Acrylic fabrication questions? I can help!

Thanks again Marc. Do you sleep? :)

I thought of that (back wall reinforcement) as well. The overflow is only on one side of the tank though. Could asymmetry be a bad thing too?

I realized that I've goofed. I glued some plumbing to the back of my bulkheads. So, laying it flat will be a problem. :) I suppose I'll have to clamp it (shaping or not) and rely on capillary action. Perhaps I can still use the guitar wire approach.

This is why I call it a "practice" tank!
 
That's going to be a minor problem. If you can set the tank on a flat surface so the bulkheads are hanging over the edge, you'd still have support for the area you plan to glue against.
 
Good news; I followed Acrylics & Marcs suggestions and cut the crrylic sheets for my overflow box and sump baffles. I went to Lowes & Home Depot for weld-on #3 but both stores had GE's '100% Silicone Sealant for seaning lexan and other plastics'.
My guess this stuff (in a tube) is probably Silicone I and therefore isn't good enough a bonding agent. Am I right and should hit the yellow pages for the weld-on #3 solution. From what I've read on this thread, it's a solvent and needs an applicator. Jim
 
I would definitely get some Weld-on. Here's a solution in a pinch, but you still need an applicator: Hobby Lobby sells a type of acrylic bonding glue in the modeling section of the store. It is a small glass bottle with clear liquid and it has a paintbrush attached to the inner lid.

You can order the applicator bottle from USplastics.com

You can also call any sign shops in your area to see if they can get you some Weld-on and applicator bottle.

Weld-on #16 is thicker, like super glue gel, but quite a bit messier. If you go that route, go to Hobby Lobby and buy some glue applicator tips. A five pack will cost you about $1.49, and you press one onto the end of the Weld-on squeeze tube. Cut the tip off slightly to make the opening a bit larger, and apply the bead that way. The tip will help control the flow, and avoid a mess. This version needs to be applied sparingly, maybe 1/16" to 1/8" bead wide. If you apply it like one would apply caulk, it will be a huge mess. The solvent shrinks by 33% and can cause craters, or at the very least giant air bubbles will appear in the fillet of glue. So use it as necessary, possibly applying a bit more when necessary after it has had time to fully cure.
 
Thanks Marc. I checked US Plastics (on-line) and I was disappointed to find the Weld-on3 is a can with a applicator brush (just like the PVC cement). In my case I need a very fine applicator because I have to place the acrylic sheet in place before appying the solvent (I have an acrylic tank with a european brace that prevent prefabricating the overflow box).
It's an easy install (plates are a tight fit and can be installed seperately as long as I can get a fine tip applicator. I'll check the hobby stores on Monday. Thanks for your help. Jim
P.S. Do you know if the polycarbonaate glue is methyl chloride solvent?
 
That I don't know. I'm not a chemist, I'm a hobbyist. :D

USPlastics will carry both though. So get the can and the applicator at once.
 
you can use mek. It is methyl elthyl keytone"spelling" don't know I guess that's why they call it" m.e.k"...same solvent found in weld on.... Which can be found at paint stores....it is actually used as a paint thinner and sometimes with fiberglass....
 
<a href=showthread.php?s=&postid=13888909#post13888909 target=_blank>Originally posted</a> by jimnrose
Thanks Marc. I checked US Plastics (on-line) and I was disappointed to find the Weld-on3 is a can with a applicator brush (just like the PVC cement). In my case I need a very fine applicator because I have to place the acrylic sheet in place before appying the solvent (I have an acrylic tank with a european brace that prevent prefabricating the overflow box).
It's an easy install (plates are a tight fit and can be installed seperately as long as I can get a fine tip applicator. I'll check the hobby stores on Monday. Thanks for your help. Jim
P.S. Do you know if the polycarbonaate glue is methyl chloride solvent?
Click to expand...
The can comes with the brush but just use a bottle like the one here:
http://www.tapplastics.com/shop/product.php?pid=409&
USPlastics may sell these as well, dunno.

For polycarbonate, use either acrylic solvent like 3 or 4 or use THF (tetrahydrafuran) which is the primary ingredient in most PVC pipe cements. Come to think if it, more likely to find the Weld-on 3 or 4 ;)
MEK doesn't work all too well on much, works in a real pinch but not recommended, and is not found in neither Weld-on 3 nor 4. IPS used to use it as a buffer many years ago (slows down the reaction,) but no more.

HTH,
James
 
here is a cure all for polycorbonate I have been using for years now check into lords adhesives they have a product that is a urethane adhesive the number is 7550a/c I have yet to see a product that can compare I work with acrylic and lexan everday or polycarbonate I should say I have been doing this for 15yrs I run the plex shop here in vegas at a major sign company.....I have to join acrylic and lexan all the time...it uses a little gun with mixing tips but they are cheap it is a 2 part system very strong and crystal clear almost like weld on 40 but a lot easier to work with I think you guys should check into it.....it is pretty good for almost any plastic I use it on cast, extruded,lexan,cross links, PVC,pretty much any plastic you can join with it....it is almost a cure all like duct tape for plastic.....let me know what you think......lee
 
IME it makes nice looking joints but I used it to laminate acrylic and polycarb and was able to delam them with a little shock. So, I won't use it for aquaria where there are several forces at work. It works as a glue rather than a solvent, but for the purpose of just making things stick - it's fine IMO/IME, just wouldn't advise it for anything that's keeping water off your floor.

