Acrylic fabrication questions? I can help!

the foam has been crushed down its 3/8 under the gap and 3/4 where its touching the tank the stand is fine and so is the tank the foam has been crushed in that area
 
I'm going to leave this to someone else. If it were me, I would want to see the foam the same thickness the whole area under the tank so that the stand and tank were both in contact with the foam, or at least reasonable close (like 1/32"), but I literally have never used foam under a tank before, so I have no frame of reference. 1/4" seems like a lot but I guess it depends on how easily the stuff crushes down.
 
Your issue is the bottom panel of acrylic is bowed, which is pretty normal. The middle has sagged down, so the edges are not setting down on the stand. When you add some water it will even out.
 
Your issue is the bottom panel of acrylic is bowed, which is pretty normal. The middle has sagged down, so the edges are not setting down on the stand. When you add some water it will even out.
this is the likely scenario.

FWIW, other than covering up screw heads, foam of this nature does absolutely nothing beneficial for acrylic tanks. Not being critical, just not sure where the idea came from :)

James
 
this is the likely scenario.

FWIW, other than covering up screw heads, foam of this nature does absolutely nothing beneficial for acrylic tanks. Not being critical, just not sure where the idea came from :)

James


Is it the foam I used, or no foam is beneficial except for screwheads or so..?



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Ahhh! Neoprene makes perfect sense. It compresses but not permanently, and it would relieve pressure of imperfections / dirt also, plus when it compresses it would smush all the way down so you wouldn't have to cover it up.

Of course, I have seen very few acrylic tanks with anything underneath them except a nice thick piece of plywood. Our LFS has a 1500g tank with a metal frame stand and plywood under it and nothing else.

So James, do you recommend putting neoprene under an acrylic tank. how thick, and is my rationale above for using it correct?
 
Ahhh! Neoprene makes perfect sense. It compresses but not permanently, and it would relieve pressure of imperfections / dirt also, plus when it compresses it would smush all the way down so you wouldn't have to cover it up.
yup, and it accommodates for uneven material thicknesses, just perfect for our purposes, but... more expensive

Of course, I have seen very few acrylic tanks with anything underneath them except a nice thick piece of plywood. Our LFS has a 1500g tank with a metal frame stand and plywood under it and nothing else.
it's all I do as well. On one tank I used neoprene, but other than that - just doubled-up plywood :)

So James, do you recommend putting neoprene under an acrylic tank. how thick, and is my rationale above for using it correct?
Rationale is correct. As for recommending it - I usually just say "if you want to use anything - 1/4" neoprene, but other than that - don't bother." Not sure if that's a recommendation per se ;)

James
 
If there is anyone working neoprene in your area they probably have tons of unbacked scraps. When it's shipped they often use layers of unbacked neoprene to keep the backed neoprene from getting scratched.

Neoprene will become permanently depressed over time though, I have lots of it with big creases from too much pressure.
 
Hey I appologize as you have probably already covered this topic. I am currently planning a build for a small frag tank dimensions- 36L x 18W x 12H and I am unsure as to how thick the acrylic needs to be. Also I would like to know the ABSOLUTE minimum safe thickness if I will be using a continuous 2"w eurobrace with a 4"w centerbrace as well as 1" rim bracing on the outside edges and a foam support underneath the bottom to prevent pinpoint stress and sagging. Thanks!
 
What size pin should I use for the pin method? I have #17 push pins from Wal Mart. I will be welding 3/4 material with Weld on 3. Also what size applicator should be used?
Thanks guys
 
James,

Been working on the router table design. I remembered you said that someone could build their own for about $300 or so and be better off versus a purchased one...

I've been getting pricing on a mounting plate for a router table. I'm gagging on the price. I have only found one place that can get 3/4" aluminum plate, and he said $240 for an 18"x18" piece, plus about $80 to fabricate with all the holes. UGH!

a 1/2" thick 12" x 12" plate was about $85 material though.

Is there a reason for the large plate? Any way I can scale it down to the minimum needed?
 
For the price of those mounting plates, I wouldn't use one at all. Just buy another fixed router base for your router and permanently mount it to the table. Drill the holes from the top to screw into the base and counter sink the base a bit into the bottom so you can still get bits fully up to the surface. Then fill in the bolt holes on the top with a little bondo or wood epoxy and cover the entire top with a glossy formica. No need to use a plate.
 
Ok, James, any problems with doing that?

I've seen designs done that way, but figured the purpose of the mounting plate would be to eliminate any possibility of the router flexing out of vertical. I suppose that this will not matter much for me, since I currently do not plan to make anything thicker than 1/2", maybe 3/4" at the most. At that point I would probably upgrade.

The $150-$200 saved by eliminating the mounting plate could go towards a larger table...since I have already decided that 2x5 or whatever I was planning wasn't big enough, and I was going to up it to 4x5 or 4x6 (space restriction). It also means that I can get one (or two!!) more bases and put other router locations in. I'm thinking one about 12" from the 4' end on center (so I can make anything 48") and another just off-center of the table for ease of use.
 
ATT. James or Floyd, Any suggestions on my last post about sizes?
I am ready to start welding less this info.

Thanks Guys, you have been very helpful
 
I was going to leave that one to James...but I would say that WO #4 will give you a longer soak time. You're using Polycast if I remember right, what I have seen recommended by James is that you mix up your own solvent using straight Methylene Chloride and then adding about 5% (but no more than 10%) 'glacial' acetic acid, which delays the cure time long enough for the MC to 'bite' into the Polycast, which helps since Polycast is denser (aka 'mole weight' and 'there I go again')
 
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