Boss Adapter Connecting Up To 32mm ABS Waste Wipe

[danielson]

I have a boss adapter to connect to my basin waste to soil branch but the I am trying to work out what connector I need on the boss itself to connect up my 32mm solvent weld waste pipes.

I currently have a solvent weld adapter in the first picture below and my ABS 32mm waste fits in there to solvent weld. The problem is the adapter is PVC and read you cant solvent weld ABS to PVC. I then found the following adapter which would work as it doesn't require solvent welding the waste onto it however how would I then convert to a solvent weld pipework further up - do I need a coupler of some sort? I don't want to use push fit pipework as it will be behind tiles so working out a way of changing from push fit (at the boss connector) to solvent weld later on...

Adapter For Boss

 

[Ric2013]

I'm not saying it isn't true, but I'm not aware that you can't solvent weld ABS to PVC. That said, I can't remember having ever done it. Where did you read this anyway?

Personally I'd try it on one joint and see if it works as I suspect it will work.

If you are correct, however, that they cannot be solvent welded, the best bet in a DIY situation (and being aware of what is going to be realistically available to you) is to use a 1.25" "compression" or "universal" coupling.

But, in any case, if you already have an adapter that doesn't require solvent welding and fits, I'm assuming it uses an O ring so why do you need to convert at all? ABS and MPVC wastes are the same diameter in my experience so I'd have thought what fits one will also fit the other.

 

[danielson]

I'm not saying it isn't true, but I'm not aware that you can't solvent weld ABS to PVC. That said, I can't remember having ever done it. Where did you read this anyway?

Personally I'd try it on one joint and see if it works as I suspect it will work.

If you are correct, however, that they cannot be solvent welded, the best bet in a DIY situation (and being aware of what is going to be realistically available to you) is to use a 1.25" "compression" or "universal" coupling.

But, in any case, if you already have an adapter that doesn't require solvent welding and fits, I'm assuming it uses an O ring so why do you need to convert at all? ABS and MPVC wastes are the same diameter in my experience so I'd have thought what fits one will also fit the other.

I haven't got the adapter that is push fit (with an o-ring I believe) as it says it will fit 32mm pipe and not sure if you can then insert an ABS pipe (38mm outer diameter) into this and then solvent weld the rest of the setup. That would be the ideal situation if this fits in the OSMA 2S399G adapter as I can compression fit the pipe onto the connector and then solvent weld the rest of the pipe.

I just did a bit of searching on the internet about ABS-PVC and quite a few sites said it is not possible. I think it is better to play it safe and use this...

OsmaSoil 2S399G 40mm Ring-Seal Boss Adaptor Grey - https://www.travisperkins.co.uk/soil-pipe-and-fittings/osmasoil-2s399g-40mm-ring-seal-boss-adaptor-grey/p/758541

Not sure if I'm getting too wound up by the different outer diameters of non solvent weld and solvent weld pipes for this connection.

I have just found this one and saves me solvent welding the boss onto the pipe which is an option but this connector does say it fits BOTH pushfit and solvent weld pipes which is perfect. I think the osmasoil connection will be the same to be fair.

Mechanical Soil Pipe Boss Connector - https://mcalpineplumbing.com/traps/condensate-traps-and-fittings/bossconn110-blc-mechanical-soil-pipe-boss-connector

 

[Ric2013]

The trouble with information on 'quite a few sites' is sometimes people copy and paste what they read on other sites. You'd have done do far better to post on THIS forum and ask specifically 'Can I solvent weld an ABS waste pipe into a U-PVC fitting?' as I suspect it's your title that means you aren't getting many hits. But don't... because it's already there under a different title and the conclusion was that while you can probably get away with it on a low-pressure application such as drainage, it's not good practice.

So you've come on a plumbing forum and taught ME something! Thank you.

Going back to your problem, you are right to be cautious about diameters. I get fed up with them and it's basically easier to think in terms of 1.25", 1.5", and 2" sizes, and be aware that push-fit (PP) is smaller size (and I try to avoid it anyway).

I'd suggest the ring seal is a push fit system and strictly for PP push-fit pipe, not ABS.

