Acrylic fabrication questions? I can help!

[H20ENG]

Hi James,
I was wondering what you use to clean your bits and blades after getting streaks of melted pvc and acrylic on them. (I know, you DON'T get streaks with your stock of new, pretty bits and blades )

But, hypothetically, if you had to remove something like that, what would you use? I was thinking of soaking the blades in some MEK or something. Lots of stuff removes wood pitch, but melted plastic is different...
Thanks,
Chris

[RokleM]

That's odd. I can't say I've ever had chunks get stuck in the router bits. Are you taking off very large sections at a time? Even when I've done that, I only have a "dust" per say on the bit. I use a solution that feels partially oil based I received from woodcraft to clean/store the bits. I doubt it would work well at removing chunks though.

Here's my big creation finally in place (after playing with a number of acrylic projects). Still a ton of work to do (probe holders, power re-run, pipes/tubes to cover re-route, doors to put on, etc).







Before heh...

[RokleM]

Probably worth adding some build pics...

[H20ENG]

Nice work! Fun working with thick material after so many smaller jobs. Thin stuff is way harder to work with.

My router bits dont get gummed up really, but my saw blade definitely has streaks of melted plastic (mostly pvc).

[Acrylics]

Chris,

When acrylic starts melting onto the plate, it's time to get resharpened
PVC is absolute murder on carbide blades so I have different blades for odd & ends cutting.

I'm not real sure what I'd use to be honest, I'm lazy, when stuff starts melting on 'em - must be dull. But, hypothetically speaking, I'd probably use methylene chloride.

Eric,
Nice work

James

[RyanBrucks]

rockle, very inspiring stuff


out of curiosity, can you use thinner material on the bottom of a tank without sacrificing much?

for example, a 36x18x18 tank, could it have 3/8" on the side and 1/4" for top flange and bottom? would it have roughly the same strength as the same tank all 3/8?


Thanks
Ryan

and fwiw I haven't ever seen melted acrylic on my blades, but I DO see a buildup of the paper material on the blade which almost turns into wax. Every once in a while it will cause things to catch. I can scrape it off with my fingernail though. the paper on the top of the piece I am working on often snags my router which is probably the largest cause for nicks in my edges.

[Acrylics]

Ryan,
Yes, you can use thinner material on the bottom. I think you'll be fine with w/ 1/4" on top & bottom on that size tank. There are limits to this type of thing though; if the tank could be built from 1/4" and you use 3/8" for the vertical panels, then 1/4" for the top & bottom is fine. But if building a larger tank that requires say 3/4" construction, don't use 1/4" for the top & bottom, may seem like common sense but people do it. For that I'd stay using 3/4" for the top and *maybe* 1/2" on the bottom. Meaning don't go down in thickness for the top from what it could be solidly built from but if you used 1" for the vertical panels - you can use 3/4" for the to since it could be solidly built from 3/4" all around. Similar for the bottom, but you can often go down one thickness for the bottom; ie., if the tank should be made from 1" material, you can usually go down to 3/4" for the bottom. OTOH, there are limits to this as well going the other way in the sense that I've rarely seen (hobbyist size) tanks requiring greater than 1" for the bottom. Hoping this makes sense

James

[scouncil]

James, you said I could get a 48x20x20 tank out of one sheet of acrylic, does that include all the baffles to divide the compartments, or can I get 3/8" for the inside baffles (hoping to use 1/2" for the tank itself..... Hate to make 2 trips for the acrylic if we can make just one (but DH always says 3 trips are always required for every project).
Susan

[Acrylics]

Hi Susan,

No, doesn't include baffles unless you dont plan on having a top in which case it would include baffles, and then again if you use *just* eurobracing and no crossbrace - then you can get some baffles out of the top cutout. A 3" eurobrace cut out of a single piece will yield a 14 x 42" piece you can use for the baffles (minus kerf space). FWIW I almost never recommend going without a full top. In this sump, if there are baffles in the center - then you really don't need the centerbrace. 3/8" would probably be fine for the baffles.
Cut list:

2 pcs 48.25 x 19.125 (front & back)
2 pcs 19.125 x 19.125 (ends)
2 pcs 48.25 x 20.25 (top and bottom)

Finished size for gluing after machining 1/16" off the gluing edges:

2 pcs 48.25 x 19 (front & back)
2 pcs 19 x 19 (ends)
2 pcs 20.25 x 48.25 (top & bottom)

Should come out of any 99+" sheet with careful cutting and one "drop" measuring ~10 x 19" which could be used as a baffle. Polycast and Cyro Acrylite GP will certainly yield this out of a sheet, can't say about PlexiGlas G with any degree of certainty (I don't buy this material so can't remember the exact sheet size)

And your DH is probably generally correct but do your homework and have a plan and you won't have to

HTH,
James

[scouncil]

Full top over the whole thing? I was going to leave it open. Too hot? I have to leave it open over the skimmer part (it's really tall). FWIW (no speaka de txtng)? and Kerf space (the space where the water goes under the middle baffle?

