pipe for clamps

[Bob Riefer]

Hi!
I'm re-working my clamps situation, and need some advice on pipe. I've searched an searched and read and read... not a lot of consensus out there on a seemingly simple topic.

I saw a youtube recently where the poster uses "plated electrical conduit" cut to shorter lengths and joined with couplings.

Benefits to his approach are:
- Zinc? plated surface (as opposed to hot dip galvanized) provides better "bite" for the clamp hardware
- Shorter lengths joined together allow easier storing of shorter clamps and a lot of flexibility in sizing your clamps
- electrical conduit couplings easily screw on/off (as opposed to taper thread couplings that cinch tighter the further they are threaded)


My issue is... there's a lot of pipe out there, and tough to make head's or tails of.


EMT conduit is very cheap ($5 for 10 feet) but is thin walled, bendy, and unable to be threaded. So this one is out.

Intermediate Metallic Conduit (IMC) is interesting... able to be threaded, stronger than EMT, lighter than RMC... Maybe?

Rigid Metallic Conduit (RMC), in galvanized steel, I think is what is typically used by most. When (say) Grainger talks of RMC being "galvanized" (https://www.grainger.com/search/electrical/electrical-boxes-conduit-raceways-strut/conduit-fittings-outlet-bodies-and-mountings/conduit/metallic-conduit?optOut=0&searchQuery=electrical+conduit&sst=1) are they talking about "hot dipped galvanized" (in other words, not a change from the slipping issue I have already?). My local electrical supply houses have no idea what I'm asking when I call them.

Rigid also comes in aluminum, which seems like it would be much friendlier to carry around the shop etc. But is it strong enough?



So.......... my questions recap:
- Agree that EMT is too thin to use?
- Would IMC be a candidate?
- Is galv steel RMC the typical product used?
- Is "galvanized" RMC the same thing as "hot dip galvanized"?
- Is aluminum a candidate?

[Andrew Seemann]

EMT sounds way too thin, IMC wouldn't be much better. RMC and galvanized water pipe are pretty much the same thing. Aluminum would probably be too soft and get chewed up by the steel clamp parts.

I use off the shelf black pipe. Not sure what problem is being solved here, regular pipe as worked well for decades.

A lot of hand tight couplings in your pipe is not going to be good for rigidity. You could tighten them with a wrench, but that seems be rather complicated when you want to grab a clamp, plus it dings up the pipe.

[Bob Riefer]

Not sure what problem is being solved here, regular pipe as worked well for decades.



Thanks, very helpful! lol

The original post clearly states that pipe clamp hardware can slip on hot dip galvanized pipe. Soo..... looking to solve for that.

Second issue noted is that "regular pipe" is not as easily defined as you'd think. In your case, you think "regular pipe" is black pipe which leaves black marks on wood unless you solve for that somehow else (not interested in that personally). In other's case, "regular pipe" means hot dip galvanized pipe (issue noted above again). And then there's youtube guy that mentions plated pipe as a good substitute (clamps don't slip, cheaper than hot dipped according to him, easier to add/remove couplings as compared to black pipe).

As for hand tightening couplings... I join, and have watched many others more experienced that me do the same, my existing hot dip galvanized pipes together with hand tightened couplings already... The force is almost entirely inwards (not near as much laterally) so this has worked very well. Just building on this existing concept that has been around for "decades"

edit: So... I'd still be interested in insights on my questions above please.

;)

[Bill Carey]

EMT sounds way too thin, IMC wouldn't be much better. RMC and galvanized water pipe are pretty much the same thing. Aluminum would probably be too soft and get chewed up by the steel clamp parts.

I use off the shelf black pipe. Not sure what problem is being solved here, regular pipe as worked well for decades.

A lot of hand tight couplings in your pipe is not going to be good for rigidity. You could tighten them with a wrench, but that seems be rather complicated when you want to grab a clamp, plus it dings up the pipe.


^^^agree^^^

And I have found the black pipe from Menards to be much smoother and cleaner than anywhere else.

[Jim Becker]

Off the shelf black pipe from the 'borg for me, too, for the few pipe clamps I have in my shop.

[glenn bradley]

I've read long discussions about all sorts of reasons for one thing or another. I have run galvanized pipe from the BORG for nearly 20 years without issue. I'd read that black pipe stains, galvo can too but to a much lesser degree. I put bits of tape at the joints when gluing up panels so I don't have to clean off the pipes so the whole black versus galvo discussion became moot after the fact :). I bought 10' sticks. The BORG would cut once and thread the resulting ends for free so I had them cut at about 3'. I picked up a few couplers and have been able to do anything that I might use pipe clamps for ever since.

