Acrylic fabrication questions? I can help!

[BeanAnimal]

Epoxy might be another way to do it, but most epoxies are brittle IME.

You may want to check your facts before you do much more estimating

Epoxy is a generic term that describes a very large family of (usually) thermosetting resins that set (polymerize) to form a very densely cross-linked chain. Certainly products in any polymer family can be formulated to be more or less flexible...

 

[H20ENG]

+1!!! NEVER use silicone grease on a bulkhead! Once you squish out a gasket you'll forehead slap yourself.

Hand tight plus a 1/4 to 1/2 turn usually means using a bulkhead wrench

As for the silicone grease... I properly installed bulkhead does not need silicone grease or sealant as the pressure of the flange against the gasket (exerted by the nut) is what provides the sealing force. The silicone grease only helps to allow the gasket to squish out of place under the pressure of the flange

 

[x2uranium]

Acrylic Question.

I am in the process of building a skimmer. I am building a beckett style skimmer I have the mixing box already fabbed up using 1/4" extruded acrylic. My question is about extruded tubular acrylic. I have priced out Cast acrylic and its entirely too expensive. My acrylic place quoted me $49 / ft for 8" OD. for 1/4". 3/16 was a bit lower but not by much. Now they sell 1/8" Extruded in a bit smaller sizes up to 6" OD which I am not concerned with the size as I can make adjustments as I go, but My question really is can I get away with 1/8" Extruded for body portion of the skimmer? I have read that its hard to work with. The sheet stuff cuts fine on my table saw with a fine tooth blade on it. I just need to know if its possible because the price is almost a 1/5th the cost of cast. I just cant afford it. So my question really is will it work? I really dont feel like making a square skimmer but I will if this wont work just want some info from the experts.

-Thanks in advance.

 

[Floyd R Turbo]

Hand tight plus a 1/4 to 1/2 turn usually means using a bulkhead wrench

As for the silicone grease... I properly installed bulkhead does not need silicone grease or sealant as the pressure of the flange against the gasket (exerted by the nut) is what provides the sealing force. The silicone grease only helps to allow the gasket to squish out of place under the pressure of the flange

Good to know! I've never had that problem...yet...so I guess I will make sure not to do that anymore! Thanks bean

 

[BeanAnimal]

There are types of gaskets and seals where the silicone grease serves a purpose. In a situation where a seal or gasket mates to a moving surface, the added librication keeps the seal or gasket from binding and deforming. In those types of situations the seal or gasket is restrained in position by mechanical means.

To keep this on-topic... that would mean a groove in acrylic flange to accept an o-ring for mating a twist-lock skimmer cup

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You should be able to click on the thumbnails to see larger images... I had trouble attaching them here

 

[fickle1]

Back to the acrylic to PVC bonding, what about Weld-On 4052? I have seen it mentioned before for this application.

http://www.avastmarine.com/ssc/do/product/adhesives/WELDON-4052-APP

 

[Hotpuppy]

You are doing it again (formulating assumptions and applying them as fact to support the answer you want to hear).
.... The irony is that your makeshift pvc to acrylic joint is in more danger of failing than a properly welded flex to hard pvc joint.

It would appear that your logic and assumption often find themselves in conflict with each other...

Look, I appreciate your experience and what you've shared... but you simply do *NOT* know more than IPS *and* Cyro. You don't. Period. There is no discussion... you can believe what you want. You can be childish and refuse to share information because you disagree with me...

I'll stick to the engineering calculations, the solvent manufacturer, and the material manufacturer's recommendations that jive with the experience of someone who has installed 15,000 to 20,000 pools. All of which, I might add, point to the same conclusion I reached.

As for PVC and spa-flex.

Flexible hose is the devil in plumbing..... it has a significantly higher co-efficient of drag than rigid pipe and is very likely to have additional bends which add to the drag in the system. It can be used as a strain relief, but the problem with spa-flex is it's non-maintainable. If it gets brittle or you stretch it too far it pulls away from the solvent weld and breaks.

Where as something like this: reinforced hose can easily and inexpensively be changed when it becomes brittle after a few years.

Personally, I prefer this type of hose... it's more expensive, but more durable and transluscent. It's also drinking-water rated. 6 inches would be enough to act as a strain relief.

