# UK equivalent of WELD ON 4



## Geoffrey Rea (7 Jun 2019)

As per the title, looking for the UK equivalent of WELD ON 4. 

Got a crack in an acrylic overflow box that hasn’t gone all the way through but should be able to get some bonding agent into the crack via capillary action to prevent any further issue. Luckily in an area that isn’t going to be exposed to water.

Any brand that anyone is aware of that’s readily available in the UK that is of the same watery consistency or even thinner for bonding acrylic?


----------



## Mark bowen (8 Jun 2019)

You want to tensol 12


----------



## Geoffrey Rea (8 Jun 2019)

Thank you @Mark bowen


----------



## soggybongo (8 Jun 2019)

I have always used ema plastic weld, its really runny so capillary action will spread throughout the crack after a few seconds it will slightly melt and fuse the crack sets in about 2 min. doesn't leave any residue.


----------



## Geoffrey Rea (8 Jun 2019)

Thanks @soggybongo


----------



## zozo (8 Jun 2019)

Those solvents for welding acrylic are a Mixture of several compounds, Dichloromethane for the biggest part, part Chloroform and part Monomers.

In case you need a strong as possible bond (Aquarium building) we absolutely need the monomers in the solvent. This helps to aline the molocular structure in the weld and give strenght. Without monomers the molocular structure will be erratic and thus less strong and somewhat brittle.. But it still welds and not to be seen with the nacked eye, since its on molecular level. 

For reparing a crack that doesn't need to hold any force any solvent will do to close it again. Thus you could use pure Dichloromethane, this is still considered the best acrylic solvent out there. This stuff is used and available in a variety of products and industries. For Brush cleaning, Degreasing, paint stripping etc As long as it is pure Dichloromethane you can use it.

But Acetone also could be used, its a simmular effective solvent.

In the early days before Dichloromethane was discovered as such a good acrylic welding solvent. Acrylic was commonly welded with Chloroform only.. Used to be available via pharmacies.. But nowadays due to horor stories not that easily available anymore for the regular every day costumer asking for Chloroform.

Thus if its just a simple crack in a pipe or a box that doesn't need to hold a ton of strenght. You don't need any special secret recepies, you could simply use acetone, you wont notice the diference.


----------



## ian_m (8 Jun 2019)

Not sure about acetone, can lead to stress crazing in acrylic. Chloromethane based is best as had a decent "open time", but can be difficult to buy, especially low viscosity mixes, due to "wrong use issues". Else dichloromethane works well but dries quicker


----------



## Geoffrey Rea (8 Jun 2019)

Thank you @zozo and @ian_m 

More to go on. Attempting to avoid stress crazing and to use as little as possible anyway with a hypodermic needle. The area the crack is in isn’t subject to any load but is close to an existing weld so being cautious.


----------



## zozo (9 Jun 2019)

Google glue acrylic with acetone and you find some data and videos. It's a prety common household solution for small projects.


Tho i would not recomend a syringe and certainly not a plastic one with a rubber seal on the piston. Anyway you always have to push a tight fitting piston in the syringe very dificult to apply a few drops. It's easy to always apply way to much causing a lot of solvent running off. Rather get a small 5cc dispenser bottle with a needle top.
https://www.banggood.com/5-30ml-PET....html?rmmds=search&ID=515476&cur_warehouse=UK

Even using chloromethane or any other top noch solvent you still can get crazing. It doesn't depend on the solvent but depends on how clean and especialy how straight the cut is you want to glue. If it aint a perfect flat straight edge you want to glue together. And cannot clamp with an equaly applied force over the intire surface  you will always see the irregularities and crazing in the weld later on. It also depends on the thicknes of the acrilyc, glueing or working with 10mm is more difficult and needs more expertise than gluing 4mm. Irregularities in pressure applied over the surface during the curing process will show as crazing.  

Whatever you are going to decide on, it wont make the crack in the box go away.


----------



## zozo (9 Jun 2019)

What also oftenly is done, depending on the crack that needs to be repaired.. You can dissolve some acrylic shavings into the solvent before applying it. This makes the solvent a tad thicker. You can make a gel if you want and run a clear weld bead over the crack. 

Just practice on some scrap material. It's fun to find out where you can go with this..


----------



## Geoffrey Rea (9 Jun 2019)

3cm long, not all the way through, travels up to the existing weld:


----------



## zozo (9 Jun 2019)

All the way to the top? Edit:  Oh sorry, can't be with only 3cm.. If it contains no water, i would not do anything to it.


----------



## Geoffrey Rea (9 Jun 2019)

No disappears into the existing weld between the 2cm - 3cm mark. Hence the concern about expansion with heat.


----------



## Geoffrey Rea (9 Jun 2019)

Thanks @zozo just seen your edit.

I’m familiar with glass but not cast acrylic so appreciate your input. Very aware it’s easy to make things worse. Will mark the crack with some tape and make sure it doesn’t creep.


----------



## zozo (9 Jun 2019)

If it were mine i'd run some solvent from the top to the 2nd mark and leave the rest as is.


 

If you run solvent over the rest of the crack, it will always show i'm afraid looking worse than is now. And it will stay a weak spot anyway.


----------



## Geoffrey Rea (9 Jun 2019)

zozo said:


> And it will stay a weak spot anyway.



It’s this point that makes doing anything moot. It’s right at the back of the unit and positioned at the back of the tank where no one will ever see it. Aesthetics are out but would rather not run the possibility of risking the unit.


----------



## Aqua sobriquet (9 Jun 2019)

I think I’d weld the entire crack before it gets any worse.


----------



## Geoffrey Rea (9 Jun 2019)

It’s difficult to say if it would get any worse Aqua sorbriquet. Outward pressure on that particular section from water is going to be pretty non existent. I figure it’s the weight of the water downwards that puts a demand on the welds and it will only ever be 2-3” of water and the unit is 12” tall. Out of 24” of weld on that axis only 1” is compromised. I know it’s crude but taping the corner at 90° at that section may suffice for it to never be an issue.

All a bit of a faff but grateful for the advice everyone 

This all began by the delivery company beating the hell out of a box marked fragile


----------



## sparkyweasel (9 Jun 2019)

Geoffrey Rea said:


> It’s this point that makes doing anything moot. It’s right at the back of the unit and positioned at the back of the tank where no one will ever see it. Aesthetics are out but would rather not run the possibility of risking the unit.


In that case, you could weld an additional piece of acryllic sheet right over the crack, fixing to both sides, and  going beyond the end of the crack. Then it can't open up, or extend itself.


----------



## Geoffrey Rea (9 Jun 2019)

That’s a good point @sparkyweasel 

Planning a build with some acrylic this summer anyway so should be more familiar with it as a material in due course. Another option, thanks for the suggestion.


----------



## oscarlloydjohn (9 Jun 2019)

I think tensol 12 would work fine for that. Since it is low viscosity, it would be pulled into the crack through capillary action.

Oscar


----------

