Sheet metal bending

[smiles79]

I'm trying to start doing some of my own fabrication. What are you all using to bend sheet metal? I'd like something that doesn't brake (heh) the bank. Does anyone have some info for me?

 

[fredintoon]

I'm trying to start doing some of my own fabrication. What are you all using to bend sheet metal? I'd like something that doesn't brake (heh) the bank. Does anyone have some info for me?

Hi smiles,
what I've done is to clamp the sheet metal between two lengths of steel square tube and whack the panel over with a big wooden mallet.
Note that square tube has rounded edges that'll leave a curve in the bend and you can't bend the work piece sharper than a right angle.
Sharper curves can be made by using the toe of a length of angle iron instead of one of the square tubes.
Best you angle-grind a radius on the angle-iron's toe to remove the sharp edge that may start a crack in the fold you are making.
Annealing the work piece is good.
Anneal sheet steel by heating to cherry red along the fold lines and let it air cool.
Anneal aluminum by heating along the fold lines until a sliver of wood leaves a black trail on it. Again, let it air cool and note
that some aluminum alloys re-harden themselves after annealing in less than a day.

 

[Ratranger]

Depends on what your goals are. If you are staying fairly thin and want sharp bends and small brake from harborfreight can get you started. If you want gentle curves, cheapest would be a bag and a hammer, higher priced would be an english wheel. Then there are shrinker and stretchers

 

[smiles79]

I saw the harbor freight ones, but didn't think 18 ga max would be stiff enough for some things. Thoughts?

 

[halfmile]

I don`t recommend this but I actually saw a guy bend a very thin piece of aluminium by placing the fold line on the inner edge of a metal door and closing it to achieve the desired bend. It made a nice straight even bend. I`ve had a HF 36" brake for several years and it works great on 16 gauge and thinner. If I had it to do over again I would spend the extra money and buy a adjustable box brake.

 

[weaselbeak]

I made my own brake. Just look at some images, and use slightly heavier steel. If you can fab anything, you can make one of these. I can bend fairly heavy stuff up to 40 " long, just over 90*, I'd say around 110* as I've never actually measured that. I don't have a picture, but there are lots of them out there.

 

[MaxPete]

and note
that some aluminum alloys re-harden themselves after annealing in less than a day.

....which means that once you anneal aluminium, you have to "get on with the job" fairly soon (within an hour or two would be best). If you diddle around thinking about it for a day or two, the workpiece will have hardened again, and you'll likely crack it if you try to bend it.

The other thing is that aluminium does NOT change colour when you heat it - so don't look for any cherry red glow or anything like that. If you heat it enough, it will simply melt into a pretty silvery puddle.

The "wood test" described above by Fred is really the only way to know if the workpiece is hot enough. That also points out a downside of working with aluminium - is looks the same hot as it does cold and so there is a risk of a very serious burn if you are not paying attention to what you doing.

 

[kshansen]

That also points out a downside of working with aluminium - is looks the same hot as it does cold and so there is a risk of a very serious burn if you are not paying attention to what you doing.

I knew that all along but it came back to me fast one day.

I stopped by the local shop that does starter and alternator repairs and there was this guy TIG welding up the bores of a batch of alternator housing so they could rebore them for the drive end bearings. Like dummy I decided to take a look at one he had done! Did not take long to figure out it was time to put it back down!

 

[upthemaiden]

I have one of the 30" brakes from Harbor Freight. I bought it when I needed to make some brackets for something and the hammer/vise method wasn't working out. I actually used it to bend some 1/8th stainless steel(somewhere between 10-11ga I think according to this random chart I found in google images...), about 4-5" wide. Thicker than it said it bend, 17ga steel max, the bends weren't quite as sharp as something thinner would have, but it worked out well. I wouldn't buy it with a plan to bend metal that thick on a regular basis, but on random occasions it can definitely bend more than it says. A lot of good ideas online for ways to strengthen them up a bit too. A good investment for what I paid for it. I'd love to have something bigger and stronger, but this one lays nice and flat and clamps/bolts to your work bench, so it's a much better option for storage if you don't have a dedicated shop with somewhere to store all of these bigger tools.

 

[smiles79]

For anyone that may come across this in the future:

I ended up buying a 20-ton Harbor Freight hydraulic shop press, and the 20-ton press brake kit from Swag Offroad. The press is normally $179.99, I ended up getting 25% off and got it for just over $140. The press brake kit costs $169.99 (shipping included), and needs to be welded together. You can buy a fully assembled kit for somewhere around $269.99. This kit is supposed to be able to bend a max thickness of 3/8" steel. Can't wait to use it!