Acrylic fabrication questions? I can help!

[dattack]

<a href=showthread.php?s=&postid=13893994#post13893994 target=_blank>Originally posted</a> by Acrylics


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

I bought the MCBond and it glues really well except their seems to be very small amounts of microbubbles on the edges on both sides after I let it dry. It looks like a perfect joint when the pins are released and after 15 minutes, however, there are some annoying microbubbles not internally but on the edges.
I tried Plexiglass, spartech, and chemcast and it all does the same problem. Had to switch to some local cement.

 

[reefdat]

I bought the MCBond and it glues really well except their seems to be very small amounts of microbubbles on the edges on both sides after I let it dry. It looks like a perfect joint when the pins are released and after 15 minutes, however, there are some annoying microbubbles not internally but on the edges.

Guess I can not post a picture but above is my same problem! Where does one get this gun you are talking about? There are several that will pitch in for one as we want to make more goodies.

 

[troylee]

google weldon #42 applicator gun.......im not sure on the net but i got one locally........i hear ebay has them to.....

 

[dattack]

The only problem with using the 42 gun is that you have to buy a case of the glue which runs to a few hundred dollars.

 

[reefdat]

<a href=showthread.php?s=&postid=13952711#post13952711 target=_blank>Originally posted</a> by dattack
The only problem with using the 42 gun is that you have to buy a case of the glue which runs to a few hundred dollars.

The guys say that is not a problem as we will all chip in. We have looked for it but can't find it. What do you look for, as the #42 gun is not enough info. to get the correct thing. Help, thanks.

 

[reefdat]

<a href=showthread.php?s=&postid=13952451#post13952451 target=_blank>Originally posted</a> by troylee
google weldon #42 applicator gun.......im not sure on the net but i got one locally........i hear ebay has them to.....

Troylee, Thanks. Did not see this before. Found it!

 

[reefdat]

weldon #42 applicator gun

weldon #42 applicator gun

Gun $185 to $260 depending who you get it from, plus $42.00 for a tube of 42 glue that is small! We decided to pass, now that we have looked into it and it is the same a Weldon 40, just more convenient.

 

[Bugs]

Hello Jame,

I have build several sumps in the past using scraps acrylic with the combinations of cast and extrude acrylic using Weld-On #4 and I let it curred 24 hrs period. The problem that I ran into was when I left it outside under the indirect sunlight for several weeks and the joint seemed to break when I applied some pressure. Do you know why that is? Thanks in advance.

 

[phishcrazee]

Ok, this has probably been covered somewhere in the gargantuan thread, but I don't have the time at the moment to read all the pages........

My question; if solvents can bind two pieces of acrylic together, can they also be used to take two pieces apart? I have a 75g acrylic sump and really want to move one of the chambers wall, but each wall was "cemented" into place with a solvent If I apply the solvent to the joint and lightly tap near the jointed area with hammer etc, will it dissolve the bond if I do this while the solvent is still wet? Or am risking cracking the tank/ruining it's integrity? Am I stuck with just cutting that sucker out?

 

[Acrylics]

<a href=showthread.php?s=&postid=14269116#post14269116 target=_blank>Originally posted</a> by Bugs
Hello James,

I have build several sumps in the past using scraps acrylic with the combinations of cast and extrude acrylic using Weld-On #4 and I let it curred 24 hrs period. The problem that I ran into was when I left it outside under the indirect sunlight for several weeks and the joint seemed to break when I applied some pressure. Do you know why that is? Thanks in advance.

There's been some discussion of such in the past. Some think that UV degenerates joints, *possible* but I find in unlikely as even 1/4" will filter all of UVC and virtually all UV below 380nm so if the UV doesn't "get" to the joint, how could it degenerate it, but again it is within the realm of pure possibility. My thoughts tend to look more at a combination of: Differentials in expansion/contraction, the joint is already a stressed area as compared to sheet stock, and the latent moisture in the material itself freezes and degenerates the material from the inside out. Since the joint is the most stressed area, it would be the first to show the signs of this.

I haven't done any testing specific to this so couldn't say with absolute certainty.

<a href=showthread.php?s=&postid=14270111#post14270111 target=_blank>Originally posted</a> by phishcrazee
Ok, this has probably been covered somewhere in the gargantuan thread, but I don't have the time at the moment to read all the pages........

My question; if solvents can bind two pieces of acrylic together, can they also be used to take two pieces apart? I have a 75g acrylic sump and really want to move one of the chambers wall, but each wall was "cemented" into place with a solvent If I apply the solvent to the joint and lightly tap near the jointed area with hammer etc, will it dissolve the bond if I do this while the solvent is still wet? Or am risking cracking the tank/ruining it's integrity? Am I stuck with just cutting that sucker out?

