Fastening PVC

[Pat]

I have installed PVC pipe many times over the past decades and know how to apply the glue. However, the project I am working on right now is a little different. I am using black 1.25" "furniture grade" PVC from formufit.com to build a frame for a large awning.

I have built what I want but have not glued it together yet. Due to the tight fit, it almost stays together well enough without any glue. The thought of pulling each joint apart, glueing it, and then putting it back together scares me. I realized I have no idea how long it takes the glue to set up. For water pipe, I clean it, apply the glue, push it together and then leave it alone for a few hours. But, for this project, how long do I have to rotate joints before the glue is set? 10 seconds? a minute? 10 minutes? I have no idea.

So I have two questions:

1. How long do I have after applying the glue to work with the joints before the glue sets? (if it is a very short time, is there slower glue available?)

1. Are there other ways to assemble PVC? For example, would a single self-tapping screw at each joint work? (Remember, this pipe will not be pressurized). With a screw, I would also be able to disassemble the frame later for storage or to make modifications.

Thanks for your ideas, Pat

[trader_4]

Not very long. The glue starts to set up right away, gets more difficult to move in maybe 30 secs and it's probably not very movable at one minute. Couple mins, forget about it.

If there is a slower glue, I've looked for it before and never found it. I too thought it would be a good idea for some projects.

A screw probably wouldn't be as strong, would be more prone to cracking there, etc., but it might work. Other problem is that with the glue, the glue actually melts the plastic, some of it essentially becomes fluid, so that the joint can be fully seated. With the joint dry, it's very hard to get it to fully seat. Even if you put some lube on it, I think it still may be hard to get it to come together all the way, keep it there while you drill a hole.

[micky]

How could it matter? Just push the pipe into the connector. Takes 4 seconds. By the time you get to the next joint, the first will be firm enough not to get messed up. If perchance one would come apart, you could use a knife or sandpaper to remove the glue before trying again. Once you get all the joints connected, let it sit for an hour, although I think 5 minutes is enough. Especially since it doesn't have to be water-tight.

Sure, why not?

I think you should plan now where you expect to take it apart for storage.

[trader_4]

It matters when you have several fittings where they essentially have to be done at the same time to assemble it. If the first one sets up before you get to the last one, there won't be a last one.

If perchance one would come apart,

Good luck with that.

[micky]

Very unlikely to be a problem on a large awning.

Well, it's not going to happen anyhow.

[trader_4]

Maybe so, but we don't know how exactly it has to come together. All I know is that he says he has a lot of experience with working with PVC and he's looking for glue that will give him more working time. Having to assemble several critical joints essentially all at once is the only time I've ever wished that there was a glue with a slower cure time. So, I've been there and giving him the benefit of the doubt. It sounds to me like maybe he doesn't want to assemble one corner, then find out it needs to be moved a bit when he gets to the next corner to make it line up, etc. If that isn't the problem, then the question makes no sense.

.> >

Good thing, eh?

[dadiOH]

Sure a small screw works just fine. Lots of PVC furniture has been done that way.

[Pat]

Exactly. That is the problem. It was hard to get it all together with no glue due to some smaller pieces forming squares. Unlike water pipes, everything has to line up.

Thanks to all for your responses. I think I will go with screws. The appearance won't be quite as nice, but the joints will be mostly covered by the awning material anyway. And, the awning material will help hold the frame together.

Thanks, Pat

[gfretwell]

The slower glue is the "heavy duty" usually sold in big cans (Oatey has a black label) It is really made for big pipe where you take longer to get the glue applied and putting them together may be slower. It is still pretty fast if you want to move it around.

One tip for the OP is to use blue painter tape at the end of the joint so he can peel the tape off, taking the excess glue with it. Just don't wait to do it. It will leave a clean glue line.

[Dean Hoffman]

Would heating the connectors then compressing them work? Heat gun then apply pressure with a hose clamp? I'm thinking of the clamp with the screw for tightening. Remove the clamp as you go.

[Jerry.Tan]

You only glue one at a time. Put a pencil mark on the pipe and fitting so you know EXACTLY where the pipe and fitting should be (do the pencil mark when it's dry fit). You mentioned BLACK pipe, so if you cant see a pencil mark, I'd probably use some whiteout.

[trader_4]

The point is that in some cases, you can't glue one at a time, because once one is done, you can no longer do the other. They have to go on at the same time. Imagine having two pipes emerging from a wall six inches apart, they stick out 2". You need to connect the two using a piece of PVC and two elbows. The only way to do that is to do both ends at the same time. That's the kind of situation the OP is dealing with. There are plenty where it's worse, pool eqpt pads are where it happens frequently. You may have 3 fittings that need to go together at the same time.

Also, dry fitting is problematic. The pipe and fittings are not made to go together when dry. You can get the pipe part way in, but getting it in fully without glue is nearly impossible. I have used the marking technique occasionally, to mark the angle the fitting and pipe need to align at. But marking doesn't solve the issue the OP is having.

[Pat]

Trader, You have been explaining my issues better than I have. Thank you. Regarding the following paragraph, dry fitting has not been a problem for this project. A light tap with a rubber mallet has worked well. Pat

[micky]

I would be glad to use a light tap with a rubber mallet, but I can't tell where Trader is!

[trader_4]

Do you even realize that the fittings he's tapping together are special ones designed for PVC furniture and not the typical water ones? Think that may make a difference? For the problem with dry fitting PVC plumbing fittings:

But then you think that a fitting that you glued up and it went wrong can be salvaged by cleaning it up with a knife or sandpaper..... Nuff said.

[TimR]

Or a coupling.

[trader_4]

You mean a union? Not clear that solves the problem either. If you glue up two separate halves of a union, without the union being together, you may not get the two halves to be perfectly square with each other. When you glue up the second half, they may be out of alignment. And unions are a source of leaks, that are avoided unless really necessary. I sure wouldn't look at it as a solution to the simple plumbing problem presented. You just do both sides at the same time. In that example, it's easy. But there are plenty of more complicated, close quarters situations where it's not simple and a longer glue time would be a real benefit.

[TimR]

Yeah, union, couldn't think of the right word.

It might work in some cases, as PVC pipe has some flexibility. But I agree, slower glue would be a better solution.

What if you refrigerate the glue? Does that give you some time? It does with epoxy.

[trader_4]

The cure time does increase with lower temps. IDK if it would be enough to help all that much, but it might. And there is some temp below which it's not supposed to be used, ~40F I think. Other problem would be you could chill the glue and the fittings, but not the pipe in many cases. It still could be a good idea if you want to try to get some additional time, can't hurt.

[micky]

The previous line here was meant as humor.