The mechanical fit is a compression fitting and should be fine with either kind of pipe. Probably a good idea in that there is something to be said for being able to remove things if need be, as it can be very hard to get the alinement precise with solvent weld and having at least one place you can tweak can be useful. You can't get much better than McAlpine so I'd say it's a good solution also as that kind of boss clamps onto the soil stack without solvent weld, which you may find easier anyway.

Myself, I tend to use the system below which provides a rubber fitting, thus avoiding a solvent weld joint and which is why I've never had to try to connect dissimilar plastics: They do fit ABS-size pipes, but I must say I'm now wondering whether I've been abusing them in making them do so (note 40(1.5") and 50mm(2") sizes of adapter are also available):

BES.co.uk | Next Day Delivery On 15,000 + Plumbing Supplies

Order strap bosses and other solvent weld fittings online at BES.co.uk. Low Prices, Free Next Day Delivery Available, 15k Plus Products in stock. P/N: 24978.

www.bes.co.uk

BES.co.uk | Next Day Delivery On 15,000 + Plumbing Supplies

Soil Pipes & Fittings / Boss Adaptor - Order Gas and Plumbing Supplies online at BES.co.uk. Low Prices, Free Next Day Delivery Available, 15k Plus Products in stock P/N: 11191

www.bes.co.uk

PS Are you sure your ABS pipe is 38OD? I'd have been expecting 36...

 

[danielson]

The trouble with information on 'quite a few sites' is sometimes people copy and paste what they read on other sites. You'd have done do far better to post on THIS forum and ask specifically 'Can I solvent weld an ABS waste pipe into a U-PVC fitting?' as I suspect it's your title that means you aren't getting many hits. But don't... because it's already there under a different title and the conclusion was that while you can probably get away with it on a low-pressure application such as drainage, it's not good practice.

So you've come on a plumbing forum and taught ME something! Thank you.

Going back to your problem, you are right to be cautious about diameters. I get fed up with them and it's basically easier to think in terms of 1.25", 1.5", and 2" sizes, and be aware that push-fit (PP) is smaller size (and I try to avoid it anyway).

I'd suggest the ring seal is a push fit system and strictly for PP push-fit pipe, not ABS.

The mechanical fit is a compression fitting and should be fine with either kind of pipe. Probably a good idea in that there is something to be said for being able to remove things if need be, as it can be very hard to get the alinement precise with solvent weld and having at least one place you can tweak can be useful. You can't get much better than McAlpine so I'd say it's a good solution also as that kind of boss clamps onto the soil stack without solvent weld, which you may find easier anyway.

Myself, I tend to use the system below which provides a rubber fitting, thus avoiding a solvent weld joint and which is why I've never had to try to connect dissimilar plastics: They do fit ABS-size pipes, but I must say I'm now wondering whether I've been abusing them in making them do so (note 40(1.5") and 50mm(2") sizes of adapter are also available):

BES.co.uk | Next Day Delivery On 15,000 + Plumbing Supplies

Order strap bosses and other solvent weld fittings online at BES.co.uk. Low Prices, Free Next Day Delivery Available, 15k Plus Products in stock. P/N: 24978.

www.bes.co.uk

BES.co.uk | Next Day Delivery On 15,000 + Plumbing Supplies

Soil Pipes & Fittings / Boss Adaptor - Order Gas and Plumbing Supplies online at BES.co.uk. Low Prices, Free Next Day Delivery Available, 15k Plus Products in stock P/N: 11191

www.bes.co.uk

PS Are you sure your ABS pipe is 38OD? I'd have been expecting 36...

Yeah your right I could have worded my title a little bit better - either way I wont be risking it and will stick to the same materials if I need to solvent weld.

The McAlpine boss that I have found looks good as on their main website under the features it states 'Universal connection for pushfit or solvent weld waste pipe' which is perfect as you can connect your ABS size pipe in the connection and then solvent weld any more subsequent joins you may have. That way as you say you dont have everything solvent welded up and forced yourself into a corner for any further adjustment!

