Acrylic fabrication questions? I can help!

[Floyd R Turbo]

Example: IMG code from Photobucket in a private directory. Can you see it?

 

[easttexas]

 

[easttexas]

ok, been so long, I was using the info on the wrong picture. got to got all the way till it pops up by itself. been a while.

anyways, heres the first one I posted, and the zoom in was before

 

[dahenley]

I'm seeing them now. (the last 2 you posted)

 

[easttexas]

good deal. I don't remember having to go that far with Jeep Forum to get the pictures up, but, oh well. had a learning curve over there too

 

[easttexas]

what'da ya think Floyd?

 

[Floyd R Turbo]

I don't know for sure, my gut tells me that extending the euro like you have shown does little to strengthen the tank because it's so thin/narrow due to the cutout. Also the change in width at the end makes me wonder if the inside corner of the euro might become a weak point.

Right now I'm slammed at work so I can't add much more, just thoughts off the top of my head.

 

[easttexas]

ok, I stole this from another post today because it is really close to what I am planning (and the guy did a really good job). the only difference is I was going smooth overflow instead of fingered, and I was going to run the top piece over the weir and flush trim it in. I'll radius the inside corners more than the bits radius if needed though. I'm going around standard 1" radius sheetrock corners

https://www.dropbox.com/s/1vjwrsf0tezxxgu/Rear-Iso-1.jpg

 

[Floyd R Turbo]

I'm not the expert opinion on this one, I get the idea. I think as long as the overflow box is overbuilt and maybe even make that end piece one size thicker, you'll probably be fine, possibly without extending the euro...

James?

 

[aldiaz33]

ok, thai you acrylics for the info.

so 50 mil for the front is the absolute minimum?

about the sealing, a supplier in the netherlands told me to seal it with acrylic sealer with no acid, you say silicone.
Does the silicone bond enough of seal it for long time?

regards

James can correct me if I'm wrong here, but I believe he was under the impression that you would be adhering the acrylic panels directly to the steel frame, as opposed to essentially building the acrylic tank within the frame and welding the acrylic panels to one another. To bond acrylic to acrylic, you would want to use a solvent such as Weld-on 3 or weld-on 4 (Pros here can correct me if there is a better solvent to use). To bond acrylic to the the steel frame I believe you would use a silicone or polyurethane product.

If you will be adhering the acrylic to the steel frame, the material (assuming you use 50 mil acrylic) will take up 50 mil of the 10cm in the corner joint, leaving the steal frame to overlap the acrylic panel by only about 50 mil.
It sounds like more overlap would be better, although not sure if it's a non-starter.

From what I have heard, public aquaria builders use 3Mâ„¢ Marine Adhesive/Sealant 5200 for adhering acrylic to metal frames, but this is just from what I have heard; disclaimer- I have no first hand experience with this product.

In regards to acrylic thickness:
I'm guessing James is thinking 50mil is best for the front panel because although height is a main factor in determining acrylic thickness, the extra length does factor into the thickness that should be used. Since the side sheets are not as long, they can probably be ok at 38 mil.

Can someone else confirm or provide their thoughts on the best way to make Michael's tank water-tight?

 

[Steveb]

Is there a way to tell by looking at an edge if it has been flame polished? I have tried contacting the maker but it was too long ago and no one wants to say yes or no...

If I use a 20x magnifier I see what appears to be lines across the width of the edge. If I use 45x magnification I see some what "may" be bubbles, under the surface in the acrylic but also still see the lines at the surface.

[edit] Just looked at a piece of scrap acrylic (arkemia) and it appears to have the same type of bubbling under the surface so I'm thinking what I am seeing is NOT an indication of flame polishing...

I wish I could take a pic but have not been able to get my camera to focus on such a small optic plus keeping it all steady is impossible..

The reason I am asking this is I would like to add a one piece eurobracing to the top.... its 60x36x14 (3/8") has two baffles that run the width (36") up to about 7" and then there is a 2" gap and then another piece that runs the width (36") from 9" to 14". This was done to prevent light spill in the center compartment. Or is eurobracing even needed?

 

[TriNewbie24]

Most likely he went over the edges with a propane torch. Not very many builders actually "flame polish" as the setup can cost a couple of thousands bucks. I think eurobracing is needed for the size. If it was built with 1/2" then I would say not needed as the baffles would've provided enough bracing on the panels to help with deflection.

 

[Floyd R Turbo]

if it's flame polished, you will likely still see remnants of the router cut edge, which would be perpendicular lines across the edge. flame polishing typically does not totally get rid of these. The edge might be irregular and you typically don't want to make too many passes with the torch

If it was hand or machine polished the edge would probably look much more consistent.

Either way if you wanted to put a euro on it, you would want to prep the edge with a router to get rid of the polishing, however that was done.

I'm with Tri though, with the baffles you have, at best all you need is a strip brace across the 5' sides, not a full euro, not IMO.

 

[Steveb]

Thanks for the feedback guys!

I had thought about routing the edges down but but there is a large flat piece along the back left corner for pipe attachment...



How much are we talking about removing to prep it?

What about installing a strip 1/2" down along the inside edges?

Actually the only place I saw deflection when filled to 12" was along the right end at 1/4", the middle section deflected about 1/8" IRC, it has been a while since I did all of that. But I do remember that right end making me a little nervous...

 

[bmanzie]

Need advice on sanding acrylic to remove scratches. Am I in the right place?

 

[Floyd R Turbo]

Yeah I've posted a few times in this thread about it, try using searching this thread for the word 'polish' and you will probably find it

 

[jdstank]

Is there an amount of time that needs to pass to "re-purpose" acrylic? I have a tank that just came out of service that is going to have some of the panels cut down and resized for a different tank. Seeing that acrylic absorbs a small percentage of water I was concerned about welding before the acrylic has had a chance to dry out so to speak.

 

[Floyd R Turbo]

I seem to recall discussing this in this thread at some point within the last year, I think it takes on the order of 16 weeks for a tank to reach the peak adsorbtion point when first set up, but I'm not sure what the reverse timeframe is. I suppose that would be directly related to the environment it was in, meaning, put a fan on it in a warm dry room and it would probably dry out faster. I think at least 2 weeks in the best scenario.

 

[dahenley]

is the used acrylic bowed or bent though?
i think there was someone a while back that was fighting with used bowed acrylic while making something… (you can't just clamp it and bend it back during the assembly/glue process…)

 

[jdstank]

I seem to recall discussing this in this thread at some point within the last year, I think it takes on the order of 16 weeks for a tank to reach the peak adsorbtion point when first set up, but I'm not sure what the reverse timeframe is. I suppose that would be directly related to the environment it was in, meaning, put a fan on it in a warm dry room and it would probably dry out faster. I think at least 2 weeks in the best scenario.

Will probably go on the high end then of 3-4 months, better safe than sorry. Wish it was summertime, I could definitely use the natural sun/heat to dry it out. It's far from the 80-90's in our neck of the woods right now.

is the used acrylic bowed or bent though?
i think there was someone a while back that was fighting with used bowed acrylic while making something… (you can't just clamp it and bend it back during the assembly/glue process…)

Negative, just wet so to speak from being a tank.