+Dogfish Posted July 20, 2017 Share Posted July 20, 2017 I have started on my tank build. I need to build the sump. I found 2 suppliers of cast acrylic sheet in Austin that do cuts. Since the sump is 60" x 30" I need accurate cuts with minimal blade marks so i dont have a lot of waste. I can do this with 2 sheets. Does anyone have any experience with either Regal or Laird here in Austin? Laird is a bit cheaper than Regal but im not familar with how good either of them are at cutting. Cheers Link to comment Share on other sites More sharing options...
Timfish Posted July 21, 2017 Share Posted July 21, 2017 Either should be fine but I use Austin Plastics on Krammer Ln. If you use Sci-Grip's 2-part #40 it will bridge gaps and gives a much stronger joint than the single part #3, #4 or #16. #40 does give off lots of VOCs while curing so you need to have very good ventilation. When using #40 there needs to be a 1mm gap between the pieces and the pieces need to be held in place for 30 minutes or so while it cures. Link to comment Share on other sites More sharing options...
+Dogfish Posted July 21, 2017 Author Share Posted July 21, 2017 Thanks Timfish How hard is #40 to mix and work with? How do you create a 1mm gap and still get the # 40 into the whole surface of where the 2 pieces meet? Will the pin method work? If so how long do you wait before pulling the pins? Cheers Link to comment Share on other sites More sharing options...
Timfish Posted July 22, 2017 Share Posted July 22, 2017 #40 is a lot more work to use but it gives a much stronger glue joint and does not have the propensity of solvent types to develop crazing over time that weakens the glue joint. (I've seen sumps I was able to pull apart.) You need a good scale, the one I use is +/- .5 gram. I use tiny chips of acrylic but the pin method is workable but they need to be left in until the 2-part sets so they will leave small gaps, not much of an issue unless the pins go all the through the joint. #40 is about the viscosity of 80 or 90 weight oil so you'll need to use an applicator to get it into the joint and it helps to have the parts set so the glue runs into the joint. Link to comment Share on other sites More sharing options...
+Dogfish Posted August 26, 2017 Author Share Posted August 26, 2017 Timfish thanks. What sort of applicators do you use with #40. Im not sure I will be able to tilt the long pieces on edge very far. How much of an angle do you need to get it to flow under the seam? I was going to make a jig to hold the pieces at 90° but that was for working on a flat level surface (1" mdf). I might be able to tilt that surface but dont want to have it distorted. Maybe a 2x4 under one side. Will a 2" rise over a span of 5 ft work? I take it that it will dissolve the chips making them clear. I have a 5 foot seam working with 1"thick acrylic . How long a working time will I have to get the seam filled? Link to comment Share on other sites More sharing options...
Timfish Posted August 26, 2017 Share Posted August 26, 2017 Using a 2x4 is what I've often used. Be sure to use painters tape on the outside of the joint to keep the glue in place and to keep from gluing your sump to your work table. The glue has the viscosity of about 80 or 90 weight oil so it takes a few moments for it to run into the joint. Jiggling one side gently helps work it in a bit more evenly. To help make the 1 mm gap needed I pour a little bit of #40 onto a piece of polyethelene (cheap plastic cutting boards should work), let it set up, then cut or break off tiny pieces about a diameter about 1/3 the thickness of the acrylic your using. Hair color applicators from a beauty supply place work good for gently squeezing it into the joints. Link to comment Share on other sites More sharing options...
+Dogfish Posted August 26, 2017 Author Share Posted August 26, 2017 Hey Thanks... With 1" acrylic should I use a 1mm gap or increase it to 2mm ? Hair color applicators , never thought of those. Was thinking marinade injector. Link to comment Share on other sites More sharing options...
Timfish Posted September 6, 2017 Share Posted September 6, 2017 Sorry to take so long to get back with you! I would stick with the 1mm gap. If you're having problems getting the #40 all the way into the joint you can thin it with Scigrip's #3061. I use hair color applicators because they are easier to clean out for reuse. Marinade injectors will work and you might find them better to use in some situations, it's something to experiment with. Link to comment Share on other sites More sharing options...