[Wes Grass]

Black iron gas pipe. I bought pieces roughly twice as long as I wanted and sawed them in half, so I wouldn't be snagging my hands on sharp pipe threads.

If that isn't good enough, you can get stainless steel. A 10' 3/4" is only about $150 ;-)

[Brian Bumpers]

FWIW in my area, plumbing supply companies sell the pipe at half the price of big box stores. I just picked up 6 20’ pieces for about $1 per foot. I cut to desired length, thread and I’m good to go.

[Prashun Patel]

Sorry I can't help with specific working properties of the pipes you mention.

I use black gas pipe.

For my use, having a bunch of 30" and 48" pipes gets me through most of my needs. 30"'s are not so long that they are cumbersome on smaller glue ups. Coupling them does introduce a slight bend, but it's not been too much of an issue, and worth the trade-off for not having to keep 72" pipe around for the random wide glue ups I might do once a year.

I appreciate the staining issue. I have a bunch of 5mm shims (Dominos, actually) that are used as standoffs. Even with non-marking pipe, the pipes can dent your surface.

[Andrew Seemann]

My black pipe was probably from Menards or Home Depot or both. Standard schedule 40 black/gas pipe. I have access to a pipe threader, so for me it was easy to make whatever lengths I wanted. If I'm worried about marks from the pipe, I put poly sheeting or wax paper over the pipe or work. For laminations, I usually glue before final planing, so the planer removes any discoloration.

I've got galvanized and black pipe, in general, I prefer the black pipe, but that is probably because my galvanized pipe is old water pipe that has started to get powder (zinc oxide?) on the outside of the pipe.

One thing I found is that if you start with standard 10' pipe, cutting the pipe into lengths of 60" and 30" works better than 48" and 24" if you work with lots of 24" and 48" pieces.

[Matt Day]

As said, you’re trying to solve a problem that isn’t there. Black pipe clamps have been used for decades and decades by some of the best furniture makers in America. Buy some black pipe and get back to woodworking!

[roger wiegand]

Black iron gas pipe. No problems that I've noticed yet, It's been ~50 years.

[Lee Schierer]

I use pipe clamps exclusively. Some have black pipe and some have galvanized pipe. All but one of my clamps utilize a toothed jaw on the adjustable end to grip the pipe. I have never had one slip. I have one clamp that the adjustable end uses angled steel plates to grip the pipe. That clamp is on black pipe. It does slip sometimes even on the black pipe. I also use pipe couplings tightened by hand when I need extra long clamps. I've made clamps over 12 feet in length and none of the sections are more than four feet long with no issues.

[Darcy Warner]

Who is this "expert" on YouTube because anything other than black iron pipe is going to cost a whole lot more.
Ridgid conduit is expensive.

[Darcy Warner]

I use pipe clamps exclusively. Some have black pipe and some have galvanized pipe. All but one of my clamps utilize a toothed jaw on the adjustable end to grip the pipe. I have never had one slip. I have one clamp that the adjustable end uses angled steel plates to grip the pipe. That clamp is on black pipe. It does slip sometimes even on the black pipe. I also use pipe couplings tightened by hand when I need extra long clamps. I've made clamps over 12 feet in length and none of the sections are more than four feet long with no issues.

I have made 20 footers when I was building hardwood decks.

[BOB OLINGER]

FWIW, I use black iron pipe from Lowe's or Menards. Personally, I like pipe clamps because they're cheaper, have flexibility in changing length including option of going long, and they're strong. I have a few bar clamps of various lengths.

[Bob Riefer]

FWIW in my area, plumbing supply companies sell the pipe at half the price of big box stores. I just picked up 6 20’ pieces for about $1 per foot. I cut to desired length, thread and I’m good to go.


Good tip! I'll check there for sure. Thank you!

[Bob Riefer]

Sorry I can't help with specific working properties of the pipes you mention.

For my use, having a bunch of 30" and 48" pipes gets me through most of my needs. 30"'s are not so long that they are cumbersome on smaller glue ups. Coupling them does introduce a slight bend, but it's not been too much of an issue, and worth the trade-off for not having to keep 72" pipe around for the random wide glue ups I might do once a year.




Good point of reference, and I agree. A slight bit of bend on infrequent instances of needing to go really long is worth it compared to keeping mega-clamps around the shop.

