Weld-On #4 vs #42

[h2so4hurts]

I shim and clamp. Because the air bubbles set quickly and it's way easier to shim them than fart around with clamps to do it.

 

[h2so4hurts]

Nah, I don't necessarily care for the rounded edge look. If #4 is good enough of a bond, then Im fine with that. I don't prefer to spend $200 on an applicator gun for the 40/42 just to have that look.

Don't need the gun for tilt method, just mix it and pour. It's sold in both cartridges and tubs. 4 is like 2500 psi. Glass tanks with silcone are 45. I think you'll be ok :)

 

[JustinForMayor]

I shim and clamp. Because the air bubbles set quickly and it's way easier to shim them than fart around with clamps to do it.

You have the pins in the acrylic joints, obviously.. Im still not following on the shims though. From what I've seen, the shims go underneath the tank?

 

[h2so4hurts]

Shims go under the pin on the outside of the panel you're welding to. Have other shims on hand too so you can squeeze out bubbles in between shims if they pop up.

 

[JustinForMayor]

Im curious as to how the shims help though? It's a flat surface, so when you clamp down after you pull the pins? Whats the difference whether you have shims there or not? Sorry, I don't mean to seem dumb lol. Im just trying to see how the shims help with air bubbles when the tank is only resting on them.

 

[h2so4hurts]

The acrylic has flex. Shimming adds pressure to push the bubbles out. I promise you'll be happy you have the panel shimmed if you get an air bubble in the seam ;). You also do not want to over clamp, just enough to hold it in place. Don't clamp so hard it squeezes everything out of the seam.

 

[JustinForMayor]

The acrylic has flex. Shimming adds pressure to push the bubbles out. I promise you'll be happy you have the panel shimmed if you get an air bubble in the seam ;). You also do not want to over clamp, just enough to hold it in place. Don't clamp so hard it squeezes everything out of the seam.

Makes sense. But what is the difference between it sitting on a flat/level surface and clamping rather than sticking shims under there? I promise this is my last question, lol!

 

[h2so4hurts]

Again, you can focus the pressure where the bubbles are so you can get them out before they set. Practice. I think you'll see what I mean :) Expect your first seams to be terrible. So plan for those to be in the back of the tank :)

 

[JustinForMayor]

Again, you can focus the pressure where the bubbles are so you can get them out before they set. Practice. I think you'll see what I mean :) Expect your first seams to be terrible. So plan for those to be in the back of the tank :)

I gotcha..makes sense..so do you shim before you apply the #4 or after you pull the pins and see where the bubbles are? You're right..once I do a couple joints, itll make sense a lot more!

 

[h2so4hurts]

Put the bottom panel down. Place shims every 6". Place the top panel and hold it in place with a 90 degree clamp. Pin a gap above the shims. Check that everything is squared up, lay the 4, start pulling the first pin after 4 min, shim the bubbles.

 

[JustinForMayor]

Put the bottom panel down. Place shims every 6". Place the top panel and hold it in place with a 90 degree clamp. Pin a gap above the shims. Check that everything is squared up, lay the 4, start pulling the first pin after 4 min, shim the bubbles.

Appreciate the information! Thank you!.. When you built yours, did you do a euro brace or a top?

 

[h2so4hurts]

I eurobrace everything. I've built probably 10 tanks. Including my current 500 out of 1.25". Still need to finish that story ;)

 

[JustinForMayor]

That's awesome! Do you add the eurobrace at the very end?

 

[h2so4hurts]

I add the top 2nd to last. Bottom goes on last so that the tank can breathe and cure properly. I rout all my top panel openings out of a sheet.

 

[Carz]

if you look at h2so4hurts pic, that corner clamp he is using is a life saver.

 

[JustinForMayor]

if you look at h2so4hurts pic, that corner clamp he is using is a life saver.

What is it called, ill order it on amazon? And does that just help keep it square?

 

[h2so4hurts]

Search framing clamps and they'll come up. $25 each or so

 

[JustinForMayor]

Search framing clamps and they'll come up. $25 each or so

 

[JustinForMayor]

That looks like it makes it a heck of a lot easier to keep in a perfect 90 degree angle when drying.

 

[Nonya]

Laser

Just noticed that your first post said the parts were laser cut and then you said later they are CNC cut. I would be sure they are CNC cut. If not you must sand the edges. I start with 150 grit and work down to 400. My laser leaves micro grooves that will create gaps/bubbles. These never leak, but the bubbles look like crap on clear. Colored acrylic will hide any bubbles or cracks, but they are weaker joints. If you calculate the dimensions you have given you are looking at 250+ gallons of water.

CNC describes the type of machine itself, not the manner in which the material was cut. CNC can use high pressure water and abrasive, router, or laser.
Agree that laser cut would be a problem. Heating the edge while cutting changes the properties of the acrylic at the edge.