Help me build an aluminium racing toboggan....
Discussion
maser_spyder said:
My attempts at welding haven't been a total disaster. I know it's not the tidiest weld, but I've had about 4 hours practice in my entire life, so cut me some slack!
If that's the result of four hours of practice then I am deeply impressed. I thought that welding aluminium was meant to be very difficult?Bravo, sir. What model of welder did you buy?
Oli.
zcacogp said:
maser_spyder said:
My attempts at welding haven't been a total disaster. I know it's not the tidiest weld, but I've had about 4 hours practice in my entire life, so cut me some slack!
If that's the result of four hours of practice then I am deeply impressed. I thought that welding aluminium was meant to be very difficult?Bravo, sir. What model of welder did you buy?
Oli.
I think it's called a Cobel, WSE200, 200A AC/DC tig welder. Basically a cheap, basic, pedal operated welder.
You should see my practice bits though, they really are quite funny!
Actually, it's not that hard if you have a bit of a background in soldering. You heat both parts of the metal, and feed in the filler rod, which 'fills' the gap.
In fact, I reckon anybody could do this ^^^ in a few hours, but hats off to the guys that can 'lay dimes' and get all the ripples looking right, which is way, way beyond my talents, and very hard indeed.
In one of the youtube videos I watched, a guy referred to 'time under the helmet', which makes sense to me. The more you practice, the better you get. It's a steep initial learning curve, which shallows after a few hours. It's fairly quick to get a 'basic' weld (as seen above!), it's the tidy stuff that's very hard to get right.
Happy for any input, if anybody has any suggestions!
Just a little update for anybody listening.
Materials didn't ship in time to arrive for the weekend, so no major progress, apart from adding the bracing on the front and rear struts. I was just going to do the rear, and let the main front brace take the strain, but for the extra weight it was going to cost (about 150g), it was worth adding a small front cross brace.
So that all done, it's now very firm, you can jump up and down on the spring section with no distortion in the runners. Just a bit of flex, which is what I needed all along. Ive also drilled the holes for the suspension unit and test fitted, which is all good so far.
And I've run out of gas!
maybe too much practice.... Will pick up a bottle tomorrow.
So, having done all of this by Saturday afternoon, I spent the evening working out the seat. I've made the bending jig for the rear part, which is similar to the one for the runners, the other front bends I'm going to do on the hop, and line it up by eye. There's seven bends to go in the front section, one at the rear, and three on each side to make it ergonomic and prevent your legs getting bruised, the three each side are the ones to line up by eye, which will be interesting!
So, I narrowed the seat down to;
1) Cordura - used for motorbike clothing and other heavy duty stuff. Stitched seam and strung from the seat frame. Cheap and flexible, but potentially uncomfortable if it sags.
2) GRP - cheap and solid, and less likely to hurt myself if any of my welding gives way!
3) Carbon fibre - relatively expensive, but strong, and would look good....
So in the end, I went for none of these. I found Kevlar to be just a little bit cheaper than CF for the cloth, so bought just enough to do a three layer lay-up.
Now, I've never made a plug or mould before, so it's a new one for me. I've bought some rather clever plasticine stuff that you melt in a pot, cover your plug, and it makes a nice solid mould good for up to ten pieces. Then melt it again, and start over. How good is that? So I need to make the metal part of the seat first, then make a wooden plug that's the same size and shape as the seat, cover it in mould stuff, then use epoxy resin and Kevlar cloth to get a nice, solid seat.
I plan to use machine screws to bolt it to the seat frame.
So materials have been purchased for that, once again, I've bought far too much, and probably have enough to make half a dozen seats!
Still, if my welding is anything to go by, I'll use it all just making one good one...
