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Solvent Welding Course Recommended For ALL

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Unread postAuthor: MrCrowley » Wed Oct 29, 2008 1:05 pm

john bunsenburner wrote:I think it is irresponsible to say such a thing at a so ridiculessly easy test... What is if i dont use pvc? Will you still not take me seriously?

In fact, I wont even take you seriously on here until you can prove to me that you passed this thing.


First of all, another member said that, not me. That member is a moderator but has a buisness to run along with many jobs and school too, so hardly frequents the forum anymore.

I also believe he is not being entirely serious, obviously if a good solvent-welding job can be seen on one of your cannons you'll be fine in his books. It was more or less a tactic to get as many people as possible to take the test.

Yes it is easy. I've discussed this in the above post. Solvent welding is very easy when you know what you are doing. IT IS SUPPOSED TO BE. It's hard to make a test about solvent welding hard, when the solvent welding is easy.

You really only need to learn a few basic facts and rules to know how to solvent weld. Such as the 'twist turn' as you push the PVC pipe and/or fittings together.

Also I don't see how the quote you posted is 'irresponsible'.

How easy the test is has nothing to do with anything, it teaches you how to solvent weld and that's what matters.

What's your problem?

If you're not using PVC in a cannon, then this test obviosuly doesn't apply to you, does it?


The test will be easy for some and hard for others. It depends how much you already know or have learnt. I found my trigonomics test quite easy, did some of my friends also find it easy? No. Because I had studied and they hadn't.


Until you can tell me exactly why you think this test is irresponsible, it'd be great if you stopped kicking up this dead topic for no reason. Don't tell me the test is 'too easy' either, because that's bullsh|t. It has nothing to do with anything and I have no idea why you think it does and why you think everything is irresponsible.

Use some common sense.
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Unread postAuthor: Ragnarok » Wed Oct 29, 2008 1:49 pm

MrCrowley wrote:I also believe he is not being entirely serious, obviously if a good solvent-welding job can be seen on one of your cannons you'll be fine in his books. It was more or less a tactic to get as many people as possible to take the test.

I would also like to say that it's over 2 years old, and judging by some of the forum archives, poor solvent welding was a much more rife activity then, so it was more appropriate for it's time.

Yeah, we do have the odd rant at someone who's made their cannon with superglue, but that's not all that common any more...

...usually they go n00b, ask before they try and we rant at them then instead!!! :D
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Unread postAuthor: john bunsenburner » Wed Oct 29, 2008 2:10 pm

OK iv never had a piece of pvc pipe in my hand and passed the test in 10mins...it took longer to subscribe...something must be wrong dont you think?

maybe i have not expressed my self clearly: all im saying it is irresponsible to judje the seriosity of a person on these forums by the completion of this test!
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Unread postAuthor: Ragnarok » Wed Oct 29, 2008 2:29 pm

john bunsenburner wrote:maybe i have not expressed my self clearly

Sgort was joking - people do that sort of thing. :roll:

We don't judge seniority by passing tests - if there is any such thing on these forums, which there usually isn't*, it's based on actual knowledge and intelligent posting.

*That said, there is sometimes a veteran/intermediate/newbie progression, usually judged by each individual member.
There are also the "forum experts" who's time and posts can sway a discussion, because the forum veterans (and intermediates as well, usually) respect their experience.

Trust me, getting to that rank is not defined by any kind of test, just consistently accurate knowledge.
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Unread postAuthor: jrrdw » Wed Oct 29, 2008 2:31 pm

all im saying it is irresponsible to judje the seriosity of a person on these forums by the completion of this test!


It at the very least means you have applied yourself to learn something.

They still haven't sent me anything, I sapose Ipex doesn't take locksmiths seriously when it comes to solvent welding.
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Unread postAuthor: iisthemuffin » Wed Oct 29, 2008 2:52 pm

john bunsenburner wrote:OK iv never had a piece of pvc pipe in my hand and passed the test in 10mins...it took longer to subscribe...something must be wrong dont you think?

maybe i have not expressed my self clearly: all im saying it is irresponsible to judje the seriosity of a person on these forums by the completion of this test!


I suposse ill pipe in here. If not to prove point, for entertainment.

Solvent welding is pretty straight forward. Clean your pipes. Apply primer. Apply Cement. Push pipe into fitting while turning at 90 degrees. Its that easy. Give or take a few things. Its not entirely complicated.