JMO,
James
 
James, thanks for the TAP Plastic site. I'll call them on Monday because I can't tell the difference between TAP acrylic and IPS Weld-On3 cement. This site also has Novus posihing mataerial which I also need because the new tank has a pretty large scrap mark on the outer surface that needs atttention.
Happy Holidays, Jim
Troylee, thaks for your inputs but the TAP solvent and needle applicator is what I'm lookng for.
 
no problem i was just giving suggestions.........i actually use weldon #3 followed by the lords 7550a/c for a nice clean bead on the fish stuff i build........because #16 sucks shrinks and gets ugly........recently i have been using #40 to it is my favorite but it is so darn messy.....
 
let me ask you this james.......do you use 40 alot???? i have tried different things with it and tested about every solvent/glue on the market....i normally glue 2 pieces together at a 90 and let it set for a week then flip it over and smash it with a hammer....out of all the test i have done i found #3 to be the strongest the joint never breaks it is always the acrylic around it........and when i use #40 it breaks the joint instead of the acrylic???? this is suppose to be stronger according to the manufacturer.........i found mixing the 40 up and adding a little number 3 to it makes a flawless seam and the strongest i can find..............ime.....or imo.....what's your thought's on this?????
 
The "joint strength" listed for 40/42 has (IMO) no relation to the real world. Actual joint strength depends on how much "bite" there is into the material being glued. "Bite" can depend on ambient temp, material temp, mole wt of the material, age of 40/42, and so on. AFAIK, joint strength data is based on "average" solvent joints, say 50-60% joints in which a rough saw cut is glued up, in such cases 40/42 will be stronger but against a perfectly glued seam? I dunno about that, prove it to me IPS :) Also, the amount of 40 that you make at any given time (batch size) will determine the mix ratio, the more you make at any given time, the less catalyst you use else there will be too much heat build-up which will affect the joint strength, cure times, etc (kinda like concrete in this regard.) Got to remember also that 40/42 is an actual acrylic resin, so can have expansion & contraction rates that can vary from the material being glued. Is this the reason? I doubt it, but is one more variable in the equation. So, to say it (40/42) is "stronger" is ridiculous IMO as there are too many variables.

BTW, get a 42 gun, makes using this stuff more manageable. It is more expensive, but the time savings will offset that IME.

As for solvents, MCBond is my favorite of all the commercially available, but it has it's own set of issues so I prefer to use my own solutions that I can tailor to the given application.

James
 
James, a question.

James, a question.

James, I have followed a ton of the threads that you gave advice on. I am a hobbyist and try to make some of my own things as, well money! Here is my problem. I use CHEMCAST GP. I can cut it with table saw (10" with 80 tooth blade for acrylic) or route it, with still have the same results, bubbles. I do have less bubbles if I route it. I use shims .007 between the parts to be glued, run the glue which is Caseway Acrylic Adhesive # SC-94. Adjust the wooden shims to lift the bottom piece that is being welded. All this is on a piece of the rigid insulation. Set a timer for 2 minuets and then remove the .007 shims. Bubbles, bubbles, what am I doing wrong?
 
i would say your glue/solvent try weldon...... #3 is tricky to work with 16 no good unless you like bubbles but 40 and 42 are winners......it should help you out alot.........or as james mentioned above mcbond....and maybe try acrylite gp.........just because it is cast don't mean it will weld good.......ime i think acrylite gp or plexiglass gp are the best for nice clean weld's.......some stuff i have used like optix just suck's all the way around..........
 
Reefdat,

First, I wouldn't recommend Chemcast, I've heard of too many tanks failing that were built using that material. They're fine for a year or two then the tanks literally come apart, and these were tanks build by shops that do this for a living. I'd personally recommend Polycast brand followed by Acrylite GP and then PlexiGlas G, only those brands and in that order of preference...for whatever that's worth :)

Rigid insulation is just too rigid IMO, try a softer foam. I like 3/16" camper shell foam mounted on 3/4" particle board but just me, allows me to shim afterwards if necessary and still has a little resistance.

Solvent should be fine, very similar to MCBond or the old Weld-on 5 but as with any premixed solution, no way of knowing what the actual ratios are.

Generally, waiting 2 minutes is far too long for .007" wires. The solvent has already started to set by the time you pull the wires, try a few practice pieces only waiting 30-40 seconds and see how it goes with your solvent. Also make sure the gluing surface is absolutely clean when gluing, any spec of dust in the joint can become bubbles.

If you can show a pic or two of the bubbles, maybe we can point you in more specific directions, the types of bubbles say a lot :)

Try the following thread for a step by step: http://www.reefcentral.com/forums/showthread.php?s=&postid=3062649

HTH,
James
 
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