter of width as it is depth. The euro will help with bowing which strengthens the overall build. 12" filled to only 10-11" is probably ok. I use 3/8" for all exterior walls, it just makes me feel better.

 

[thejuggernaut]

Thanks for the input about the drains. I'll continue that discussion on the other thread, don't want to get this one off topic. As far as my acrylic work being nice I say...

Thanks, I learned from the best!

 

[Royce7586]

It's not so much a matter of width as it is depth. The euro will help with bowing which strengthens the overall build. 12" filled to only 10-11" is probably ok. I use 3/8" for all exterior walls, it just makes me feel better.

Awesome thanks! Is their a page that you do a write up on the process of fabrication? This post is so long I have no idea where to look. I work at a sign shop so have a general idea of joining acrylic but my joints dont have to hold the kind of weight a fish tank does.

 

[thejuggernaut]

Start here.
This is probably the most concise thread about the subject. Obviously this thread has answers to almost any questions you could ask, but like you said, it would take about about a month to read through it. Good luck and Happy Hunting

http://www.reefcentral.com/forums/showthread.php?t=390652

 

[rickztahone]

Floyd, I remember reading (I believe you mentioned it) that when welding baffles on an acrylic tank, you do the pin method on one side only? I'm trying to visualize how to best weld in baffles in my sump and am kind of lost. Would you not cut the piece of acrylic to sit right up against the sump walls? If so, how do you get the pins in? Can you simply apply baffles without pins with weld on #4 and then simply make a pass at them with weld on #16?

 

[Floyd R Turbo]

So what you do is start by bonding all the panels one at a time to the front panel. Order doesn't matter, it depends somewhat on baffle spacing. Up/downs are the toughest. More on that later

All baffles that touch the bottom panel need to be square and identical in relation to the other panels that also touch the bottom. If you can stack and tape and square them together, then mark one side as a reference so that side on all panels is facing the same direction, then if you're off-square you're OK because they're all equally off.

Now, you flip the entire assembly over on to the back panel. Bond one end panel and let it sit for a few hours. Right after you pull the pins and before the joint sets up, make sure that the other end panel lines up right, if not, then all the panels will be off.

After 2 hours, pin the next joint & set. Check last end panel alignment again. Wait 2 hours. Keep going until you have them all done.

If you have a set of up/downs that are 3 in a row with an inch or less between them, the middle one will be hard to get at. However the middle one is usually an 'up' baffle and has no pressure on it. So for this one, I pin it along with the next baffle and do them both at the same time. Or, if you can rig it up (usually by putting a 5lb weight on the top of the assembly) you can get all 3 baffles at the same time, but this can get tricky because #1 and #3 need to be flush with the bottom joint and lining up 2 of these at the same time can be problematic. So I usually do #1, and #2 together, or #2 and #3 together so I only have to line up one critical panel at a time. What you may find is that even with CNCd parts, things don't always want to line up dead-on because of variations in the thickness of the acrylic sheet (this is a known issue and not much you can do about it) which will cause a perpendicular bonded panel to line up differently (a few mm) depending on where you bond it.

Anyways, when you set a joint if it doesn't line up quite right then you essentially have to push it into position and hold it there for a few minutes until the solvent starts to set up, and in some situations, you need to use a large bar clamp to keep it there, even some shims in really bad lineups. I'll have to dig up a pic of one huge sump I did that I have to get creative on.

So once you get all the baffles in, they are all pin set joints and very solid. Then you scrape all the junctions on the bottom & top of the assembly to get rid of any lips, ridges, and solvent drips/finger smudges and bond the euro on, then the bottom, flush trim, done

You can use #16 if you have a bubble in a baffle joint that leaks (from one side of the baffle to the other) but this is pretty rare if you are able to pin the joints. For the 'up' baffle, this is generally not structural and so you can just wick it in afterwards if you want, but I would pin it on the first side so that you only have to do one joint this way (and put it on the back so no one sees it)

 

[rickztahone]

So what you do is start by bonding all the panels one at a time to the front panel. Order doesn't matter, it depends somewhat on baffle spacing. Up/downs are the toughest. More on that later

All baffles that touch the bottom panel need to be square and identical in relation to the other panels that also touch the bottom. If you can stack and tape and square them together, then mark one side as a reference so that side on all panels is facing the same direction, then if you're off-square you're OK because they're all equally off.

Now, you flip the entire assembly over on to the back panel. Bond one end panel and let it sit for a few hours. Right after you pull the pins and before the joint sets up, make sure that the other end panel lines up right, if not, then all the panels will be off.

After 2 hours, pin the next joint & set. Check last end panel alignment again. Wait 2 hours. Keep going until you have them all done.

