plug welding
Post Reply    Forum -> General Discussion
Author Message
Molto Verboso
1963 VBB2T
Joined: 07 Nov 2012
Posts: 1105

Sun Nov 03, 2019 10:50 am quote
I was wondering what people would use to fasten two floor surface tight to do a mig welder plug weld. For instance on my Vespa I'm replacing the floor and I will first cut and remove the floor in preparation for the new floor , now under the tunnel where the lip will need to be plug welded to the new floor what are the options or methods for keeping the two surfaces tight together?
Attached is the pic of floor to be removed completely and indication of where the plug welds will go , not exact but just to give the idea. You can see how clamps are going to be able to reach from floor edge to the lip of the tunnel. I'm no body guy and do have a couple ideas of perhaps rivetting or screws to hold but are there other options?
Thanks

floor seam.jpg

Molto Verboso
Yamaha Tricity 155 Urban 2019 - MV Agusta 125 RS 1956 - Moto Guzzi Airone 250 Sport 1951
Joined: 21 Jul 2007
Posts: 1762
Location: Latina (Italy)
Sun Nov 03, 2019 11:02 am quote
The ideal machine would be a point-to-point electric soldering iron.

Molto Verboso
1979 P150X, 1983 P200E, 1987 T5, 1996 PX200E, 2011 Yamaha Fazer 600 S2
Joined: 02 Aug 2015
Posts: 1616
Location: Veria, Greece
Sun Nov 03, 2019 11:06 am quote
You need clamps like in the following video...

https://www.youtube.com/watch?v=trG5-15i9_E
Ossessionato
Piaggio Fly 150
Joined: 10 Jan 2008
Posts: 3288
Location: Sanibel Island
Sun Nov 03, 2019 1:04 pm quote
Harbor Freight is your friend.



[url] https://www.harborfreight.com/120-volt-spot-welder-61205.html[/url]

Sorry the link doesnít work. Just look in harbor freight.
Molto Verboso
1963 VBB2T
Joined: 07 Nov 2012
Posts: 1105

Sun Nov 03, 2019 2:23 pm quote
Attila wrote:
The ideal machine would be a point-to-point electric soldering iron.

Play back didn't work but I'm thinking its the same welder like the guy uses in the youtube video SaFiS posted, I have no access to something like that but I do have a welder. I just had a thought after seeing SaFiS's youtube video with the big clams, maybe I can get a couple sets of C Clamps , cut them and add on stock to join them back together.
Molto Verboso
1963 VBB2T
Joined: 07 Nov 2012
Posts: 1105

Sun Nov 03, 2019 2:26 pm quote
Tor2ga wrote:
Harbor Freight is your friend.



[url] https://www.harborfreight.com/120-volt-spot-welder-61205.html[/url]

Sorry the link doesnít work. Just look in harbor freight.
I'm in Canada so no Harbor Freight here and exchange , shipping and customs is just not feasable, I may be able to find something like the extended C-clamps on amazon though.
Veni, Vidi, Posti
74 50s x3 78 P200 84 Cosa 58 AllState 68 Sprint 80 50special + projects
Joined: 22 Nov 2010
Posts: 7323
Location: seattle/athens
Sun Nov 03, 2019 3:23 pm quote
You really want a butt weld to be most original joining the old legshield , but it's more difficult to get right, A lap weld would be stronger and look OK if done well & blended nicely. With a good lap weld, your plug weld idea can work well and add strength. Search google & youtube on those terms & come back for more opinions. But yeah, plug welds to the frame if you ain't got a nice spot welder.
Molto Verboso
1963 VBB2T
Joined: 07 Nov 2012
Posts: 1105

Sun Nov 03, 2019 3:57 pm quote
V oodoo wrote:
You really want a butt weld to be most original joining the old legshield , but it's more difficult to get right, A lap weld would be stronger and look OK if done well & blended nicely. With a good lap weld, your plug weld idea can work well and add strength. Search google & youtube on those terms & come back for more opinions. But yeah, plug welds to the frame if you ain't got a nice spot welder.
I could never pull off a good looking lapweld from the legshield to the floor front edge, has to be a butt joint there for sure. I'm more concerned with the tunnel joining to the new floor clamping the two surfaces tight for the plug weld , if clamped tight the plug weld is the easy part. I was thinking of extending a few sets of C clamps but I think they are cast material which wouldn't work out very well. Either I have to order 4 sets off amazon or drill and screw and refill with a tack.
Veni, Vidi, Posti
74 50s x3 78 P200 84 Cosa 58 AllState 68 Sprint 80 50special + projects
Joined: 22 Nov 2010
Posts: 7323
Location: seattle/athens
Sun Nov 03, 2019 5:37 pm quote
heavy lifting
Good point, but I think you're already on to what I'd end up doing anyway, sorta. First drill all the marked holes thru the frame on both sides. Then I'd clamp or tackweld your new floor into position best I could, then drill thru every OTHER hole thru the new floor and bolt 'em tight. Just use M6 bolts for smaller hole w/ nice chamfer at the top and EZ smooth weld filling, but turn up the heat a bit and be sure you get good penetration!!!