I figure that for hoses, what works on boats will be good enough for aquariums. If your aquarium leaks, it's irritating. If your boat leaks it may cost you more than a wet rug. The sailing and powerboating community has spent alot of time and energy figuring out what hoses are durable and how to clamp them securely and safely.

The first type of hose would not be recommended for continuous use below the water line. The second type is.

 

[Hotpuppy]

Back to the acrylic to PVC bonding, what about Weld-On 4052? I have seen it mentioned before for this application.

http://www.avastmarine.com/ssc/do/product/adhesives/WELDON-4052-APP

I'm not familiar with that.. but when I pull up the application data PDF it shows as having a reasonably weak bond at 1200psi. Keep in mind that Acrylic has a tensile strength of 10,000 psi, and PVC is 7,000 psi. I would guess that you will experience adhesive failure if it is used under any structural pressure.

WO16 16 has a strength of 2200 PSI after 7 days...... twice as strong.

WO40 is 4,000 psi at room temperature, and 7000 psi if you bake it for a week at 150 degrees F.

When I spoke to Cyro and IPS they both recommended WO16. Acrylics, who has a ton of experience in our application prefers 40. But keep in mind he gets paid the big bucks to make pretty joints..... which 40 excels at. 40 is expensive to get and requires you to be able to mix components very accurately in grams.

And of course, Internet Experts believe that you shouldn't bond these too materials. :uhoh3:

My spin on it...... and I'm not an expert, but I've researched the :deadhorse1: out of it....

WO16 is fine for things like PVC fittings, but not for tank walls as the primary adhesive. It's good for small gap filling.

WO40 is better for anything cosmetic or where structural strength is important. the bond offered by 40 is 200% stronger than 16, but 40 requires special mixing and application techniques and tools that you may not have. It's excellent for gap filling.

Heck 16 requires a syringe too.... I'll have to share a picture of how I load 16 into a syringe. It's a much easier way to handle it.

Here is a chart that should help. I guess we can add Ridout Plastics to the list of heathens who disagree with the Internet Experts about what adhesives are recommended for cast acrylic to PVC. :lol:
Adhesive Recommendation Chart for plastics

This gets a tad technical, so just to put it in perspective.... RTV108 from Momentive (formerly GE) has a tensile strength of 400 psi.

3m 5200 - widely regarded as a permanent bond (as in be sure you don't ever want to take it apart again) is only 700 psi......

So that gives you an idea about the bond enabled by any of the solvent adhesives.

WO4 is a 2500 psi bond btw, and WO3 is 2500.

I mentioned RTV108 because it's widely accepted as being an ideal glass sealant for aquariums..... at only 400 psi.

SCS1200 btw, is 480 psi and about $3/less per tube. lest I digress... my point here is that acrylic adhesives are significantly stronger than silicone sealants used in regular aquaria.

So, all things being equal, a glass aquarium will let go long before a PVC to Cast Acrylic bond.... at least according to me, the strength data, Cyro, IPS and generally everyone except a couple of Internet Experts :uhoh3: on RC.

 

[Hotpuppy]

Here is why you want to use the largest pipe for a given flow.....
Pressure Loss chart

This excludes fitting losses....

 

[Steveb]

adhering stone/tile to acrylic tank wall

adhering stone/tile to acrylic tank wall

I have been thinking about attaching limestone or travertine tile across the back of my 96x40x24 acrylic tank like this:

interspersing Marco Rocks Primecuts like this

randomly throughout.

Anyone have any ideas on the best way to adhere stone to acrylic? With glass I would use silicon. Would that be adequate for a semi permanent bond?

The two scenarios I'm contemplating:

a) permanent bond i.e. trying to remove it is darn near impossible

b) (favored) semi permanent i.e. I could stick something between the tile/stone and acrylic and pry it loose w/out fear of the tile/stone falling off under normal operation.

I realize this has nothing to do with actual acrylic construction but thought since it is acrylic related this might be the place to post the question...

 

[BeanAnimal]

Flexible hose is the devil in plumbing..... it has a significantly higher co-efficient of drag than rigid pipe and is very likely to have additional bends which add to the drag in the system. It can be used as a strain relief, but the problem with spa-flex is it's non-maintainable. If it gets brittle or you stretch it too far it pulls away from the solvent weld and breaks.