And people have told you he was kidding but you continue to talk about him being irresponsible. It was a joke so let it go.

You obviously understand the concept and im sure just aobut eveyone else does too. And if they dont they will politely be corrected and guided ont here way. I find it irresponsible to kick up a topic that is 2 years old just to make a comment that doesnt have any intelligence or use behind it.
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Unread postAuthor: IMagius » Wed Feb 03, 2010 4:31 am

First Thread I read ... Figured I had to start somewhere and why not make sure I wasn't wrong in my assumptions of how to cement two pieces together.

That course was easy enough for me. Passed :lol:
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Unread postAuthor: Selador » Thu Dec 02, 2010 2:38 am

iisthemuffin wrote:Solvent welding is pretty straight forward. Clean your pipes. Apply primer. Apply Cement. Push pipe into fitting while turning at 90 degrees. Its that easy. Give or take a few things. Its not entirely complicated.



First of all, the links in the OP no longer work.

~~~

You make no mention of sanding the connections before priming and glueing.

I have also seen it said on this forum, at least a couple times, that sanding is not necessary.

This concerns me enough, that I decided I should say something about it.

Strictly speaking, maybe people have been getting by with this. But I would never solvent weld, without sanding first.

I worked in construction for more than 26 years. Some of those years I was even a general contractor.

If you ever came onto my jobsite, and solvent welded PVC pipes, without sanding them first, you'd be run off the jobsite, and never be welcome again.

It may not be 'strictly necessary', but it makes a better weld. One that you can be more sure of, than without sanding.

If you don't use enough primer or glue, and/or do not use them correctly, you can have a failure. But I have seen failures in connections where it was obvious that enough glue and primer was used, but the connection wasn't sanded first.

This happened often enough, and builders had to pay for enough re-plumb jobs, that it became standard practice to sand first. And I was not the only one who would have kicked you to the curb if you didn't sand first.

They make a brush especially for the job. (Roughs up the inside of fittings, and the outside of pipes.) If you are not going to sand, then at least use the brush. (I'm thinking that they probably wouldn't bother making the brush, if it wasn't a pretty good idea to use it.)
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Unread postAuthor: MrCrowley » Thu Dec 02, 2010 2:50 am

I have to say I take the word of the manufacturers, after all, they'll be the ones left with a law suit on their hands. If sanding the joints made a significant difference in weld strength, why wouldn't they include it in their solvent welding guides?

Last I checked, both Oatey and IPEX don't mention sanding joints before solvent welding.

By the way, looks like the new course guide is located under "training" on their website.
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Unread postAuthor: Selador » Thu Dec 02, 2010 4:14 am

MrCrowley wrote:I have to say I take the word of the manufacturers, after all, they'll be the ones left with a law suit on their hands. If sanding the joints made a significant difference in weld strength, why wouldn't they include it in their solvent welding guides?

Last I checked, both Oatey and IPEX don't mention sanding joints before solvent welding.

By the way, looks like the new course guide is located under "training" on their website.


I took the course, and passed 100%

If you are going to "take the word of the manufacturer", then you should not be using PVC or CPVc to make airguns, at all.

This was stated in the instructions part of the 'course'. And was the subject of a question, both in the quiz, and in the final test...

IPEX solvent cements must never be used in PVC or CPVC systems using, or being tested with compressed air or gasses. These materials are not designed to convey compressed gases.

On a better note... Can you imagine the spudgun you could make with this ?
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Unread postAuthor: MrCrowley » Thu Dec 02, 2010 4:24 am

Your comparison has a bad case of apples and oranges, regardless, the only reason I ignore that warning from the manufacturer is because it only exists due to the failure characteristics of PVC. Using compressed air instead of water doesn't make a difference until the PVC fails. If the pipe is rated for 260PSI it doesn't matter if you're using water or compressed air, so my, and most others, reasoning is that the pipe has no reason to fail if used correctly so the warning can be ignored.

I'm using PVC less and less these days though, I just hate that feeling that it could fail at any moment even though it is unlikely to do so. Like pneumatics, PVC has very limited potential :D
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Unread postAuthor: jrrdw » Thu Dec 02, 2010 7:48 am

Link in original post updated.
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Unread postAuthor: Technician1002 » Thu Dec 02, 2010 10:04 am

On sanding or not sanding, in some studies I have done, it boils down to the penetration the glue joint has into the PVC. The failures are due to a lack of surface penetration. There are 2 causes for that. Not enough primer, or not enough time for the primer to penetrate the surface of the pipe. Let's cover the two items in detail. Understanding how something works goes a long way in understanding the failures.