So, the question people are probably thinking, is why the heck are you doing this? Well, it's simple. I have a job where I have a lot of responsibility. I'm the crux of quite a few different hinges, and things tend to only happen if I make them happen. I love it, and wouldn't do anything else, but sometimes, you just have to let the inner child in you have some fun, and do something a bit different. I also love learning new skills, and find learning in general very fulfilling. I also seldom get chance to do anything practical, even though I find it very fulfilling. There's really nothing better than looking at something you've made, however shoddy, and knowing that you made it all happen! So far, I've learnt about aluminium cutting and shaping, welding, jig making, general fabricating, and in the next few days, I'll be making my first composite fabrication. Superb.
I heartily recommend doing stuff like this, it's been years since I actually made anything, and it's been great fun all along.
Pics to follow!
Materials didn't ship in time to arrive for the weekend, so no major progress, apart from adding the bracing on the front and rear struts. I was just going to do the rear, and let the main front brace take the strain, but for the extra weight it was going to cost (about 150g), it was worth adding a small front cross brace.
So that all done, it's now very firm, you can jump up and down on the spring section with no distortion in the runners. Just a bit of flex, which is what I needed all along. Ive also drilled the holes for the suspension unit and test fitted, which is all good so far.
And I've run out of gas!
maybe too much practice.... Will pick up a bottle tomorrow.So, having done all of this by Saturday afternoon, I spent the evening working out the seat. I've made the bending jig for the rear part, which is similar to the one for the runners, the other front bends I'm going to do on the hop, and line it up by eye. There's seven bends to go in the front section, one at the rear, and three on each side to make it ergonomic and prevent your legs getting bruised, the three each side are the ones to line up by eye, which will be interesting!
So, I narrowed the seat down to;
1) Cordura - used for motorbike clothing and other heavy duty stuff. Stitched seam and strung from the seat frame. Cheap and flexible, but potentially uncomfortable if it sags.
2) GRP - cheap and solid, and less likely to hurt myself if any of my welding gives way!
3) Carbon fibre - relatively expensive, but strong, and would look good....
So in the end, I went for none of these. I found Kevlar to be just a little bit cheaper than CF for the cloth, so bought just enough to do a three layer lay-up.
Now, I've never made a plug or mould before, so it's a new one for me. I've bought some rather clever plasticine stuff that you melt in a pot, cover your plug, and it makes a nice solid mould good for up to ten pieces. Then melt it again, and start over. How good is that? So I need to make the metal part of the seat first, then make a wooden plug that's the same size and shape as the seat, cover it in mould stuff, then use epoxy resin and Kevlar cloth to get a nice, solid seat.
I plan to use machine screws to bolt it to the seat frame.
So materials have been purchased for that, once again, I've bought far too much, and probably have enough to make half a dozen seats!
Still, if my welding is anything to go by, I'll use it all just making one good one...
So, the question people are probably thinking, is why the heck are you doing this? Well, it's simple. I have a job where I have a lot of responsibility. I'm the crux of quite a few different hinges, and things tend to only happen if I make them happen. I love it, and wouldn't do anything else, but sometimes, you just have to let the inner child in you have some fun, and do something a bit different. I also love learning new skills, and find learning in general very fulfilling. I also seldom get chance to do anything practical, even though I find it very fulfilling. There's really nothing better than looking at something you've made, however shoddy, and knowing that you made it all happen! So far, I've learnt about aluminium cutting and shaping, welding, jig making, general fabricating, and in the next few days, I'll be making my first composite fabrication. Superb.
I heartily recommend doing stuff like this, it's been years since I actually made anything, and it's been great fun all along.
Pics to follow!
maser_spyder said:
My attempts at welding haven't been a total disaster. I know it's not the tidiest weld, but I've had about 4 hours practice in my entire life, so cut me some slack!
As you probably know - everything must be 100% clean. If you touch tip onto the job and it goes all black you need to stop, clean it up and start again.
Get yourself a STAINLESS STEEL mini wire brush. Clean all work up before starting even if it looks clean!.
Finally that round tube in that photo looks like its been coated or anodised - if it has, you need to clean it back to bare ally.
eliot said:
maser_spyder said:
My attempts at welding haven't been a total disaster. I know it's not the tidiest weld, but I've had about 4 hours practice in my entire life, so cut me some slack!
