Acrylic Fabrication Q & A

[Matthew Frost]

The router bit I'm using is a Bosch 3/4-1/2 shank in craftsman variable speed router. I'm not to concerned with the chatter. What concerns me is the pitting/pin holes. I was planning on using WO4.

That looks abnormal to me. It looks to me like the bit may not be spinning fast enough or clearing out cuttings fast enough. How much are you trying to trim off at once?

 

[Lowell Lemon]

The router bit I'm using is a Bosch 3/4-1/2 shank in craftsman variable speed router. I'm not to concerned with the chatter. What concerns me is the pitting/pin holes. I was planning on using WO4.

The router bit you are using is cut for wood or some othe product than acrylic. The pitting is a result. You can get carbide router bits made for acrylic from FTM Plastics online. The hook angle of the router bit is incorrect for plastics and that is why the chatter and tear out creating pitting.

 

[rbarr110]

The router bit I'm using is a Bosch 3/4-1/2 shank in craftsman variable speed router. I'm not to concerned with the chatter. What concerns me is the pitting/pin holes. I was planning on using WO4.

I looked at some of the leftover acrylic I had cut for my sump and it looks similar, not as many pin holes, but a few. I recommend an O-flute bit for acrylic.

The sump has been holding water without leaks for a 3-4 weeks now. I used pins method for the important joints. I think the pins method "melts" the acrylic enough so when you put the 2 pieces together, it fills the little voids. I used Weld-On 3 which is very thin/water like.

 

[lapin]

Keep separate bits for wood and get others for acrylic. Wood will dull your bits. I like spiral cut bits for acrylic, to pull the work piece down to the table as well as pulling the chips away. It gives me a lot smoother cut using non professional shop tools like mine which are usually under powered .

 

[thinwall]

I really appreciate all of ya'lls advise. This morning I'm going to order the bits that lemon suggested and try those.

 

[Ming_]

Good day everyone.

I am in the process of making my sump tank. As i am located in Singapore, weld-on acrylic adhesive are quite difficult to purchase.
What i have found is something called MTC-90 acrylic glue that can be used for Acrylic, ABS, high impact Polystyrene, Butyrate and Polycarbonate. After some research, I think stuff is Methylene Chloride 90%. (No data sheet is available.) It is colourless, with water like consistency.

Assuming that is it a 90% Methylene Chloride, would this be suitable for cementing acrylic using capillary method?

Thank you!

 

[lapin]

Good day everyone.

I am in the process of making my sump tank. As i am located in Singapore, weld-on acrylic adhesive are quite difficult to purchase.
What i have found is something called MTC-90 acrylic glue that can be used for Acrylic, ABS, high impact Polystyrene, Butyrate and Polycarbonate. After some research, I think stuff is Methylene Chloride 90%. (No data sheet is available.) It is colourless, with water like consistency.
Assuming that is it a 90% Methylene Chloride, would this be suitable for cementing acrylic using capillary method?
Thank you!

I could not find the chemical make up of the product. If it is methylene chloride it should be fine. It seems to be watery like weld-on. I would call the supplier in Singapore and ask some questions just to be sure. You can also contact sign fabricators that use acrylic and ask them what they use. I did find a youtube video on how to use it and it was a weld-on video.

 

[Scrubber_steve]

I have read that acrylic absorbs water.
If this is the case then why don't acrylic sumps & tanks continuously leak water?

 

[lapin]

I have read that acrylic absorbs water.
If this is the case then why don't acrylic sumps & tanks continuously leak water?

All material has moisture content. Including, Rock, Glass, Acrylic, Wood, ect. Certain materials absorb more water than others. In certain cases that can lead to the water passing thru the material. In an aquarium, water in the tank will be absorbed on 1 side as well as moisture in the air from the other. The amount is very little in acrylic. Under normal atmospheric conditions acrylic contains about 0.5 percent water. The issue you have is "bowing" of thinner materials. Where humidity differentials get too close together without enough "buffer" inside the acrylic. This results in distortion to the whole piece with help from water pressure. Over time water will pass thru almost all material. It is a universal solvent. In the case of acrylic it takes a very long time in relation to our lifetime.

