Acrylic fabrication questions? I can help!

[sean04]

I've been practicing using scrap pieces to weld using weldon #3. I've been using the pins method but, I can't seem to get a bubble free joints.

On the opposite end I'm not getting a bead. The bubbles I'm getting is on the edge of the side I'm applying the weldon. Very similar to the below attached pictures.

I'm using 3/8" plexiglass G.

How do I determine if I'm squeezing out too much or too little? On one of the pieces I didn't get a continuous bead on the side I'm applying the solvent on. It was like intermediate beads.

I've also noticed that the solvent wicks really far ahead. Am I squeezing out too much?

James,

I've been working on a tank made of 3/4" Plex-G. We set the vertical joints with little issue. The top euro looked good except for right at the joints of the vertical panels in each corner where I forgot to scrape off the little bit of solvent that goos out when you pull the pins and then adjust the panels to be flush (oops). It's not horrible, but quite a few small bubbles right there on the corners. Much to worry about? Top is 1/2".

But, this is the real reason for my post below. We set the bottom joint and bubbles seemed to 'form' in a few spots as we ran the solvent in. As we filled it, the joint looked good and filled, then the bubbles would just form almost out of nowhere. Here's a few pictures. Tell me if this is really anything to worry about:

The tank is 48 x 19 x 30 H, 3/4 walls, 1/2 top/bottom, euro has 2.5" perimeter w/6" center, 2.5" radius corners. Used pins method, wiped both panels with denatured alcohol, blew off with air compressor, then canned air after pins, joint was still wet when be pulled the pins too so there was a nice fillet all around. Solvent was straight MC w/5% to 6% AA.

The only thing I can think of is maybe we should have shimmed the pins a little more aggressively all around to get them really tight. We really only needed to shim the corners and a little on the ends - table is a little crowned in the middle (maybe 1/8" higher), but the double-sided foam MDF boards seem to take care of a lot of that. Also I had one bad bubble (second pic) that seemed like the solvent didn't want to fill in, it was filling in at the inside and outside edges like a "U" then the solvent closed in around it making the bubble. Strangely this was over the crown in the table.

Could this be dust particles? I have noticed that it's kind of hard to clean the edges perfectly because of static. Even after wiping with alcohol and compressed air and canned air, I can't always get all the dust off. Is there a trick?

Is this joint doomed, or just unsightly?

Being the largest thing I've built to date, I am discovering that I may need to make some modifications to my table or technique, or both. I hope you can shed a little light on this...thanks in advance.

EDIT: PS the bubbles in Pic #3 are elongated because the joint floated after we pulled the pins, and we noticed it just in time to re-adjust it...

 

[Floyd R Turbo]

bubbles can form around dust particles in the seam. I wipe down all joints with denatural alcohol then blow off with compressed air, then after pinning the joint I blow it out again with canned air.

The pics I posted above were illustrating such issues. Couldn't quite get the joint to run free of bubbles. Since then we have figured out that you rarely can. The trick it to have a couple of syringes ready (get from a medical supply store, insulin syringes) and before pulling the pins you suck the bubbles out. It helps to have someone else pushing solvent while you suck the bubbles out too, but is not always necessary.

The fillet is what helps prevent bubbles from pulling into the edges of the joint, and if you let it sit too long before pulling the pins this will just end up pushing out as bumps, some have suggested that after filling the joint you do a high-speed solvent pass and then pull the pins, I've found that this works OK but you still end up with tiny bubbles in the fillet. I've seen tanks from big tank makers with this also, so it is not of great concern, just aesthetic.

The last build I just finished had perfect seams all the way around. Not a single bubble.

 

[Floyd R Turbo]

bubbles can form around dust particles in the seam. I wipe down all joints with denatural alcohol then blow off with compressed air, then after pinning the joint I blow it out again with canned air.

The pics I posted above were illustrating such issues. Couldn't quite get the joint to run free of bubbles. Since then we have figured out that you rarely can. The trick it to have a couple of syringes ready (get from a medical supply store, insulin syringes) and before pulling the pins you suck the bubbles out. It helps to have someone else pushing solvent while you suck the bubbles out too, but is not always necessary.