It would appear that you are contradicting your own logic:


To point to a few instances.

• You reasoned that your DIY joint would be safe because the plumbing would be supported yet you view flexible pvc as unsuitable because it may get pulled away.
• You reasoned that the FLEX in a rigid 1" pipe would protect your joint from torque loads, but denonce the ACTUAL FLEX PVC as unsuitable because it could pull away.
• You keep saying that flex PVC will get brittle, yet it is has far more plasticizer than the hard PVC you wish to work with and will "brittle" long after the rigid PVC it is attached to.
• You refer to flexible PVC as the devil becuase it will restrict flow, yet you advocated using a more restrictive king nipple and "flexible tubing" in its place.

I think you will find that more people would be willing to interact with you if you refrained from talking to them as if they know nothing, it is somewhat off-putting to say the least. This forum is chock full of VERY kind, informed, talented, experienced and well educated people with and without credentials to show as much.

You may (or may not) notice that most folks have bowed out of your discussions and it is not becuase they don't have valid input or experience. You have, for lack of better terminology, performed a document dump on anybody who has even slightly disagreed with any of your conclusions or dared respond to your posts. I am not sure what else to say, but good luck with your project (honestly) and happy reefing.

 

[BeanAnimal]

Anyone have any ideas on the best way to adhere stone to acrylic? With glass I would use silicon. Would that be adequate for a semi permanent bond?

The two scenarios I'm contemplating:

a) permanent bond i.e. trying to remove it is darn near impossible

b) (favored) semi permanent i.e. I could stick something between the tile/stone and acrylic and pry it loose w/out fear of the tile/stone falling off under normal operation.

I realize this has nothing to do with actual acrylic construction but thought since it is acrylic related this might be the place to post the question...

I don't think silicone (even a lot of it) is going to give you the adhesion you need. The rock is rough enough that epoxy type products will adhere well. I would think (and James may have a better idea) that a plastic epoxy may suffice.

That said, it may be better (and less permanent) to use a rigid structure like fiberglass grid (similar to eggcrate) to adhere the rock to and stand it up in the tank.

I don't remember for sure, but I think kcress contemplated something similar for his "Join me for a stange one" thread but ended up hanging his DIY fired clay backdrop panels.

 

[x2uranium]

Acrylic Question.

I am in the process of building a skimmer. I am building a beckett style skimmer I have the mixing box already fabbed up using 1/4" extruded acrylic. My question is about extruded tubular acrylic. I have priced out Cast acrylic and its entirely too expensive. My acrylic place quoted me $49 / ft for 8" OD. for 1/4". 3/16 was a bit lower but not by much. Now they sell 1/8" Extruded in a bit smaller sizes up to 6" OD which I am not concerned with the size as I can make adjustments as I go, but My question really is can I get away with 1/8" Extruded for body portion of the skimmer? I have read that its hard to work with. The sheet stuff cuts fine on my table saw with a fine tooth blade on it. I just need to know if its possible because the price is almost a 1/5th the cost of cast. I just cant afford it. So my question really is will it work? I really dont feel like making a square skimmer but I will if this wont work just want some info from the experts.

-Thanks in advance.

Anyone have an answer for me?

 

[Hotpuppy]

I have been thinking about attaching limestone or travertine tile across the back of my 96x40x24 acrylic tank like this:

interspersing Marco Rocks Primecuts like this

randomly throughout.

Anyone have any ideas on the best way to adhere stone to acrylic? With glass I would use silicon. Would that be adequate for a semi permanent bond?

The two scenarios I'm contemplating:

a) permanent bond i.e. trying to remove it is darn near impossible

b) (favored) semi permanent i.e. I could stick something between the tile/stone and acrylic and pry it loose w/out fear of the tile/stone falling off under normal operation.

I realize this has nothing to do with actual acrylic construction but thought since it is acrylic related this might be the place to post the question...

My choices would be:
Gorilla Glue - reef safe after fully cured
WO40 - Permanent.... it's acrylic after all and will form a mechanical bond.
any number of over-priced "reef" epoxies
Hydraulic Cement (sold as water stop cement @ Home Depot) - sets in 5 minutes.... lol. Also sold by Marco Rocks as their special cement - but to their credit I think they color it differently.