As you probably know - everything must be 100% clean. If you touch tip onto the job and it goes all black you need to stop, clean it up and start again.
Get yourself a STAINLESS STEEL mini wire brush. Clean all work up before starting even if it looks clean!.
Finally that round tube in that photo looks like its been coated or anodised - if it has, you need to clean it back to bare ally.
I had sort of worked this out for myself (the hard way!), but cheers for the tip, it's noted for the next lot!
I've actually got quite a lot quicker at the welding bit now, what was taking me a few minutes to do previously, I can now do in 30 seconds or so. In, heat, filler rod, out. It's all practice.
Just waiting for the materials to arrive, then I'll get cracking again tonight!
Just some piccy updates....
The jig to bend the seat;
A nearly finished bottom half, with the suspension unit bolted in place. This is waiting for the materials to arrive at the weekend, couldn't do any more.
Test fit of the front 'hinge' bar. The middle tube is a solid aluminium rod, but it's quite heavy, and I might change it for tube instead. At the moment, it'll slide in and out, so still easy to change over.
Front bars welded on.
And the pretty much finished bottom half;
So, I managed to bend the rear part of the seat section, but there was no way I was bending the front bits as well, it's just too thick material. So I went for cutting slits and welding them up. To be honest, I'm not over-pleased with the seat. It might look better with the kevlar top on, but if I get chance, I might attempt another one made of 1" thick tube instead of square section. It should bend a lot easier, and be equally as strong. It's functional, but I'm not 100% proud of it.
The front of the seat will be welded to another of the large tube sections, fitted to the middle part of the front bar.
I also have to weld some supports on the seat, and put the cross member on the seat for the suspension mount. I ran out of 'noisy' time tonight (it's a bit rude to be cutting and grinding at gone 9pm), but will crack on again tomorrow.
I've also been investigating runners, and have had a change of plan from the stainless steel ones I was going to get. I managed to find a supplier that can cut me strips of UHMWPE (Ultra High Molecular Weight Polyethylene), which is much lighter than stainless, and slipperier than a politician. Not desperately expensive either. It's the same material they make the bases for skis from, so is repairable, and they'll be replaceable too, just in case I wreck them!
With a bit of luck, more updates tomorrow....
The jig to bend the seat;
A nearly finished bottom half, with the suspension unit bolted in place. This is waiting for the materials to arrive at the weekend, couldn't do any more.
Test fit of the front 'hinge' bar. The middle tube is a solid aluminium rod, but it's quite heavy, and I might change it for tube instead. At the moment, it'll slide in and out, so still easy to change over.
Front bars welded on.
And the pretty much finished bottom half;
So, I managed to bend the rear part of the seat section, but there was no way I was bending the front bits as well, it's just too thick material. So I went for cutting slits and welding them up. To be honest, I'm not over-pleased with the seat. It might look better with the kevlar top on, but if I get chance, I might attempt another one made of 1" thick tube instead of square section. It should bend a lot easier, and be equally as strong. It's functional, but I'm not 100% proud of it.
The front of the seat will be welded to another of the large tube sections, fitted to the middle part of the front bar.
I also have to weld some supports on the seat, and put the cross member on the seat for the suspension mount. I ran out of 'noisy' time tonight (it's a bit rude to be cutting and grinding at gone 9pm), but will crack on again tomorrow.
I've also been investigating runners, and have had a change of plan from the stainless steel ones I was going to get. I managed to find a supplier that can cut me strips of UHMWPE (Ultra High Molecular Weight Polyethylene), which is much lighter than stainless, and slipperier than a politician. Not desperately expensive either. It's the same material they make the bases for skis from, so is repairable, and they'll be replaceable too, just in case I wreck them!
With a bit of luck, more updates tomorrow....
Looks very very good
Just a quick amateur hour question, but do you steer it the same way as a plastic sledge down your local snow covered hill? (i.e. by leaning and transferring weight?) Though quite a few of the car sledge designs I have seen recently have had a movable single ski.