Thanks for the links - the boss looks similar to mine and the seal looks like a good alternative to the solvent option. I have solvent welded a few times but I am a little bit wary with doing it on the boss connection as worried it could be a weak point for potential leaks especially if I have never done one before!

The ABS pipe I have purchased is 36mm outer diameter but I was getting the numbers mixed up as my house actually has polypipe ABS which (WS11W), annoyingly, is 38mm and means I cannot connect it up to the more easily available floplast pipe.

 

[Ric2013]

The other advantage of the McAlpine fitting is that, unlike a weld-on boss that 'needs' gap-filling cement (not the normal brush-on type as used for other joints) to be installed properly, the McAlpine fitting doesn't need adhesive at all.

 

[danielson]

The other advantage of the McAlpine fitting is that, unlike a weld-on boss that 'needs' gap-filling cement (not the normal brush-on type as used for other joints) to be installed properly, the McAlpine fitting doesn't need adhesive at all.

Is the gap filling cement still solvent based though? Would you recommend a specific one for this. Seen polypipe do one but its about £20! Saw on a review the Mcalpine one that the rubber seal didn't last long !

 

[Ric2013]

Yes, it is solvent, and it is weirdly expensive. I have fitted bosses with the normal stuff: I suspect many people do. But after installing a boss and having a leak that I had to solve, this came up in conversation with my former plumbing teacher (who is more experineced than me), and I was told the proper way to do it was with the gap filling version. I haven't actually fitted any bosses since this conversation, so haven't tried it myself, just saying it is the correct product.

GFC is expensive when you are only buying it for one joint, which was one reason I suggested the mechanical boss might suit you better.

Yeah, that's interesting about the McAlpine one and the odd bad review they seem to get. A lot of plumbers on here seem to rate them highly. I haven't personally tried them, but I can't imagine they are generally unreliable. From looking at the reviews on Screwfix and watching a couple of videos online, I can only imagine that the product fits some soil pipes better than others or that people are either not quite following instructions correctly, not deburring the hole, leaving a load of swarf where it needs to be clean, or that they simply had a faulty product.

 

[danielson]

Yes, it is solvent, and it is weirdly expensive. I have fitted bosses with the normal stuff: I suspect many people do. But after installing a boss and having a leak that I had to solve, this came up in conversation with my former plumbing teacher (who is more experineced than me), and I was told the proper way to do it was with the gap filling version. I haven't actually fitted any bosses since this conversation, so haven't tried it myself, just saying it is the correct product.

GFC is expensive when you are only buying it for one joint, which was one reason I suggested the mechanical boss might suit you better.

Yeah, that's interesting about the McAlpine one and the odd bad review they seem to get. A lot of plumbers on here seem to rate them highly. I haven't personally tried them, but I can't imagine they are generally unreliable. From looking at the reviews on Screwfix and watching a couple of videos online, I can only imagine that the product fits some soil pipes better than others or that people are either not quite following instructions correctly, not deburring the hole, leaving a load of swarf where it needs to be clean, or that they simply had a faulty product.

Yes I think the McAlpine is the way to go and like everything there are always going to be some poor reviews.

I am pretty OCD with DIY plumbing as I am well aware of the consequences if its not done right!

Will have one last look into the GFC and weigh up weather me applying GFC is going to be more reliable in the future over using the McAlpine one. If I prep the surfaces well the application method is no different to using solvent cement?

thanks for your help

 

[Ben-gee]

My suggestion if using strap boss is solvent weld boss and the rubber bung type inserts- these give you the play/deformation that will save the boss connection if the pipe is hit and aid alignment of wastes.
Never used gap filling cement, unnecessary in my opinion, best to get a strap that “does up” around the back of 4”; be it ratchet teeth or preferably nut/bolt.

 

[ShaunCorbs]

Same I’ve never used gap cement but I do glue both surfaces eg the pipe and the boss

 

[danielson]

I have a

My suggestion if using strap boss is solvent weld boss and the rubber bung type inserts- these give you the play/deformation that will save the boss connection if the pipe is hit and aid alignment of wastes.
Never used gap filling cement, unnecessary in my opinion, best to get a strap that “does up” around the back of 4”; be it ratchet teeth or preferably nut/bolt.