I think this is actually relevant..... I was planning to put my rock on acrylic "bases" anyway..... that way I don't have it bonded to my tank and at the same time it isn't balanced.

Btw, you will need to probably mechanically abrade the acrylic if you aren't using an acrylic specific adhesive....

 

[Hotpuppy]

It would appear that you are contradicting your own logic:


To point to a few instances.

• You reasoned that your DIY joint would be safe because the plumbing would be supported yet you view flexible pvc as unsuitable because it may get pulled away.
• You reasoned that the FLEX in a rigid 1" pipe would protect your joint from torque loads, but denonce the ACTUAL FLEX PVC as unsuitable because it could pull away.
• You keep saying that flex PVC will get brittle, yet it is has far more plasticizer than the hard PVC you wish to work with and will "brittle" long after the rigid PVC it is attached to.
• You refer to flexible PVC as the devil becuase it will restrict flow, yet you advocated using a more restrictive king nipple and "flexible tubing" in its place.

I think you will find that more people would be willing to interact with you if you refrained from talking to them as if they know nothing, it is somewhat off-putting to say the least. This forum is chock full of VERY kind, informed, talented, experienced and well educated people with and without credentials to show as much.

You may (or may not) notice that most folks have bowed out of your discussions and it is not becuase they don't have valid input or experience. You have, for lack of better terminology, performed a document dump on anybody who has even slightly disagreed with any of your conclusions or dared respond to your posts. I am not sure what else to say, but good luck with your project (honestly) and happy reefing.

Thanks for your feedback.

If the spa-flex is not straight it constitutes a bend. In a typical small tank this probably irrelevant.... in a longer run it constitutes a bend and is factored in to head calculations.

It's not my favorite material. It is the primary source of leaks in two hot tubs I've owned. My friend who does pools says they find leaks with it all the time. But hey, if it works for you.... great.

 

[Hotpuppy]

Acrylic Question.

I am in the process of building a skimmer. I am building a beckett style skimmer I have the mixing box already fabbed up using 1/4" extruded acrylic. My question is about extruded tubular acrylic. I have priced out Cast acrylic and its entirely too expensive. My acrylic place quoted me $49 / ft for 8" OD. for 1/4". 3/16 was a bit lower but not by much. Now they sell 1/8" Extruded in a bit smaller sizes up to 6" OD which I am not concerned with the size as I can make adjustments as I go, but My question really is can I get away with 1/8" Extruded for body portion of the skimmer? I have read that its hard to work with. The sheet stuff cuts fine on my table saw with a fine tooth blade on it. I just need to know if its possible because the price is almost a 1/5th the cost of cast. I just cant afford it. So my question really is will it work? I really dont feel like making a square skimmer but I will if this wont work just want some info from the experts.

-Thanks in advance.

Anyone have an answer for me?

Hey there, I'm not an expert, but I'll share what I know.... Acrylics is one of the only true experts on here btw.

Extruded is not as strong, it is very sensitive to stress, absorbs more water, and is something like 400% more expansive for a given temperature change then cast.

Realistically, you aren't building a 15 foot skimmer..... So extruded will probably work. As for thickness..... you have a couple of options.

1) Benchmark - go look at what the commercial units are using. Call them and ask them if they are using extruded or cast acrylic. Don't tell them you are building one... just tell them you are concerned about longevity.
2) look at the tank requirements for height and compare them to yours. Tank requirements are based on a flat panel and primarily concerned with bowing. A circular tube will not bow. By it's very nature it's reinforced. I would -guess- that you can go a couple of sizes thinner...

Lastly, keep in mind that if you go thinner you are going weaker. This means that if you bump your extruded tubing it may crack and potentially leak.

The other thing you could do is use solid PVC or solid acrylic for most of it and then use just a small section of clear to facilitate checking for bubbles.

Just be sure to figure out how to join everything together before you go buy materials.

If you have access to CNC you can make flanges to reinforce your tubing as well.

 

[BeanAnimal]

Hey there, I'm not an expert, but I'll share what I know.... Acrylics is one of the only true experts on here btw.

