Weld-on #40 and #42

[Dieselhybrid]

Great thanks guys. I'm sure I can get it close to 45 degrees. I have plenty of room to rotate the tank. It's large 8x3x2.5.
I think I'll mix smaller amounts and do one seam at a time to start.

The heat causing crazing is a concern. How do I avoid that?

I have scuba gear and a scuba compressor so I can wear a tank and breathe clean air.

Thanks so much Wednesday and Phixer


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[Dieselhybrid]

Also can you recommend an applicator?

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[Phixer]

Here's what I use.


You can't eliminate the heat generated by the chemical reaction of the cement polymerizing but you can manage it by not pouring huge amounts at once. Remember that the more you pour the greater propensity for bubbles and the more heat generated. You should be fine as Wednesday mentioned by pouring one fillet at a time, the SCUBA / OBA is a smart idea. Keep a clean work area.

When using 40 I weigh it, mix it and thin with a little 3061 , pour it into a large syrenge for control...then inject it into place. 42 is applied using mixing guns in sizes 50ml and 230ml. The 50ml applicator is priced better but since I focus on large custom tanks I prefer the larger applicator for longer seams. I started with 42 and like it, however I would recommend using 40 mixed in cups and poured directly if the application is a 45 degree inside fillet. 40 and 42 are the same thing and work well in the right hands but can equally spell disaster if not careful. The applicator is Swiss made and is expensive as hell, (no idea why, it's very basic) I searched high and low for the best price and found a site called http://www.theengineerguy.com/sells that had the best deals.

 

[johnny potatoes]

This has been very informative as I just picked up a 450 (5x3x4) with a bad bottom corner. My plan is to use a piece of 1" quarter round at the bad area. I have one question about the #40/ #42. Do I need to mask of the areas I'm not sealing? Is it ok to get the glue on the rest of the tank? Thanks

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[wednesday13]

This has been very informative as I just picked up a 450 (5x3x4) with a bad bottom corner. My plan is to use a piece of 1" quarter round at the bad area. I have one question about the #40/ #42. Do I need to mask of the areas I'm not sealing? Is it ok to get the glue on the rest of the tank? Thanks

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Good choice on the acrylic square stock/rod...great way to beef up ur seams and ensure uve created a large contact area for the glue fairly easily. No need to mask anything off. The #40-42 heats up when curing so it kinda melts into the sheets a bit. Any tape/mask will be melted there forever lol so def. Be careful/clean when ur working. Any glue you spill will leave a mark even if u try and wipe it off. Its possible to sand/buff the glue drips off but thats another project in itself so i usually dont bother and just try to b as clean as possible. You may still want to tip the tank up when ur glueing to ensure the glue puddles in the seam u want. Even if only a few inches, itell prevent any glue from running as opposed to if its upright. The glue is a syrup consistency but will run thin before it sets up so u have to tip the tank a bit to trap it in place before it dries.

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[Egon]

Good info guys, thanks!

 

[johnny potatoes]

Good choice on the acrylic square stock/rod...great way to beef up ur seams and ensure uve created a large contact area for the glue fairly easily. No need to mask anything off. The #40-42 heats up when curing so it kinda melts into the sheets a bit. Any tape/mask will be melted there forever lol so def. Be careful/clean when ur working. Any glue you spill will leave a mark even if u try and wipe it off. Its possible to sand/buff the glue drips off but thats another project in itself so i usually dont bother and just try to b as clean as possible. You may still want to tip the tank up when ur glueing to ensure the glue puddles in the seam u want. Even if only a few inches, itell prevent any glue from running as opposed to if its upright. The glue is a syrup consistency but will run thin before it sets up so u have to tip the tank a bit to trap it in place before it dries.

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Thanks Wednesday, you've answered my questions. I was worried the glue would leave marks, thanks for the tip about the tape melting. As far as tipping the tank it's a 5x3x4 so I have to be in the tank to do the work, not sure how to pull that off. Thanks again

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[TekWarren]

Great information here. I recently purchased a used 125g and while it does not leak I can see signs of stress and was worried about getting acrylic rod placed in the seams well enough. The "tip and pour" method seems like something I can manage well enough. Do you guys think that 2 pints of #40 will be enough for a standard size 120 gallon?

Thanks

 

[TekWarren]

Well I've poured most of my tank, ended up needing to order another jug to finish it. I don't know if I'm not stirring long enough or what but I've got bubbles in ever poured seem, not horrible but they are there. Also, I've oddly seen crazing occur near the seams I've poured that I am certain where not there before. Did I do something wrong?

 

[wednesday13]

Well I've poured most of my tank, ended up needing to order another jug to finish it. I don't know if I'm not stirring long enough or what but I've got bubbles in ever poured seem, not horrible but they are there. Also, I've oddly seen crazing occur near the seams I've poured that I am certain where not there before. Did I do something wrong?

Its impossible to mix the glue and not create bubbles...however, they can be removed in a vaccum chamber or on a vibration table. Most people dont have those on hand so anything that vibrates can be placed by your mixing cup to expel the bubbles. In a pinch place ur mixing cup on a chair and shake the chair around by hand and u will see the bubbles rise to the surface. Instructions say to let the glue sit for 3-5min after you mix so this is a good time to shake it up. Blowing on the surface of the glue is also a trick to remove bubbles.

As for heat crazing....this is very normal. Thicknesses 1/4-1/2" heat up alot when curing and are removed by baking/aneeling. Since we at home cant do this in giant ovens were stuck with the crazing. All crazing is doing is revealing the micro stress fractures on the surfaces of material. There always there on used tanks u just cant see it until its heated up. Can be an eye sore yes...but better than a leaky tank. Material 3/4"-1" crazes alot less as the heat is distributed more. Older "yellowish" acrylic crazes the worst. Again, very normal and not detrimental to anything but looks.
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