I appreciate the help!! And I don't need a lot of room for the skimmer, right? Just enough to fit it and not crowd it, but have a relatively large return area?

Rokle, why didn't you build 2 and send me one..... it's beautiful!!

[RyanBrucks]

hes probably recommending a top piece so you can cut it into a top flange.

http://www.melevsreef.com/acrylics/s...iy/flange.html

[scouncil]

Oh, I've got it. Extra stability. So I'll still need the flange even if I have the baffles? They wouldn't provide enough stability?

I know the flange would be the best. My current 100 gal is acrylic and the flange is the pain in the butt item that makes it difficult. Of course this will be at ground level.....

[dudedudedude]

The thread seems to deal with rectangle tank/sump construction so I might be off topic but, I would like to make an acrylic cone similar to ATB’s skimmers. I have found an online calculator that tells the shape of sheet to cut for a particular size cone. What I was wondering was if this method would be successful. I am going to make a sheet metal cone that has the angle and bottom outside diameter of the desired acrylic cone. McMaster has the softening temperature of their cast acrylic at 80 degrees C. I was thinking that I could cut out the appropriate shape for a cone, heat the cut out cast acrylic piece in boiling water until it reaches 100 degrees C too. Then with water proof thermally insulated gloves take out the softened sheet, join the ends together by hand and then place and press it into the inside of the metal mold so that a cone with a vertical seem is formed. If the seam is not perfect, once cooled I will seal it with some weld on. Will this work?

Thanks,
Sean

[Acrylics]

Susan,
The top flange adds structural integrity. I would almost always recommend it and yes - in this case as well. How many 80 gallon tanks do you see out there with no top bracing? What do the baffles do for the sides without baffles attached? The top flange will take pressure off of the joints themselves and I recommend this highly, especially to DIYers whose joints are not always of professional quality, though there are certainly exceptions to this.
Hope you take this in the constructive manner intended

Sean,
80C is definitely wrong for making it pliable. I haven't checked the McMaster site but 80C is a working temperature, not a forming temp. A good forming temp will be more in the neighborhood of 150C or 300F so water will not work, should be done in an oven.
And no, the pliable pieces will not stick together to make a strong bond. You will need to glue the cone together with Weld-on 40 or similar. In order for an inside form to work well though, the acrylic has to be cut *exactly* right with an allowance for shrinkage. (acrylic will shrink when formed)

James

[dudedudedude]

Would clear PVC be more feasible? I do not have access to large enough of an oven.

[Acrylics]

Originally posted by dudedudedude
Would clear PVC be more feasible?

In what way? Forming clear PVC would necessitate similar operations.

James

[dudedudedude]

Well, I am just thinking that for the same size cone, PVC would require lower temps to maintain and would thus make it more easy to perform the forming in the cone. I have never done anything like this so this is just speculation.

[Acrylics]

ah, I gotcha. PVC really is nasty stuff to heat up though, just plain nasty smellin' - can't be good for ya at all stuff, and this is coming from someone that plays in solvents all day.

James

[dudedudedude]

Well, say I made a box oven and had it so I could maintain it at 150C. If I am working with 1/4" cast acrylic would I have a decent amount of time from taking it out of the oven to form it or would it be a race?

Thanks for all the input so far,
Sean

[scouncil]

James, I'll do the flange on top, just asking..... and no, constructive criticism is what I need since I have only a minimal idea of what I'm doing!! I appreciate the help.
Susan

[Acrylics]

Sean,
Yep, you'd have a coupla minutes.

Susan,
Do a search for a thread entitled "DIY tank, step by step" with "acrylics" as author, and any date as the time frame (it was a few yrs ago). It should give you some pretty good insights into building the tank. Baffles are just an extra step but the tank structure itself is exactly the same.

James

[crab0000]

I actually got the search function to work, so here is a link http://archive.reefcentral.com/forum...k+step+by+step

[Nammy]

Bump

[Acrylics]

Thankx Crab

[scouncil]

Yes, thanks Crab!