Then plug weld the other holes you drilled only thru the frame. Now remove the bolts one by one and press a piece of copper against the bottom of each hole to plug weld from the top. Now we see how well you can do on that butt joint, it's gotta be last I think, but maybe a few tackwelds at the beginning so it stays where you want.



BTW, the pros use Cleco clamps thru 1/8" holes that pull sheet panels in nice and tight.




But this should work fine for a little plug welding.
We'll need lots of pics and maybe a kind mod can move this to the NSM side where it'll be properly vetted?
Molto Verboso
1963 VBB2T
Joined: 07 Nov 2012
Posts: 1105

Sun Nov 03, 2019 7:51 pm quote
Voodo I think that is a good idea with the nut and bolts but wouldnít doing the same with pop rivets give the same result and when the plug welding is done drill out he rivets and fill like you said with the copper backing? Those clecos are a great option but seeing as they are pulled out when job is done itís very similar to rivets. Yes the butt weld will be very last , I plan to leave the new floor longer than what is being cut out and then mould it to the the front shield down near the floor and cut the new floor closer for a hopefully nice seam to weld.
Sponsor
Granturismo 218
Joined: 04 Feb 2013
Posts: 5605
Location: South Carolina
Sun Nov 03, 2019 10:32 pm quote
I would ask someone who welds for a living how to do this. The answer you get might be a little more accurate.
Veni, Vidi, Posti
74 50s x3 78 P200 84 Cosa 58 AllState 68 Sprint 80 50special + projects
Joined: 22 Nov 2010
Posts: 7323
Location: seattle/athens
Mon Nov 04, 2019 2:32 am quote
Motovista wrote:
I would ask someone who welds Vespas for a living how to do this. The answer you get might be a little more accurate.
Yeah that's good advice, and also ppl who have done like it and lived to tell about it years later.
How would you do it if you had to?

Lynn, I'd prefer the nuts & bolts (w/ washers is best), because you can draw them tighter than most pop rivets and because you can still adjust and change stuff more easily. Make your holes tight or a bit oversize, whatever you like.

When you do the butt joint, start from the inside a little at a time working out and swap sides to allow each side to cool so it doesn't try to buckle. A little tack on the outer ends of the joint should be OK or clamp it well. Disclaimer: I've never done exactly this.
Molto Verboso
1963 VBB2T
Joined: 07 Nov 2012
Posts: 1105

Mon Nov 04, 2019 5:25 am quote
Motovista wrote:
I would ask someone who welds for a living how to do this. The answer you get might be a little more accurate.
I agree , as Voodo mentioned Clecoís may be more the way the guys that do this for a living would do it, just like a welder rigger
would also do it a bit differently.
Hooked
BV 350
Joined: 22 Nov 2016
Posts: 430
Location: Nebraska
Mon Nov 04, 2019 10:50 am quote
Maybe
Does the other side not need replacing? I'd seriously consider doing both sides, using one piece, so you could get a better-supported attachment to the tunnel. Split the current welds, drill holes for the plug welds. Might be as easy to hold the replacement panel up against the tunnel with a floor jack and some suitable lumber to keep it flat. Butt-welds where the panel joins to the front shield, spacing the welds and allowing them to cool in between (like when you weld a replacement panel to a car body), so as not to warp the panel. Grind and paint, and you'll never notice the welds.
Molto Verboso
1963 VBB2T
Joined: 07 Nov 2012
Posts: 1105

