Acrylics adhesive

[gjuarez]

Hey guys, I bought a plastic adhesive at my local hardware store. It says that it could be used on platics, it also mentions it could be used on polystyrene, which I imagine it falls under the plastics group. The name of this adhesive is Duco Plastic and Model Cement and it specifies that it bonds plastics. It mentions that it contains Ethyl Acetate, which I believe might be the main chemical its made of. Does this sound like the same stuff weld-on is made of? WIll it work on acrylic and/or plexiglass? Why or why not? It was pretty expensive at 2.50 for a 1/2 fl. oz. I am planning on buying weld-on anyways but I still want to know if I can use this one for now. Unlike weld-on, this stuff is accesible here in the valley and if it could be used I could later use it for an emergency. So what do you guys think? Let me know.

BTW, I tried it out about an hour ago with two pieces of plexiglass and it seems like it is bonding pretty strong, I just dont know know if the bond will be strong enough to make a sump.

[Henry]

Is that the glue that is used for model cars?

[pilot_bell777]

Looking at my Weldon 16 tube......

Contains Methyl Ethyl Ketone (78-93-3), Methylene Chloride (75-09-2), and Acrylic Resin (No CAS No.)

[gjuarez]

SO this is probably not what I should use. I will be getting some weld on through tap platics, its fairly cheap.

[gjuarez]

BTW, how well does acrylic or plexiglass bond to glass. THe reason I ask is because I want to do an external overflow for my tank and I would rather use acrylic rather than glass because its easier to drill. Is the bond strong enough to sustain the flow?

[matt]

The weldon solvent welding "cements" like weldon #3 are primarily methylene chloride, usually cut with some acetic acid to slow the evaporation process. I would definitely not use the stuff you have to build a sump. There's a place called "craftics" in NM that mail orders weldon products. I suggest you get some weldon #4 for your main solvent welding, and some weldon #40, which is a two part polimerizing cement, for any seam problems that might arise or simply to run a little "bead" of the stuff along the joints if you're not 100% sure of your solvent welding. I'd avoid #3 as it evaporates REALLY fast and unless you're quick you can have some problems. Actually, the best stuff I've heard of is called "MC bond" but it's only available in gallon cans from the manufacturer.

Have fun! Hopefully I'm going to get back into a little acrylic work sometime soon myself.

[matt]

BTW, how well does acrylic or plexiglass bond to glass. THe reason I ask is because I want to do an external overflow for my tank and I would rather use acrylic rather than glass because its easier to drill. Is the bond strong enough to sustain the flow?

I'm not sure what you mean by an external overflow other than a regular overflow box, but I can tell you that acrylic does not bond to glass. Usually you use silicone, which bonds well to glass but not well to acrylic, to attach internal overflows, but they are almost always not subject to any sort of tensile pressure, meaning their location in a corner, with water on the outside, tends to push the acrylic/glass joint together rather than pull it apart. You can slightly increase the strength by roughing up the acrylic with some fine sandpaper in the area the silicone will go.

Someone once did a little test of gluing acrylic to glass, and the strongest adhesive he found was weldon #40. But, weldon does not say that this will work, so be warned!

[LoneStar]

The guy at Regal sold me some Weld-On 3 the other day. I told him I was using it to do a few repairs and then eventually build a sump. He said 3 was all I needed but since I couldn't remember any of the other Weld-On numbers, I didn't ask for them. #3 was very runny but worked very well. I used it to fix a few broken peices on the base of my waste container for the skimmer.

What would be a good Weld-On number that would be more 'GEL' like in consistancy to use for filling in small gaps? Weld-On #4, #14, #40??

[gjuarez]

Matt, here are some pics to show you what I mean. THe pics are from a guy's tank in RC. I have been following his thread and a few others on external overflows. Everyone seems to be having success, including myself, well at least with the pieces of scrap glass I have tried it on.

[LoneStar]

Is that glass cut with 'comb' type slots?

[gjuarez]

same tank with livestock

[gjuarez]

Yes it is. It was cut with a handheld dremel and a diamond bit. I have purchased both and I have been praticing. I havent cracked a single piece of glass yet. I even drilled a nice 1 and 3/4 hole for a 1 inch bulkhead. I am starting hopefully this weekend on my tank.

[pilot_bell777]

Weldon 16 is the best to use "Gel" type to fill gaps and spaces......

[LoneStar]

Yes it is. It was cut with a handheld dremel and a diamond bit. I have purchased both and I have been praticing. I havent cracked a single piece of glass yet. I even drilled a nice 1 and 3/4 hole for a 1 inch bulkhead. I am starting hopefully this weekend on my tank.


Nice! That tank looks good too.



Weldon 16 is the best to use "Gel" type to fill gaps and spaces......


Thanks Pilot, I'm going back to Regal on Friday to buy some. Not to mention raid their scrap bin again! I pulled out some good sheets of 1/4" acrylic out of there last week, most 18 x 35 or larger...

