Acrylic fabrication questions? I can help!

[SUMMERS]

http://www.mcmaster.com/


#8486K597

[bnplu]

thecoralreef731, here is a link. there are loads of sites on the net.

http://www.rplastics.com/plastictube.html

[get-r-done]

Acrylic Man,

can you tell me what welds with a stronger joint. Weldon #4 or #16?

Thanks

Jim

[Acrylics]

get-r
All things being equal - they should be on par as chemically they are roughly equivalent. That said, all things are not equal including the edge preparation. I am not a fan of #16 at all as it is simply sloppy, messy stuff but does have *some* advantages over #4 if the edges are not straight and smooth. #16 can slightly fill some uneven areas where #4 or similar solvents can't. A better choice would be #40 as it won't evaporate nearly as much so when you see it wet - will stay that way, not the case at all with #16 which will evaporate by 50% or more so the joint will "shrink" - hope this makes sense.

James

[get-r-done]

James


thanks for the reply. what is your feeling on Weldon #3?

Is this hard to work with? Number 3 is the solvent that is sold at the place where I get my Acrylic from. They also sell # 16.


Jim

[Acrylics]

Weld-On #3 is very similar to #4, it contains the same ingredients - just in different ratios. #3 reacts/evaporates faster, meaning less working time. My general recommendation is to use #3 with extruded materials and #4 with cast.

HTH?,

James

[get-r-done]

James

Sounds good!!!

thanks for the advice

Jim

[scuglass]

hi i am planning on building my own 75 gal tank

dimensions 48l x 19w x 19h

what thickness of cell cast acrylic would u recomend? 3/8 or 1/2

what method on glueing do u recomend? needles and shims?

what weld on should i use 40?

how many holes can i drill while still maintaining strength? i was planning on drilling 2 in the bottom (one in each of the back 2 corners) and 9 spread out along the bottom of the back wall

would this be alright and do u have ne other sujjestions or tips

[mabblizzard]

i just built a 5'X2'X2' acrylic tank and i needed to know how i should go about makeing the overflow

[Randall_James]

Acrylics, could you describe or give me a picture of how you build your jigs? I made some for holding work will doing edges etc, but I am having some problems joining pieces at 90 degree angles and still accessing the work to make sure I am not flooding the stuff with weld-on.

Also when bonding these pieces, how do you go about the protective paper?
I have been lightly scoring the bonding area and then peeling the stuff off so only that area is exposed. (the weld-on and I seem to have issues at times, I think I need to reevaluate my applicator)

[GreshamH]

My 90 degree jigs (made out of MDF) have the bottom corner notched out so you can stick you needle under it. Melev IIRC uses normal construction squares, with the corner notched out. I grabbed a few $4 plastic squares recently and notched them out, but I haven't used them yet They seem better them my jigs though, small, yet lighter

[mfinn]

Acrylics
I want to add a baffle in a sump that is being used now and I don't want to pull the sump out from under the stand because of all the plumbing and pumps, etc.
Say I drain the sump, dry the area that the new baffle is going in. Using Weld-on #3, how long before I can start the sump back up?
How about if I have to use Weld-on #16?
Thanks

[maldivian_chicken]

I want to build an external overflow box for an acrylic tank
instead of the normal in tank overflow. The reason is
that I know whatever I do, I won't be happy with the noise.
The in tank overflow with the top bracing plate makes it
difficult to change the plumbing. With an external, I can
fiddle all I want.

To get water to flow to the external overflow, I'm thinking
of just cutting a horizontal slit across the back of the tank,
say 1/4" by 10", about 2" from the top, so water is skimmed
into the external overflow, and the 1/4" gap is small enough
that I shouldn't need to worry about fish or snail going through.
Without the teeth, cleaning should be easy.

Can I use a plunge router and a 1/4" carbide spiral cutter
and just plunge it in from the outside of the back wall and move slowly horizontally? How do I prevent chip out in the inside surface? Will
backing it up with a piece of MDF or another sheet of sacrificial
acrylic work? What RPM should I use to do this? I've never
used a router on acrylic before. (Well, once I tried to route
a template using acrylic and it shattered the acrylic into hundreds
of tiny bits, so I'm scared of working with acrylic).

thanks,
/tom

[zekni]

Hi there..

Building a 120"x36"x48" tank.

Which weld-on# should I use? 40?

Is the pins method a-okay for a tank this size?

Thanks

zek

[Acrylics]

Originally posted by Randall_James
Acrylics, could you describe or give me a picture of how you build your jigs? I made some for holding work will doing edges etc, but I am having some problems joining pieces at 90 degree angles and still accessing the work to make sure I am not flooding the stuff with weld-on.

Check out the following thread, gives some pics of some of the jigs we use, I like simple and these are about as simple as it gets
http://archive.reefcentral.com/forum...hreadid=390652

Also when bonding these pieces, how do you go about the protective paper?
I have been lightly scoring the bonding area and then peeling the stuff off so only that area is exposed. (the weld-on and I seem to have issues at times, I think I need to reevaluate my applicator)

Just peel it up against a straightedge.

[QUOTE]Originally posted by mfinn [B]
I'd let it sit 24hrs for either. WO 16 *is* WO 3 with some monomer (acrylic) tossed it.

Originally posted by maldivian_chicken Can I use a plunge router and a 1/4" carbide spiral cutter
and just plunge it in from the outside of the back wall and move slowly horizontally? How do I prevent chip out in the inside surface? Will
backing it up with a piece of MDF or another sheet of sacrificial
acrylic work? What RPM should I use to do this? I've never
used a router on acrylic before. (Well, once I tried to route
a template using acrylic and it shattered the acrylic into hundreds
of tiny bits, so I'm scared of working with acrylic).

