Any tips for using Weld On 40?

[Wippjas]

Looking for a little advise here.. I bought some Weld on 40 to put together a Calcium reactor made of acrylic tube and PVC.

1.What is the best way to divide the two components and mix them without creating too many bubbles?

2.I bought two different sizes of plastic syringes to remove the fractional portions of the mixtures, but am not sure if the plastic syringe will melt.

3.Can I mix the two on a piece of scrap acrylic without changing the characteristics of the compound??

4.Once the PVC and tube body are glued, will I risk the joint strength if I then drill the holes for the PVC fittings or should I drill first and then glue?

Thanks,

[Beaner3]

You could make a vacuum type chamber out of acrylic, and then place the mixing vessel (with mixed 2 part in it) into the vacuum chamber to "pull" the bubbles to the surface, skim the bubbles off with a tongue depresser, and then apply to surface. make sure you get a good vapor blocking respirator, that stuff is mega potent!!

[Wippjas]

<a href=showthread.php?s=&postid=11894960#post11894960 target=_blank>Originally posted</a> by Beaner3
You could make a vacuum type chamber out of acrylic, and then place the mixing vessel (with mixed 2 part in it) into the vacuum chamber to "pull" the bubbles to the surface, skim the bubbles off with a tongue depresser, and then apply to surface. make sure you get a good vapor blocking respirator, that stuff is mega potent!!

Thanks for the suggestion.

I have a cabon respirator, but I suppose I should wait till it warms up. I was hoping to get this done sooner in the basement but maybe I'll wait until I can open windows or do it in the garage?

[hebygb]

I wouldnt worry about the bubbles if:

The two pieces being glued fit flush when dry fit together. That the joiend surfaces are at least 1/8" thick and in contact.

The weldon product is a solvent, essentially melting and then hardening the surfaces of the pieces together. It is not a glue. Therefore when the weldon is applied to the pieces, and they are squeezed together... any air bubbles will be squeezed out or be removed during application, the solvent will do its work, and the bond will be strong. Many times users use the thicker Weldon product to compensate for flawed surface/edge preparation... This is a fundamental flaw in craftsmanship and compromises the integrity of the bond. Weldon is not to be used as caulk.

[Wippjas]

<a href=showthread.php?s=&postid=11895236#post11895236 target=_blank>Originally posted</a> by hebygb
I wouldnt worry about the bubbles if:

The two pieces being glued fit flush when dry fit together. That the joiend surfaces are at least 1/8" thick and in contact.

The weldon product is a solvent, essentially melting and then hardening the surfaces of the pieces together. It is not a glue. Therefore when the weldon is applied to the pieces, and they are squeezed together... any air bubbles will be squeezed out or be removed during application, the solvent will do its work, and the bond will be strong. Many times users use the thicker Weldon product to compensate for flawed surface/edge preparation... This is a fundamental flaw in craftsmanship and compromises the integrity of the bond. Weldon is not to be used as caulk.

Thanks for the info.

I was only using this product because it was supposed to be the strongest bond for PVC and acrylic. I am also entertaining the thought of building a tank in the future, so I wanted to get a little experiance with the stuff.

So as with Weld on 4, you just want enough solivent to soak the edges of the panels?

[Acrylics]

Actually, 40 works more as a glue than a solvent. 40 is an acrylic resin and will not dissolve acrylic as a solvent would. What is usually done is to leave a gap (1/16-1/8") and fill the gap with 40. Apply enough to ooze out of the joint a little, do not mash down and try squeeze out any of the 40.

As for respirators, need to get one for "organic vapors" but you get used to the smell ;) Some folks get pretty bad headaches from the stuff so if you are one of those, use the respirator.

1) poly cup, if you want - get one of those poly measuring cups to measure the stuff in. When done, let it harden in the cup, the squeeze the cup and the hardened 40 will come out easily. The bubbles are part of it, the vaccum chamber is what is usually done. You can control it a bit once you get used to it by regulating pot life by adding different amounts of catalyst. More catalyst = shorter pot life = less time to get the bubbles out. But, you cannot put in like no catalyst and expect to get a pot life that is too long, won't harden correctly.

2) it will not dissolve syringes. It will ruin the rubber plunger though after a coupla uses if you get multiple uses out of the syringe

3) yep, you can - will not dissolve acrylic as a solvent would

4) drill first then glue, not so much for joint strength but if you mess up, you will have then screwed up 2 pieces and the time in gluing.

HTH,
James

[Wippjas]

Thanks, this helps a ton... I just wasn't comfortable with the application explinations that I've seen for working with Weld On 40.

Is that poly cup you are talking about the same ones that some auto body shops use for paint mixing??

[manderx]

Is that poly cup you are talking about the same ones that some auto body shops use for paint mixing??
i use syringes for measuring (and sometimes applying), yogurt cups for mixing, and paper plates if i ever need to spread it out for dipping an edge in it (no need to waste even scrap acrylic).

