Weld-on #40 and #42

poppalina

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Weld-On 42 bonds all acrylics, including extruded, cell cast and continuous cast, as well as molded parts and some cross-linked sheets. It will also bond acrylic to polyester, butyrate, polycarbonate, PVC, styrene, and other materials.

This is what I read it also states that 40 and 42 are the same as wednesday13 stated the applicator is the only difference.
So my question is would this work to repair the plastic frame, also for the tip and pour method on acrylic tanks would #42 with the applicator tip make for a neater job.
 

wednesday13

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Ill answer ur second question first lol...in my opinion whats the point of paying extra for #42, a special gun to use the cartridges, and the cartridges when you can just buy #40 and shoot it out of all different kinds of applicators specific to each job. I use larger type syringes, squeeze bottles in a range of sizes and even just pour seams right out of a mixing container. Yes #42 may be neater in the aspect of not making a mess on ur acrylic and for cleanup but as for performance theres no difference with the right tools/applicators than can be found around the house or a dollar store.

Now back to why its not always best to use #40-42 on other types of plastics for lol...will it work? Yes....how well does it work is the real question. it does not give you the same results and strength as when you use it on acrylic. There are different solvents and methods like heat welding used to bond these other types of plastics for a reason. Ill try to find a data sheet from the weldon website for different materials. For example, say acrylic to #40/42 bond is 100% adhesion. #40/42 to a.b.s. or p.v.c. may drop as low as 40-60% adhesion. Thats a huge difference when were dealing with water pressure and making a water tight seal. If you tried to use a.b.s. sheet and #40 to construct a tank it would explode. Heat welding is used for most all plastics other than acrylics/polycarbs because it literally melts the sheets togehter. Cheap plastics like glass tank trim are just that, cheap plastics. Sometimes there not worth fixing. Its very possible the heat created when the weldon #40/42 starts to cure can warp, distort, or even melt the trim.
Just getting the point across the glue is not full strength on other materials. It may work for a certain case, it may not. More for non structural applications. I think u could get away with fixing some tank trim. I also think u could probably pull it back apart very easily lol...

Getting 2 things to stick together is easy, scotch tape will do that lol...physically melting them together permenatly with solvents/epoxies/heat can be harder and there are different ways to permenatly bond different materials. Just like putting regular silicone on acrylic. Yes it will stick, but u can also pull it right back off.

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Fergy

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Hi wednesday13 wanted to get your experienced input on this. Thanks a ton.

Hi, this is some great info!

I just picked up a 180 off CL that looks OK on the seams, some minor crazing but it holds water. I want to reinforce it and was thinking to use #40 and 1/2" triangular bead around the bottom and vertical seams, but considering maybe just fillet the 4 vertical seams for better aesthetics.

Is there any reason to not use the bead all the way around? Seems like more bonded surface area will = stronger, and take less bulk of #40 to do. Unfortunately not going to be able to get into it for at least a month but the deal was too good to pass on.
 

wednesday13

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Hi wednesday13 wanted to get your experienced input on this. Thanks a ton.
Id just do the whole tank and never worry about it down the road. A couple pints of #40 should be enough to tip an pour all ur seams with a 1/4"-1/2" bead. Sounds like u dont need a whole lot of glue but even 1/4" bead will reinforce the tank and prevent ur bad spots from spreading.

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Fergy

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Id just do the whole tank and never worry about it down the road. A couple pints of #40 should be enough to tip an pour all ur seams with a 1/4"-1/2" bead. Sounds like u dont need a whole lot of glue but even 1/4" bead will reinforce the tank and prevent ur bad spots from spreading.

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Great thanks!

Just to be sure, you say that using just a bead of straight #40 will be as strong as using some 1/2 triangle rod and the #40? I guess I should have said rod instead of bead in the first place
 

Fergy

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Another quick question you probably have an answer for:
is reinforcing the top brace with some sanwiched 1/2 or 3/4 acrylic a good idea? it flexes down a bit when filled. if so, best to do on inside or on top of tank?
 

wednesday13

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Great thanks!

Just to be sure, you say that using just a bead of straight #40 will be as strong as using some 1/2 triangle rod and the #40? I guess I should have said rod instead of bead in the first place
I wasent sure, i had a hunch u meant acrylic square/triangle stock lol sorry. But yes either way will do the same thing in the end. You are correct you will use less glue with the square/triangle stock. If ur tank seams arent that bad #40 alone will look alot cleaner imo. Just preference really which way u want to go. Ends up being the same peice either way really.

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wednesday13

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Another quick question you probably have an answer for:
is reinforcing the top brace with some sanwiched 1/2 or 3/4 acrylic a good idea? it flexes down a bit when filled. if so, best to do on inside or on top of tank?
U can do top or bottom of the brace or both...id do inside the tank first and see if it solves the problem...only reason is to keep the top flush for lids, not a big issue. If it still bows u can do the outside top aswell.

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