If you have a set of up/downs that are 3 in a row with an inch or less between them, the middle one will be hard to get at. However the middle one is usually an 'up' baffle and has no pressure on it. So for this one, I pin it along with the next baffle and do them both at the same time. Or, if you can rig it up (usually by putting a 5lb weight on the top of the assembly) you can get all 3 baffles at the same time, but this can get tricky because #1 and #3 need to be flush with the bottom joint and lining up 2 of these at the same time can be problematic. So I usually do #1, and #2 together, or #2 and #3 together so I only have to line up one critical panel at a time. What you may find is that even with CNCd parts, things don't always want to line up dead-on because of variations in the thickness of the acrylic sheet (this is a known issue and not much you can do about it) which will cause a perpendicular bonded panel to line up differently (a few mm) depending on where you bond it.

Anyways, when you set a joint if it doesn't line up quite right then you essentially have to push it into position and hold it there for a few minutes until the solvent starts to set up, and in some situations, you need to use a large bar clamp to keep it there, even some shims in really bad lineups. I'll have to dig up a pic of one huge sump I did that I have to get creative on.

So once you get all the baffles in, they are all pin set joints and very solid. Then you scrape all the junctions on the bottom & top of the assembly to get rid of any lips, ridges, and solvent drips/finger smudges and bond the euro on, then the bottom, flush trim, done

You can use #16 if you have a bubble in a baffle joint that leaks (from one side of the baffle to the other) but this is pretty rare if you are able to pin the joints. For the 'up' baffle, this is generally not structural and so you can just wick it in afterwards if you want, but I would pin it on the first side so that you only have to do one joint this way (and put it on the back so no one sees it)

While you made it very straight forward, it does some rather complicated. I will mull that over for a while and see where I stannd, lol. I kind of wish I had a glass sump now, lol.

Thanks Floyd.

 

[rickztahone]

You wouldn't happen to have a video of you using this technique would you?

 

[thejuggernaut]

I ordered some slip bulkheads for the overflow. Hopefully by middle of next week I can do some tests on the system. If I get the front section built by thursday that should give it 5 days to cure before introducing it to water. Ill make a video once I start doing drain tests.

 

[Floyd R Turbo]

While you made it very straight forward, it does some rather complicated.

It's less complicated than trying to bond a baffle in after you have the bottom on. Trust me. You have to either scrape out the fillet or round off the corner to get the panel to touch, then your wick in joint will be full of bubbles and likely will leak, so you'll have to run 16 over it a few times, or silicone it (which works too).

Once you do it you'll see that it's actually rather easy taking it step by step

You wouldn't happen to have a video of you using this technique would you?

I don't, sorry.

 

[rfgonzo]

I'm building another sump, this time following your instructions welding two sides and also the baffles to the Front/ back panel all at once. My question is do you use shims? For the baffles? Not sure how you would go about doing this with shims or if it's even possible.

 

[Floyd R Turbo]

Good question: you can easily shim up on the end panels, and this is where it matters. But you are correct, it is really difficult to shim up a gap for a baffle. This is where using the MDF strips with foam on both sides really helps, if the whole panel has these under it, any inconsistencies of your work surface will be lessened and this becomes much less of a problem.

But, if you do have problems in the middle of a baffle joint (you can see this when you dry-fit the joint before pinning), the foam strips raise up the project off the table and sometimes this is enough to take a very long shim and sneak it inbetween the mdf/foam strip and the horizontal panel. Usually though, this is not a problem that I have run into.

 

[NEReef]

Hey I am looking for some input on what are ok temp/ weather conditions for using methyl chloride for patching cracks not edge jointing? It being cold and gross up here in MA I don't want to hold off till it is nicer outside, but I also am concerned about using the chemical indoors for health reasons. Also since it is thin and I am trying to join to large flat surfaces it seems like the pin method won't work so how do i go about bonding two large flat surfaces together?

 

[Floyd R Turbo]

weather affects curing time, too cold and the joint can cure slow, too hot and it cures fast, both can cause a weaker joint than doing it at 70-75 F. Humidity affects clarity of the joint, too much and the solvent will dry with a whitish surface. Both of these can be eliminated by using 15% Ethylene Dichloride but at $180 a gallon I shall pass (it's also a nasty carcinogen)

But that all mainly matters for joints. For panel laminating, don't worry. Just about any temp is OK but I would shoot for 55-60F minimum, so if you have to leave the garage door open to heat up the space a bit from the house heat, that'll work.

Plus it is mainly the material and solvent temp that matters, you can warm them up inside for a few hours and then take to the garage and that will work OK.

for laminating surfaces it depends a bit on how big the surface is. you can literally brush the solvent on and then slap the piece together but you have to work fast and it's going to look like %#$@. But it will work. If it's a very large surface, you can use a #16 needle in a 2 oz bottle and squeeze a whole bunch out in a line along one edge, then start contact along that edge and lower the panel down by bowing it in the middle and "work" or "push" the solvent to the other edge. Having another hand to apply more solvent as you go helps. But you don't get much working time, the panel can set up on one end as you're lowering it so either work very fast or line it up perfect from the get go (of have one person watching alignment as you go)

You can also use #16 for this instead of #3 or #4. Still have to work fast but cures a bit slower so you get more working time. But you have to go before it starts to skin over.