Yeah I have seen a few videos now and they suggested doing both the surfaces and a bit of the strap.

I will have a look into the rubber bungs for the boss then as I definatly want some flexibility with the basin waste! Do you use the rubber bung then ABS waste for the rest for welding other joints further along the run?

 

[ShaunCorbs]

I use pollypipe boss and boss to 11/4 don’t like the rubber joints as I feel they could leak later on as there only pushed in

 

[danielson]

I use pollypipe boss and boss to 11/4 don’t like the rubber joints as I feel they could leak later on as there only pushed in

The 1 1/4 boss you use do you then solder your waste pipe into that or have a boss adapter that is compression fitting onto the waste pipe if that makes sense?!

 

[ShaunCorbs]

Solvent weld the boss to the reducer

then solvent weld the boss to the stack leave an hour normally

then solvent weld the pipe into the adapter

 

[danielson]

Solvent weld the boss to the reducer

then solvent weld the boss to the stack leave an hour normally

then solvent weld the pipe into the adapter

Ok thanks

 

[Ric2013]

Solvent weld the boss to the reducer

then solvent weld the boss to the stack leave an hour normally

then solvent weld the pipe into the adapter

Does that mean you have solvent welded ABS to PVC at some point along the run (unless you run all your pipework in M-PVC)?

 

[WC1]

Isn't 21.5 overflow pvc? - often welded to abs via the purpose made reducer

 

[Ric2013]

Isn't 21.5 overflow pvc? - often welded to abs via the purpose made reducer

Yes, I think it is. I'm sure we often weld ABS to PVC but it's technically wrong, it would seem, so the OP doesn't want to do it.

I suppose if a manufacturer will specify that a fitting is to be used for that specific purpose of welding dissimilar plastics, that's another matter entirely.

 

[WC1]

Standard weld looks fine for both.

 

[ShaunCorbs]

Does that mean you have solvent welded ABS to PVC at some point along the run (unless you run all your pipework in M-PVC)?

tbh it’s a possibility as I don’t look at what city’s give me in regards to boss and adapter

 

[Ric2013]

tbh it’s a possibility as I don’t look at what city’s give me in regards to boss and adapter

Then it seems to be that while solvent welding ABS to PVC may be 'wrong', it seems to work

 

[danielson]

Then it seems to be that while solvent welding ABS to PVC may be 'wrong', it seems to work

I went to city and they gave me the boss and adapter but went back today to get the push fit equivalent adapter to see what that is like. I had a go on some scrap 4 inch on drilling the hole for the boss adapter as I had a spare 57mm hole cutter in the garage but I think may actually be a 55mm hole required for the hole itself. I have a picture of the hole below not sure if I am going to benefit much by drilling a smaller hole as I would hope the solvent cement (gap filler is on order today GFC100) would do the job....

Its interesting to know what you do in the trade regarding the PVC to ABS solvent weld and seems like many do it that way with no issues. If there were big issues with it I would imagine it would be strictly not advised as a disclaimer on instructions for items. Now for me to decide weather I use the push fit one in the picture below or the solvent adapter I have.

I haven't bothered deburring this hole I cut as it was just to see the fitment.

 

[WC1]

If the op tries a mech boss next time - no glue needed !

https://www.NoLinkingToThis/p/mcalp...Np9X0DD44RjMyiKDktBoCTskQAvD_BwE&gclsrc=aw.ds

 

[danielson]

If the op tries a mech boss next time - no glue needed !

https://www.NoLinkingToThis/p/mcalp...Np9X0DD44RjMyiKDktBoCTskQAvD_BwE&gclsrc=aw.ds

To be honest by the time I faff around finding a smaller hole saw I may as well buy the McAlpine one and send the solvent cement back.

I really like the idea of being able to compress both either ABS or PVC pipe to the connector on the boss so you can then solder further along he connection.

 

[WC1]

Looking back on page 1 I can see that you already considered it. Mech boss is genuinely very good kit.