Sand bending 101 old school meets modern tech.

[NASTYZEN]

I recently had a customer send me some Alu. tubing to bend up as waterlines for a Migal race car. Problem was it was 30 mm dia odx 26 id. Darn I have only Imperial sizes for my mandrel bender.
Time for sand bending.Old school at least my take on how it's done. This method works on steel tubing as well.
Step one, use 6061 T-4 Aluminum tubing for this to work. It is softer than T-6 and can be bent.
step two, plug one end of the tube.

step three,fill with silica quarts sand tapping the tube between each cup of sand to pre compact a little, be careful not to dent it ,T-4 is soft..I like medium grit sandblast sand the best.

Step four,
Once filled insert a loose fitting plug into the tube. I like to have a champher in the plug to keep the threaded rod centered.

Step five weld a threaded plug on the end of the tube.

Step six, compact sand by screwing in threaded rod till tight,then bounce on floor a couple times tighten a little more and so on till it's really tight.
Now were ready for bending.
I have plenty of material so I'm going to try a test. Instead of using heat like the traditional way,I'm going to try a bend in my home made mandrel bender,cold!

How daring!

The tube set up in the bender. I found 1 1/4 in. was just over 30 mm.

Ok bend!








DoooH!

Didn't get very far.

 

[theoldwizard1]

With the sand compacted that hard, I'm not surprised.

I am curious as to what your solution will be !

 

[charle10]

We bend smaller soft copper like that at work (cooling lines for induction heaters), with a few differences. We tape one end, fill it with coarse sand, then tape the other end, then bend. My understanding is that the sand just keeps the tube from collapsing at the bend, it will deform a little but won't collapse.

No pictures of the Doh!? Did your hydraulics not have enough ooompf or did the pipe split? What does the bend look like without the sand in it, did it deform to much for your liking?

 

[MP&C]

Red grease? (or did your fingers get in the way?)

 

[4Tigers]

I have bent some tight corners on aluminum fuel lines What I use is steel cable coated with plastic, You can buy this at the better hardware stores The cable I have is clear plastic coated very flexible
I than use tube benders or wooden two piece fixtures made with a router for very tight curves I.E. the front to center carburetor on Pontiac Tripower

lube with WD-40 so it pulls out easy

 

[NASTYZEN]

With the sand compacted that hard, I'm not surprised.

The sand being compacted is the key to sand bending.
Some of the time, cold bending in the bender actually works.From one batch of material to another you never know??That's why I tried the easy way first.

No pictures of the Doh!? Did your hydraulics not have enough ooompf or did the pipe split? What does the bend look like without the sand in it, did it deform to much for your liking?

Hmm. I can see them?wtf?

Red grease? (or did your fingers get in the way?)

LOL!Yeah, workmans comp. would get a gas out of my contraption!
I use chain saw bar oil. Works great and it's cheap.

I have bent some tight corners on aluminum fuel lines What I use is steel cable coated with plastic, You can buy this at the better hardware stores The cable I have is clear plastic coated very flexible
I than use tube benders or wooden two piece fixtures made with a router for very tight curves I.E. the front to center carburetor on Pontiac Tripower

lube with WD-40 so it pulls out easy

That's a good Idea. I saw them fill up tubes with water and then frozen on HOW it's Made for trumpet parts. that could be another option.There's so many ways to do things.

OK. Sand bending with heat.
Iv'e often done this free hand by clamping it in the vise and bending without using a die or template. Seeing it's Alu. I went with a die to minimize the kinking on the inside radius.
Once set up, a little pre heat is in order. It's as if your tube was now a full bar. Heat transfer takes a little longer and has to be progressive. If you use ordinary sand you will find that it melts into glass at this point and can even explode! Use Silica Quarts sand blasting sand! Or be prepared for explosive pipe bending.

Anchoring one end and starting the bend.

You have to heat from a distance and keep moving. All the while applying steady pressure on the tube.

Le bend

Second bend

A little beading with a home made tube beader to keep the hoses from popping off.

Le job done.

 

[bobadame]

Very nice work. Can you show details of the beader?

 

[NASTYZEN]

Very nice work. Can you show details of the beader?

Thank's , here you go

 

[bobadame]

Now that is extremely sweet. Thanks for taking the time to show it.

