Acrylic fabrication questions? I can help!

[Acrylics]

<a href=showthread.php?s=&postid=13026371#post13026371 target=_blank>Originally posted</a> by just dave
How critical is the measuring of #40? It says it is a 100 parts A to 5 parts B (20-1) so do you folks weigh it, measure it or just eyeball it?

It's not critical. For small amounts you can use even 10:1 if you wanted, that's what 42 is. If you use 10:1 on large batches though, you can cause problems though as the stuff gets hot, remember there's a chemica reaction going on which creates heat. So 20:1 or thereabouts is fine, I just eyeball it. 30:1 works too, just gives a little longer pot life and takes longer to cure. Not sure I'd push it much past that though.

HTH,
James

 

[kirsto71]

Another question if i may what is the best way to glue PVC pipe to acrylic (i have to repair a pvc connection on an old calcium reactor)

Thanks heaps everyone.

 

[Acrylics]

Best way to glue PVC to acrylic is Weld-on 40 but 16 will work too, perhaps not as well as 40 but still workable

HTH,
James

 

[just dave]

<a href=showthread.php?s=&postid=12970940#post12970940 target=_blank>Originally posted</a> by Acrylics
Hi Just Dave,

1/4" gap would be fine, just pouring more 40

I'd most likely use 40 to glue it back if you left it as-is. If we were to refinish the tube and base, then solvent would be fine. If you wanted, glue the ring down first, then glue the tube down using 40 then fill the gap with same, should work great.

I've made the repair as you suggested. Is 40 toxic for any period while it's curing? How long should it sit before it's placed in service? Can more 40 be poured in the ring on top of the existing 40 and if so how long should I wait before the second application?

 

[firedogg2]

This has probably been asked before as well but maybe I'm just not grasping the concept. When using a templet to make a cut in acrylic such as the holes in the top from the previous post. How do you secure the templet to the piece of acrylic you are going to be cutting and still be able to use it on a router table. I've used clamps before but I was using a handheld router. I don't think I would be able to slide the acrylic on the table with clamps on it. Thank you in advance.

 

[melev]

Double stick tape would work, firedogg2.

James, do you have a picture of how you blow air into the router as you cut the material? We're discussing this process in Calvin's thread.

 

[firedogg2]

Melev, I feel like an idiot. That makes to much sence. Thank you. You do great work. Thank you for all of the information you offer everyone.

 

[Acrylics]

<a href=showthread.php?s=&postid=13053587#post13053587 target=_blank>Originally posted</a> by melev
James, do you have a picture of how you blow air into the router as you cut the material? We're discussing this process in Calvin's thread.

Look in my gallery
It's just a piece of rod that I hollowed out and tapped a 1/4" pipe thread with a little brass ball valve. It works for outside edges, for inside edges, I hold the air hose by hand or have someone else hold the air for me.

HTH,
James

http://reefcentral.com/gallery/data/500/32445Pict0055.jpg
http://reefcentral.com/gallery/data/500/32445Pict0054.jpg

 

[melev]

How much air is coming out? I have a valve I have to squeeze to let air out.

 

[Acrylics]

In CFM, not sure exactly. I keep my air at 175psi so comes out pretty fast to keep chips clear. You could probably get away with 50psi pretty easily.
Put a quick release on the ball valve so you can take the air gun off and use this instead, or better - use a "Y" or splitter of some sort. Hope this makes sense

James

 

[melev]

A ball valve or screw valve (like for welders) - that would work. Hmmm. Thanks.

 

[khoivo1]

hi

hi

i know this thread is so long ,,i can't read them all,,,i only have one question
how do you do polished up the outside edges?? is there a page in this thread that i can just go there and read?/ thanks


QUOTE]<a href=showthread.php?s=&postid=9385560#post9385560 target=_blank>Originally posted</a> by bchbum189
Ok so i posted pics of the last lid I made and there were some improvements to be made. So here is my newest tank, 120"x24"x30", 5" lip all way around with 5" center braces and 3" minimum on each side of overflows between the braces if that makes sense.

