DIY- "Pins" method of gluing acrylic.

[Zephrant]

Aaron- That makes it clearer. I think what is happening is that the Weldon #16 is skinning over, then you are adding some weight. The extra weight forces some glue out, but it can only escape at the weak points of the "skin", so looks like bubbles. Try adding the weight earlier, or pressing down more when you assemble.

Weldon #16 is at least 70% solvent. When you try to fillet with it, it has to shrink to about 1/3 its size. If the surface skins over first (as it normally does) then the inner portion shrinks away from it, making bubbles. The only solution is to not try to fillet with Weldon #16 unless it is extremely thin.

Rad- That right hand table is part of a "Router table kit" that came with the Craftsman saw. It is also available separately. It does work well for most cases. Having that big fence is great. There is a cheapo kit that is supposed to go on the fence to turn it in to a split fence as needed, but it is a royal PITA to adjust, so I never use it. In this case, I did not need anything other than a straight fence.


Well you guys convinced me to try Weldon #3 tonight. I picked up a few cans when I was at the candy store today. I made up a pair of 10"x6" overflow boxes with it, and it seamed to work well. Very fast. I'll see tomorrow if the joints are strong enough, but for this use, it should be fine.


Zeph

 

[melev]

I think that #16 has to go on very thin to avoid those bubbles. I've even worked it as it was hardening, using a pin to poke the bubble and press the airbubble out of the seam, which is pretty annoying.

#3 goes a VERY long way. I buy a small can, and can build several sumps from it. I'd bought a small squeeze bottle with a needle applicator, and find that one bottle filled is enough for each project. I think I've built about 7 sumps now and have used less than 2 cans.

 

[oneputt67]

too much solvent

too much solvent

hey zeph,

i am ready to glue my pieces but decided to do some practice runs with scrap acrylic. i'm working with WO #4. i am able to get seams with very little to no bubbles. however, i seem to be using too much solvent. they ooze out of the sides when the pins are pulled and pressure applied. how can i avoid this? i tried using less solvent but i don't get full coverage in the seams. how can you tell if you have enough solvent in one spot and needle applicator should be moved?

the method i use (which is obviously incorrect) is to apply enough solvent so the routed edge gets "wet". that is when i start moving the applicator needle. the result is too much solvent.

i've read and heard about the term "filet" in acrylic. what is it referring to?

thanks.

 

[Zephrant]

Yep, this method does have some "ooze". When you pull the pins, some goop should squirt out on all sides. It will dry clear, and will be hard to see if done well.

It sounds like you are doing it right- Fill the gap completely, and let sit for one minute, then pull the pins. If the acrylic has softened so much that the pins are glued in, you waited too long. Keep a set of needle-nose pliers handy so you can get a grip on the pins to pull them.

If you use smaller pins, you get less of an ooze. I have been considering going to a fine copper wire instead of pins, but have not bothered to try yet.

A fillet is what you see in the corners of a glass tank. The goop that is smoothed out to each pane, but fills the crack with a 1/4 round bead.

In acrylic work, it is not nearly as big, but it refers to a small amount of dissolved acrylic that hardens outside the joint, adjacent to the two panels. Having the fillet means that you softened the material enough before you pulled the pins, so that the panel seated in well, and pushed out a little bit of the dissolved acrylic.

Zeph

 

[Cheapreef]

If you use smaller pins, you get less of an ooze. I have been considering going to a fine copper wire instead of pins, but have not bothered to try yet.
Zeph

I've been using aluminium foil folded over 3 times and about 1/8" wide, seems to work very well. I get little oozing from this method, still get some just not as much as the pins. Just thought i'd share that.

Clinton

 

[melev]

Sounds like you could run a sheet of foil through a shredder to get the strips cut quickly. Do you glue all of it, or only where the foil isn't, then pull the strips out and fill in those zones?

 

[H20ENG]

Seems the foil would be too flimsy and cover too much area. Maybe folded its better.
I use copper wire. Use solid if you want a certain gauge, or untwist some stranded and twist some to your own thickness preference. I twist a little loop in the end so its easy to grab and pull out.
$0.02
Chris

 

[oneputt67]

thank you all for your help. i successfully joined by sides and baffle this morning. no bubbles and hardly noticeable "oozing". i tested the tin foil version but covers too much area. had much better success with the pins.

now ready to attach the back. i plan to continue to use the pins method since i have had success with it. however, i don't think i will be able to use this method for the baffle. i am constructing a rectangular reactor so i have no space to get my hands in there when attaching the back. any suggestions on how i can get this done? should i join the sides to the back first with the pins method? then just use the capillary method in attaching the baffle to the back panel.

thanks again for your help.

ray

 

[H20ENG]

You can glue an internal baffle without any pins. The glue will still wick into the joint and soften the acrylic. When doing this without pins, I will usually keep running the needle along the joint and dispensing the glue so it can have a longer contact time before drying up.
HTH,
Chris

 

[Zephrant]

Chris- I knew I had read about that trick here someplace, thanks!