[Bob Riefer]

One thing I found is that if you start with standard 10' pipe, cutting the pipe into lengths of 60" and 30" works better than 48" and 24" if you work with lots of 24" and 48" pieces.




Smart!! I hadn't considered what specific lengths I would want yet, but this will be part of the consideration.

[Bob Riefer]

As said, you’re trying to solve a problem that isn’t there. Black pipe clamps have been used for decades and decades by some of the best furniture makers in America. Buy some black pipe and get back to woodworking!


LOL... I'm spending plenty of time woodworking (running out of wood in fact!) and don't mind a few minutes researching how to best upgrade from old, dust (zinc oxide?) pipes that aren't working well to something better. I may very well end up with black pipes, but maybe not.

[Bob Riefer]

I have one clamp that the adjustable end uses angled steel plates to grip the pipe. That clamp is on black pipe. It does slip sometimes even on the black pipe.

I also use pipe couplings tightened by hand when I need extra long clamps. I've made clamps over 12 feet in length and none of the sections are more than four feet long with no issues.


Thanks for the confirmation that coupling is a good approach!

Interested around the angled steel plates to grip the pipe... A couple of my clamps are like this, so combined with deteriorating pipes (mine literally look "chalky" at this point) I think that's contributing to slippage. Hopefully the cheap fix (replacing pipes that are too far deteriorated) will do the trick.

[Ron Selzer]

Emt definitely would not work for this application
IMC I believe would work for you
Rigid definitely would work for you
IMC and Rigid electrical pipe come with straight cut threads and couplings.
Once you cut the conduits shorter, then the pipe die cuts tapered threads
I very rarely use my pipe clamps since getting Dubuque aluminum bar clamps, only bring them out if over 6'

Good luck
Ron

[Jeff Duncan]

Count me in for plain old black iron pipe as well. I have lengths from 2' up to 10' and that handles everything I've needed. On the odd occasion I need longer I just clamp 2 clamps to each other, no bothering with connectors or anything. Just b/c its been around for a long time doesn't mean it isn't still good, or that there's necessarily anything better;)

Having said that... to each his own. If you find something you prefer to use then thats all that matters.

good luck,
JeffD

[Andy D Jones]

I've used 3/4" black pipe for over 30 years. My grandfather used the same. In fact, I inherited some of his pipe clamps. I also have a set of Pony heads that are deeper reaching and reversible. On those, the adjustable head slides, and the foot is threaded onto the pipe end. Most of my pipe clamp heads are Pony, but I also have some Craftsman heads that have a toothed cam that doesn't grip the pipe as well as the Pony ones do.

I've started using more Dubuque Universal aluminum bar clamps though. They are much lighter and easier to handle, especially one-handed. The jaws always line up, and my hands don't get nasty when I use them. And they are still made in USA.

-- Andy - Arlington TX

[Bill Dufour]

Black pipe from the Borg. Wash it down with a rag and paint thinner. I do have some aluminum pipe. It scars easy and make sit hard to slide the moveable clamp. It raises slivers that cut your hands as you move it around. It does not stain the wood and it is much lighter. I have no idea where you could buy any. Mine came from a dumpster. I repalced it with black pipe.
Bill D

[Phillip Mitchell]

I believe you’re overthinking it. Black gas pipe or silver (galvi?) pipe works extremely well. I’ve used hundreds of pipe clamps in both of these 2 materials and only have ever had (1) slip and I think it was actually the clamp itself, not the pipe that was malfunctioning.

There are easy ways to make sure that the black from the pipe doesn’t transfer to your wood.

Like Darcy, I have clamped together 2 10 (+) footers to pull together timber frame assemblies from time to time. The fact that you can rotate / offset the screw end from the clamp and is also a huge bonus in versatility.

[Rod Wolfy]

I had a couple 8' black pipe clamps, but only used them for 1 protect. I recently went to HD and got galvi 6', then cut them in half (to 36”). They've worked great. I could always get a short coupler, if I needed to join then back together.

[Bill Dufour]

Home depot will do one cut and thread the ends for free. Not sure if it is per pipe or you have to do several single pipe purchases to get them all cut and threaded for free. I do know they will cut a ten foot pipe in two and thread both ends for free even for two pieces at the same time. No idea if there is any maximum free cuts like there is for wood.
Bil lD

[Robert Engel]

I used galvanized pipe for many, many years and yes it does gall and slip a little hit the the hammer solved it.

But I switched over to black iron pipe and it it much better. Either one will leave black stains on wood, though.

I think its good to have a few around with threaded ends and couplings so you have the length when you need it.