The fillet is what helps prevent bubbles from pulling into the edges of the joint, and if you let it sit too long before pulling the pins this will just end up pushing out as bumps, some have suggested that after filling the joint you do a high-speed solvent pass and then pull the pins, I've found that this works OK but you still end up with tiny bubbles in the fillet. I've seen tanks from big tank makers with this also, so it is not of great concern, just aesthetic.

The last build I just finished had perfect seams all the way around. Not a single bubble.

 

[sean04]

Thanks Floyd.

So what's the trick to making a continuous bead on the edge your applying the solvent to?

I'm assuming there will be no bead on the opposite (or internal) side that the solvent is not applied to. Correct?

 

[Floyd R Turbo]

Practice. This is my 7th project and I just got it right.

I think you have the basic concept down, if you end up with a few bubbles in the middle of the joint (not a result of solvent sucking in when it evaporates) then it's just a matter of making sure your edges are prepped well (routed, wiped clean, blown off, etc) and your comment about the bead leading the needle by quite a bit sounds right. If it's way, way ahead, then you might not have enough space made by the pins, on 3/8" material I can usually run about 3-5" per second with the bead about 3/4" in front of the needle if that helps for perspective (that's just off the top of my head). I think that's using a 22 gauge needle but I'm going to stop at the medical place and see if I can get 20 gauge. We used flexible 20 gauge needles for the 1/2 and 3/4 builds just to get enough flow. For any joint shorter than 2 feet and material 1/2" or less I would think 22 ga would be plenty. The top/bottom joints needed 2 of us to get them filled before they started setting, and with the time needed to suck out bubbles that's why the joint ended up with the beads on the inside (didn't run solvent around those). also the joint floated after pulling the pins so needed to slide the joint to line it up, that may have had something to do with it

HTH

 

[radone]

Quick question here

What can I use to adhere cell cast and PVC together?
How about Cell cast and ABS?

Looking @ replacing the body on a deltec skimmer

Thanks

 

[peppie]

Tank size

60'' long X 30'' wide X 30'' tall 3/4'' polycast

Can I use 3/8'' material for the bottom and top euro brace, or do I need to use 1/2''

 

[peppie]

Tank size

60'' long X 30'' wide X 30'' tall 3/4'' polycast

Can I use 3/8'' material for the bottom and top euro brace, or do I need to use 1/2''

 

[Floyd R Turbo]

Quick question here

What can I use to adhere cell cast and PVC together?
How about Cell cast and ABS?

Looking @ replacing the body on a deltec skimmer

Thanks

WO 40 or 42 would work, I can't recall exactly but I think 4052 is another one that works for acrylic to PVC or ABS

Tank size

60'' long X 30'' wide X 30'' tall 3/4'' polycast

Can I use 3/8'' material for the bottom and top euro brace, or do I need to use 1/2''

I would use 1/2"

 

[rrg1974]

I'd like to have your feedback on a the thickness of a tank. I'm planning to build a 45x22x24, do I need 3/8" or 1/2"?

 

[Floyd R Turbo]

With width and height (45 x 24) dictate that one. 3/8" will hold, preferrably if it's Polycast (which is 0.375 not 0.354), and you would want a good sized eurobrace too, but you can get 3/4" Plex-G for that price I believe. 1/2" would be better. Still though if your technique is good (that has a lot to do with it) then it's just a matter of how much boq you're willing to accept.

James would have a better answer for you I'm sure. Hopefully he can chime in on your question

 

[pentrix2]

i'm trying to find weld on #5 but i can't find them. i only see weld on 3, 4, 10, 16...

reading the previous threads it says to mix 10-20% of weld on #5 with #4 so it can dissolve a little slower giving it a stronger bond.

 

[pentrix2]

nvm, i found it on eplastics.com

 

[jimmyj7090]

Frag tank build, please reality check my plan

28x14x7 frag tank, 4" of one end partitioned off to accomidate a bean style drain.

