weld-on 4 *only* or...

[corro]

is weld-on 4 sufficient for building a sump/refugium out of acrylic or should i also plan on reinforcing the seams with weld-on 40. i did a search, but had a hard time finding a definitive answer.

thanks!

[kgross]

If you do a good job with joints and have a good bond with the weldon 4 it is all that you need.

KIm

[kanankeban]

I agree on than, with good seems weldon 3 or 4 is enough for a sump...

[corro]

thanks much! :)

[agiacosa]

To the extent your finished edges are good (jointer or router) and you use the pin method, Weld-n 4 should be sufficient. If the above is not correct, then follow with a bead of Weld=on 16 not 40.

[Acrylics]

Originally posted by agiacosa
To the extent your finished edges are good (jointer or router) and you use the pin method, Weld-n 4 should be sufficient. If the above is not correct, then follow with a bead of Weld=on 16 not 40.

I thinx I'd argue that last one with ya, Weld-on 40 is a superior product for this application. Weld-on 16 is approx 50% solvent which amounts to 50% evaporation by volume. Weld on 40 is an actual acrylic resin which will fill much better.

HTH,
James

[agiacosa]

Weld-on 40 has a tendancy to pull pieces together causing stress as it dries. The 16 will accomplish the same thing without the stress.

That's what I've been taught, anyway.

[NAGA]

MC Bond from Polysciences rules!!!

40 degrades over time

16 is not very strong

4 is pretty good though if you have good machining

[Acrylics]

Originally posted by agiacosa
Weld-on 40 has a tendancy to pull pieces together causing stress as it dries. The 16 will accomplish the same thing without the stress.

That's what I've been taught, anyway.

#40 will shrink a little but the bead itself will shrink from the outside in as it evaporates, it will not pull pieces together.
40 is actually designed to "cast" joints (to fill a gap between two pieces). Imagine gluing a strip of acrylic into the corner of a joint - this is exactly what you're getting with #40 as it is an acrylic resin.
#16 is designed to glue slightly imperfect surfaces instead of using #3 or #4. I'm not sure how it became popularized as a "filler", perhaps 'cuz it's cheaper and easier to find but it's not a very good one.
BTW, if you wanna make your own 16 just get some methylene chloride and acrylic shavings and mix it together as this is precisely what it is.


Originally posted by NAGA
MC Bond from Polysciences rules!!!

40 degrades over time

16 is not very strong

4 is pretty good though if you have good machining

Come on NAGA, look at the at the ingredients in MC Bond, unless they've changed it recently it just methylene chloride, acetic acid, and acrylic monomer, just a watered down version of 16 with some acid thrown in. While it's nice stuff - it's not *that* nice ;)

40 will degrade over time however public aquariums have more tanks built by this method than any other. Hell Cyro actually recommends this method over others because you don't have to have good machining.

16 & 4, I agree with ya on

If you really want nice stuff, you need to get ethylene dichloride, it has recently had much bad publicity (for good reason, check the MSDS). It is what used to be in Weld-on 4 before the state of CA got a hold of 'em. The stuff has quadrupled in price the last couple of years and is harder to find but is by far the best IMO and still my fav and standard.


James

[wetworx101]

Not to throw a wrench in the works here, but what about some of the other WELDON varieties?? I saw a WELDON 42 recently...as well as some others in the lower numbers (5 and 10). Are these of any good use or are they not good for aquarium use?

[NAGA]

Acrylics,

for the guy who is going to build his own tank the 40 is not a good choice. It does degrade and eventually will fail without proper annealing and even then it is a doomed seem in time. Yeah, sure public aquariums use it a lot........I have built tanks for public aquariums and whenever 40 has been used it has been annealed and professionally applied. 28 which is a step up from the 40 in strength is very tricky to deal with unless you have worked with it for a while. In this forum we are talking about the avg. Joe putting something together. 40, 42, 28 are not the glues to use without a fair amount of practice and knowledge of how these work. MC Bond is easy to use and so is the 4 and 5 of Weldon. I have used MC Bond for over 9 yrs and 40, 28, for almost as long. Have not used the dichloride you mentioned though but, I am curious about it and perhaps do some hunting on the topic.

[Acrylics]

Originally posted by wetworx101
Not to throw a wrench in the works here, but what about some of the other WELDON varieties?? I saw a WELDON 42 recently...as well as some others in the lower numbers (5 and 10). Are these of any good use or are they not good for aquarium use?

Weld on 42 is pretty close to #40 only that the 42 is prepackaged at a 10:1 ratio while for most purposes 40 is mixed by the fabricator at a 20:1 ratio. #42 comes in a cartridge and is used with an applicator gun & static mixing tips, the same as used in 2 part epoxies. The cartridges run about $28, the gun is $180, and the tips are about $2 each.
...probably not for the average hobbyist :)

James

[Acrylics]

Originally posted by NAGA
Acrylics,

for the guy who is going to build his own tank the 40 is not a good choice.