+Dogfish Posted September 14, 2017 Author Share Posted September 14, 2017 On 9/5/2017 at 9:35 PM, Timfish said: Sorry to take so long to get back with you! I would stick with the 1mm gap. If you're having problems getting the #40 all the way into the joint you can thin it with Scigrip's #3061. I use hair color applicators because they are easier to clean out for reuse. Marinade injectors will work and you might find them better to use in some situations, it's something to experiment with. Hey, You are the best. The #40 is great. I did an 8" practice seam using the 1mm gap. It came out perfectly clear except for a single bubble that's about the size of a pin head. I think it was because I went over the seam 2 times. The first time it looked like the stuff was seeping in and and there would not be enough to fill the gap.I lifted the syringe at that point. It was hard to see how much was going into the gap using blue painters tape. Can I use cellophane tape or do you have another idea? Also the syringe tip I was using was a bit small and I had a hard time filling and dispensing the #40. I used another syringe from the Aiptasia killer stuff without a tip and it worked a lot better. I didn't have a seam ready but it did suck up and push out 100x better. I made a few lines of the #40 to make chips for the next practice piece. Will they dissolve and become clear when #40 is applied to the seam? Link to comment Share on other sites More sharing options...
Timfish Posted September 14, 2017 Share Posted September 14, 2017 It takes practice to learn how much glue to push out to fill a joint with a single pass, and it changes a bit with different applicators and thicknesses of acrylic. with a basic tensile rating of 2000 psi bubbles like that are just an aesthetic issue but sometimes you can fill them by puncturing the thin film that forms over the top of the bubble and squeezing in some glue. I use cellophane packing tape and painters tape. Vinyl tapes like electrical tape will melt though so if your not sure of the backing used test it first. The chips you use will always be noticable, sometimes I've just put them at the very ends if I want the joint to look as clean as possible. Link to comment Share on other sites More sharing options...
Timfish Posted September 14, 2017 Share Posted September 14, 2017 Oooops! I noticed there weren't any sanding marks. On the face of a piece of acrylic, not the cut edge, it's best to lightly sand with some 220 grit or 300 grit sand paper tp make sure there isn't any residue from the protective paper applied. If I'm worried about aesthetics I'll just get get most of the joint surface and the scratches will be invisible unless you get a real clsoe up picture with a camera like the one you posted. Joints can be sanded and buffed out also so they are almost invisible. Link to comment Share on other sites More sharing options...
+Dogfish Posted September 15, 2017 Author Share Posted September 15, 2017 11 hours ago, Timfish said: It takes practice to learn how much glue to push out to fill a joint with a single pass, and it changes a bit with different applicators and thicknesses of acrylic. with a basic tensile rating of 2000 psi bubbles like that are just an aesthetic issue but sometimes you can fill them by puncturing the thin film that forms over the top of the bubble and squeezing in some glue. I use cellophane packing tape and painters tape. Vinyl tapes like electrical tape will melt though so if your not sure of the backing used test it first. The chips you use will always be noticable, sometimes I've just put them at the very ends if I want the joint to look as clean as possible. Thanks. I ordered some of the thinner. My concern is that the small batch I mixed up did not have a very long working time. I have to run 4ea 5ft seams to cement the sides to the bottom of my tank. Maybe mix a few batches as I go . I will sand the flat surface as recommended and see how that goes. I always clean with alcohol 2 times and still get lint. :))) Prob will create a better bonding surface sanded. Maybe 400 grit wet/dry. Link to comment Share on other sites More sharing options...
Timfish Posted September 15, 2017 Share Posted September 15, 2017 #40 is trickier to use because it has such a short pot life. The thinner helps apply it faster but doesn't extend the pot life or limit the forming of surface skin any. Good news is you can do a glue joint is stages. I would caution against using alcohol, it's quick evaporation rate can cool acrylic fast enough to crack especially after gluing. Better to use naptha for cleaning it but I mostly just use clean dry towels to wipe the surfaces clean before glueing. Link to comment Share on other sites More sharing options...