Please stop going out of your way to disparage the general community here at RC. While James is certainly an expert and his advice is well regarded, there are many others here at RC who can also be deemed as "acrylic experts", you have already had input from several of them. While YOU may not like advice that is contrary to your opinion, you as a self proclaimed "non expert" should not be advising others as to who is an expert or taking personal shots at people becuase they don't agree with your opinion.

absorbs more water, and is something like 400% more expansive for a given temperature change then cast.

Oddly, within the last 24 hours you took time to post nearly a dozen long paragraphs explaining the thermal expansion of materials and how it really didn't matter because or equipment remains at a fairly constant temperature. Nonetheless:

Acrylite FF (continuous cast = extruded) sheet:
Coefficient of Linear Thermal Expansion:
0.000040 in/in - °F

Acrylite GP (cell cast) sheet:
Coefficient of Linear Thermal Expansion:
0.000040 in/in-°F

Spartech Polycast (cell cast) sheet:
0.000042 in/in-°F

Palglas (extruded) sheet:
0.000039 in/in-°F

Plexiglas G (extruded) sheet:
0.000039 in/in-°F

By my "non expert" math, that is nowhere near 400% difference and is in fact essentially 0% difference in thermal expansion properties. The reality is that most extruded products expand LESS not MORE per degree F in temperature rise. The numbers above were taken DIRECTLY from the product datasheets. Perusal of other related product datasheets will show similar data.

Water absorption my differ slightly between cast and extruded and brand, but again a quick look at that datasheets shows that it is essentially the same. If I remember correctly Jame's data indicates a similar conclusion with regard to water absorption.

If you have access to CNC you can make flanges to reinforce your tubing as well.

CNC is not a requirement to make flanges, a simple router and template jig is more than sufficient. That said, I am not sure what "reinforcing" flanges are. While we (in most cases) must connect a flange at each end of the tube to accommodate connection to the body, collection cup, lid or whatever, adding flanges to the cylinder body along its length is not something that would be advised to any benefit.

Examples of flanges cut using a router:

​

​

 

[TheFishMan65]

x2uranium ,

Is this an internal or external? If it is internal how much water do plan to place it in? You only have pressure from the water above the water line. Also it has a lot of air so it is lighter than plain water. I have a NAC 7 cone, the cone is formed from a sheet so it has a line the whole length of the cone. It might be 3/16, but I realy don't think it is 1/4 (I would have to measure to be sure).

Any way (no expert), but I expect the 1/8 would be fine for an internal skimmer with 6-8 inches of "skimming action".

 

[BeanAnimal]

Thanks for your feedback.

If the spa-flex is not straight it constitutes a bend. In a typical small tank this probably irrelevant.... in a longer run it constitutes a bend and is factored in to head calculations.

As does using flexible tubing and a king nipple, the alternative you advised.

Secondly, nobody told you to use a long run of SpaFlex. There was only passing comment that a small section could help remove stress from the joint and/or buffer any shock due to a bump or movement.

It's not my favorite material. It is the primary source of leaks in two hot tubs I've owned. My friend who does pools says they find leaks with it all the time. But hey, if it works for you.... great.

While the product may not be your favorite material, it is well rather well regarded, durable and suitable for our applications if installed properly.

Please allow me to kindly point out another contradiction that appears to be a common logical theme here:

You appear to have great regard for pool and spa installers/manufacturers in one breath and use their advice to support your positions. At the same time you use the opposite logic and blame skimmer and other equipment manufacturers for cutting every corner in order to explain why other materials or methods show failures.

• Consider that SPAS are thrown together as fast as possible with rather unskilled labor and as little QC as possible.
• Consider that your average pool installer may or may not be a skilled laborer or expert and that many pools and spa are very poorly installed at best.
• Consider that hard plumbed PVC can be cited as the source of countless leaks due to poor joints, "brittling", movement, etc.

In any case, this discussion needs to move away from this thread, as it is not fair to those who are here looking for help with acrylic fabrication. If you wish to continue discussing plumbing, head back to your other thread or start a new one regarding this subject

 

[dahenley]

Bearings:

A simple and non permanent way would be to use a sheet of acrylic and make a "L" shape. The bottom would cover with sand, and the back can be drilled and use zip ties to hold against, or something of that nature. Just a secondary suggestion.
The small space behind would be a breeding ground for pods and such. (I've seen it before)

Good luck.