[gjuarez]

YEs it does, I bet its a fun project too. Lately I have really been cruising the DIY pages on various websites. Making stuff is another hobby that I am starting to enjoy. Not bad, you make your own stuff, have fun doing it and save some money for this hobby.

[matt]

Lonestar, weldon #40 is much better than #16 for repair. Weldon #16 is basically the solvent (just like #3 or #4) but with acrylic mixed in to thicken it. So, it's not really an adhesive at all, it just melts acrylic in the place it touches, and then (hopefully) hardens well...the problem is that air always gets trapped inside if you have any sizable gaps to fill. It works great if you have something like a plaque or some acrylic toy or something, but it's not very good for aquarium use. Unfortunately, it's what all the plastic shops will sell you...for really good repairs, get the #40.

Weldon #3 is very similar to #4, except #4 is slower evaporating and gives you a little more time to get your joints lined up; it's also stronger because the slower evaporation lets it melt a little more of the joint. For non-water bearing joints with thin extruded acrylic, #3 is ideal because it's so fast. But, for 3/8" cast (that's what I always use) weldon #4 produces a stronger joint. In terms of how you use it, there's not much difference.

Jerry, as far as that type of overflow goes, the absolute best way to do it IMO would be to use glass; it's a bummer to drill it, but then you can use silicone to attach it really securely. If you want to try acrylic, try to keep it "narrow" with regards to front to back. (tank to wall) This way you'll minimize the volume of water for a given length of glass-acrylic joint, and maybe even fabricate a couple of "hooks" on each side that would go over the tank top, that way you'd kind of be hanging it on the side of the aquarium. That could add some strength. I guess I would use silicone, but I'd use ALOT against the acrylic and I'd really rough up the plastic well. Someday it's going to come loose, that's my guess. But what's life without taking a few chances!

Another way to increase the strength, (just a guess) would be to cement a strip of 1" wide acrylic along the edge of your overflow. So, when you press the thing up against the aquarium, the joint is 1" wide rather than 1/4" wide. That's much more area for the silicone to grab; might make a difference. You could also research the use of weldon #40 for this type of joint, although I wouldn't get my hopes up. It might look great when it's first on there, then six months down the road come off the glass. I honestly don't know.

Good job on the dremel drilling, that looks very difficult to me. After doing that kind of work, isn't it easy to drill a hole for a glass overflow?

[pilot_bell777]

Well I use Weldon 16 sort of like silicon in the seams and it works great. If you run a bead of that stuff on a peice of cardboard you will see that it does harden and create its own ""Plastic""

Not going to get in an argument over which Weldon is best though..... it doesn't matter. I'm just telling you what I used. I have two weldons..#4 and #16. I use #4 for bonding joints and 'gluing' and then the #16 for sealing and filling.

Personally though Jerry....you already did the hard part with cutting the overflow out of glass, I would just take 4 sheets of glass and bond them togther to finish out the overflow. If you drill the hole for the drain before putting it all together, that should be ALOT easier on you.

[dwdenny]

[quote]
Thanks Pilot, I'm going back to Regal on Friday to buy some. Not to mention raid their scrap bin again! I pulled out some good sheets of 1/4" acrylic out of there last week, most 18 x 35 or larger...

What do they charge for weldon and the crape pieces? I will be in SA in December so i might stop by and get some as well as some scrape pieces.

[demodiki]

May I hijack and ask what type of tool you guys use to cut the acrylic/glass? I am thinking in particular about the baffles, etc.

[pilot_bell777]

Acrylic I used a table saw with a high tooth blade or a jig saw with an acrylic blade, then overlap it and trim the extra off with a router. Baffels, i would just use the table saw.

dont' cut glass so can't answer that! LOL

If it is thin enough you can score it with a utility knife over and over and over and then snap it but that has to be REAL thin acrylic.

[Darth-Tater]

Regal charges $1.10 a pound. Weldon 16 is about $8.99 for the med size tube. They usually have lots of nice scrap pieces

hope this helps


Dang you are right I bought 10 pounds for 10 dollars. not 10 cents a lb. It's a good thing I don't teach math. :lol

Just call me Math impared Tater :o

[LoneStar]

When I was at Regal last week, it was a dollar ($1) a pound. I pulled out 25 pounds worth but the guy cut me a deal and only charged me $20. I figured I will just mess with the scraps to practice with. The Weld-On 4 came in a little can, about the size of pvc primer, and it was like 3 or 4 bucks. The applicator was another 3 bucks. I left there with the Weld-On, applicator, and scraps (4 large pieces) for under $30. Not bad because I'm already making a stand with it for my skimmer right now at work!!

[dwdenny]

thanks DT yeah that helps a lot. I am going to try to run over there while I am in town and get some stuff. Weldon #4 and #16. I take it they have the applicator there as well?

[gjuarez]

To cut my glass and drill holes I have been using a hand held dremmel and some diamond coated tip bits. So far I havent had any problems and it seems kind of easy.