Neat idea on the Al foil- I bet the sheet doesn't roll on it like it does the pins. Maybe I'll take some solid core #22 wire or so, and hammer it flat a little. hmmm....

When I do inside baffles, I put them in after all four sides are done, but before I put on the top and bottom. That way I can trail fit them. I have started using Weldon #3 to put them it. I still space them up a touch with a pin at each end, wick it in, and drop it. It still makes a clearer joint then what I get when I just wick it in from the sides. It seams like I always get bubbles that way.

Zeph

 

[melev]

I too like that idea about using copper wire with a loop to tug them out!

We just had our (DFWMAS) club meeting at my house this evening, and I held an acrylics demonstration to show how it can be cut, routed, sanded, buffed and bent for the members. I threw together a very simple specimen container like the LFS use to hang on the tanks. Our president commented that it looked like it could be the outer box of an overflow system.

I tried to keep it moving at a good pace so no-one would get too bored, and answered questions to give people better ideas of what they could do, and what it might cost.

Later, several came up to me to let me know they'd be ordering sumps. No problem - I think it is fun to make this stuff.

I"m going to make a hanger bracket for the SCWD unit, and if it comes out nicely, post a picture for others to copy. Since 3iQ doesn't supply any.

 

[C_Kritter]

ok, i messed up in joining my front, back and side panels. when i dry fit the flange to the rectangular reactor, i noticed a gap about 1/32 of an inch. it is an area where i can no longer scrape. can i continue using Weld-On #4 to join the flange or should i use Weld-On #16 instead? Or, should i use #4 to adhere the flange to the body then bead on #16 to create a seal? thanks for any input.

ramon

 

[Zephrant]

M- Sounds great! I've been considering doing the same, but our reef club is pretty small at the moment.

CK- Can you get a clamp on it to compress it together a little? (Don't torque it very much, just a little.)

If not, then I'd try a bead of #16, then mate them together and let them dry. Add another bead of #16 on both sides of the problem area, but keep it a VERY small bead, or it will pull away and leave air bubbles behind it.

Drop a picture up here if you can-


Zeph

 

[C_Kritter]

ok, i used WO #4 and clamped them together. seem to have joined nicely (without bubbles) but i still feel a little uneasy about the joint. can i still use WO #16 to make the joint stronger? should i bead the WO #16 in the corner then run my finger through like when applying silicone? thanks.

ramon

 

[Zephrant]

If the joint is clear, you don't need to add anything else. Let it dry for about a week though, just to make sure.

If you are paranoid, you can glue in a little triangular gusset in that joint. Just cut one on the table saw, put it in place, and wick in the #4 on both sides. Hold it in place for a few minutes by hand, and you are done.

Zeph

 

[williamrandel]

Polycarbonate

Polycarbonate

Has anyone ever tried using polycarbonate? i was just wondering because i know that it is "unbreakable" . it has a few bad qualities in that it scratches, but will withstand even a gunshot without breaking. i don't think it would make a good tank but you might could use it for a sump. i just don't know if you can glue it?

 

[Zephrant]

Sorry- No experience there. Polycarbonate is more flexible, which would mean more bowing from the same thickness.


Zeph

 

[qwuintus]

How come the end of the bottom piece sticks out a bit?

 

[Cheapreef]

Easier to glue, and you router it flush after.

Clinton

 

[melev]

Zephrant,

I'm working on another sump this evening, using Glad Baggie twist ties that have been stripped to allow me to insert bare wire in the joint. So far, 3 sides are glued.

I decided to review this thread since I've never used pins before, and I noticed you don't even have them completely inserted to support the entire material in your pictures. They look like they are in about 1/16th or 1/8th of an inch. I didn't notice that before.

When I was preparing my joint to be glued, I immediately realized if the wire went too far out the other side (inside the sump), the glue would wick along the wire, so I had it even with the inner edge. I'm using 1/4" acrylic, and the wire is 1/4" in the joint. Hope that makes sense.

I noticed you talked about leaving it for four hours to bond, but my work area doesn't really work that well for me. I usually have one side I work from and need to rotate my project to put that next joint in front of me.

I can't wait to see how clear these seams will be after this!