No, it's not - I agree with you there. I suggest it not for a main adhesive/cement but rather for sealing joints instead of #16 - for this particular application, it is a far superior product.


It does degrade and eventually will fail without proper annealing and even then it is a doomed seem in time.

generally true, most of the failures I have seen are due to differentiation in expansion/contraction between the acrylic and #40 or because of poor material being used, not because of direct failure of the resin.


MC Bond is easy to use and so is the 4 and 5 of Weldon.

No arguement here, it is easy to use as is #4 and I never suggested otherwise. :) My issue is with the use of #16 as a "filler" when it is not designed to be one and is a poor one at that.


I have used MC Bond for over 9 yrs and 40, 28, for almost as long. Have not used the dichloride you mentioned though but, I am curious about it and perhaps do some hunting on the topic.

Well I've got a few years on ya :) I used MC Bond for several years and was generally always happy with it but it is not the only solvent as you well know. One can make their own for much cheaper and be more in control of the reaction time in doing so.

Do check out the EDC, it is an excellent solvent, flows extremely well w/ or w/o acid and is slower than straight MC so it gives a little more working time. Great for cast material. It will go under the name ethylene dichloride or dichloroethane.

As for the "average Joe" building his own tank thing. My feeling is that the average Joe *should* (IMO) understand as much as possible the practical advantages of different materials and solvents to bond them. Else the tank is more apt to fail. While I am in absolutely no way a fan of #40, it does have it's place in the industry whether it be for the hobbyist or professional. For some purposes - #40 is the best alternative and should be understood.

James

[wetworx101]

This huge debate was why I had such a hard time trying to make fuges for my tank with plexi. Then it turned out that going to the local glass shop and having them cut/bevel 1/4" plate glass for my sumps, fuges, etc, was a whole lot cheaper...and silicone is easier to work with. I ended up building my fuges (stand behind models as well as sump) out of plate glass. The shop even drilled holes for the bulkheads....did I mention that glass is about 1/3 the cost of plexi??? And I know that the fuge will not fog, mar, scratch, or just plain fall apart years from now.

[Zander]

what would be the best weldon for gluing in an overflow box that has straight sides in a preiviusly filled aquarium that has a very slight bow (1/4")????

[Acrylics]

Originally posted by sdgtivr6
what would be the best weldon for gluing in an overflow box that has straight sides in a preiviusly filled aquarium that has a very slight bow (1/4")????

Personally I'd use something similar to MC Bond or Weld-on 4, of course a little effort has to made to be sure whichever panel you're gluing to is flat, whether by shimming or clamping.

HTH,
James

[J_Freeman75]

I'm wanting to build a new tank. It'll be 2'x2'x2' cube, and hold somewhere around 60 gallons (Just a quick estimate). I was planning on building it with the IPS weldon #4. I figured that since you all are on this topic I'd try to get some input. I've been to my local plastics dealer, and will be ready to purchase in the next month. So any good info before I buy would be great.

Thanks,
J Freeman:rollface:

[corro]

great thread! thanks for all the info and replies!!! it sounds like it would be good to apply a #16 seal over my joints, for safety!

------------------------------------------------------------------------

Originally posted by J_Freeman75
I'm wanting to build a new tank. It'll be 2'x2'x2' cube, and hold somewhere around 60 gallons (Just a quick estimate). I was planning on building it with the IPS weldon #4. I figured that since you all are on this topic I'd try to get some input. I've been to my local plastics dealer, and will be ready to purchase in the next month. So any good info before I buy would be great.

you might also want to checkout the garf website also ... it has a pretty cool <i>tank size --> acrylic thickness</i> calculator. i believe it is in their DIY section.

[wetworx101]

I love my Oceanic 24" cube (called a 60gallon as well)...so much I want to make a 30" cube...

[gonereefin']

I've seen it for sale somewhere but there had to be a $100 dollar minimum order. US Plastics has only Weldon 16 and Savko doesnt carry it either. I've been looking for quit a while
Thanks, great thead.
Randy.

[corro]

Originally posted by gonereefin'
I've seen it for sale somewhere but there had to be a $100 dollar minimum order. US Plastics has only Weldon 16 and Savko doesnt carry it either. I've been looking for quit a while
Thanks, great thead.
Randy.

being pretty new to this forum, i'm not sure if direct http links are an acceptable practice. are they? i dont want to break any rules! :)

but... if you do a google search for tap plastics you will find it under the shop --> repair products --> plastic adhesives section on the tap plastics website. I also got a 2oz. applicator bottle at the same time which I found to be absolutely necessary. they had pretty quick shipping and were really nice about modifying my order via email the next day when i wanted to add a couple of hinges. I dont know if they have the best prices (because i had a hard time finding weld-on 4 also), but they seemed reasonable.