Also polished up the outside edges

[/QUOTE]

 

[RokleM]

khoivo1, you use very fine grit sandpaper (400, 600, 1500) then some of the polishing material like novus.

 

[Acrylics]

There are 3 primary ways of polishing the edges:

Flame polishing; usually hydrogen/oxygen torch. This is the method used on most every tank sold. It heats up and glazes the top of the acrylic. Very fast method. Downside is that it stresses the material, esp extruded acrylic.

Sand & buff; generally the preferred method by DIYers. A little time consuming but results are generally good. Downside is can burn the acrylic if not careful and because it uses friction to act - can stress acrylic though not nearly as much as flame polishing.

Micro-Mesh/Everclear; sand and sand and sand some more, often out to 12,000 grit abrasive cloth (yes, twelve thousand grit.) Very tedious, very time consuming, but yields the best results IMHO. Places nearly zero stress on the acrylic since you are (generally) not using any motorized attachments, usually completely by hand. Downside is time, a simple 24" seam can easily take a couple hours or more. Kits are available at www.micro-surface.com and www.etr-inc.com

HTH,
James

 

[calvin415]

James what method do you typically use? Is a flame so stressful that it will risk the integrity of the welds? I just can't imagine having to hand sanding over 52 ft of edges on my project...

Also, when I hand sand the edges I also end up getting into the display and have to end up sanding everything out to a high grit... Any pointers on keeping the sanding to just the edge or do you typically sand it into the display?

 

[khoivo1]

how do you flame polishes,?? just go fast over edge? ,,,will it burn or flame smokey looks?? i like fast method

 

[Acrylics]

<a href=showthread.php?s=&postid=13057872#post13057872 target=_blank>Originally posted</a> by calvin415
James what method do you typically use? Is a flame so stressful that it will risk the integrity of the welds? I just can't imagine having to hand sanding over 52 ft of edges on my project...

Hi Calvin,
Not really stressing enough to kill the joints welds per se though opinions on this can vary. Just make sure you don't get any alcohol or any other solvent on the material after it's been torched. Gotta remember that to glue acrylic does, be default, stress acrylic so it's an area that you have to be somewhat careful with.

Also, when I hand sand the edges I also end up getting into the display and have to end up sanding everything out to a high grit... Any pointers on keeping the sanding to just the edge or do you typically sand it into the display?

Run a piece of tape to act as a barrier to keep you from veering into the display area, I use that blue painting tape for this, does the job and doesn't leave any residue. You do want to leave a little of the display area to be blended in, maybe 1/4" or so. So if the tank is made from 1/2", you'll want to sand 3/4" or so, make sense?

FWIW, only sand the joints that will be visible, if the top joint will be under a canopy - don't bother, same goes for the bottom - if the bottom joint will be hidden by a lip - don't bother

<a href=showthread.php?s=&postid=13058313#post13058313 target=_blank>Originally posted</a> by khoivo1
how do you flame polishes,?? just go fast over edge? ,,,will it burn or flame smokey looks?? i like fast method

Think of it like an airbrush but using a torch, you do want to go pretty fast with it. Properly done, it won't burn or smoke off. The flame will simply bounce off the material leaving a polished edge.

HTH,
James

 

[khoivo1]

ok i am ready to try some acrylic cutting and glueing here,,but i would need to buy some tools yet,,,,
any body know a good table saw combo with router build in ,,where i can buy one?? maybe with dust collector,,??and i plan to keep it for long time,,just for hobby not big like comercial..thanks

 

[Chihuahua6]

When cutting acrylic should it have a strong odor?
My husband cut my scrap piece on his table saw and the whole workshop and attached garage smelled like a nail salon.

 

[melev]

<a href=showthread.php?s=&postid=13060382#post13060382 target=_blank>Originally posted</a> by Chihuahua6
When cutting acrylic should it have a strong odor?
My husband cut my scrap piece on his table saw and the whole workshop and attached garage smelled like a nail salon.

That can happen. You'll smell it as he glues the acrylic as well, and especially when he flame polishes.

Wait, did you check his nails?