Hey guys.
I’ve searched high and low all over the web for mig or tig welding Al plate to cast Al. No joy. So this forum is one of my last resorts.
The Task:
Fabricate a high-speed, relatively low-tension winch spool from a cast aluminum scooter wheel and 0.25” thick Al plate sides.
The unit will be used as a stationary winch for ground-launching hang gliders and ultralight sailplanes. The tow-line spool must fit within the confines of the scooter’s trailing arms (a direct substitution for the wheel / tire). The donor scooter is a Yamaha Majesty 400cc scooter, and it’s engine and drivetrain, electronics, cooling system, etc, will be exhumed from the chassis and installed within a purpose-built steel frame. Tow line will be Samson 7/64” Dyneema line of 6400 ft in length. Calculations indicate that this line will easily fit within a spool of 5” inches internal width with an inner diameter of 13” (tire seating diameter) and an outer diameter of 22”, with an inch of radius to spare, wound on with zero tension.
Lines speeds that will be generated by this scooter winch will be normally 20-25 mph @ a max of 300 lbf tension while towing, and 60-70 mph @ ~200 lbf tension while reeling in line after glider release.
The spool’s side plates must withstand much bending moment created by the many layers of high-tension, low surface friction (slippery) line. How much bending moment is hard to calculate due to very scarce literature available on it’s larger cousins. Any data is mostly proprietary property of the large winch manufacturers.
Hopefully that abbreviated description fulfills your curiosity as for the project’s requirements. Here’s a vid that shows a slightly more powerful scooter winch doing it’s thing: https://www.youtube.com/watch?v=mnS_jTl-JYw
I have a well used, well tested Millermatic 251 with a Spoolmatic 30a. Though I have never used the spool gun or tried my hand at aluminum-anything, I can run nice looking, good performing welds in steel.
Others have done similar fabs for their scooter winches, but none of the garage-built winch builders are weldors, and haven’t given me solid details to ensure longevity and safety. One experienced tow pilot/instructor indicated that he used 0.25” 6061-T6 plate with lap joints to a cast Al wheel, but had a friend in the aerospace industry weld it for him (TIG).
Lap vs Butt joints:
The task that I’m needing your expertise in is to point me toward the best practices to weld aluminum plate material (side plates) onto the cast aluminum wheel rim with lap joints, or perhaps butts.
For lap joints, the two disk-shaped side plates need to be at least 0.25” thick, inside diameter is ~12.5”, outside diameter is 22”. The inside plate diameter is chosen to provide clearance for the disk brake caliper as well as ease in welding the lap joint to the rim. If using butt joints, the inside diameter of the side plates would be roughly 14.25” and be welded to the rim lips after appropriate prep, however the interior spool width would be at least 0.5” less compared to if it had lap joints.
Also, I am thinking of trimming down (reducing the max radius of) the rim lips from the wheel, as they splay out axially from the rim so that a flat plate will not lay flat across their whole surface (the intersection of outermost rim lip edge and disk plate would be only a very thin circle). Either that or grinding the exterior or building them up to create the proper, axially-flat faying surface. This is supposing that I will weld lap joints rather than butt joints. Lap joints will give me more internal spool width, and that is the goal. Is there any ideas about the strength differences between lap and butt joints for plate welded to cast?
Al Plate Series:
So Maxal has a guide that provides some good info on MIG/TIG welding Al plate (http://www.maxal.com/files/quicksite...g_6-11_doc.pdf), but little for cast.
From their guide, it would appear that 5083-H32 retains it’s strength far better than 6061-T6 (AW, no PWA). 5356 filler is suggested, and 4xxx series is firmly not suggested.
Many other sources suggest welding cast Al with 4043 or 4047, as 4047 has a lower melting point. As I understand, 5083 has a high magnesium content, and to use a low Mg-content filler is not suggested for 5xxx series base materials.
As 6061 has a lower Mg content (< 2.5%), fillers 4043 or 4047 are indicated to be ok, though the AW tensile strength would be much less than 5083, if 5083 could be welded successfully to the cast stuff. I do not know if the cast wheel / 6061 side plate weldment would warp with PWA to T4 or T6. PWA would have to be outsourced.
I have little idea as to the composition of my cast wheel, though it appears to be anodized with a clear-coat.
Preheating:
After all the normal surface prepping, should I ensure the cast wheel is fully pre-heated to avoid the inevitable weld-heat problems, and what is the recommended temperature? Is a propane heater out of the question for the very real possibility of carbon soot deposits?
I could be all wet in my reasoning, so please correct me if I am ( please support your arguments with reasoning).
This is my vid of towing on a 250cc scooter. Could only manage about 600 ft maximum altitude gain with the small engine’s lower output power and roughly 2500 ft of line to the turning block, 5000 ft of line total: https://www.youtube.com/watch?v=FWAiSDa92Wo
Yeah, this post looks like it should go into the projects forum, but since it has to do with a method not addressed previously, I thought it would be better suited in Welding Discussions. I could be wrong.