Just a quick amateur hour question, but do you steer it the same way as a plastic sledge down your local snow covered hill? (i.e. by leaning and transferring weight?) Though quite a few of the car sledge designs I have seen recently have had a movable single ski.
WorAl said:
Bill said:
I'm genuinely impressed. Obviously I'll laugh my tits off when you get a spring suppository 
if you're really lucky I'll post up a pic of the POS I knocked up last winter 
Ahhh go ahn go ahn go ahn if you're really lucky I'll post up a pic of the POS I knocked up last winter ETA:
Edited by Bill on Tuesday 16th November 11:52
Right, time for another update.
Materials having arrived, and noisy time allowed again, I pressed on to cutting the centre tube section to size, and welding on the seat;
Then adding the cross member that secures the suspension to the seat. I'll add some triangular supports to this, just to add a bit of extra strength, but ran out of time last night.
The whole thing, flipped over to finish the welding;
I then cut and welded the curved parts to the seat. Again, these will have some supports welded in tonight/tomorrow, just to add a little more strength. These prevent the back of the seat from bending. The force on the back of the seat travels through the curved tube, down to the front of the seat section, and in turn, helps the runners to lift left/right and aide turning. They look pretty funky too.
So, a couple of support and strengthening bits aside, that's pretty much the frame finished.
The one thing I'm not 100% happy with is the square section seat. Looking at it again, I would have preferred a tubular section to make it more curvy.
Because of the way it's made, I can actually remove the top half in seconds, so I could fabricate a completely new one to replace it. At the moment, I just want to get it finished, but I may well fettle and improve later.
There's about 10cm of travel at the rear of the seat where your arse will be, which is plenty to take out the worst of the bumps.
I forgot to mention, one of the other reasons for making a suspension toboggan, is that I fractured my spine a few years ago (T11, T12 and L1), and jolting it doesn't do it much good!
The materials to make the kevlar (or maybe carbon fibre) seat have just arrived, so I'll be getting on with the last few bits, and making the 'plug' for the seat tonight.
More updates to follow!
Materials having arrived, and noisy time allowed again, I pressed on to cutting the centre tube section to size, and welding on the seat;
Then adding the cross member that secures the suspension to the seat. I'll add some triangular supports to this, just to add a bit of extra strength, but ran out of time last night.
The whole thing, flipped over to finish the welding;
I then cut and welded the curved parts to the seat. Again, these will have some supports welded in tonight/tomorrow, just to add a little more strength. These prevent the back of the seat from bending. The force on the back of the seat travels through the curved tube, down to the front of the seat section, and in turn, helps the runners to lift left/right and aide turning. They look pretty funky too.
So, a couple of support and strengthening bits aside, that's pretty much the frame finished.
The one thing I'm not 100% happy with is the square section seat. Looking at it again, I would have preferred a tubular section to make it more curvy.
Because of the way it's made, I can actually remove the top half in seconds, so I could fabricate a completely new one to replace it. At the moment, I just want to get it finished, but I may well fettle and improve later.
There's about 10cm of travel at the rear of the seat where your arse will be, which is plenty to take out the worst of the bumps.
I forgot to mention, one of the other reasons for making a suspension toboggan, is that I fractured my spine a few years ago (T11, T12 and L1), and jolting it doesn't do it much good!
The materials to make the kevlar (or maybe carbon fibre) seat have just arrived, so I'll be getting on with the last few bits, and making the 'plug' for the seat tonight.
More updates to follow!
RacingPete said:
Looks very very good
Just a quick amateur hour question, but do you steer it the same way as a plastic sledge down your local snow covered hill? (i.e. by leaning and transferring weight?) Though quite a few of the car sledge designs I have seen recently have had a movable single ski.
Pete, yes, basically.Just a quick amateur hour question, but do you steer it the same way as a plastic sledge down your local snow covered hill? (i.e. by leaning and transferring weight?) Though quite a few of the car sledge designs I have seen recently have had a movable single ski.
There are three ways of turning, and you can use a combination of the three to get a good turn.