[Wippjas]

<a href=showthread.php?s=&postid=11897673#post11897673 target=_blank>Originally posted</a> by manderx
i use syringes for measuring (and sometimes applying), yogurt cups for mixing, and paper plates if i ever need to spread it out for dipping an edge in it (no need to waste even scrap acrylic).

Thanks, great idea with the yogurt cups. I was thinking about using cardboard or paper as you suggest, but I wasn't sure if the paper would absorb the catalyst causing it to harden faster or slower. I thought that the mixing may need to be done somewhat like Bondo for cars by folding it rather than mixing... I was again afraid of bubbles.

I might be overanalyzing this stuff, but better safe than sorry.

[hebygb]

I stand corrected. I always thought 40 was just a thicker version of 4, and behaved in the same manner (as a solvent). Thanks Acrylics. Learn something new everyday. Since it is a glue, is there a risk that 40 will seperate (given that it doesnt actually join the edges the same as 4)?

[Acrylics]

<a href=showthread.php?s=&postid=11903353#post11903353 target=_blank>Originally posted</a> by hebygb
Since it is a glue, is there a risk that 40 will seperate (given that it doesnt actually join the edges the same as 4)? Yep, sure is. Dependent on many factors; monomer:catalyst ratio (which changes with volume mixed BTW), ambient temp at application, mole wt of material, thermal expansion/contraction, etc.
The *major* downside to it is that you'll never be absolutely positive of how much "bite" it has to the acrylic panels. I've seen tanks last for years and I've seen them fall apart on first fill. In either case, the joints looked equal at installation, which can give a false sense of security. With solvents, you know within a few minutes to hours how good the bond is.
They both have their pros & cons, IMO though, it's better for most DIYers to stick with solvents at least until there is a *need* for 40/42

HTH,
James

[hebygb]

Thanks... and please... no more kcals and mole speak... yikes... LOL

[aaron7405]

I have been using weld on 40 on my big proyects, actualy I use wedone 40 if I am usisng 1/2"+ thick acrylic, but I mixed with a thiner WELDON 306. This will make the 40 more thin and the air bubble will came up easear.

Also what I do and will help a bit, as the 40 give you a good amount of time to be set, after I make the mix (part A, thiner and part B), I place the conteiner on a sander so the move will make the bubble to came up, or you might use some centrifugal forse to separe the bubbles too, never try the last one LOL but I think will work.

If you want a beter finish I tape very close to the joint before I glue, after Its glued I use a kalk squeeze to get the glue exess, when I squeeze try to get the glue on the tape and then I remove the tape.

I hope this help

[Crit21]

I have been using weld on 40 on my big proyects, actualy I use wedone 40 if I am usisng 1/2"+ thick acrylic, but I mixed with a thiner WELDON 306. This will make the 40 more thin and the air bubble will came up easear.

Also what I do and will help a bit, as the 40 give you a good amount of time to be set, after I make the mix (part A, thiner and part B), I place the conteiner on a sander so the move will make the bubble to came up, or you might use some centrifugal forse to separe the bubbles too, never try the last one LOL but I think will work.

If you want a beter finish I tape very close to the joint before I glue, after Its glued I use a kalk squeeze to get the glue exess, when I squeeze try to get the glue on the tape and then I remove the tape.


Aaron, How much thinner do you add to the Weldon 40? Have you ever thinned it 1:1 with Weld-on 3061?

[mcgyvr]

Aaron, How much thinner do you add to the Weldon 40? Have you ever thinned it 1:1 with Weld-on 3061?

Crit21 unless you want to drastically effect the properties/weaken the bond do not use more than 10% 3061 to thin 40A

[Crit21]

Thanks. I saw that on the Weld-on site, but I was hoping Aaron would weigh-in. He appears to have used 40 on a number of projects similar to mine.

[mcgyvr]

Thanks. I saw that on the Weld-on site, but I was hoping Aaron would weigh-in. He appears to have used 40 on a number of projects similar to mine.

Ok cool..just letting you know what the actual manufacturer of the product states...

[Crit21]

Sometimes people have "hacks" that work well despite what the manufacturers say. I think it's strange that Weld-on 40 and 42 have identical strength specs when cured, yet the formulations are different, requiring a 20:1 mix for 40, and 10:1 for 42.

[BroodNash]

"unless you want to drastically effect the properties/weaken the bond do not use more than 10% 3061 to thin 40A"

Thanks, mcgyvr! Will keep that in mind as well.

[lapin]

On 1" I thin by 10% - helps with flow into the joint. It also can help the bubbles rise out of the mixture while mixing. After filling the syringe, let it sit, point down for a min or 2 while the bubbles rise. This should prevent any from coming out when applying. If I have a long joint requiring a lot of #40 I prepare 2 syringes. I find it easier to apply steady pressure if the syringe plunger is not pulled out to the max. If you have big hands then maybe it does not matter.