Sanding is a fix for the Symptom of another problem. Poor penetration of the primer. Excess sanding removes material and you guessed it, weakens the joint due to poor penetration due to low pressure in the assembled joint. The sanding if you do it should be a light sanding to score the surface of the pipe for the solvents to penetrate, not remove the outside layer.

The primer is highly volatile. This means it evaporates quickly. In hot weather or windy conditions this is much faster resulting in poor penetration. The proper solution is to apply primer for a longer duration, eg second application to keep the joint wet long enough for the primer to work. To see how this works, apply primer to a pipe about 5 times in a row and then try to scratch it off the surface with your fingernail. You will find the surface is very soft. Apply glue and the joint will be solid with good penetration.

The other cause of poor penetration is related to gluing problems. The surface layer of primer MUST fully penetrate the pipe and fitting before applying the glue so the application of glue does not remove the primer. If your glue brush is purple, you are gluing too soon. Slow down and let the primer be absorbed fully into the surface of the PVC. Don't wait for it to fully dry back out of the PVC either. You want to glue while the surface is softened by the primer.

Properly glued joints are very reliable. Any employer that would kick an employee to the curb for making proper joints is an employer that does not understand fully what they are doing and may simply rely on industry short cuts to get the job done. Sanding is faster, does a decent job, so it's practice can get a decent job done quickly.

In windy, excessively cold or hot locations, I prime at least twice.

Ask if the employer has had any joints cut apart and the penetration measured in a cross sectional analysis. A scientific measurement of the joint tells the truth.

I am trained to use one of these. I doubt the kick to the curb employer has considered measuring joint penetration.
http://www.used-line.com/c6631692s0-Hitachi_S_4700.htm
Unless your employer does failure analysis, I doubt he has access to one.

All journeyman level plumbers should understand the basics of how solvent based primer works, not just the apprentice level of just to it this way. Do you want Journeyman level work or just apprentice level work?
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Unread postAuthor: Selador » Thu Dec 02, 2010 3:58 pm

Good reply.

Good points, and well made. (Well enough to convince, -me- anyway. LOL)

One last factor... The building inspector.

In my last decade or so of work, if the inspector didn't find evidence of both primer and sanding, they would fail the job.

If one were knowledgeable and energetic enough, (and didn't have too much to lose on a particular job), they could probably challenge the inspector with studies, cutaways, etc...

But even if you are 100% right, you'd still only stand a 5 to 25% chance of convincing the inspector themself, let alone the entire department.

When something like that becomes so established in the 'system', you end up failing plumbing inspections.

Failing plumbing inspections and having to re-plumb is very costly.

Ergo, you begin getting rid of employees who refuse to do the job in the accepted way.
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Unread postAuthor: Technician1002 » Thu Dec 02, 2010 4:21 pm

Well put.. In any job, you do what is required to meet the building code and pass the inspections.

Often the inspector will challenge a builder to see if the builder is qualified. As a case in point, I had to change an electrical panel in a house. The new panel has a master breaker on top. This meant the remaining breakers were lower in the panel. To get the wires to reach the breakers, some had to be extended.

The inspector asked be about the splices, and I quoted the appropriate section of the National Electrical Code to him. The panel passed on the first try except I didn't add a second ground rod outside as required by the code revision.

Knowing the code and being able to prove knowledge of it and showing your work is up to code goes a long way in an inspection. If I didn't know the code, I doubt he would have passed the installation, but required an electrician to go over it in detail. Inspectors have seen many botched home jobs to be wary of them. Learn the code for your area. The inspector can't make his own rules. Be able to quote any proper portion of the code to support your work and you will be fine if your work meets code.

If the code does not require sanding, the inspector can't require it.
Knowing the code can prevent an inspector from flunking the job.

Edit;
If it is a large job, submit your joints and sanded joints to a certified national testing laboratory. Showing for example a 2 inch solvent welded joint parts at 2550 lbs and a sanded joint parts at 2435 lbs goes a long way to supporting your work. The inspector will have to justify his position. Feel free to properly challenge an inspector's finding. Most of the time he can quote the code violation, so most of the time he is right.
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Last edited by Technician1002 on Thu Dec 02, 2010 4:59 pm, edited 1 time in total.
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