1/4" acrylite GP (I know, it's not on the SAFE list anymore, but it's all I've been able to get locally) all around.

I'm assuming that so far this a reasonable plan, my main question is about the top/brace. Would a 1.5" eurobrace with 2" rounded corners be adequate? Would I need a wider eurobrace and or add a center brace?

TIA
j

 

[Dustin1300]

I'm considering buying a 'ten a cor' acrylic tank that's never been setup and curious whether this tank is strong enough and whether I should pull the trigger?!

Tank is 96"X48"X30" with 3/4" acrylic all around.

Thread tank is in is as follows for more specifics:

http://reefcentral.com/forums/showthread.php?t=2134733

Is this tank built strong enough or should I pass the deal up because it's ultimately not a deal? I originally was looking at a 96"x36"x30" tank and many of the manufacturers stated that they would go with 1" acrylic and not sure if this is required or not. Having the experts giving a blessing would be great. A good deal is not worth having a flood in my house and having MAJOR losses.

Thanks in advance!

Dustin

 

[dahenley]

Dustin, I think 3/4 will work, but you will see deflection in the front.

I saw that tank, and I know the skimmer is built like a tank.
The thing I didn't like was the tank being "new" but looked to be plumbed with tank, its brown and not clear. So, its either used, or they are using old plumbing for a fresh huge tank.

That's what comes to mind when i saw it.
Good luck. And that's a huge tank and I wish I could fit a tank that large.

 

[Floyd R Turbo]

It's probably OK, my main issue with the big manufacturers is their choices on the eurobrace and wall thickness. The cutout for the overflow access disconnects a good % of the back wall from the brace and their corner radius is never enough on the access holes. So those are points to watch carefully.

The big T is notorious for building to the minimum so yeah 3/4" will be good but like dahenley said you will just see a little deflection.

Moving and transporting the tank is critical. Make sure you get people that know what they're doing.

Setting the tank absolutely perfectly level is 100% critical. That stand looks adequate (maybe James can comment on that as well) but I would double up on the plywood, 2 sheets of new 3/4" ACS (has an orange stripe on the end of it) should do fine. James recommended this and only this IIRC or also you can get a sheet of 1/4" neoprene ($$$) between the tank and plywood, which is also what James has said that he does (if anything) in lieu of foam board (which he has never recommended).

 

[Floyd R Turbo]

double post

 

[Dustin1300]

All, thanks for the reinforcement I needed yesterday to boost my confidence and ensure that I should pull the trigger on this one. (Thought I replied to this thread already but have been talking to a lot of people ensuring I made the right decision)

I was planning for a 96X36X30 tank but this came across my plate and was a really good deal. I'm awaiting the seller to bring the tank tomorrow as I've taken the day off work to take delivery of it. I'll be storing it for a short while to build up a budget to get that part of the build going but have a few projects around the house which will be completed before the wife gives thumbs up on the DT

Floyd, I'd like to also thank you for your contributions to the ATS community. I've not yet built mine but have read the first 45 pages of the ATS basics and will be supplementing this large system with a custom built ATS along side an SRO 7000 or SRO 8000 skimmer.

If anyone is interested in joining my build feel free to do so here:

http://reefcentral.com/forums/showthread.php?t=2075733

With the addition of the new tank I'll be pushing 1000 gallons total system volume so it's going to be an interesting ride! First water test on 350 gallons of the system will happen over the weekend if all goes as planned.

 

[rrg1974]

With width and height (45 x 24) dictate that one. 3/8" will hold, preferrably if it's Polycast (which is 0.375 not 0.354), and you would want a good sized eurobrace too, but you can get 3/4" Plex-G for that price I believe. 1/2" would be better. Still though if your technique is good (that has a lot to do with it) then it's just a matter of how much boq you're willing to accept.

James would have a better answer for you I'm sure. Hopefully he can chime in on your question

Thank you very much for your input. I was thinking in using 1/2 Plexi-Glas G for this build with eurobrace.