Acrylic fabrication questions? I can help!

[BeanAnimal]

Are you using the pins method? Are you using shims to tighten up the gaps or just allowing the panel to sit flat on the work surface?

[dattack]

I have tried both methods but my guess would be placement of the weights on both sides of the MDF jig. My guess is the weights are pressing down too much on the ends.
I am going to try it again and see how it goes for the other panels for my prop tank.
Thanks.

[dattack]

Hehe. Still doesn't work for some reason. Minor nuisance. No bubbles anywheres except a few at the end.

[mountaindew]

Jame, acrylics.?
did i read your reply on previous pages right? can you glue pvc to acrylic with weld on 40 or what would you use?
Thanks for any help

[RokleM]

Yes, Weld-On 40 works well for that.

[BeanAnimal]

dattack are you waiting long enough to get a nice thick glue layer? Maybe using a bit more solvent and waiting a bit long will allow the panels to disolve a bit more. This would mean more filler (larger fillet) and less air?

[Acrylics]

dattack,
got a pic? there are several things that commonly cause this; not using foam under the pieces, a curve in the material from machining the piece, a step in the material if it was machined on a jointer, or even touching the ends when you glue to make sure they are flush - the surface tension of touching them pieces can draw some solvent out.
If you are gluing on foam, try placing a .030-.060" shim under the ends, see if that helps.

Mountaindew,
Yes, you can use 40.

James

[BeanAnimal]

I had thought about the ends of the material being slightly over machined and causing a gap... I am glad mentioned it james, as I lost my train of thought during the reply.

How come your always a step a head of me

[mountaindew]

James,
thanks again for sharing your vast knowledge of plastics!

[jay24k]

Got a question. A local reefer helped me build a prop tank. We did it out of 1/4" acrylic. It is 36"x36"12". Water level will be about 9 inches. I put a 4" Eurobrace around the top and I put triangle overflows where the longest side is 15" on the back corners. Pressing hard on the acrylic doesn't show any sign of bowing. I completed this last Saturday and the seems all look very good.

How long before I can water test it? I wanted to wait at least a week but other sites state 24 to 48 hours. I'm going to let it sit in my garage for about a week with water. I'm building a stand that will also have a trim piece going around the bottom which I think will not only make it look nice but give additional bracing just in case.

The calculators I've seen states 1/4 inch material to be used for any tanks up to 72" in lenth and 12" or smaller in height.

So when I can I begin testing the tank. Obviously if I see heavy bowing, I won't use it but I think with the huge eurobrace and the overflows, I don't see any issues. Since it is only a propogation tank, if additional pieces are need to glue in, I don't have an issue with that.

Thanks!

[H20ENG]

Hi Jay,
I'll bet you see slight bowing, simply due to the 36" length. Probably less so if it is cast vs extruded. That is a shallow tank, so I'm sure it will hold fine. Thats a nice size frag tank, enjoy

[BeanAnimal]

I prefer to use 3/8 for just about anything... Actually 1/2" is what I really prefer. I don't like bowing, and the smaller the eurobrace the more functional the tank will be.

[jay24k]

I probably would of also, but that's all there was. 1/4" it is. I felt for a prop tank, I didn't care about the Eurobrace size. I felt putting a single lumenarc over it would really make this tank 100% effecient. Plus, I can put a ton of frags in my tank. My current tank has zero sand space and I have corals growing out of the water in 50% of the tank preventing my bigger fish from swimming.

Any recommendation on when to test it with water? It's been a week as of tommorrow.

[H20ENG]

2 weeks is best, but it will hold after a week.

[Acrylics]

A week should be fine, I'd fill 'er up

James

[jay24k]

Sweet. Will test out tommorrow. Can't wait to get this thing going.

I had another question since everyone is helpful and no one else is taking your time . I wanted to purchase some 1/4" to build a sump. He mentioned they had plexi and plexi polycast. Is one more durable? I think the local store here must be overpriced but I could be wrong. Regular sheet 4'x8' was 155.00 and the polycast was around 350.00. Seems kind of pricy for 1/4".

[Acrylics]

IMO Polycast brand acrylic is better, but not *that* much better, that price is obscene. Polycast usually runs 10-15% more than other brands such as Acrylite GP or Plexi-Glas G.
Neither is more durable, just that Polycast 1/4" actually is 1/4"(.250) and not 6mm (.236") and glues a bit better.
1/4" Polycast is somewhat uncommon in retail areas and they probably have it because some job specified that brand and they paid too much for it, that or they're just plain greedy, but just my opinion
For whatever it's worth, I buy, well, *alot* of Polycast and have never even heard of pricing that high for 1/4". Just stupid high, you're very correct in thinking it's overpriced.

If they have Plexi-Glas G for $155/sheet - it's a fair price, if it's Plex MC - it's a bit high IMO but not obscene.

HTH,
James

[jay24k]

Thanks James. I'll have to check in Orlando where I can probably get a reasonable deal.

[jjoos99]

I was wondering if there was a debonding agent available for acrylic glues? I have a reactor chanber that the fitting was glued into the acrylic chanber wall and it has broken and I need to get it out.
Thanks
Jeff

[bchbum189]

if there is a debonding agent, i havent heard of it. Acrylic glue isnt really a glue but a solvent that causes a chemical reaction melting 2 pieces of acrylic together. For anything to remove that, would surely damage the material as well.

[jjoos99]

anyone have any ideas as to how to get this broken pvc fitting out of the acrylic wall of my reactor. It is threaded both male and female. If there is no debonder I might have to drill it out as close as possible to the threads and then try and retap it.
thanks
Jeff

[jjoos99]

anyone have any ideas as to how to get this broken pvc fitting out of the acrylic wall of my reactor. It is threaded both male and female. If there is no debonder I might have to drill it out as close as possible to the threads and then try and retap it.
thanks
Jeff

[kgross]

Is the fitting glued into the reactor, or threaded into it?

[jjoos99]

it is treaded but it also looks as if it was glued when it was treaded in. I have some easy outs at work to back it out with but if it is glued in I dont think that those will work without breaking something.
Jeff

[Bowman]

You really have 3 options. The first is the CAREFULLY drill out the broken fitting and then CAREFULLY retap the threads. Drilling an tapping Acrylic tube is not generally recommended because the curvature of the tube does not provide proper thread contact area for a good seal, hence the probable reason it was glued in place in the first place.

Second is to get a PVC pipe fitting that matches what you are trying to do and sand/cut/machine the mating surface of the fitting to the profile of the acrylic tube. Once it matches the outside profile of the tube. use Weldon #40 and glue it place on the reactor.

Third is to get a Uniseal the size of your pipe or tube penetration then drill the reactor body to fit the Uniseal. Install the uniseal into the reactor then install the tube or pipe thru the uniseal. Uniseals are designed to seal penetrations in iregular shapes i.e. drums tubes etc.

The forth is to send it to me and I will find it a good home