Using WeldOn 40

[Lythronax]

Hello everyone!

I'm making a few little aquariums from cast acrylic... or trying to, at least. I've used WeldOn 4 with moderate success, however, my cuts are imperfect and sometimes leave a ~1-2mm gap along the seam. The Weldon 4 simply doesn't fill the seams well enough to push out all of the bubbles in some areas (like the photos below).

(Yes, it's  very messy. Cleanliness comes after structural integrity. These are just my own aquariums, so I'm not worried about presentation.)

I'd like to use WeldOn 40, but it isn't the most approachable adhesive. I was going to tape the inside of the seam, use thicker guage needles to suspend the acrylic, and use a syringe to inject the adhesive between the two panels before removing the pins to squish the two together. I'm thinking this should remove any significant bubbles.

How does this sound? Any tips for a first timer?

 

[FUNGI]

Get better cutting tools.....

 

[KrisReef]

Hello everyone!

I'm making a few little aquariums from cast acrylic... or trying to, at least. I've used WeldOn 4 with moderate success, however, my cuts are imperfect and sometimes leave a ~1-2mm gap along the seam. The Weldon 4 simply doesn't fill the seams well enough to push out all of the bubbles in some areas (like the photos below).

(Yes, it's  very messy. Cleanliness comes after structural integrity. These are just my own aquariums, so I'm not worried about presentation.)

I'd like to use WeldOn 40, but it isn't the most approachable adhesive. I was going to tape the inside of the seam, use thicker guage needles to suspend the acrylic, and use a syringe to inject the adhesive between the two panels before removing the pins to squish the two together. I'm thinking this should remove any significant bubbles.

How does this sound? Any tips for a first timer?

Keep trying. You will figure out what works for you. I have had similar results with acrylic so I know I will also never be a commercial operation, but my ugly seams have held just fine.

I like Weld on #16, and I wish I had a proper cutting table & saw for better edges to work with. :cool:

 

[Lythronax]

Keep trying. You will figure out what works for you. I have had similar results with acrylic so I know I will also never be a commercial operation, but my ugly seams have held just fine.

I like Weld on #16, and I wish I had a proper cutting table & saw for better edges to work with. :cool:

In an ideal world, I would have proper equipment as well. It's become evident, however, this is not an ideal world. Haha!

In the meanwhile, I'm determined to make do. Is it the viscosity that you prefer in the WeldOn 16? Have you found it helps in filling gaps a little?

I've been advised that bubbles here and there, such as the ones pictured, are unlikely to be of significant consequence in the immediate future. They only span mayhe 4" totals out of 48", the rest of the seam is free of bubbles.

 

[GSPClown94]

Have you tried using an edge scraper to clean up your rough cuts?

 

[Lythronax]

Have you tried using an edge scraper to clean up your rough cuts?

You know, I have one in the mail. Perhaps I've been impatient. I have sanded them down with 200 grit on an orbital sander, which I thought would be adequate. I was skeptical that the edge scraper would be much more effective, but perhaps I was wrong?

 

[GSPClown94]

You know, I have one in the mail. Perhaps I've been impatient. I have sanded them down with 200 grit on an orbital sander, which I thought would be adequate. I was skeptical that the edge scraper would be much more effective, but perhaps I was wrong?

Try out the edge scraper and see if that helps. It worked well for me when I used a hand saw to cut acrylic for a DIY frag rack. Sandpaper might also work but I think using an orbital sander has the potential to lead to high and low spots across the edge. Maybe just tape the sandpaper on a flat surface and manually drag the acrylic across the sandpaper would work better?

 

[Lythronax]

Try out the edge scraper and see if that helps. It worked well for me when I used a hand saw to cut acrylic for a DIY frag rack. Sandpaper might also work but I think using an orbital sander has the potential to lead to high and low spots across the edge. Maybe just tape the sandpaper on a flat surface and manually drag the acrylic across the sandpaper would work better?

I'll give it a shot when it arrives tomorrow! The manufacturer's instructions for WeldOn 40 advise roughing the edge with a high grit sandpaper, so I'll likely run the edge scraper and follow-up with a light sanding. My main concern (and reasoning behind using an orbital sander) was that I may be too heavy-handed with the edge scraper, and with a slight tilt to either the left or right hand side due to an uneven application of pressure may result in an unintentional bevel.

I am happy to report that using the WeldOn 40 has given me completely bubble free seams, and quite easily, at that. It really does fill gaps well. There is some crazing, however I did not anneal the acrylic for this test, which I believe that can be attributed to. It's extremely solid, though. That being said, I am exceptionally messy. A significant amount of cement extruded from the sides when the pieces were set together, resulting in a somewhat unsightly bead around the seam. When I'm actually assembling the aquariums I'll try to lay down some painters tape to catch the excess, and perhaps be a bit more delicate in my application. I'd love to hear from others with experience using this product if they have any advice to offer. Unlike the solvent, as the cement should not be compressed too heavily, I worry that attempting to wipe away the excess cement may cause the piece to shift as it is not clamped down with any significant pressure. Similarly, if the cement is uncured enough to remove the tape that was used to catch the excess, a slight bump could shift the seam. If it's cured enough to hold the pieces in place, it likely will have cured over the tape as well, rendering it unremovable.

At this rate, however, I think it's in my best interest to use the cement rather than solvent given the relatively crude nature of my cuts. As I'm simply looking to have it hold water, the results are somewhat optimistic at this juncture. Just thinking out loud here, if anyone has any feedback.

 

[Greg Smith]

I'll give it a shot when it arrives tomorrow! The manufacturer's instructions for WeldOn 40 advise roughing the edge with a high grit sandpaper, so I'll likely run the edge scraper and follow-up with a light sanding. My main concern (and reasoning behind using an orbital sander) was that I may be too heavy-handed with the edge scraper, and with a slight tilt to either the left or right hand side due to an uneven application of pressure may result in an unintentional bevel.

I am happy to report that using the WeldOn 40 has given me completely bubble free seams, and quite easily, at that. It really does fill gaps well. There is some crazing, however I did not anneal the acrylic for this test, which I believe that can be attributed to. It's extremely solid, though. That being said, I am exceptionally messy. A significant amount of cement extruded from the sides when the pieces were set together, resulting in a somewhat unsightly bead around the seam. When I'm actually assembling the aquariums I'll try to lay down some painters tape to catch the excess, and perhaps be a bit more delicate in my application. I'd love to hear from others with experience using this product if they have any advice to offer. Unlike the solvent, as the cement should not be compressed too heavily, I worry that attempting to wipe away the excess cement may cause the piece to shift as it is not clamped down with any significant pressure. Similarly, if the cement is uncured enough to remove the tape that was used to catch the excess, a slight bump could shift the seam. If it's cured enough to hold the pieces in place, it likely will have cured over the tape as well, rendering it unremovable.

At this rate, however, I think it's in my best interest to use the cement rather than solvent given the relatively crude nature of my cuts. As I'm simply looking to have it hold water, the results are somewhat optimistic at this juncture. Just thinking out loud here, if anyone has any feedback.

How did it turn out?
I know old post but did you use cast acrylic or extruded? I wouldnt think weldon 40 would cause crazing that fast on cast acrylic
Did you space the pieces apert with pins and then pull them after you injected the adhesiveor put the adhesive on both sides and put together