Mon Nov 04, 2019 12:38 pm quote
Jimding wrote:
Does the other side not need replacing? I'd seriously consider doing both sides, using one piece, so you could get a better-supported attachment to the tunnel. Split the current welds, drill holes for the plug welds. Might be as easy to hold the replacement panel up against the tunnel with a floor jack and some suitable lumber to keep it flat. Butt-welds where the panel joins to the front shield, spacing the welds and allowing them to cool in between (like when you weld a replacement panel to a car body), so as not to warp the panel. Grind and paint, and you'll never notice the welds.
Yes it will be both sides being replaced , an entire floor panel. Just had a thought is which do you drill the holes in for the plug weld , the new floor or the lip on the frame? Iím hoping to get the floor attached leaving excess for the leg shield butt weld and once the floor is welded to the frame Iím hoping I will get a more accurate idea of where to cut the new floor metal to butt up otherwise Iím just guessing where the seam should be. That is a good idea with the floor jack pushing up but again if I drill the new floor for the plug welds well the plug weld holes need to be facing up and the jack idea I donít think would work.
Hooked
2005 et4
Joined: 23 May 2015
Posts: 430
Location: oshawa ontario canada
Mon Nov 04, 2019 2:53 pm quote
We don't have Harbour Freight in Canada, but look around for a Princess Auto near you. It's out equivalent basically
Ossessionato
LXV 150 3v ie. Midnight Blue (Sold)
Joined: 06 Dec 2010
Posts: 2998
Location: Bangkok
Mon Nov 04, 2019 6:19 pm quote
Re: heavy lifting
V oodoo wrote:
Good point, but I think you're already on to what I'd end up doing anyway, sorta. First drill all the marked holes thru the frame on both sides. Then I'd clamp or tackweld your new floor into position best I could, then drill thru every OTHER hole thru the new floor and bolt 'em tight. Just use M6 bolts for smaller hole w/ nice chamfer at the top and EZ smooth weld filling, but turn up the heat a bit and be sure you get good penetration!!!

Then plug weld the other holes you drilled only thru the frame. Now remove the bolts one by one and press a piece of copper against the bottom of each hole to plug weld from the top. Now we see how well you can do on that butt joint, it's gotta be last I think, but maybe a few tackwelds at the beginning so it stays where you want.



BTW, the pros use Cleco clamps thru 1/8" holes that pull sheet panels in nice and tight.




But this should work fine for a little plug welding.
We'll need lots of pics and maybe a kind mod can move this to the NSM side where it'll be properly vetted?
These aircraft skin pins were my second thought my first though was pop rivets first, then fill.

But even with skin pins you would still need to fill the holes.
Hooked
BV 350
Joined: 22 Nov 2016
Posts: 430
Location: Nebraska
Thu Nov 07, 2019 12:58 am quote
I'd
Lynnb wrote:
Just had a thought is which do you drill the holes in for the plug weld , the new floor or the lip on the frame?
Simply from an access perspective, easier to drill the holes in the lip, and weld from above, unless you want to turn the whole assemply upside down to weld it. Also it preserves the integrity of the replacement floor panel against rust, with no holes drilled in it. I guess it depends on whether you think it will rust from water from above or below.
Molto Verboso
2018 Vespa GTS 300 ABS- Bianco
Joined: 20 Apr 2013
Posts: 1924
Location: E. KY
Thu Nov 07, 2019 10:59 am quote
I get it that you may like DIY solutions. Worth considering taking to an AB shop and have them resistance/spot weld the parts. I'm downsizing and sold my MIG but I'd MIG it at home shop if mine. I still have an oxy/acty setup so now I'd braze it most likely but my buddy has a better way to weld it than I do.
Veni, Vidi, Posti
74 50s x3 78 P200 84 Cosa 58 AllState 68 Sprint 80 50special + projects
Joined: 22 Nov 2010
Posts: 7323
Location: seattle/athens
Thu Nov 07, 2019 8:52 pm quote
Re: I'd
Jimding wrote:
Lynnb wrote:
Just had a thought is which do you drill the holes in for the plug weld , the new floor or the lip on the frame?
Simply from an access perspective, easier to drill the holes in the lip, and weld from above, unless you want to turn the whole assemply upside down to weld it. Also it preserves the integrity of the replacement floor panel against rust, with no holes drilled in it. I guess it depends on whether you think it will rust from water from above or below.
If the plug welds are good and solid, it won't make any difference, but I'd MUCH rather weld it upside down, through the floor into the heavier frame flange section. Then you are welding where it's wide open instead of crowded next to the tunnel as well.