+Dogfish Posted September 20, 2017 Author Share Posted September 20, 2017 On 9/15/2017 at 7:48 AM, Timfish said: #40 is trickier to use because it has such a short pot life. The thinner helps apply it faster but doesn't extend the pot life or limit the forming of surface skin any. Good news is you can do a glue joint is stages. I would caution against using alcohol, it's quick evaporation rate can cool acrylic fast enough to crack especially after gluing. Better to use naptha for cleaning it but I mostly just use clean dry towels to wipe the surfaces clean before glueing. I figured out how to make a bubble free joint. Piece of cake, sort of. The thinner helped a lot. Filling from the inside makes the outside that was taped an easy clean up with a router and some polishing. I am having an issue on my sump baffles. The tape side ends up looking like crap and not easy to clean up. Too much outflow. I tried putting the tape in more of a 90 degree bend at the joint, to keep too much glue from escaping the joint. That does not allow air to escape, causing the joint to not fill all the way thru. I have to go back after its dry and fill from the other side. I found the same issue when I used cellophane tape. Maybe you have another idea? More of a pain than anything. Link to comment Share on other sites More sharing options...
Timfish Posted September 22, 2017 Share Posted September 22, 2017 Sorry! I just noticed your post from Wednesday. Basicly I do an interior joint the same as a corner joint, tape one side and let gravity flow the glue into the joint. I do find it a bit tricky taping the joint. Often I'll use several pieces taping 6" or 8" at a time. I like to use blue painters tape as I can see when it's actually stuck to the acrylic and it has a little bit of stretch. To get a tight fit with the tape I loosely fold it in half and try to get it stuck to one side and as close to the joint as possible before sticking it to the other side. And if it helps the gap on dividers can be a little wider, unless your using really thin acrylic the loss of a little structural support with a wider glue joint is negligible. Link to comment Share on other sites More sharing options...
Timfish Posted October 7, 2017 Share Posted October 7, 2017 I'm curious how you're doing with interior joints? I don't use interior baffles but sometimes when I'm doing a sump in sections or a irregular shape to fit a stand as completely as possible I might end up with interior walls. Here's an interior joint with 1/2". The left side is the taped side with blue painters tape and the right side was "up" when the joint was glued. I could have gone back after finishing applying glue and popped the bubbles that formed on the right side with a dental pick but this would never been seen so I didn't worry about it. The bubbles on the left side are less than a 32" and if I had thinned the glue and jiggled the joint they could have been worked out. Link to comment Share on other sites More sharing options...
+Dogfish Posted October 8, 2017 Author Share Posted October 8, 2017 9 hours ago, Timfish said: I'm curious how you're doing with interior joints? I don't use interior baffles but sometimes when I'm doing a sump in sections or a irregular shape to fit a stand as completely as possible I might end up with interior walls. Here's an interior joint with 1/2". The left side is the taped side with blue painters tape and the right side was "up" when the joint was glued. I could have gone back after finishing applying glue and popped the bubbles that formed on the right side with a dental pick but this would never been seen so I didn't worry about it. The bubbles on the left side are less than a 32" and if I had thinned the glue and jiggled the joint they could have been worked out. I have the same issue. This sump is 3/8 and this is an interior baffle seam. One side is pretty clean the other has bubbles all over it. Since its a sump and not going to show I was not too concerned. On my DT I will not have any baffles to worry about just the bottom seams. The tank will be framed, picture frame style on the bottom and top edges, so appearance will not be an issue. Its an outside corner tank with 2 sides facing out. 1 corner edge will face out with no way to hide it, so that seam will need to be perfect. Link to comment Share on other sites More sharing options...
Timfish Posted October 8, 2017 Share Posted October 8, 2017 Hmmm, you might try using less catalyst. That will extend the pot life and and along with using thinner give you more time to get the small bubbles out. You can also tape bothe panels on the inside 3/16" of 1/4" from the joint to give you a straight clean line on the edge of the glue joint. Link to comment Share on other sites More sharing options...