All mine have 54" clamping capacity with 30" extensions, or you can put two long ones together and easily clamp 8'.

[Bob Riefer]

Thanks again for the helpful replies!

(and thanks to those that are very concerned with my time spent 'over thinking', very thoughtful of you to help me watch after the 23 minutes I've spent on this so far while also watching the Michael Jordan documentary ;-) )


The net result is...

- My existing RMC (which I already have owned and used for over a decade, and grandad used for many years before that, are chalky and allow slippage) needs to be replaced.

- Consensus is that EMT is too thin, Aluminum is too soft, and IMC (while it might work) was so similar in price to RMC that I'm skipping that. This leaves RMC and black pipe.

- The supply houses around here think that there's only one type of coating on RMC (galvanized) so, I guess that takes any other possible choice out of this category. Not sure what youtube guy was talking about, or if things changed over time, because no one around here believes the same. Oh well.

- Galvanized rigid metal conduit (which I think is probably what I have already) and black pipe are commonly available... the RMC is currently cheaper than black pipe at least locally here.

- Electrical supply houses and plumbing supply were (somewhat surprisingly) both more expensive than Lowes and Home Depot (who seem to have price matched each other).


Soooo... With my curbside pickup order at Lowes this week, I'm grabbing a few fresh sticks of the stuff I already have (galv RMC) and will cut/thread at home. My existing pipes that are too far gone will be gifted to the neighborhood scrapper.

[Frank Pratt]

IMC and Rigid electrical pipe come with straight cut threads and couplings.

I've used rigid conduit for 40 years and have never seen, or cut, straight cut threads on the conduit. It's always tapered.

[Tom M King]

I keep three 20 foot lengths, with a coupling on each, for clamps up to almost 60 feet long. They find a use maybe every 10 years, in working on houses.

[Alex Zeller]

A friend owns a sprinkler business. Black pipe is about 75% of their business. What I can tell you is it may be the same but black pipe seams to come in two different black finishes. The first is a mat black color and sheds black stuff. The second looks like it's been clear coated. I don't know if he can specify which one he can get but with about 100 sticks of 3/4" in his shop at any given time it was easy to sort out the pipes with the clear coat. I had him cut and thread 5 stock length pipes into numerous sizes. Cutting and threading for him is real easy since he has a real cold cut saw and his threader uses what looks like a tap that spins around the outside edge. I offered to pay him but he said it was like $20 worth of pipe (because he buys in bulk) so I turned a large wooden bowl for him. If you need a lot of pipe for pipe clamps check with a sprinkler business. Chances are they will give you the best price around as long as they aren't busy.

[Bill Dufour]

I suppose your existing galvanized pipe could be dipped in acid to remove the zinc. Do this in a piece of pvc pipe with a cap glued on. Do it outside as it releases hydrogen gas. I would jet a hole into the ground deeper then 1/2 of the longest pipe I have and then put the pvc in the hole , add iron pipe the pour in acid to cover the pipe. It will be fun to pour out the acid and pipe into a clean bucket for reuse.
Bill D.

[Rob Luter]

I use black pipe from Menards. Pretty smooth. I use blue tape during glue ups to prevent marking the wood.

[Bruce Wrenn]

I use BIP. It's cheaper at steel distributors if you buy non pressure tested. I own both cutter and threader. Most of my pipe came from salvage yards. It was "take out" when a building was remodeled, and sprinkler system had to be rebuilt. Cheaper to do all new than to rework existing. Paid princely sum of $0.15 a pound for it Now because of insurance, you can't go into a salvage yard. Remember that if you want a 24" clamp, you need about a 30" piece of pipe. For couplers, I use rigid conduit couplers. Each pipe clamp has one on the end of exposed pipe. No damage to threads, plus no searching for a coupling when needed.

[Anuj Prateek]

Thanks, very helpful! lol

The original post clearly states that pipe clamp hardware can slip on hot dip galvanized pipe. Soo..... looking to solve for that.

Second issue noted is that "regular pipe" is not as easily defined as you'd think. In your case, you think "regular pipe" is black pipe which leaves black marks on wood unless you solve for that somehow else (not interested in that personally).

;)

I have bunch of pipe clamps and I use 3/4" black pipes sold at home depot.

- when I bought them they left black mark everywhere - wood, hand, etc. I washed them with TSP (1 large teaspoon and some in a liter of warm water) and Scotch Brite. Black marks are no more a problem.

- never had any slipping problem with them. Don't know if they will skip, if not cleaned.


Downside:

- they are heavy. I guess aluminum pipes will be lighter.