 

[Victoria M]

my acrylic tank is giving me trouble...scratches. it seems the work my husband is putting into it really fixes some & makes new. I have googled, you tubed and sanded and buffed. does any body got some magic advise to share?

 

[rbarr110]

my acrylic tank is giving me trouble...scratches. it seems the work my husband is putting into it really fixes some & makes new. I have googled, you tubed and sanded and buffed. does any body got some magic advise to share?

It is highly unlikely that you can fully restore it, however, you have to work through several grits. When I have "restored" scratched acrylic before, I went 200-400-600-800-1200-1600-2000 grit steps with wet sanding at 800 and above, then used Novus polish steps 1, 2, and 3 to buff. It came out really well, but is way more work than it is worth in my opinion.

 

[lapin]

my acrylic tank is giving me trouble...scratches. it seems the work my husband is putting into it really fixes some & makes new. I have googled, you tubed and sanded and buffed. does any body got some magic advise to share?

First is it on the outside? if so I think you are on the right track
You need to "wet sand" the large scratches so you cannot feel them with your finger nail. Maybe 600 grit or 800 grit. Try to go in 1 direction only. It makes it a bit less messy if you tape off the area, so you are not sanding any more area than needed. Then using finer and finer wet sand paper, you sand in the opposite direction each time you change grits. Once you get to 3000 grit, its time to polish. You can do this with a buffing pad like they use to polish a car or a drill mounted sponge made for this. Novus or Meguiars makes polishing liquids. If you are at 3000 grit you can use the Novus #1 to polish/clean the area. Try not to put too much pressure on the pad or cloth or you will create more swirl marks. Use a lot of water with the polish. This will make for less haze., but a bigger mess. I find that if I still have some haze I use a new clean microfiber cloth to finish off the area. Make sure between sanding and polishing you clean the area as not to create more scratches. It also helps to change polishing pads often. I find if I do the final polishing by hand it comes out better than with power tools. This is a labor intensive process. Easier to do with an empty tank. I have spent hours restoring tanks so it can be done. Remember that people will be looking into your tank at the wonders. Only you are going to see those very fine haze scratches.

 

[Lowell Lemon]

It is highly unlikely that you can fully restore it, however, you have to work through several grits. When I have "restored" scratched acrylic before, I went 200-400-600-800-1200-1600-2000 grit steps with wet sanding at 800 and above, then used Novus polish steps 1, 2, and 3 to buff. It came out really well, but is way more work than it is worth in my opinion.

There is a kit from Mico Mesh that works great for acrylic restoration. Try to Google it the company might pop up.

 

[soter]

Hi to all the acrylic gurus.
First of all, thanks for creating this useful topic.

Please I need some advice with acrylics. After my first failure attempt to have my first own custom tank with glass. And after selling my previous tank as scrap, now I planing to buy a custom tank with plexi, the dimensions for this new build are 72x24x24. The builder with some experience, told me that whit 1/2 inch of thick will be ok without any bow or failure in long term. So I'm planning to go with 5/8 thick instead. But the price is too high as 500 bucks only for the extra thick. The question here, what recommend me to do? Is enough 1/2? Is enough 5/8?

 

[lapin]

The thicker you go, the larger the bonding area. I would go as thick as you can afford. My tank is 5'x5'x 34"tall. I made it out of 1" thick material. It does have a full top with 4 each 16"x16" holes. A weir along one end for the coast to coast overflow. I used weldon #40 / 2 part to bond the pieces together so my seams would not have bubbles. It has no bowing. I can climb on top of it with no issues.

 

[Scrubber_steve]

The thicker you go, the larger the bonding area. I would go as thick as you can afford. My tank is 5'x5'x 34"tall. I made it out of 1" thick material. It does have a full top with 4 each 16"x16" holes. A weir along one end for the coast to coast overflow. I used weldon #40 / 2 part to bond the pieces together so my seams would not have bubbles. It has no bowing. I can climb on top of it with no issues.

How do you deal with coralline algae removal off the surfaces without scratching?