1) Push your foot on the outside runner to push it down. The inside runner lifts up, and changes the shape of the runners against the slope, so makes a turn.
2) Get your inside foot dug in the snow. Slows one side of the sled, to makes a turn. Down-side, it throws snow in your face!
3) Lean right back (more speed) and drag your inside hand behind you. Works in the same way as digging your foot in, but no snow in the face.
A mixture of all three gives you a good, clean turn.
The speed comes from leaning right back, lifting the front of the sled, and creating as little friction as possible with the snow, so a 'luge' type of sled is probably fastest on a flat surface. However, most of the toboggan runs where we're going are not perfectly flat, hence the suspension!
Beyond Rational said:
Amazing build. How is the budget looking at this stage?
Ummm. Not too bad.
OK, it's bad.
£400 on welding gear and consumables, which is the brunt of it.
£150 on aluminium so far, but I've got enough left over to make at least another two toboggans (some of the bits you only use a short length of a long piece).
About £30 on carbon fibre and moulding gear to make the seat, although this could be used to make an infinite number of them.
Breaking it down, I've used to make one sled;
£11 - 1 x 1 1/2" x 1" length for the bottom runners
£7 - 1" x 1" length for the seat frame
£10 - 2 x 3/4" length tube for the bottom rods and curved seat bits
£3 - 1 1/4" tube for the hinge
£2 - 1" tube for the hinge
£5 - suspension unit
£4 - Stainless bolts, nuts, etc.
£12 - Carbon fibre and epoxy to make the seat
left to spend - about £10 for the PE material to make the ultra slippy runners.
Makes a total spend, including welding rods and paint, of about £70.
Price to buy a 'professional' one is about £400, although the 'proper' one has a much nicer seat, and is far better welded than mine!
top effort!Constructive criticism though?
Once you start bumping your way down hill the load on that first weld after the curve on the seat will be considerable. The weld is sited parallel to the likely point point of flexion in the curved load bearers you've welded on. Although it would spoil the aesthetics a bit I would be tempted to weld a length of tube between the seat (just aft of the first weld) and the load rail to prevent it flexing under load. Just a thought
911motorsport said:
top effort!Constructive criticism though?
Once you start bumping your way down hill the load on that first weld after the curve on the seat will be considerable. The weld is sited parallel to the likely point point of flexion in the curved load bearers you've welded on. Although it would spoil the aesthetics a bit I would be tempted to weld a length of tube between the seat (just aft of the first weld) and the load rail to prevent it flexing under load. Just a thought
The seat will be fitted over the top and machine-screwed on to the frame, which will add a bit of strength, but not much.
Duly noted, I've got a bit of material that'll pad it out a bit so will use that. I might even put a cross-piece to brace it as well.
That particular point is where the small struts for the load bearers will be (once I get around to it), which should add a little strength, but again, not much.
I intended to bend that bit, rather than cut and weld it, but the material was just too strong to do it well.
Criticism more than welcome!
OK, time for another update from the weekend.
Not much I could do, other than the final bits, welding in the support sections, and plodding on with the seat (which I'm waiting to dry back).
So, the seat plug, at the very first stage....
The base in primer, at last.
And the top section, with the new support bars in place.
The new bracing should spread a bit of the force of the suspension unit in to the rest of the frame.....
I love paint. Hides all manner of sins (and shoddy welding).
Went for gloss black, sleek....
Just some decals to make and fit, then lacquer to finish it off, and that's the frame finished.
Watch this space for the seat!
Not much I could do, other than the final bits, welding in the support sections, and plodding on with the seat (which I'm waiting to dry back).
So, the seat plug, at the very first stage....
The base in primer, at last.
And the top section, with the new support bars in place.
The new bracing should spread a bit of the force of the suspension unit in to the rest of the frame.....
I love paint. Hides all manner of sins (and shoddy welding).
Went for gloss black, sleek....
Just some decals to make and fit, then lacquer to finish it off, and that's the frame finished.
Watch this space for the seat!
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