Flip it over and weld it like this, easy peasy.
Molto Verboso
1963 VBB2T
Joined: 07 Nov 2012
Posts: 1105

Fri Nov 08, 2019 10:09 am quote
Re: I'd
Jimding wrote:
Lynnb wrote:
Just had a thought is which do you drill the holes in for the plug weld , the new floor or the lip on the frame?
Simply from an access perspective, easier to drill the holes in the lip, and weld from above, unless you want to turn the whole assemply upside down to weld it. Also it preserves the integrity of the replacement floor panel against rust, with no holes drilled in it. I guess it depends on whether you think it will rust from water from above or below.
I'm 80% sold on the nut and bolt idea and flip it over to weld from the bottom. Once the welds are done as was suggested use a copper pipe to weld against to fill the holes back in, a good penetration will add to integrity, just have to very the welding areas to limit the heat/warping.
Molto Verboso
1963 VBB2T
Joined: 07 Nov 2012
Posts: 1105

Fri Nov 08, 2019 10:14 am quote
Kantuckid wrote:
I get it that you may like DIY solutions. Worth considering taking to an AB shop and have them resistance/spot weld the parts. I'm downsizing and sold my MIG but I'd MIG it at home shop if mine. I still have an oxy/acty setup so now I'd braze it most likely but my buddy has a better way to weld it than I do.
I have a new Mig welder ,I'm just getting the hang of it. Been 35 years since I did any stick welding.
Molto Verboso
1963 VBB2T
Joined: 07 Nov 2012
Posts: 1105

Fri Nov 08, 2019 10:16 am quote
Getting things narrowed down, will the frame need some bracing before cutting and peeling the old floor off?
Molto Verboso
2018 Vespa GTS 300 ABS- Bianco
Joined: 20 Apr 2013
Posts: 1924
Location: E. KY
Fri Nov 08, 2019 11:15 am quote
Lynnb wrote:
Kantuckid wrote:
I get it that you may like DIY solutions. Worth considering taking to an AB shop and have them resistance/spot weld the parts. I'm downsizing and sold my MIG but I'd MIG it at home shop if mine. I still have an oxy/acty setup so now I'd braze it most likely but my buddy has a better way to weld it than I do.
I have a new Mig welder ,I'm just getting the hang of it. Been 35 years since I did any stick welding.
I was (as in was!) a skilled welder but doing AB work at home as a sideline I welded infrequently. It is a practice makes perfect trade. Students spend many hours in a booth doing various modes and positions. Occasional welding requires practice even more so. Kind like golf, etc.. When I had a critical weld appearance or strength I'd practice a few minutes on same type/gauge metal, then make my weld.
Given that I worked in tech schools where they did every type of weld, I never kept stick welding stuff at home as it was shop fee plus materials to have someone else do it.
Hooked
BV 350
Joined: 22 Nov 2016
Posts: 430
Location: Nebraska
Fri Nov 08, 2019 11:17 am quote
If
If you wanted to be absolutely sure, you could weld up a square-tubing jig to bolt to the suspension attach points and steering head. The u-channel should have good beam stiffness, but might not be too torsionally rigid without the floor, so twisting would be the likely failure mode. Probably want to make sure the width of the channel is not changed when you are bolting it to the new floor plate as well.
Molto Verboso
1963 VBB2T
Joined: 07 Nov 2012
Posts: 1105

Fri Nov 08, 2019 11:30 am quote
Kantuckid wrote:
Lynnb wrote:
Kantuckid wrote:
I get it that you may like DIY solutions. Worth considering taking to an AB shop and have them resistance/spot weld the parts. I'm downsizing and sold my MIG but I'd MIG it at home shop if mine. I still have an oxy/acty setup so now I'd braze it most likely but my buddy has a better way to weld it than I do.
I have a new Mig welder ,I'm just getting the hang of it. Been 35 years since I did any stick welding.
I was (as in was!) a skilled welder but doing AB work at home as a sideline I welded infrequently. It is a practice makes perfect trade. Students spend many hours in a booth doing various modes and positions. Occasional welding requires practice even more so. Kind like golf, etc.. When I had a critical weld appearance or strength I'd practice a few minutes on same type/gauge metal, then make my weld.
Given that I worked in tech schools where they did every type of weld, I never kept stick welding stuff at home as it was shop fee plus materials to have someone else do it.
I'm doing plenty of practicing, my regular job keeps getting in the way and now the cold snowy weather is on us so prepping the shop ( heating ) is another time consumption , but I'm in no hurry.
Team Scooter Trash for Petfinder Foundation   Vespa Wasp Pin Badges   Cool Ass scooter seat cover
Post Reply    Forum -> General Discussion
[ Time: 0.1773s ][ Queries: 25 (0.0254s) ][ Debug on ]