Thanks
-doug
I’ve searched high and low all over the web for mig or tig welding Al plate to cast Al. No joy. So this forum is one of my last resorts.
The Task:
Fabricate a high-speed, relatively low-tension winch spool from a cast aluminum scooter wheel and 0.25” thick Al plate sides.
The unit will be used as a stationary winch for ground-launching hang gliders and ultralight sailplanes. The tow-line spool must fit within the confines of the scooter’s trailing arms (a direct substitution for the wheel / tire). The donor scooter is a Yamaha Majesty 400cc scooter, and it’s engine and drivetrain, electronics, cooling system, etc, will be exhumed from the chassis and installed within a purpose-built steel frame. Tow line will be Samson 7/64” Dyneema line of 6400 ft in length. Calculations indicate that this line will easily fit within a spool of 5” inches internal width with an inner diameter of 13” (tire seating diameter) and an outer diameter of 22”, with an inch of radius to spare, wound on with zero tension.
Lines speeds that will be generated by this scooter winch will be normally 20-25 mph @ a max of 300 lbf tension while towing, and 60-70 mph @ ~200 lbf tension while reeling in line after glider release.
The spool’s side plates must withstand much bending moment created by the many layers of high-tension, low surface friction (slippery) line. How much bending moment is hard to calculate due to very scarce literature available on it’s larger cousins. Any data is mostly proprietary property of the large winch manufacturers.
Hopefully that abbreviated description fulfills your curiosity as for the project’s requirements. Here’s a vid that shows a slightly more powerful scooter winch doing it’s thing: https://www.youtube.com/watch?v=mnS_jTl-JYw
I have a well used, well tested Millermatic 251 with a Spoolmatic 30a. Though I have never used the spool gun or tried my hand at aluminum-anything, I can run nice looking, good performing welds in steel.
Others have done similar fabs for their scooter winches, but none of the garage-built winch builders are weldors, and haven’t given me solid details to ensure longevity and safety. One experienced tow pilot/instructor indicated that he used 0.25” 6061-T6 plate with lap joints to a cast Al wheel, but had a friend in the aerospace industry weld it for him (TIG).
Lap vs Butt joints:
The task that I’m needing your expertise in is to point me toward the best practices to weld aluminum plate material (side plates) onto the cast aluminum wheel rim with lap joints, or perhaps butts.
For lap joints, the two disk-shaped side plates need to be at least 0.25” thick, inside diameter is ~12.5”, outside diameter is 22”. The inside plate diameter is chosen to provide clearance for the disk brake caliper as well as ease in welding the lap joint to the rim. If using butt joints, the inside diameter of the side plates would be roughly 14.25” and be welded to the rim lips after appropriate prep, however the interior spool width would be at least 0.5” less compared to if it had lap joints.
Also, I am thinking of trimming down (reducing the max radius of) the rim lips from the wheel, as they splay out axially from the rim so that a flat plate will not lay flat across their whole surface (the intersection of outermost rim lip edge and disk plate would be only a very thin circle). Either that or grinding the exterior or building them up to create the proper, axially-flat faying surface. This is supposing that I will weld lap joints rather than butt joints. Lap joints will give me more internal spool width, and that is the goal. Is there any ideas about the strength differences between lap and butt joints for plate welded to cast?
Al Plate Series:
So Maxal has a guide that provides some good info on MIG/TIG welding Al plate (http://www.maxal.com/files/quicksite...g_6-11_doc.pdf), but little for cast.
From their guide, it would appear that 5083-H32 retains it’s strength far better than 6061-T6 (AW, no PWA). 5356 filler is suggested, and 4xxx series is firmly not suggested.
Many other sources suggest welding cast Al with 4043 or 4047, as 4047 has a lower melting point. As I understand, 5083 has a high magnesium content, and to use a low Mg-content filler is not suggested for 5xxx series base materials.
As 6061 has a lower Mg content (< 2.5%), fillers 4043 or 4047 are indicated to be ok, though the AW tensile strength would be much less than 5083, if 5083 could be welded successfully to the cast stuff. I do not know if the cast wheel / 6061 side plate weldment would warp with PWA to T4 or T6. PWA would have to be outsourced.
I have little idea as to the composition of my cast wheel, though it appears to be anodized with a clear-coat.
Preheating:
After all the normal surface prepping, should I ensure the cast wheel is fully pre-heated to avoid the inevitable weld-heat problems, and what is the recommended temperature? Is a propane heater out of the question for the very real possibility of carbon soot deposits?
I could be all wet in my reasoning, so please correct me if I am ( please support your arguments with reasoning).
This is my vid of towing on a 250cc scooter. Could only manage about 600 ft maximum altitude gain with the small engine’s lower output power and roughly 2500 ft of line to the turning block, 5000 ft of line total: https://www.youtube.com/watch?v=FWAiSDa92Wo
Yeah, this post looks like it should go into the projects forum, but since it has to do with a method not addressed previously, I thought it would be better suited in Welding Discussions. I could be wrong.
Thanks
-doug
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