I'd be hesitant to do this for a coupla reasons:
By cutting a slit in the tank, your are potentially weakening the tank as there will be no bracing at all in the area. If the tank was not built well to begin with (proper thickness or better), the chances are good that the tank could fail originating from the slit.
Plunge routing in acrylic is not always enjoyable, esp if not used to it. Acrylic can be "grabby" and also melt so the problems can arise from going too fast or too slow.

If'n ya wanna do it anyway:
I'd advise drilling a pilot hole slightly larger than the router bit you wish to use and going through that instead of plunge routing.
Make a series of vertical slots rather than a horizontal one
Backer boards will be of little use for this.

If nervous: do not do it

Zek,

I simply wouldn't advise this tank for a DIYer. The tank will weigh in around 1500lbs when completed and will have to flipped several times during construction and will have many thousands of $$ in material so I just can't recommend it.

FWIW, "Pins" method and WO 40 don't mix, two completely different processes. One can either/or - but not both, the viscosity of #40 won't allow for it.

HTH,

James

[Randall_James]

If I fly to Portland OR, Do you think I could get a day or 2 of tutoring?

[Acrylics]

LOL! Shouldn't take *that* long. 95% of what one needs to know to do this stuff well can be learned within about an hour. The rest is simply practice and spending a few $$ on good tools, tables, that sorta thing, but mostly practice. Of course it *is* easier to learn when you can see it in person, this is understood. So, if ever in the 'hood, give me a shout and if we aren't terribly busy - can show ya a few things.

James

[bobr]

Acrylicman,
I constructed an internal overflow out of .25" lucite using a 2-part plastic bonder epoxy. The epoxy worked great as far as strength, but I am now worried about whether it is safe to be in the water.

How do I know if it will be safe or not? I couldn't find the weldon stuff anywhere or I would have used it.

Thanks for all your help,

[Acrylics]

Bob, you may have to check with the mfr of the product you used. I couldn't tell ya, maybe someone else might chime in.

James

[maldivian_chicken]

James,

I didn't realise that cutting a slit on the back
of a tank to use as overflow will weaken the tank structurally,
but you're right.

Back to a drawing board. I want to have a centre overflow
but don't want to have this big thing in the middle of a
tank like a traditional overflow. That's why I want the overflow
to be outside the tank (with easy change of plumbing as a bonus).

Will a series of 1/4" holes instead of a slit be better if the spacing
between the holes are wide (say 3/8" or more) so that the top and bottom are essentially still tied together? I wonder how many 1/4" holes are needed to flow say 200 to 400gallons per hour.

/tom

[Acrylics]

Why not just cut a coupla bulkhead holes in the upper back? Maybe not as neat as an external overflow but will serve the purpose and is easy to do. Just put a filter screen on it and you're ready.... maybe?
FWIW I had 2 x 1" bulkheads on one of my tanks like this and I got ~600gph (total) out of them with ease.

HTH,
James

[tha_reids]

Great thread people!!!
More info in here than entire web

Anyone with acrylic background want to discuss annealing?
I have worked with alot of different plastics including cell cast acrylic and lexan in the past. CadCam routing, cutting, drilling, bending and bonding these materials was common place.
We never ever annealed the acrylic. Never had crazing issues.
These items were more architectual in nature then structural.

So, when is it necessary to anneal acrylic tanks? I hear alot of talk about cutting, router clean up then annealing the items before assembly but what about the stress/heat caused by the bonding routing and polishing that takes place afterward? Cut, route,drill, fit, anneal, then bond, route, polish. Why not do all machining, bond, polish then anneal entire tank to relieve stress afterward?

Anyway, I just DIYed my sumps using 1/2" cast. I bought the 1/2" acrylic for use on the main tank but decided to get some practice before taking on the main tank project. FYI Wholesale on this plastic has jumped about $45 this year here in CA (bay area).
Petroleum is up.

So, I put my sumps outside to do some tests, sun light at certain angles give off rainbow shades in joints. This is stress related right??? Like viewing thru polarized lenses?

Do we need to anneal?

Thanks for the thread
and thanks to all that put time into this thread!

[Randall_James]

Ok I went with a MAPP gas torch to try flame polishing and it works. MAPP burns in between propane and Acetylene.

It appears that my flame needs a little tuning yet, but the results so far are really good. I am just doing this on the exposed edges that I have already done a radius on to knock off the sharpies.. I does tend to pull thinner pieces < 1" into a bit of an arc on long stretches. Is the normal for it to pull up like this a bit or is it because the torch is not hot enough?

[goby1]

tha reids, do you mind if I ask where you got your 1/2'' cast from in the bay area? And the $$? I'm just about to DIY with 1/2'' cast, and can't find consistent pricing around here (easy bay).

Also to all: after all this thread (read whole thing, plus melev's documentary), I can't seem to figure out the flush trim routing deal. Is it better to jig a router to the tank (melev) or push the whole tank through a routing table? Why do the flush trim bits, with the bearings, not work without an auxiliary guide? Thanks, this thread is one of the best I've read, esp. the info from Acrylicman and Acrylics. G1

[NorthernCF]

I slide my tanks on the table. But, they are only 2'x4's; Try that on a 300gallon tank . (Make sure the protective papper is still on if you are using a table router).