Acrylic fabrication questions? I can help!

[Epicreefer]

It's an old and less than ideal bit I think, probably under powered router too. I'm just messing around with acrylic right now and trying out some things. Luckily acrylic costs me about $2/sf. I have welded the router flush pieces as well and get good results, I was jut trying some unorthodox things and found the light sanding helped a great deal.

 

[IMAMONSTER]

THanks for the response everyone will have to try something different.

 

[Crit21]

James & Acrylics, here's a good one for you. I emailed WWM, but I expect the usual answer with no useful content.

I have a 28" wide x 8' long x 4' tall, 1 1/4" thick acrylic aquarium with a long crack in the end panel near the bottom. I've read many articles/posts about mating another panel over the crack with Weld On 3 or 4, but it would be too visible and ugly, even if I use a full-size panel to cover the old one. Does anyone have experience using something like Weld-On 40 or 42 to join panels or repair cracks?

I was thinking about using my Dremel on a low speed setting to avoid melting the acrylic and a 1/8" or smaller diameter bit to widen the crack just enough to inject pre-mixed Weld-On 40/42 into the gap with a large syringe from my local animal supply store.

According to the technical data, Weld-On 40 has a strength of 4,000 lb per sq in after a week when cured at room temperature, 5,700 at 120 degrees F, and 7,000 at 150 degrees F. Even at room temperature it sounds strong enough to do the job. I can use a heat source to slowly heat the area and keep it at a high temperature for improved strength, then slowly lower it to room temperature at the end to prevent cracking.

Has anyone ever tried this? Were you successful?

 

[Crit21]

duplicate post

 

[Acrylics]

James & Acrylics, here's a good one for you. I emailed WWM, but I expect the usual answer with no useful content.

I have a 28" wide x 8' long x 4' tall, 1 1/4" thick acrylic aquarium with a long crack in the end panel near the bottom. I've read many articles/posts about mating another panel over the crack with Weld On 3 or 4, but it would be too visible and ugly, even if I use a full-size panel to cover the old one. Does anyone have experience using something like Weld-On 40 or 42 to join panels or repair cracks?

I was thinking about using my Dremel on a low speed setting to avoid melting the acrylic and a 1/8" or smaller diameter bit to widen the crack just enough to inject pre-mixed Weld-On 40/42 into the gap with a large syringe from my local animal supply store.

According to the technical data, Weld-On 40 has a strength of 4,000 lb per sq in after a week when cured at room temperature, 5,700 at 120 degrees F, and 7,000 at 150 degrees F. Even at room temperature it sounds strong enough to do the job. I can use a heat source to slowly heat the area and keep it at a high temperature for improved strength, then slowly lower it to room temperature at the end to prevent cracking.

Has anyone ever tried this? Were you successful?

First, I would ignore the technical data. We will never see the pressures involved to worry about strength. The issue is injecting the 40/42 into the crack.

I've never done this exact thing as I don't do many repairs at all. That said, I don't see any reason why it couldn't work, though I would use a router and machine a slot along the crack rather than use a Dremel as the Dremel would tend to melt a lot of material vs the router. Ideally, you'd use an angled cutter so that the slot angles down (wide on the outside, narrow on the inside.) You will most likely have some discoloration because the 40/42 will be a different color than the acrylic - 40/42 tends to have a slightly yellow tint to it. You will also have some finish work - sanding and polishing, but I don't see any reason why it couldn't work.

HTH,
James

 

[Crit21]

Thanks Acrylics. A router typically operates at about 30,000 RPM, but a variable-speed Dremel can operate as low as 3,000 RPM. I want to keep the gap as narrow as possible to minimize the repair visibility, and maximize the strength of the joint. The smallest bit I can find is 1/8" in diameter. They make a router adapter for the Dremel that keeps it square to the surface and helps the user accurately guide the Dremel. I did want to use a tapered bit to machine a slight taper that's wider on the inside surface of the tank so the water pressure would force the Weld On into the slot.

 

[Acrylics]

Thanks Acrylics. A router typically operates at about 30,000 RPM, but a variable-speed Dremel can operate as low as 3,000 RPM. I want to keep the gap as narrow as possible to minimize the repair visibility, and maximize the strength of the joint. The smallest bit I can find is 1/8" in diameter. They make a router adapter for the Dremel that keeps it square to the surface and helps the user accurately guide the Dremel. I did want to use a tapered bit to machine a slight taper that's wider on the inside surface of the tank so the water pressure would force the Weld On into the slot.

it's not about RPMs, it's about chip clearance and frictional heat from surface contact.

Don't worry about smallest cutter, not IMO anyway as you'd have a hard time pressing the 40 into an 1/8" slot.

