Acrylic fabrication questions? I can help!

[adova]

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%).

Sheesh - isn't there a shelf life on the solvent? I thought I was seeing standard Weld-on at ~1 year.

 

[Floyd R Turbo]

Weld-on has many other ingredients, mostly required by Orange County CA IIRC in order to make it compliant. i.e. fillers. When the MC offgasses out of the mixture, the concentration becomes too low to act as a solvent.

Once I had a container of WO #4 that had maybe 10% left in it. I tried to bond something and it didn't do anything, anything at all. I was able to wipe the solution off the acrylic and it looked like nothing had happened.

This stuff is 99.9% Methylene Chloride. If 50% of it offgasses, it's still 99.45% MC. Pretty much indefinite shelf life. Now when you mix it with AA, the AA does not offgas nearly as fast, so if you let it sit around in mixture long enough, the concentration of AA will tend to increase. I've let it sit in the 8oz jar for a month or more and then I just add a few ounces of MC to make sure it's strong enough and I've had no problem with that. I think James recommends that you use a mixture within a week though.

 

[saintsnsinners]

Advice in a new sump build.

72 x 17 x 22

In the middle there will be a 20" tall divider (fuge), on the right side there will be a 20" long skimmer section with 10" tall bubble trap.

can this safely be made from 1/4"? If so, how thick of a Euro brace? I was also thinking about routing a center brace down the center. trying to avoid stepping up to 3/8".

 

[rfgonzo]

1/4 won't cut it at a height of 22" 3/8 is even pushing it, but if you have a euro brace 3'' wide around the whole diameter with 6'' cross bracing every 24 inches you should be fine. Personally for 22 inches high I would go with 1/2 cell acrylic. Floyd will more than likely give some solid advice.

 

[hvacman250]

Will 1/2" cast be sufficient for a 20x20x20 cube with no euro-bracing?

 

[Floyd R Turbo]

Saints, gonzo is right, no way I would do that in 1/4". I've seen tanks that tall out of 3/8" but IMO, still pushing it. 1/2" is much safer

Hvacman, no. Rimless acrylic tanks require a lot thicker material. Normally, 1/2" is what you would use for a standard eurobraced tank at up to 24" tall. A rimless tank would likely need more like 1" or maybe 1-1/4". Really, not exaggerating.

 

[hvacman250]

Saints, gonzo is right, no way I would do that in 1/4". I've seen tanks that tall out of 3/8" but IMO, still pushing it. 1/2" is much safer

Hvacman, no. Rimless acrylic tanks require a lot thicker material. Normally, 1/2" is what you would use for a standard eurobraced tank at up to 24" tall. A rimless tank would likely need more like 1" or maybe 1-1/4". Really, not exaggerating.

How thick of a brace would I need in the center? I trust you, but its amazing a 20x20 panel with 18" of water requires 1". Do I need the 3" perimeter w/ 3" brace like I see recommended, or can I go smaller?

 

[Floyd R Turbo]

For a 20x20, no center brace, just a 3" perimeter brace is all and 1/2" material.

The issue with rimless is bowing. Using 1/2" material would rip the seams apart

 

[Floyd R Turbo]

Also you might be able to use 3/4" because it's only 20" panels, but I would have to consult James before verifying that.

 

[thejuggernaut]

That Meguiar's Ultra Cut is no joke! While it doesn't take the tooling marks out, it shines up the joints in seconds. A medium sized bottle of it was $34 dollars, but really works well. I am using a straight flute for my flush cutting because I haven't ordered an upcut bit yet. Does the upcut leave a nicer finish?

 

[saintsnsinners]

That Meguiar's Ultra Cut is no joke! While it doesn't take the tooling marks out, it shines up the joints in seconds. A medium sized bottle of it was $34 dollars, but really works well. I am using a straight flute for my flush cutting because I haven't ordered an upcut bit yet. Does the upcut leave a nicer finish?

What joints? are you polishing the edges?

 

[thejuggernaut]

Yea. After the it is all glued up and you have flush routed the edges. It makes the edges look shiny but you can still see where the router left its tooling marks. You can use progressively higher sandpaper before you polish it up to remove the routing marks, but it takes allot of time. Floyd recommended the ultra cut and I figured it would work, but not in only a few seconds. Kind of expensive, but works good. I'm probably just going to shine up the outside box for the overflow, but will probably sand and polish the inside box to make it look really good. I'll post before and after photos once I get done!

 

[Floyd R Turbo]

Yeah it works nearly instantly, I forgot to mention that.

I'm not sure about the difference w/r to the bit. Been a while since I used a straight flute flush trim bit, but I don't think it makes a huge amount of difference. The upcut is mainly used for chip clearance, and it does a good job of that.

 

[rfgonzo]

That Meguiar's Ultra Cut is no joke! While it doesn't take the tooling marks out, it shines up the joints in seconds. A medium sized bottle of it was $34 dollars, but really works well. I am using a straight flute for my flush cutting because I haven't ordered an upcut bit yet. Does the upcut leave a nicer finish?

Not sure, I've never used a straight flute, always a up-cut bit. I have a ATO to finish tomorrow for a friend. I'll try to take some pictures and do one side with the straight flute and the other side with an up-cut. You do still have sanding to do with a up-cut though.

 

[thejuggernaut]

I looked at the Amana one you recommended. They were pretty high, but as usual, nice stuff cost money.

 

[thejuggernaut]

Not sure, I've never used a straight flute, always a up-cut bit. I have a ATO to finish tomorrow for a friend. I'll try to take some pictures and do one side with the straight flute and the other side with an up-cut. You do still have sanding to do with a up-cut though.

I'd appreciate it!

 

[saintsnsinners]

Yea. After the it is all glued up and you have flush routed the edges. It makes the edges look shiny but you can still see where the router left its tooling marks. You can use progressively higher sandpaper before you polish it up to remove the routing marks, but it takes allot of time. Floyd recommended the ultra cut and I figured it would work, but not in only a few seconds. Kind of expensive, but works good. I'm probably just going to shine up the outside box for the overflow, but will probably sand and polish the inside box to make it look really good. I'll post before and after photos once I get done!

Good to know, I've never used it before. what type of buffer are you using to apply it?

 

[Floyd R Turbo]

...and that doesn't mean they will last necessarily. A buddy of mine had his 1/2" Amana upcut blow up on him. Found half the bit in the wall, the rest a few months later. He also had a Whiteside bit blow, but he was routing PVC. Hasn't found that one.

I've never had it happen. I imagine that it might have something to do with technique and feed rate. I had a bearing fly apart once tho.

 

[thejuggernaut]

Just a cheap orbital buffer I got at Home Depot, but I was looking and I think one of these would be nice if you have a decent aircompressor. It isn't huge and would let you do edge work better.

http://www.harborfreight.com/3-inch-pneumatic-polisher-kit-99934.html

 

[Floyd R Turbo]

Good to know, I've never used it before. what type of buffer are you using to apply it?

You can use a 3-stitch wheel, an orbital buffer (black & decker $30 @ Lowes) or a high speed polisher. Could probably do by hand too