 

[mike13u]

Good stuff. Thanks for shareing.

 

[srmofo]

Ive seen some guys pop dents out of headers by freezing them. They just bolt a piece of steel onto the flanges and fill with water. The hard part is convincing the wife you need to put your header into the freezer overnight.

 

[skiingman]

That beadroller is wicked cool. Can you explain the purpose of the thumbwheel on the male die end? I'm staring at it and not understanding, clearly the bigger female die is dynamic, but what is going on at that end?

Thank you. Very cool tools you've made.

edit: is it a depth stop?

 

[EVOLVO]

I'm wondering if you pre-annealed the tubing before packing it with sand maybe you wouldn't have to heat it as you bend it.

OT, ever had anyone tell you to "go pack sand"? I always wondered what it meant

 

[srmofo]

I'm wondering if you pre-annealed the tubing before packing it with sand maybe you wouldn't have to heat it to bend it.

OT, ever had anyone tell you to "go pack sand"? I always wondered what it meant

It started out as "go pound sand" ...back in the day they use to fill rat holes with sand and they had to pound it down into them. It was considered a job for morons so when someone told you to pound sand, they meant you were a *****.

 

[EVOLVO]

Pound Sand, that was it. Another damn senior moment! Thanks for the explanation.

 

[NASTYZEN]

Thank you, guys for the kind words. If it can help someone out one day then I shall be happy!
Never heard that go pound sand expression before?See all the neat things you learn on GJ!

Skingman,your right, that thumb screw is for the depth gauge. I will eventually extend the inner mandrel shaft and add a handle for twisting. It tends to not turn very well and I can't get the bead as deep as I would like before it starts to wrinkle or fold the tube.

Evolo, The material is T-4 instead of T-6. That means it's already annealed or softer. I have had T-6 annealed by the heat treater guy before. But the problem is that you have to get it hardened again after your done playing with it. It stays really soft like 3003 alloy. Whereas the T-4 will get back up to T-6 in time and retains it's properties.

 

[Okie Pete]

Thanks for sharing .

 

[NASTYZEN]

Sand bending DOM 1 3/4 x .125 tubing.

I can make large dia. bends with my mandrel bender. But on the smaller 3.0''rad. the tube tends to break, so...........sandbending it is.

The quarts sand. finer is better than coarse.



The sand compressing setup. Weld a cap at the other end. Fill. Weld the setup at the other end



compressing:
I compress with the air gun until it wont turn any more, then bounce the tube on a large metal plate until it gets loose and repeat the cycle until I can bounce it off the plate about 10 times before it coming loose again.



I like to clamp my table to my forklift for this part.
It's important to heat all around evenly and giving the heat a chance to soak in the metal and sand. Cherry red, not white with sparks coming out of it......
Rush it and the results will be poor







Done.



Where it went.

 

[KPSquared]

so, I've always been under the impression that using heat to bend for a cage was a huge no no. . .is that not the case? Something about weakened metal?

 

[ptschram]

so, I've always been under the impression that using heat to bend for a cage was a huge no no. . .is that not the case? Something about weakened metal?

While I don't know about the wisdom or lack thereof W/R/T the heating, why bother? I just clamp it in the bender and open the air valve and let 'er rip until it's bent to where I wanted it.

 

[racingtadpole]

I love the way you casually slip the "At this point I like to clamp my table to my forklift" step in there

 

[A_Pmech]

Another trick to file away...

 

[geologist]

Does your top tube say "Made in India"?

 

[racingtadpole]

Does your top tube say "Made in India"?

Its all good, its made with Australian Iron ore

 

[NASTYZEN]

so, I've always been under the impression that using heat to bend for a cage was a huge no no. . .is that not the case? Something about weakened metal?

Ever since 4130 Cro-moly has become popular and people started welding it with stick or mig and heating it and quenching with water n stuff. There has been a problem.
That's why many say you don't heat cage tube.
Not every one has the knowledge or the skill set to do it 'old caveman way'
I was taught this method of bending tube by my mentor and between the both of us. We must of bent dozen's and dozen's of projects this way.
Just about every rally cage I built has been used, some several times over the season....they certainly try,but so far they have failed to break one of my cages. Some guys even cut them out of there old car to put in there new one.

