weld-on 40 (42) - need advice

[valid]

i've read a lot about these, but now i need to talk to people actually using the stuff. i have some tanks where i want to reinforce the seams w/ this material. either as a filet of the material, or as a bonding agent to add in some strips of scrap acrylic. at this point i do not want to use anything else.
i priced the 42 at my local plastic shop and found the cost to be rediculous (gun~$130, 230cc cartridge~$28, minimum order 1doz)

1) anyone know where i can get less (therefore less $$ spent)?
2) anyone actually use the 40 or 42 that can give me some tips - for example: mixing/applying tips? especially #40
3) a source to purchase both/either 40 or 42? (possibly any extra you may yourself have?)

[JakePehrson]

Don't buy the gun and the cartridge. Look in your local Yellow pages and find a plastic supply house. They will be able to sell you Weld-on in a can with a simple $2.00 applicator. The whole thing should cost more than $15.00-$20.00.

[electric130]

if you are welding acrylic to acrylic, use weldon 3, 4, or 16. 16 if you want fillets. 3 or 4 if you're bonding new seams. 40 is strong, but can be a pain to deal with since it's a 2 part cement and you have to mix it right to get good results. i wouldn't bother with 40 unless you're bonding dissimilar plastics such as acrylic to PVC or acrylic to ABS.

[NAGA]

Hi,

don't buy the cartridge!!! I have used it and does not work well if you plan on building any tanks with it. Weld On 40 is easily obtained through any major fabrication shop. Best if bought from a place that keeps it refridgerated. Ok, now the 42, this is nasty stuff...........it is the same as the 40 but, with a third part(c) that is added to the (a) (b) parts. It causes the reaction to be much more aggressive. It is nasty stuff and if not used EXACTLY correct it will cause crazing and discoloration. If you plans are to build a tank to hold water.............40 is not the way to go. It degrades over time and will give. If you anneal it properly, it buys on more time and gets a stronger joint. 42 is strong stuff but, you have to really be a professional and have professional tools to use this stuff. I am not just flying off the cuff either about this. Your best bet is to use a solvent like MC Bond from Poysciences. This is the way to go on building water holding tanks. I have personally built 1000 gallon + tanks with this stuff for years. Never lets go.............the only requirement is that you have an excellent jointed edge to bond on.

Hope this helped some,

[valid]

guess i wasn't clear enough: tanks are already built. i just want to reinforce existing joints.
thanks for the comments so far -- keep 'em coming.:)

[electric130]

Originally posted by valid
guess i wasn't clear enough: tanks are already built. i just want to reinforce existing joints.
thanks for the comments so far -- keep 'em coming.:)

Originally posted by electric130
if you are welding acrylic to acrylic, use weldon 3, 4, or 16. 16 if you want fillets. 3 or 4 if you're bonding new seams.

[NAGA]

why are we trying to reinforce the joints??? Are they already popping??? I didn't realize that the tanks are already put together.........sorry. Ok..............if the tanks have already held water for some time, the material is already been stressed. If you try to put a "bead" of 40 or especially 42 on the corners, you will no doubt see a lot of little cracks appear "crazing". Unless your going to dump a whole lot of glue on there, you will not gain much if any at all. To gain anything you will need to buy a lot of glue..............the amount of which will likely make this idea cost prohibitive. Unless the tanks are popping this is a bad idea. To do it properly you will need to anneal the material/tank/joint to relieve the stress from water weight in the tank. Then dump a huge (1.5") bead across the corner of the tank. Even then I have personally seen this fail. When seems pop and you do this to keep it together it inevitably fails in time. Cut the side off and re machine the material............anneal it...........then solvent joint it together. Basically it is a B!TCH!!! A lot of work when unless there is no other way of doing it.........you buy another tank.

My 2 cents,

[dattack]

Hey NAGA,
WHere do you get the MC Bond and is it easy to apply like Weldon 3 and 4?
Moreso, how much stronger is MC Bond relative to Weldon?

[JerseyReef]

Originally posted by dattack
Hey NAGA,
WHere do you get the MC Bond and is it easy to apply like Weldon 3 and 4?
Moreso, how much stronger is MC Bond relative to Weldon?

I't really strong stuff. Much better than Weld-on, IMO and IME. It's not cheap...

http://www.polysciences.com/shop/product.asp?dept%5Fid=3004&pf%5Fid=16752

[valid]

very interesting

seems i've always heard that 40 and 42 are the same stuff - it's just that 42 is packaged conveniently (mixing gun). can you tell me what is in each product that makes one different ("nastier")from the other? i suppose i could request the msds sheets, but if you have this info handy, it sure would be nice!

btw, tanks are unused (the paper backing is still on the bottoms) polycast. 1/2" walls, 26" high. this whole idea of mine began when i noticed:

1)a few (2-3) bubble tracks (within the seams themselves) where they pulled the pins during fabrication. also, ~1/8" or less x a few feet areas on some of the internal angles where the solvent apparently pulled back a little as it dried. these areas have a kind of frothy (not crazing) appearance. joints are generally great otherwise.

2)i plan to cut some extra bulkheads in the back wall of the tanks. these back walls are not perfectly flat already.:eek1:

[valid]

thanks for the recommendation and thanks for the link regarding mc bond.
what's in it?