And don't worry about water pressure pushing it into the slot.. irrelevant. It doesn't work that way.

James

 

[Mr. Fish]

Hello,

I had posted in another thread asking about the seams of my new acrylic aquarium that I purchased and I was told to post my question here.

Basically I want to make sure that the bubbles in the seam are OK and won't cause any problems. Most of the bubbles are where the 3/4" front panel joins the 1/2" bottom.

Here are a couple pictures:

Sent from my DROID RAZR using Tapatalk 2

 

[Acrylics]

Hello,

I had posted in another thread asking about the seams of my new acrylic aquarium that I purchased and I was told to post my question here.

Basically I want to make sure that the bubbles in the seam are OK and won't cause any problems. Most of the bubbles are where the 3/4" front panel joins the 1/2" bottom.

Just from what I see, looks like they used cheap imported material and/or didn't know what they were doing.. new tank?

It may hold, can't say, but if this is a new tank - it should never have been allowed to leave the shop.

I understand if you came here looking for something more positive, but that's just bad workmanship and/or bad material choice. same same to me...

JMO,
James

 

[Mr. Fish]

Just from what I see, looks like they used cheap imported material and/or didn't know what they were doing.. new tank?

It may hold, can't say, but if this is a new tank - it should never have been allowed to leave the shop.

I understand if you came here looking for something more positive, but that's just bad workmanship and/or bad material choice. same same to me...

JMO,
James

Thanks for your help. I know that they used plexiglass g for the material. Is there anything that can be done to the seam to fix it? I looked over the entire tank and the bottom front seam looks like it is the only place that has an issue.

Sent from my DROID RAZR using Tapatalk 2

 

[Acrylics]

can't really "fix" it, but a gusset can be glued into that seam to reinforce it.
..basically a strip of square bar or triangular bar stock glued into the corner of the seam is really the best you're gonna do..

James

 

[Floyd R Turbo]

What is that white arc-shaped haze about the joint? Is that on the inside surface of the front panel?

I would say this is just poor workmanship. Perhaps a poorly prepared joint, there might have been an imperfection in the edge of the front panel that allowed air to creep into the joint as it dried. Bummer.

 

[Mr. Fish]

The white arc is a mark on the protective paper that's covering the acrylic.

Sent from my DROID RAZR using Tapatalk 2

 

[Floyd R Turbo]

LOL that messed me up man

Plex-G is a brown mask with blueish-green print. Never seen a white printed mask - you sure it's G?

 

[Crit21]

it's not about RPMs, it's about chip clearance and frictional heat from surface contact.

Don't worry about smallest cutter, not IMO anyway as you'd have a hard time pressing the 40 into an 1/8" slot.

And don't worry about water pressure pushing it into the slot.. irrelevant. It doesn't work that way.

James

I was going to use a very large syringe with the largest needle I could find to inject the 40 into the slot before it became too thick. Why do you call it "pressing"? Is it not liquid enough to inject with a wide needle until it begins to cure?

 

[Acrylics]

I was going to use a very large syringe with the largest needle I could find to inject the 40 into the slot before it became too thick. Why do you call it "pressing"? Is it not liquid enough to inject with a wide needle until it begins to cure?

no, not really. It's very syrupy and best injected with a syringe without the needle.. at least IME. That and with the large surface area to mass ratio - will make it set *very* quickly.

James

 

[Crit21]

I found this on the Weld On 40 data sheet: "In cases where a lower viscosity is desired,
WELD-ON 3061 may be used as a reactive diluent." I think this would allow the use of a syringe to feed the Weld On 40 deep into the void. A large diameter needle would still be necessary to shoot a large quantity in a short time before it begins to cure.

 

[Acrylics]

I found this on the Weld On 40 data sheet: "In cases where a lower viscosity is desired,
WELD-ON 3061 may be used as a reactive diluent." I think this would allow the use of a syringe to feed the Weld On 40 deep into the void. A large diameter needle would still be necessary to shoot a large quantity in a short time before it begins to cure.

the issue with doing this is that *all* of the 3061 will evaporate out, therefore much more of the mass you're injecting will disappear, leaving an elongated strip of ugliness without the strength.. but...

hope it works as you desire

 

[Crit21]

Good point.

 

[camaroboy8691]

did i read somewhere on this thread that before you glue your joint you should wipe it doen with denatured alcohol ? does this mean the routed edge and also the smooth part to be bonded ?


i dont know how you guys do it , but this stuff is time consuming , i spent like 2 hours last night preping just 1 sheet im using just a circular saw and hand router , im preping these 1" thick peices for my 4x8x33 tank....took awhile to get it square and true ... and also alittle to figure out how to get the best edge finish ..... 1 down , just a few to go ,. lol ..... hoping to maybe start bonding something tonight .