 

[thejuggernaut]

OK, so I know to wait 24 hours to flush cut, but how long before it is safe to get it wet?

 

[Floyd R Turbo]

I would wait a few days, then a pressure test fill is fine, but I would wait a week minimum before putting into use and my rule of thumb is a week for every 1/4" of thickness of material

 

[NEReef]

weather affects curing time, too cold and the joint can cure slow, too hot and it cures fast, both can cause a weaker joint than doing it at 70-75 F. Humidity affects clarity of the joint, too much and the solvent will dry with a whitish surface. Both of these can be eliminated by using 15% Ethylene Dichloride but at $180 a gallon I shall pass (it's also a nasty carcinogen)

But that all mainly matters for joints. For panel laminating, don't worry. Just about any temp is OK but I would shoot for 55-60F minimum, so if you have to leave the garage door open to heat up the space a bit from the house heat, that'll work.

Plus it is mainly the material and solvent temp that matters, you can warm them up inside for a few hours and then take to the garage and that will work OK.

for laminating surfaces it depends a bit on how big the surface is. you can literally brush the solvent on and then slap the piece together but you have to work fast and it's going to look like %#$@. But it will work. If it's a very large surface, you can use a #16 needle in a 2 oz bottle and squeeze a whole bunch out in a line along one edge, then start contact along that edge and lower the panel down by bowing it in the middle and "work" or "push" the solvent to the other edge. Having another hand to apply more solvent as you go helps. But you don't get much working time, the panel can set up on one end as you're lowering it so either work very fast or line it up perfect from the get go (of have one person watching alignment as you go)

You can also use #16 for this instead of #3 or #4. Still have to work fast but cures a bit slower so you get more working time. But you have to go before it starts to skin over.

So floyd if I have the materials warm in the house and i take it outside to bond the material how long do I have to wait for most of the solvents to flash off before i can bring the piece back in the house without worrying about exposing my family/pets to vapors? Since it will just be a small patch in my sump I don't really care what the joint looks like I am more concerned about strength. The chemical solvent I have is very thin. It looks like water in the dark glass bottles it came in. I have a needle applicator but was worried about just pouring a puddle on the piece then dropping a patch on top of it. Should I use paper towels to absorb any excess so as not to stress the surrounding acrylic?

Also how aggressive should I be when trying to sand out the scorch marks from the heater? Does the surface need to be prepped to a certain level before trying to patch?

 

[thejuggernaut]

I got the internal box all welded up.

I had to drill two holes in my setup to clear the bulkheads.

You can see the bulkheads sticking through the bottom, but the part is completely supported.

Getting ready to seam the bottom. The longest joint I had done so far.

Here it is hours later. Going to flush cut tomorrow evening and try some different buffing techniques.

Here is my scraping block! Exciting stuff guys!

Floyd, I got this stripping at Lowes, and it works pretty good. It's almost like memory foam. I doesn't stick to the parts. You should give it a try next time your there. Also, it is thicker than the normal stuff.

 

[Floyd R Turbo]

So floyd if I have the materials warm in the house and i take it outside to bond the material how long do I have to wait for most of the solvents to flash off before i can bring the piece back in the house without worrying about exposing my family/pets to vapors? Since it will just be a small patch in my sump I don't really care what the joint looks like I am more concerned about strength. The chemical solvent I have is very thin. It looks like water in the dark glass bottles it came in. I have a needle applicator but was worried about just pouring a puddle on the piece then dropping a patch on top of it. Should I use paper towels to absorb any excess so as not to stress the surrounding acrylic?

Also how aggressive should I be when trying to sand out the scorch marks from the heater? Does the surface need to be prepped to a certain level before trying to patch?

You just want the surface smooth and flat so that it doesn't push the patch up and prevent it from attaching fully on the 'clean' area, where you are making the seal. But this one is pretty close to the joint so I would try to make it pretty smooth. You can use 80-100 grit to get the bumps off, then go to 150, 300, 400, etc to get most of the deep ridges out. The patch job won't look the best, but it should hold.

Personally I think the biggest problem is the crack that goes through the bottom panel. This will continue to get worse unless your patch is a corner gusset and expands around the joint in question, and even then, it could still crack out. But, the solvent for the patch might wick into the crack far enough to bond it a bit and it might be OK. But you'll have to keep an eye on that.

As far as time before taking inside, a few hours and it won't be really stinky, but you might still smell something.

The solvent I use is this

And yes, I buy it by the gallon (4L) jug. The last one lasted me 4+ years. Just bought another, $52 what a bargain!

I keep it in smaller bottles for daily use

8oz Wide Mouth Amber Glass with PTFE lined lid, $4 each or something like that. I use these and mix about 4oz (120mL) with about 6-8mL of Glacial Acetic Acid (5-7%).