+Dogfish Posted October 8, 2017 Author Share Posted October 8, 2017 On the last seam, I did place a tape line on the application side close to the joint. I pulled the tape before the #40 had a chance to set and it did make for a good line. I will do that on all my seams from now on and make sure no acrylic is exposed to slobber on. I also cut the protection paper off using a razor blade on some seams. Lazy way. This left a small line. No biggie on the sump but will have to take more time and peel back the paper by hand on the DT. I found the #40 flows better when applied to a non sanded edge. I dont think this would make a strong joint as the surface would be too smooth for good adhesion. Link to comment Share on other sites More sharing options...
+Dogfish Posted October 18, 2017 Author Share Posted October 18, 2017 On 10/8/2017 at 8:16 AM, Timfish said: Hmmm, you might try using less catalyst. That will extend the pot life and and along with using thinner give you more time to get the small bubbles out. You can also tape bothe panels on the inside 3/16" of 1/4" from the joint to give you a straight clean line on the edge of the glue joint. I have a new issue. I picked up the 1" stuff for the tank. I looked at the coast to coast external overflow box pieces. 12"x50". In the picture you can see that across the length I have a warp of about 3mm. The "right" end of the picture is with both pieces laying flat. The edge is straight within 0.2mm. Checked with a straight edge. Thinner stuff no prob to straighten it out. 1" not so easy but its do able with clamps and shims. I dont really want to router off 3mm on each end after glue up. Right now I have placed a small spacer under the middle of the warped piece and weighted the ends. If it gets warm enough outside today do you think the warp will fix itself or is it something that requires more than 90 degree heat? Have not checked the side panels. Stuff is heavy. 6 lbs sq ft. Not eager to move it more than I have to. Link to comment Share on other sites More sharing options...
Timfish Posted October 24, 2017 Share Posted October 24, 2017 If you haven't noticed by now sometimes overt measures have to be taken to get my attetion. To be honest I've never measured for bowing before cutting. I have had more pronounced bowing on ends when thermoforming and it wasn't an issue. I'll try to dig up a picture and posf it. Link to comment Share on other sites More sharing options...
Timfish Posted October 24, 2017 Share Posted October 24, 2017 This isn't a good picture but it shows the top and bottom corners off by a fair amount. Link to comment Share on other sites More sharing options...
+Dogfish Posted October 24, 2017 Author Share Posted October 24, 2017 55 minutes ago, Timfish said: If you haven't noticed by now sometimes overt measures have to be taken to get my attetion. To be honest I've never measured for bowing before cutting. I have had more pronounced bowing on ends when thermoforming and it wasn't an issue. I'll try to dig up a picture and posf it. No worries. Its not like I have a deadline to meet. After a few days the piece did not relax. I ordered a human type heating pad that's 14 x 26. I will place the piece on a 2x4 near each end and suspend it over the pad. I will clamp it down with a board across the middle, to make a shallow 1mm reverse bend. The indirect heat might do the trick over a period of time. Link to comment Share on other sites More sharing options...
+Dogfish Posted October 29, 2017 Author Share Posted October 29, 2017 After some playing around I got the piece straight. What worked was to heat the middle 3/4 of the piece with heating pads on top for 6 hours with a blanket over the top. With a digital thermometer it read 163F between the pad and the piece. To help it along I placed an infrared space heater under the table. I placed a 2x4 under each end and clamped the middle down to create a 6mm reverse bend. The first time this didn't work. It cooled but still had the bend. The second time it got real cold at night while cooling and presto when I released the clamp it was straight. Link to comment Share on other sites More sharing options...
mFrame Posted October 30, 2017 Share Posted October 30, 2017 19 hours ago, Dogfish said: After some playing around I got the piece straight. What worked was to heat the middle 3/4 of the piece with heating pads on top for 6 hours with a blanket over the top. With a digital thermometer it read 163F between the pad and the piece. To help it along I placed an infrared space heater under the table. I placed a 2x4 under each end and clamped the middle down to create a 6mm reverse bend. The first time this didn't work. It cooled but still had the bend. The second time it got real cold at night while cooling and presto when I released the clamp it was straight. I wonder if a hair dryer or heatgun would have worked quicker and allowed you to target specific areas. Were you afraid of heating it too much? Link to comment Share on other sites More sharing options...
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