[Zander]

Originally posted by corro
it sounds like it would be good to apply a #16 seal over my joints, for safety!

is this a good idea?

[Zander]

weld-on #16

http://www.tapplastics.com/shop/product.php?pid=132&

weld-on 3&4
http://www.tapplastics.com/shop/product.php?pid=131&

[gonereefin']

Thanks for posting the link/suggestion to try Tap Plastics. I just ordered a pint of Weld-on 4 for $9.40, 5oz. of Weld-on16 for $4.75 and $5.75 shipping. Total less than 20 bucks. I'm pretty sure the Weldon 16 was cheeper than I paid at Us Plastics too.

Oh yeah, if you know a nurse or pharmacist, they can get you syringes for basically free,,,,they are super cheep and you can toss them when you are done. I was building an internal over-flow box once and needed to glue the inside of the box along the bottom and my arm was to big so I made an "injection injector" out of a syring and a piece of 1/2 pvc and a dowel and taped the syringe to a cut-out on the end/side of the pvc and squirted the weldon 16 out of the syringe by way of the dowel down the center of the pvc. Long description,,,sorry, but the point is syringes work great.
Thanks for the link,,,, a lot!!
Randy.

[Acrylics]

quote:
--------------------------------------------------------------------------------
Originally posted by corro
it sounds like it would be good to apply a #16 seal over my joints, for safety!
--------------------------------------------------------------------------------

Originally posted by sdgtivr6
is this a good idea?

Kinduva a trick question :)

Adding #16 as a seal or filler won't hurt but IMO it doesn't help much either in the long run *most of the time*. I've heard success stories as well using this product as a sealant, and it is difficult to argue with them. But I do try to recommend what I believe to be the best product for the application. As stated above, I believe #40 to be a superior product for this application.
There is more work involved in the #40 but I think it pays off.

BTW, if you wish - you can make your own #16 by mixing solvent and acrylic chips, router "nerf" is ideal - dissolves easily and as long as it's clean (no paper, dirt) will work very well without all the bubbles. Keep it in a sealed tupperware dish for long life.
Draw it out of the dish with a syringe (no needles)

James

[NAGA]

I agree with Acrylics,

the 40 for the project your working on would be best. 40 is no doubt stronger than the 16. It is more involved to work with but, if structural strength along with filling ability is your need then go with the 40. If you just want to fill something that does not need any strength the 16 will work just fine. If it is a big fill go with the 40.

[SciGuy2]

I've always had problems with using 16 for reinforcement fillets on joints. It draws bubbles.

Nothing ticks me off more than a perfect joint glued with 4 screwed up by putting a bead of 16 on it to reinforce the joint and then the 16 forming bubbles as it cures.

[Carribean Reef Man]

Hey Naga & Acrylics

I am getting ready to build 2 fairly large sump 60x32x36 with a coupl of baffles, euro brace, shelves with 2 inch acrylic legs for supporting the shelves.

Which glue do you think would be best.. Also I take it you add the baffles last and then the eurobracing correct?

Thanks In Advance

[Acrylics]

Originally posted by Carribean Reef Man


Which glue do you think would be best..

It depends on what specific acrylic and thickness you are using. For 99.9% of all acrylic applications, Weld-on 3, 4, or MC Bond will do well.
While we did have a conversation on the quality of solvents for different purposes, solvents are not the *key* to good, strong joints, IMO. I would rather stress material quality, consistency in squareness, size, and edge preparation are the things to be *most* concerned with. It won't matter what solvent you use if you don't have these things, it generally won't hold water for long if at all.
Only when all else is equal and of high quality do I think solvents become a *real* issue. And even then, it's mostly aesthetics.

I guess my bottom line is if your material is of good quality, pieces are square (or at least consistently oriented), sized to with a coupla thousanths, and edges machined smooth a flat, you can basically use just about any of these previously mentioned solvents and have good success.


Also I take it you add the baffles last and then the eurobracing correct?



I usually put the sides ends and baffles on the front or back first, them flip it over to the other side
then put on the top.
Glue the bottom on last.
Others may have their own ways which may differ, this is just the way I choose to do it.
I make the baffles the same time I do the ends so they are consistent in size and squareness.
I always put the top on before the bottom so I can reach in.

HTH,
James

[NAGA]

I can add to this with agreeing whole heartedly with Acrylics. I am currently building a tank 32" x 24" x 44" using 1 1/4" PolyCast brand acrylic. I am particularly fond of using PolyCast and can say that as far as consistency goes they are better than most if not the best. I used MC Bond with a little bit of Glascial Ascetic Acid added to it to slow down the reaction a bit. As Acrylics has said, the quality of the edge you are bonding to is extremely important. The edges I had to work with were diamand wheel edge finisher. The result was absolutely perfect joints accept where I left one pin a little too long:rolleyes: and left a small pin mark. Most people are not going to have the polished edge to glue on but, jointed edges that are good ones can produce excellent looking bubble free joints.