Cut the sucker out. A good joint is more of a chemical weld that can't be undone.

HTH,
James

 

[Acrylics]

<a href=showthread.php?s=&postid=14269116#post14269116 target=_blank>Originally posted</a> by Bugs
Hello James,

I have build several sumps in the past using scraps acrylic with the combinations of cast and extrude acrylic using Weld-On #4 and I let it curred 24 hrs period. The problem that I ran into was when I left it outside under the indirect sunlight for several weeks and the joint seemed to break when I applied some pressure. Do you know why that is? Thanks in advance.

There's been some discussion of such in the past. Some think that UV degenerates joints, *possible* but I find in unlikely as even 1/4" will filter all of UVC and virtually all UV below 380nm so if the UV doesn't "get" to the joint, how could it degenerate it, but again it is within the realm of pure possibility. My thoughts tend to look more at a combination of: Differentials in expansion/contraction, the joint is already a stressed area as compared to sheet stock, and the latent moisture in the material itself freezes and degenerates the material from the inside out. Since the joint is the most stressed area, it would be the first to show the signs of this.

I haven't done any testing specific to this so couldn't say with absolute certainty.

<a href=showthread.php?s=&postid=14270111#post14270111 target=_blank>Originally posted</a> by phishcrazee
Ok, this has probably been covered somewhere in the gargantuan thread, but I don't have the time at the moment to read all the pages........

My question; if solvents can bind two pieces of acrylic together, can they also be used to take two pieces apart? I have a 75g acrylic sump and really want to move one of the chambers wall, but each wall was "cemented" into place with a solvent If I apply the solvent to the joint and lightly tap near the jointed area with hammer etc, will it dissolve the bond if I do this while the solvent is still wet? Or am risking cracking the tank/ruining it's integrity? Am I stuck with just cutting that sucker out?

Cut the sucker out. A good joint is more of a chemical weld that can't be undone.

HTH,
James

 

[uncleof6]

Bump

 

[Bugs]

The pin method is used with Weld-on 3 or 4. What method do you use with Weld-on 40. Are there any link for using Weld-on 40 method? Anyone?

Thanks in advance.

 

[troylee]

there is couple different ways of using 40/42... one is machineing the edge at like a 3deg. angle and filling the voids from the outside, or you can use some very thin acrylic shims that stay in beteween to pieces being joined so there is a small gap and glue does'nt get squeezed out by the weight of the material and by meaning thin i would say a 1/16th works well....everyone has a different story, i would guess there is many ways, but these are what works best for me

 

[troylee]

btw. most diy people around here don't use it.....thats why there is not really any good info on it.....care to share what you are building??? there might be a better solvent/glue to use...40 is hard to use and makes a huge mess and not nearly as strong as ips. claims the solvents are way better imo.

 

[Bugs]

I am building a 200 gallon reef tank. I am not sure that I understand you in regards to 40 is not nearly as strong as IPS. Isn't IPS is the company making Weld-on? Please clarify.

Thanks

 

[troylee]

weldon 40 is not as strong as those ips. charts claim......the strength is really determined by how well the glue attacks the material it is being used on......and from my exp. of stress testing all different glues and solvent's weldon 3 and 4 will join the best brands of acrylic such as acrylite "gp" or plexiglass "g" better than 40 and have a stronger weld all day long.....im not saying 40 won't work but the solvent's are much stronger.....what thickness material are you using??

 

[Bugs]

I am using 1/2" thick with the dimension 68" x 30" x 24". Base upon my understanding, Weld-on 40 is used to build a big tank and it is a lot stronger than Weld-on 3 or 4. In the past, I have used Weld-on 4 to build the sump and it doesn't last as long. I used the pin method and it has no bubble. Overtime, a year or two, it breaks off easily with a slight pressure.

P.S. I am using cast acrylic to build the tank. Don't get me wrong. I like to use Weld-on 4 because it is a lot easier to work with ime.

 

[troylee]

weldon 40 is used for big tanks but there is a proccess called annealing where the tank is put in a oven and baked at x amount of degrees for x amount of time depending on the thickness....if you have accsess to one then yes you can cure the weldon 40 and get alot more stregnth out of it.....not sure what the problem with your sump was it shouldnt give away after a couple years maybe the glue joint was not good to begin with......hmm.......do you know by any chance what kind of material it was ????

 

[troylee]

maybe "james" will stop by and chime in on you exp. with the sump.....i honestly could give some really good thoughts about why it happened but not a def. answer....i have been doing acrylic for years but only making tanks and such for 2 years.....so i cant really say what the long term damage saltwater does to the joints if any like he would be able to...hmm