[kanankeban]

Your best bet is to use a solvent like MC Bond from Poysciences. This is the way to go on building water holding tanks. I have personally built 1000 gallon + tanks with this stuff for years

Should I throw away all my weldon and get some mcbond for my future projects:D
If it better I'll do it without a problem!:rollface:

[NAGA]

Ok there seems to be some confusion as to what 40 and 42 are of the Weld On product line.

42 is packaged in a gun in SOME CASES but, what makes 42 from 40 is the 3rd part(c) 40 as we all know is two part......42 is three part OK??? :D 42 has been marketed in guns much more so than 40. This is because it is done automatically for you through the gun. To mix it on your own you really have to know what your doing or you will create a mix that will be weaker/discolored/and crazed.

MC Bond is similar to Weldon 3 but, it sets up a bit slower and because of the slower set up time as well as the solvent make up being a bit different it gets a better bond and sets up with fewer bubbles and gives a cleaner seem. You still need to have and excellent jointed edge to get the good looking seems. Bubble tracks in the seems does not make a tank vunerable to leaking or popping unless there is a ton of them. It is an asthetic thing more than anything else. A big myth is that if there are bubbles in the seam it is weak. At a certain point this is correct but, there has to be so many that it truly looks weak. I would not "reinforce" the joints based on what you have described in the seams.

maybe I am up to 4 cents now:lol:

[electric130]

Originally posted by NAGA
MC Bond is similar to Weldon 3 but, it sets up a bit slower and because of the slower set up time as well as the solvent make up being a bit different it gets a better bond and sets up with fewer bubbles and gives a cleaner seem.

so then it's the same as weld-on 4. weldon 4 is weld on 3 with a slower reaction time. both are water thin. 3 just sets up in about 30 secs or less. 4 you have more time with.

[NAGA]

slower than 4...........gives a cleaner looking joint as well.

[electric130]

Originally posted by NAGA
slower than 4...........gives a cleaner looking joint as well.

so then it's like weld-on 5.

From IPS's web site - Weld-On Acrylics (http://www.ipscorp.com/ind_html/acrylics.html)

"Weld-On 5 - Water thin, slow-setting solvent cement for bonding acrylics. "

"Weld-On 4 - Non-flammable, water thin, moderately fast-setting solvent cement for bonding acrylics. "

"Weld-On 3 - Non-flammable, water thin, very fast-setting solvent cement for bonding acrylics. "

[NAGA]

You can't compare MC Bond to Weld On Setting wise it is similar to Weldon 5. Make up is otherwise different. If you want to know the differences I would go to the websites and compare. I can only tell you from experience that MC Bond makes a bond that is extremely strong.

[valid]

weld-on 42 is NOT a 3 component product - it is in fact the same components as 40, but the gun mixes them at a slightly different ratio than 40. (this was told to me by one of their people a moment ago). this person is emailing me an msds for 42 - i should get a look at it tonight. the msds for 40 is available online.

here is their website:
http://www.ipscorp.com/ind_html/productbulletins/indprodbultnpdf/PB42.pdf

and here is the quote:
GENERAL DESCRIPTION
WELD-ON 42 is a 2-componet, clear, medium bodied, reactive acrylic cement. It polymerizes by the reaction of
Component A (Base Resin) with Component B (catalyst). WELD-ON 42 is packaged in a 10:1 230ml cartridge
for use with a 2 component dispensing gun and static mixing tip. The adhesive is mixed as it passes though the
mixer tip. The mixed product polymerizes at room temperature; joints are usually hard enough for handling in
about 4 hours at 70ºF. Machining may be done after 24 hours.

NAGA - were you thinking of another product?

[Entropy]

Here is the Weld ON catalogue :)

weld on pdf (http://www.ellsworth.com/Catalog/Weldon.pdf)

(Hey I have $0.02 to throw around!)

[valid]

ok, guess it's weldon 28 then for the 3 part stuff. talked to ips folks - they said 28 is pretty much only used for spec jobs, aerospace.

[NAGA]

the 28 is just the 3rd part that is added to the 40 which how we have been told is 42. I have seen the 28 but, only as the third component that is to be added to the 40. The ratio's you speak of as far as the base two components are mixed together based on temperature and what type of application and type of reation you want to use in the joint you are making. I can tell you that you can machine this stuff as soon as 2hrs. passes. That is if you boosted the A component to speed up the reaction. All I can say is that it is a feel thing. 40/42 or 28.........it all should be used by experienced people. If one doesn't mix it properly you will not get optimum strength. That is why MC Bond is so wonderful...........it's hard to F up. There is no doubt though that 40/42/28 which ever you want to call it makes the best looking joint but, not the strongest. That third component added to the 40 though I have tested after annealing it at 148 degrees for a couple of hours.........is strong as anything.........broke the test piece through the material.........not along the joint. Again.........NASTY STUFF TO WORK WITH.......LOTS OF VENTILATION!!!:eek1:

[Zephrant]

I've gone though a quart of MCBond the last several months. I've not seen anything that would make me think it applied better than #4, or was stronger. I do notice that the fumes are nastier.

Note this post please: MCBOND (http://archive.reefcentral.com/forums/showthread.php?s=&postid=1405549#post1405549)

Zeph