 

[Victoria M]

How do you deal with coralline algae removal off the surfaces without scratching?

you don't! lol.

 

[Matthew Frost]

my acrylic tank is giving me trouble...scratches. it seems the work my husband is putting into it really fixes some & makes new. I have googled, you tubed and sanded and buffed. does any body got some magic advise to share?

Victoria, a scratched acrylic tank is 100% restorable in virtually every case. You have to be patient, and it takes a lot of work. Get some Novus 1,2,3 acrylic polish. Get a quality random orbit sander, then get some wet dry sand paper, depending on the scratches, I would start at 320 or so and sand until all of the "scratching" looks the same. You shouldn't have any scratches that are obviously different from the others or stand out. What I mean is a random orbit sander will produce a very unique sanding mark, very different from a straight scratch. When the sanded area looks uniformly sanded clean it thoroughly with water and microfiber towels. The wet dry paper will shed the abrasive as you sand, you have to get it all off when you go up in sanding grits or 600 grit paper will just push around remnants of 300 grit paper and so on.

Start with 320 step up about 50% of the grit between sandings. 320-480-7 to 800-1200-2000. This just a guide. What will happen is the acrylic will turn from looking "scratched" to looking "cloudy". You'll know your on the right track when the acrylic is wet between sandings while you clean it. It will become clearer and easier to see through.

When you've sanded with 2000 grit you are ready to polish. You can do this by hand but it will take days and when you're done your arms will look like Dwayne Johnson. Get a drill and a foam pad, Novus sells them or you can get them at any hardware store. Do small areas, 1'x1' or so. You don't need a ton of polish. Keep the drill moving and keep a moderate speed. When the polish dry or the area becomes clear add a little more polish. After polishing it should feel smooth. Repeat with the step 2 and you should have a tank that looks brand new.

I did a 90 gallon inside and out that the seller said was "ruined", I restored it to like new. It took about 20 to 25 hours and almost a complete bottle of the 1 and 2 polish.

 

[lapin]

How do you deal with coralline algae removal off the surfaces without scratching?

http://www.mightymagnets.com/
Use the algae cutter bag. You just need to clean it often and not let it go for weeks on end.

 

[Victoria M]

Victoria, a scratched acrylic tank is 100% restorable in virtually every case. You have to be patient, and it takes a lot of work. Get some Novus 1,2,3 acrylic polish. Get a quality random orbit sander, then get some wet dry sand paper, depending on the scratches, I would start at 320 or so and sand until all of the "scratching" looks the same. You shouldn't have any scratches that are obviously different from the others or stand out. What I mean is a random orbit sander will produce a very unique sanding mark, very different from a straight scratch. When the sanded area looks uniformly sanded clean it thoroughly with water and microfiber towels. The wet dry paper will shed the abrasive as you sand, you have to get it all off when you go up in sanding grits or 600 grit paper will just push around remnants of 300 grit paper and so on.

Start with 320 step up about 50% of the grit between sandings. 320-480-7 to 800-1200-2000. This just a guide. What will happen is the acrylic will turn from looking "scratched" to looking "cloudy". You'll know your on the right track when the acrylic is wet between sandings while you clean it. It will become clearer and easier to see through.

When you've sanded with 2000 grit you are ready to polish. You can do this by hand but it will take days and when you're done your arms will look like Dwayne Johnson. Get a drill and a foam pad, Novus sells them or you can get them at any hardware store. Do small areas, 1'x1' or so. You don't need a ton of polish. Keep the drill moving and keep a moderate speed. When the polish dry or the area becomes clear add a little more polish. After polishing it should feel smooth. Repeat with the step 2 and you should have a tank that looks brand new.

I did a 90 gallon inside and out that the seller said was "ruined", I restored it to like new. It took about 20 to 25 hours and almost a complete bottle of the 1 and 2 polish.

Thank you Mathew. My husband did all steps you mentioned and then redid it with the magnet method. I think we need to focus on the steps using Novus. I ordered a new bottle of step 3. I guess we will plan on taking a couple weeks. and working on it when we can. The tank is build it which makes it very hard to work inside it. Thank you for all the encouraging words.