While I don't know about the wisdom or lack thereof W/R/T the heating, why bother? I just clamp it in the bender and open the air valve and let 'er rip until it's bent to where I wanted it.

I hear you.
As I mentioned before, I have problems making a tight radius on my machine. Other wise I wouldn't spend an hour making 2 bends.
How tight of a bend can you make on your machine with 1 3/4'' x .125 DOM tube?
I get to about40deg. on my mandrel bender with a 6.0'' Rad and the tube often cracks or pops! Can't put that in a car and sleep at night.

I love the way you casually slip the "At this point I like to clamp my table to my forklift" step in there

Well, actually, I sandwiched the table between a 20000lbs plate and the lift.
Took less time.

Another trick to file away...

I know, not for everyone.But viable when properly executed.

Does your top tube say "Made in India"?

Scary isn't it!
I sure did a double take on it when I saw the made in India by barefoot children written on it.
I have only seen tubing from Sharron Tube and Bethany steel from Pennsylvania before this. Few hours drive away.
How can it possibly be more economical to send ore from Australia to India then halfway round the planet to Canada?

 

[geologist]

How can it possibly be more economical to send ore from Australia to India then halfway round the planet to Canada?

Well, ArcelorMittal (just think Mittal) used junk bonds and shady accounting to buy up global steel interests. Meanwhile, they run the price up at certain mills by foregoing modernization and maintenance so they can justify closing them.

All the while they've got the Carnegie stranglehold on raw material, thanks to collusion and complex vertical integration.

That bailout would have been better spent buying out Mittal, breaking it up, and helping out the surviving steel mills here in the states.

To put it into perspective:

Iron ore is trading just shy of $150 per ton.

What if I were to tell you that the one of the largest iron ore deposit in the world is located in Canada, with high-grade reserves estimated to equal up to 4 billion tons with proven reserves of over 800 million tons. That would make the ore itself worth around $600 billion ($150 per ton*4 billion tons) at the high end, and ArcelorMittal just acquired a 70% of it for a little less than $400 million.

http://www.investingdaily.com/11182/the-largest-iron-ore-deposit-in-the-world

 

[CarterKraft]

How tight of a bend can you make on your machine with 1 3/4'' x .125 DOM tube?
I get to about40deg. on my mandrel bender with a 6.0'' Rad and the tube often cracks or pops! Can't put that in a car and sleep at night.

With my JD2 model 32 I can do 180* bends in 1 3/4x.120 wall at 5.5 CLR
1 3/4" is a common 4x4 tube size and is ALLOT of peoples first die, the 5.5 " CLR is very common and will have zero issues tearing etc at that radius. Are you talking a 3" CLR or actual 6" CLR your bender should do that no problem at 6". I wonder if your folower is grabbing the material?

 

[xtremek]

I want to make a custom queen size head and foot board for the bed using 1" steel tubing. I've got a HF hydraulic tubing bender. My question is, should I use the sand packing method and will I need to heat the tubing? These will be large radius curves (roughly 15" or better). This article was great. Glad I read it, I was going to use play sand.

 

[Provincial]

I built a set of stair railings with a HF hydraulic bender. I used 1-1/4" black iron pipe, bent it cold, and did not fill it with sand. All the bends show some flattening, and the larger the angle, the more they flattened. They turned out well enough for my purpose, but I would not say that they are acceptable for any structural work.

The other problem with the HF bender is that the dies are sand cast and have serious imperfections. If you don't want to press dimples in your tube, you will have to get out the sandpaper and some wooden dowel the right diameter to polish the working surface of the dies.

 

[NASTYZEN]

My question is, should I use the sand packing method and will I need to heat the tubing? These will be large radius curves (roughly 15" or better). This article was great. Glad I read it, I was going to use play sand.

No heat needed, I would think on such a large dia. bend.
If your tubing wall is thin, sand should keep it from flatenig or deforming to much.
If you have extra tubing you might want to make a test bend first to see how your tubing reacts. I often make all my layouts with the test bend anyway. So as to figure where to grab the tube so the bend ends up where I need it to.
Play sand will work fine if no heat is used. Make sure it's nice and dry.

 

[NASTYZEN]

I wonder if your folower is grabbing the material?

I think that may be my problem. The Folower is mounted static. I need to mod it with bearings to have the folower move with the tube.